U.S. Fish & Wildlife Service

Recovery Plan for the 

Sonoran Pronghorn

(Antilocapra americana sonoriensis)

Second Revision

Sonoran pronghorn. Photograph by Jim Atkinson, U.S. Fish and Wildlife Service.

November 2016

i

DISCLAIMER

Recovery plans delineate such reasonable actions as may be necessary, based upon the best 

scientific and commercial data available, for the conservation and survival of listed species. 

Plans are published by the U.S. Fish and Wildlife Service (FWS) and sometimes prepared with 

the assistance of recovery teams, contractors, state agencies and others. Recovery plans do not 

necessarily represent the views, official positions or approval of any individuals or agencies 

involved in the plan formulation, other than FWS. They represent the official position of FWS 

only after they have been signed by the Regional Director. Recovery plans are guidance and 

planning documents only; identification of an action to be implemented by any public or private 

party does not create a legal obligation beyond existing legal requirements. Nothing in this plan 

should be construed as a commitment or requirement that any federal agency obligate or pay 

funds in any one fiscal year in excess of appropriations made by Congress for that fiscal year in 

contravention of the Anti-Deficiency Act, 31 U.S.C. 1341, or any other law or regulation. 

Approved recovery plans are subject to modification as dictated by new findings, changes in 

species status, and the completion of recovery actions.

LITERATURE CITATION SHOULD READ AS FOLLOWS:

U. S. Fish and Wildlife Service. 2016. Recovery Plan for the Sonoran pronghorn (Antilocapra 

americana sonoriensis), Second Revision. U.S. Fish and Wildlife Service, Southwest Region, 

Albuquerque, New Mexico, USA. 

COPIES MAY BE OBTAINED ON-LINE AT:

http://www.fws.gov/southwest/es/arizona/ and

http://www.fws.gov

A draft of this recovery plan was made available through a Federal Register notice published on 

July 2, 2015. Comments received from the public and peer-reviewers were considered in 

finalizing this revised recovery plan. FWS responses to comments can be found at 

https://www.fws.gov/southwest/es/arizona/Sonoran_Pronghorn.htm.
ii

ACKNOWLEDGEMENTS 

The U.S. Fish and Wildlife Service gratefully acknowledges the commitment, dedication, and 

efforts of the Sonoran Pronghorn Recovery Team and invited Team participants in the 

development of this recovery plan, and for their continued efforts in the conservation of the 

species. Sonoran Pronghorn Recovery Team members and invited Team participants include: 

Ole Alcumbrac* Wildlife Health Services

James B. Atkinson* U.S. Fish and Wildlife Service, Sonoran Pronghorn Recovery 

Coordinator

Aaron Alvidrez* Barry M. Goldwater Range-East (Luke Air Force Base)

Holly Barton* Tohono O'odham Nation 

Jill Bright Arizona Game and Fish Department

David E. Brown* Arizona State University

Carlos Castillo* Comisión Nacional de Áreas Naturales Protegidas

David Christianson University of Arizona

Tyler Coleman* Organ Pipe Cactus National Monument

Lizardo Cruz*2 Comisión Nacional de Áreas Naturales Protegidas

Melanie Culver U.S.Geological Survey/University of Arizona

Stephanie Doerries University of Arizona

Randy English Barry M. Goldwater Range-West (Marine Corps Air Station -

Yuma)

Erin Fernandez* U.S. Fish and Wildlife Service 

Dan Garcia2 Barry M. Goldwater Range-East (Luke Air Force Base)

Federico Godinez Leal* Reserva de la Biosfera El Pinacate y Gran Desierto de Altar

Don Jones*2 U.S. Border Patrol

John Hervert* Arizona Game and Fish Department Yuma Regional Office

Jeff Holland* The Los Angeles Zoo

Karen Howe 2 Tohono O'odham Nation

Ron Pearce1 Barry M. Goldwater Range-West

Cristina Meléndez* Comisión de Ecología y Desarrollo Sustentable del Estado de 

Sonora

Hector Munro Reserva de la Biosfera El Pinacate y Gran Desierto de Altar

Joe Oliver U.S. Border Patrol 

Leif Olsen U.S. Navy 

Horacio Ortega Reserva de la Biosfera El Pinacate y Gran Desierto de Altar

Eric Saltzer

2 Barry M. Goldwater Range-West (Marine Corps Air Station -

Yuma)

Daniel Steward** U.S. Army, Yuma Proving Ground 

Erica Stewart* Bureau of Land Management - Yuma Field Office

Tim Tibbitts*1 Organ Pipe Cactus National Monument

Ron Tipton* Bureau of Land Management - Lower Sonoran Field Office

Charles Trost* U.S. Customs and Border Protection

James Vance U.S. Customs and Border Protection

Christa Weise* U.S. Fish and Wildlife Service 

Devorah Young* Phoenix Zoo
iii

* = Sonoran Pronghorn Recovery Team Members

** = awaiting confirmation as an Recovery Team member

1

= retired

2

= no longer in position

Primary authors of this plan are Terry Frederick of Harris Environmental Group; and Jim 

Atkinson and Erin Fernandez of the FWS. We appreciate the assistance of Phil Miller in

developing the population viability analysis. We thank Paul Krausman of the University of 

Montana; and Wendy Brown (retired 2014), Julie McIntyre, Brenda Smith, and Sarah Rinkevich 

of U.S. Fish and Wildlife Service for their valuable insights and edits to the plan. Francisco

"Paco" Abarca, International and Borderlands Program Manager of Arizona Game and Fish 

Department, provided essential background information on Mexican agencies, laws, and policies. 

We thank Phil Miller and Luis Carrillo of the Conservation Breeding Specialist Group for 

facilitating meetings; Kevin Clark of the San Diego Natural History Museum for providing

information and maps for the California reintroduction areas; Ami Pate of Organ Pipe Cactus 

National Monument for developing figures of the mines in Mexico; Lirain Urreiztieta of Harris

Environmental Group for developing the range maps and management unit maps; and Jorge de 

Jesús Cancino Hernández of Centro de Investigaciones Biológicas del Noroeste for providing 

information on pronghorn management in Baja California. Thank you to Pete Sorensen of the 

Palm Springs Fish and Wildlife Service Office, Region 8, for coordinating with us on and 

reviewing the draft recovery plan and providing edits on portions of the plan relating to the

potential California Reintroduction Unit. Thank you to the peer reviewers for your valuable 

comments on the Draft Recovery Plan: Josef Warman, Espacios Naturales y Desarrollo

Sustentable A.C.; Alberto Lafon, Protection de la Fauna Mexicana; Dave Christianson, 

University of Arizona; John Winnie Jr., Montana State University; and Tim Tibbitts.

We are also very grateful to the participants of our multi-day meetings and numerous conference 

calls to develop a population viability analysis, threats assessment, and recovery actions outlined 

in this plan:

Jean Calhoun – U.S. Fish and Wildlife Service 

Terry Frederick – Harris Environmental Group 

Lisa Harris – Harris Environmental Group 

Lacrecia Johnson – U.S. Fish and Wildlife Service 

Lirain Urreiztieta – Harris Environmental Group 

Dietrich Walker – Harris Environmental Group 

Doug Whitbeck – Harris Environmental Group 
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EXECUTIVE SUMMARY

CURRENT SPECIES STATUS

The Sonoran pronghorn (Antilocapra americana sonoriensis) was included on the first list of 

endangered species in 1967 under the Endangered Species Preservation Act, and is currently 

listed as endangered throughout its range, without critical habitat, under the Endangered Species 

Act. It is also listed as an endangered species in Mexico by the Mexican Government. The 

Sonoran pronghorn is one of four extant subspecies of pronghorn, which are endemic to western 

North America. The first Sonoran Pronghorn Recovery Plan was completed in 1982; this is the 

second revision. The species’ current recovery priority number is 3, indicating the subspecies has 

a high degree of threat and a high potential for recovery.

HABITAT REQUIREMENTS AND THREATS

Sonoran pronghorn are found exclusively in the Lower Colorado River Valley and the Arizona 

Upland subdivisions of the Sonoran Desertscrub Biome and currently occur in southwestern 

Arizona and northwestern Sonora, Mexico. In winter, Sonoran pronghorn prefer sparselyvegetated, flat, open spaces that are ideal for swift running and visual detection of predators. 

However, in summer they require denser vegetation that offers thermal cover and moister forage. 

A mix of these vegetation types is essential to enable Sonoran pronghorn to use the most suitable 

vegetation type for the season. Sonoran pronghorn move nomadically in response to changing 

forage conditions and water availability as a result of sporadic rainfall. They require large 

expanses of contiguous habitat to make these movements and to persist in the harsh desert 

environment. They also require quality forage, access to water, a mosaic of suitable vegetation 

structure, and minimal human disturbance.

Threats to Sonoran pronghorn include habitat loss and fragmentation, reduced forage quality, 

altered habitat structure, extended drought and climate change, reduced access to and availability 

of water, predation, disease, loss of genetic diversity, human disturbance, and high mortality 

rates due to accidental death or poaching. Although all threats exist across the range of Sonoran 

pronghorn, the threats of habitat loss and habitat fragmentation are greatest in Sonora, Mexico,

where much of the habitat is privately or communally-owned. The impetus for this revision of 

the recovery plan is new information obtained on Sonoran pronghorn, new identified threats to 

the species, and new management efforts. The recommendations in this second revised recovery 

plan focus on management to reduce and remove threats across the range of Sonoran pronghorn 

and supersede those presented in the 1998 recovery plan.

RECOVERY STRATEGY

The recovery strategy is to secure a sufficient number of Sonoran pronghorn populations that are 

viable under appropriate management scenarios within select areas throughout their historical 

range. In recognition of the binational distribution of the species, and the unique challenges and 

opportunities this presents, two conservation units for the species have been designated, one in 
v

the United States and one in Mexico. The U.S. Conservation Unit is located in Arizona and 

California and includes the historical range of Sonoran pronghorn in the United States. The 

Mexico Conservation Unit includes the historical range of Sonoran pronghorn primarily in the 

Mexican state of Sonora. Within these conservation units there are management units, including 

the Cabeza, Arizona Reintroduction, and California Reintroduction Management Units in 

Arizona and California; and the Pinacate, Quitovac, and Sonora Reintroduction Management 

Units in Sonora. 

RECOVERY GOAL, OBJECTIVES, AND CRITERIA

The recovery goal is to conserve and protect the Sonoran pronghorn and its habitat so that its 

long-term survival is secured, populations within the conservation units are capable of enduring 

threats, and it can be removed from the list of threatened and endangered species (delisted). To 

achieve this goal, this draft recovery plan identifies the following objectives:

1. Ensure multiple viable populations of Sonoran pronghorn rangewide. 

2. Ensure that there is adequate quantity, quality, and connectivity of Sonoran pronghorn 

habitat to support populations. 

3. Minimize and mitigate the effects of human disturbance on Sonoran pronghorn.

4. Identify and address priority monitoring needs.

5. Identify and conduct priority research.

6. Maintain existing partnerships and develop new partnerships to support Sonoran 

pronghorn recovery. 

7. Secure adequate funding to implement recovery actions for Sonoran pronghorn. 

8. Practice adaptive management, in which recovery is monitored and recovery tasks are 

revised by the Service in coordination with the Sonoran Pronghorn Recovery Team as 

new information becomes available.

Downlisting Criteria: Six criteria must be met to downlist Sonoran pronghorn from 

endangered to threatened:

1. At least three free-ranging populations are viable. Two of these must be the Cabeza Prieta 

population and either the Quitovac or Pinacate population. The Recovery Team defines a 

viable population as one that has less than a 10% probability of extinction over 50 years 

and a growth rate that is stable or increasing. Furthermore, at least one new population 

must have been released, in addition to the Kofa subunit (e.g., Sauceda subunit).

A population viability analysis (PVA) estimated abundance targets to meet the Recovery 

Team definition of viability, which is different for each management unit due to different 

environmental conditions. To be considered viable, a population estimate must meet or 

exceed the abundance targets and demonstrate a population growth rate that is stable or 
vi

increasing (r ≥0) for at least five of seven years1. Abundance targets for each 

management unit are estimated from the PVA to be: a) 225 in the Cabeza Prieta 

Management Unit; b) 150 in the Kofa subunit or a new subunit (Sauceda or other future 

established subunit); c) 150 in the Pinacate Management Unit; and d) 450 in the Quitovac 

Management Unit. These population sizes must be estimated by monitoring (i.e., aerial 

surveys). 

2. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, a minimum of 90% of current Sonoran pronghorn habitat within each 

unit is retained and contiguous. This Sonoran pronghorn habitat is protected through 

agency policies, land use regulations and plans, landowner agreements, incentives, and/or 

other programs and agreements. The 90% of retained and contiguous Sonoran pronghorn 

habitat includes key habitat features such as water sources.

3. Threats to Sonoran pronghorn habitat quality in three units are stabilized or decreasing as 

measured by indicators described in Appendix E. Threats must be stabilized or decreased 

in the three management units that correspond to the three populations that meet the 

population viability criteria in Recovery Criteria number 1. In particular, the threats of 

overgrazing; unauthorized routes, roads and trails; invasive plant and animal species

threatening Sonoran pronghorn habitat; and spread of shrubby vegetation are minimized 

through agency policies, land use regulations and plans, landowner agreements, 

incentives, and/or other programs and agreements.

4. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit, and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, human disturbance is alleviated such that a minimum of 90% of 

Sonoran pronghorn habitat can be occupied by Sonoran pronghorn. 

5. Genetic diversity for three populations, as measured by heterozygosity and allelic 

richness for nuclear DNA markers, has been retained from levels indicated in Culver and 

Vaughn (2015). These three populations must meet the threshold of viability as described 

in Downlisting Criterion 1. The minimum level of heterozygosity of any of the three 

populations must be 49% (i.e., within 20% of the average heterozygosity of population 

segments (10) estimated by Culver and Vaughn (2015)). The minimum level of allelic 

richness of any of the three populations must be 1.96 (i.e., within 20% of the average 

allelic richness of population segments (10) estimated by Culver and Vaughn (2015)). 

 

1 As of 2016, aerial surveys to estimate Sonoran pronghorn population size alternate between the Cabeza Prieta 

population and the Mexico populations (Pinacate and Quitovac), so that each of these populations is surveyed every 

other year. Therefore, population estimates will be determined from surveys (in survey years) or the average 

between the previous and following year’s survey estimate (in non-survey years). For information on how 

population estimates and confidence intervals are calculated, please see the Recent Population Trends – Arizona

section of this plan.
vii

6. Effective federal, state, tribal, and/or local laws are in place in the recovery conservation

units that ensure that killing of Sonoran pronghorn is prohibited or regulated such that 

viable populations of Sonoran pronghorn can be maintained and are highly unlikely to 

need the protection of the ESA again.

Delisting Criteria: Once the Sonoran pronghorn is downlisted to threatened, the following 

criteria must be met before the species can be delisted:

1. At least three free-ranging populations are viable. Two of these must be the Cabeza Prieta 

population and either the Quitovac or Pinacate population. The Recovery Team defines a 

viable population as one that has less than a 10% probability of extinction over 50 years and 

a growth rate that is stable or increasing. Furthermore, at least one new population must have

been established, in addition to the Kofa subunit (e.g., Sauceda subunit). Established means 

that the population is stable and is no longer in need of augmentation from a captive breeding 

program.

A PVA estimated abundance targets to meet the Recovery Team’s definition of viability, 

which is different for each management unit due to different environmental conditions. To be 

considered viable, a population estimate must meet or exceed the abundance targets and 

demonstrate a population growth rate that is stable or increasing (r ≥0) for at least 10 of 14

years

1

. Abundance targets for each management unit are estimated from the PVA to be: a) 

225 in the Cabeza Prieta Management Unit; b) 150 in the Kofa subunit or a new subunit 

(Sauceda or other future established subunit); c) 150 in the Pinacate Management Unit; and 

d) 450 in the Quitovac Management Unit. These population sizes must be estimated by 

monitoring (i.e., aerial surveys). 

2. Delisting criteria 2-6 are the same as downlisting criteria 2-6.

ACTIONS NEEDED

Actions were developed for each objective. Primary actions include using captive breeding to 

increase and stabilize existing populations, as well as to establish new populations; protecting 

habitat; assuring forage and water availability; reducing human disturbance; conducting research 

and monitoring; and working with partners to implement recovery projects in the U.S. and 

Mexico. 

 

 

1 As of 2016, aerial surveys to estimate Sonoran pronghorn population size alternate between the Cabeza Prieta 

population and the Mexico populations (Pinacate and Quitovac), so that each of these populations is surveyed every 

other year. Therefore, population estimates will be determined from surveys (in survey years) or the average 

between the previous and following year’s survey estimate (in non-survey years). For information on how 

population estimates and confidence intervals are calculated, please see the Recent Population Trends – Arizona

section of this plan.
viii

TOTAL ESTIMATED COST OF RECOVERY

The Implementation Schedule provides the estimated costs of implementing recovery actions for 

the first five years after the release of the recovery plan, as well as the total cost of recovery. 

Annual cost estimates are as follows: 

Year 1 = $3,880,880

Year 2 = $1,788,570

Year 3 = $2,573,990

Year 4 = $2,576,760

Year 5 = $3,147,450

The estimated cost to implement this plan for the first 5 years is $ 13,967,645. 

Continual and ongoing costs, as well as the estimated total cost, are based on the projected 

timeframe of 20 years to recovery and delisting of the species. The total cost to implement this 

plan through the year 2036, the estimated recovery date of Sonoran pronghorn, is $27,340,950.

DATE OF RECOVERY

The estimated date of recovery is 2036.
ix

TABLE OF CONTENTS

ACKNOWLEDGEMENTS............................................................................................................ ii

EXECUTIVE SUMMARY ........................................................................................................... iv

LIST OF FIGURES ...................................................................................................................... xii

LIST OF TABLES........................................................................................................................ xii

ACRONYMS AND ABBREVIATIONS.................................................................................... xiii

PART I. BACKGROUND.............................................................................................................. 1

Brief Overview/Status of the Species......................................................................................... 2

Species’ Description and Taxonomy .......................................................................................... 4

Populations Distribution and Trends .......................................................................................... 6

Distribution ............................................................................................................................. 6

Historical Population Trends................................................................................................ 10

Recent Population Trends - Arizona..................................................................................... 10

Life History and Ecology.......................................................................................................... 15

Diet........................................................................................................................................ 15

Water Use.............................................................................................................................. 16

Home Range and Movement ................................................................................................ 16

Social Structure..................................................................................................................... 17

Recruitment........................................................................................................................... 17

Survivorship.......................................................................................................................... 18

Habitat Characteristics.............................................................................................................. 18

Soils....................................................................................................................................... 18

Topography........................................................................................................................... 19

Vegetation Communities and Structure ................................................................................ 19

Forage Quality ...................................................................................................................... 25

Succulent Foods.................................................................................................................... 25

Water Availability and Access.............................................................................................. 26

Habitat Area .......................................................................................................................... 29

Habitat Connectivity ............................................................................................................. 30
x

Areas with Modeling of Potential Habitat ............................................................................ 30

Key ecological attributes........................................................................................................... 32

Critical Habitat.......................................................................................................................... 33

Reasons for Listing/Threats Assessment .................................................................................. 33

ESA Listing Factor A: Present or Threatened Destruction, Modification, or Curtailment of 

Its Habitat or Range .............................................................................................................. 36

Habitat Loss...................................................................................................................... 37

Habitat Fragmentation ...................................................................................................... 44

Climate Change................................................................................................................. 47

Reduced Availability of Water ......................................................................................... 48

Reduced Access to Water ................................................................................................. 50

Reduced Forage Quality ................................................................................................... 50

Altered Habitat Structure .................................................................................................. 59

ESA Listing Factor B: Overutilization for Commercial, Recreational, Scientific, or 

Educational Purposes............................................................................................................ 62

ESA Listing Factor C: Disease or predation......................................................................... 62

Predation ........................................................................................................................... 62

Disease .............................................................................................................................. 63

Lack Of Genetic Diversity................................................................................................ 64

ESA Listing Factor D: Inadequacy of Existing Regulatory Mechanisms ............................ 65

Laws Protecting Sonoran Pronghorn In The U.S.............................................................. 65

Laws Protecting Sonoran Pronghorn In Mexico............................................................... 67

ESA Listing Factor E: Other Natural or Manmade Factors Affecting Its Continued 

Existence............................................................................................................................... 68

Human Disturbance .......................................................................................................... 68

High Mortality Rates......................................................................................................... 72

Catastrophic Or Stochastic Events.................................................................................... 74

Previous and Ongoing Conservation Efforts ............................................................................ 74

Conservation Efforts in the U.S............................................................................................ 74

Agencies Responsible For Sonoran Pronghorn And Their Habitat In The U.S. .............. 74

Early (1923-2002) Sonoran Pronghorn Conservation Efforts in the U.S. ........................ 75

Recent (2003 to present) Programs and Management Actions in the U.S........................ 77

Conservation Efforts in Mexico............................................................................................ 86
xi

Primary Agencies Responsible For Pronghorn and Habitat in Mexico............................ 86

Past Pronghorn Conservation Efforts In Mexico.............................................................. 88

Recent Conservation Programs And Management Efforts for Sonoran Pronghorn In 

Mexico .............................................................................................................................. 88

Biological Constraints and Needs............................................................................................. 90

PART II. RECOVERY ................................................................................................................. 90

Recovery Strategy..................................................................................................................... 90

The U.S. Conservation Unit.................................................................................................. 92

Cabeza Prieta Management Unit ...................................................................................... 92

Arizona Reintroduction Management Unit....................................................................... 93

California Reintroduction Management Unit ................................................................... 93

Mexico Conservation Unit.................................................................................................... 94

Pinacate Management Unit............................................................................................... 94

Quitovac Management Unit.............................................................................................. 95

Sonora Reintroduction Management Unit ........................................................................ 95

Recovery Goal, Objectives, and Criteria .................................................................................. 97

Recovery Goal ...................................................................................................................... 97

Recovery Objectives............................................................................................................. 97

Recovery Criteria .................................................................................................................. 97

Recovery Action Outline and Narrative ................................................................................. 108

PART III. IMPLEMENTATION SCHEDULE.......................................................................... 136

Literature Cited ........................................................................................................................... 194

APPENDICES ............................................................................................................................ 206

Appendix A. Conceptual Models of Threats....................................................................... 207

Appendix B. ESA Section 7 Consultation Map.................................................................. 218

Appendix C. PACE............................................................................................................. 219

Appendix D. Population Viability Assessment................................................................... 291

Appendix E. Threats Indicators For Delisting And Downlisting ....................................... 320

Appendix F. Threats Tracking Table.................................................................................. 321
xii

LIST OF FIGURES

Figure 1. Current (2016) and historical ranges of Sonoran pronghorn in the U.S. and Mexico..... 9

Figure 2. Sonoran pronghorn habitat in Lower Colorado River Valley Subdivision ................... 20

Figure 3. Sonoran pronghorn habitat in Arizona Upland Subdivision. ........................................ 21

Figure 4. "Palo verde chainfruit cholla association” in Arizona................................................... 22

Figure 5. Medano habitat in Sonora, Mexico ............................................................................... 23

Figure 6. Sonoran pronghorn in non-medanos habitat in Sonora, Mexico................................... 24

Figure 7. Sonoran pronghorn herd among chain fruit cholla on semi-stabilized sand dunes....... 26

Figure 8. Sonoran pronghorn habitat suitability model for Quitovac population......................... 31

Figure 9. La Herradura Mine expansion and Sonoran pronghorn locations, Sonora, Mexico. .... 39

Figure 10. Additional mine (Nochebuena) near La Herradura in Sonora, Mexico. .................... 40

Figure 11. La Herradura gold mine, Sonora, Mexico................................................................... 41

Figure 12. Mine tailings in Quitovac population area, Sonora, Mexico....................................... 41

Figure 13. BLM grazing allotments within the Kofa area, Arizona, U.S..................................... 55

Figure 14. Cabeza Prieta captive breeding pens, waters, forage enhancement. .......................... 80

Figure 15. Kofa breeding pens, waters. ........................................................................................ 81

Figure 16. Pre-release pen at Sauceda .......................................................................................... 84

Figure 17. Sonoran pronghorn management units and subunits in the U.S. and Mexico............. 96

LIST OF TABLES

Table 1. Historical population estimates....................................................................................... 13

Table 2. Wild and captive Sonoran pronghorn estimates............................................................. 14

Table 3. Summary of threats to Sonoran pronghorn by ESA Listing Factor................................ 35

Table 4. Summary of Sonoran pronghorn releases....................................................................... 82

Table 5. PVA inputs and results ................................................................................................. 100
xiii

ACRONYMS AND ABBREVIATIONS

ac Acres

AGFD Arizona Game and Fish Department

ANP Areas Naturales Protegidas (Natural Protected Areas)

ARNG Army National Guard

BLM Bureau of Land Management

BMGR Barry M. Goldwater Range

CBP Customs and Border Protection

CEDES Comisión de Ecologia y Desarrollo Sustentable del Estado de Sonora 

(Commission of Ecology and Development of the State of Sonora)

CFR Code of Federal Regulations

CITES Convention on International Trade in Endangered Species of Wild Fauna and 

Flora

CONABIO Comisión Nacional para el Conocimiento y Uso de la Biodiversidad 

(The National Commission for Knowledge and Use of Biodiversity of Mexico)

CONAFOR Comisión Nacional Forestal (National Forestry Commission of Mexico)

CONANP Comisión Nacional de Areas Naturales Protegidas (National Commission of 

Protected Areas of Mexico)

Cabeza Prieta 

NWR

Cabeza Prieta National Wildlife Refuge

dBA A-weighted decibels. The relative loudness of sounds in air as perceived by the 

human ear.

DGVS Dirección General de Vida Silvestre (Mexican Federal Office of Wildlife)

Ejido Communally-owned land in Mexico 

ESA Endangered Species Act

ft feet

FR Federal Register

FWS United States Fish and Wildlife Service

GIS Geographic Information System

GNSS Global Navigation Satellite System

ha hectares

IPCC Intergovernmental Panel on Climate Change

km kilometers

Kofa NWR Kofa National Wildlife Refuge

m meters

mi miles

MCAS Yuma Marine Corps Air Station Yuma

NEPA National Environmental Policy Act
xiv

NOM Norma Oficial Mexicana (Mexican federal law)

NWR National Wildlife Refuge

OHV Off-highway Vehicle

Organ Pipe 

Cactus NM

Organ Pipe Cactus National Monument

PACE Programa de Acción Para la Conservación de la Especie (Species Conservation 

Action Plan – Mexico’s equivalent of a recovery plan)

PROCER Programa de Conservación de Especies en Riesgo (At-risk Species 

Conservation Program of Mexico)

PROCODES Programa de Conservación para el Desarrollo Sostenible (Sustainable 

Development Conservation Program of Mexico)

PROFEPA Procuraduría Federal de Proteccion del Ambiente (Mexican Federal agency of 

environmental protection)

PVA Population Viability Analysis

RMP Resource Management Plan

SAGARHPA Secretaría de Agricultura, Ganadería, Recursos Hidráulicos, Pesca y 

Acuacultura (State of Sonora Ministry of Agriculture, Water Resources, 

Fisheries and Aquaculture)

SAGARPA Secretaría de Agricultura, Ganaderia, Desarrollo Rural, Pesca, y Alimentación 

(Federal Ministry of Livestock, Agriculture, Rural Development, Fisheries, and 

Foods of Mexico)

SEMARNAT Secretaría de Medio Ambiente y Recursos Naturales (Federal Ministry of the 

Environment and Natural Resource of Mexico) 

UMA Unidades para la Conservación, Manejo y Aprovechamiento Sustentable de la 

Vida Silvestre (Wildlife Conservation, Management, and Sustainable Utilization 

Units in Mexico)

USBP United States Border Patrol

YPG Yuma Proving Ground
Sonoran Pronghorn Recovery Plan, Second Revision

1

PART I. BACKGROUND

The Endangered Species Act of 1973 (ESA), as amended, requires preparation of recovery plans 

for listed species. A recovery plan presents a set of recommendations for the listed species 

endorsed by the U.S. Fish and Wildlife Service (FWS). This recovery plan was prepared for the 

FWS with direction and assistance from the Sonoran Pronghorn Recovery Team (Recovery 

Team). It establishes recovery goals and objectives for the listed species, describes site-specific 

recovery actions recommended to achieve those goals and objectives, estimates the time required

for recovery, estimates the cost of recovery, and identifies partners and parties responsible for 

implementation of recovery actions.

Recovery plans are neither self-implementing nor legally binding. Recovery plans constitute a 

FWS guidance document on the listed species or group of species. They outline a logical path 

from what is known about the species’ biology, life history, and threats to a recovery strategy 

and program. In some cases, recovery plans are followed by other federal agencies to meet the 

provisions of sections 2(c)(1) and 7(a)(1) of the ESA, which require federal agencies to use their 

authorities in carrying out programs for the conservation of endangered and threatened species. 

Recovery recommendations are based on resolving the threats to the species and ensuring selfsustaining populations in the wild.

A recovery plan was first prepared for the Sonoran pronghorn (Antilocapra americana

sonoriensis) in 1982, and was revised in 1998. In the case Defenders of Wildlife, et al., v. Bruce 

Babbitt, et al. (Civil Action No. 99-927 [ESH]) the United States District Court for the District 

of Columbia ruled that the FWS was acting arbitrarily and capriciously and contrary to law by 

failing to establish: 1) objective, measureable criteria or an explanation why such criteria are not 

practicable; and 2) estimates of the time required to carry out those measures needed to achieve 

the plan’s goal or, if such estimates are not practicable, an explanation of that conclusion. The 

court remanded the recovery plan back to FWS to correct. In 2002, a supplement and amendment 

to the 1998 Recovery Plan was published that used the downlisting criteria from the 1998 plan 

and provided an explanation for why delisting criteria were not practicable at that time. The 

supplement and amendment also discussed new information on Sonoran pronghorn biology and 

discussed the reasons for listing using the five factors required under Section 4(a)(1) of the ESA; 

these had not previously been applied to the Sonoran pronghorn because it was originally listed 

before the ESA was in effect.

In summer 2002, the U.S. population of Sonoran pronghorn was almost extirpated (there were 

only 21 individuals in the population; see Population Trends and Distribution section) due to the 

most severe drought on record in southern Arizona, the effects of which were exacerbated by 

other threats, including restriction of available habitat, rapid increase in border-related human 

disturbance, and others. Sonoran pronghorn in Mexico did not decline as severely in the same 
Sonoran Pronghorn Recovery Plan, Second Revision

2

year (285 individuals in the population; see Population Trends and Distribution section). In 

response to the near extirpation of the U.S. population, the FWS, Arizona Game and Fish 

Department (AGFD) and other cooperating agency partners began intensive conservation 

actions, including construction of water developments and forage enhancement plots, 

supplemental feeding, and a captive breeding program in the U.S. Active management efforts 

were not implemented in Mexico at that time. The captive breeding program on Cabeza Prieta 

National Wildlife Refuge (Cabeza Prieta NWR) has been successful in producing animals for 

release, and the Recovery Team subsequently initiated the establishment of two nonessential 

experimental populations under section 10(j) of the ESA on Kofa NWR and BMGR East (east of 

Highway 85) using pronghorn from the Cabeza Prieta NWR captive breeding pen. The 

nonessential experimental (10(j)) population area also includes other unoccupied areas within 

Sonoran pronghorn historical range. The impetus for this revision of the recovery plan is new 

information obtained on Sonoran pronghorn, new identified threats to the species, and new 

management efforts. 

This revised plan addresses Sonoran pronghorn throughout its range in Mexico and the U.S., 

including suitable areas of its historical range within the U.S. where additional population 

establishment is ongoing or proposed. The revised plan establishes recovery goals and 

objectives; and provides objective, measurable criteria for downlisting and delisting the species. 

It also incorporates expanded threats and viability analyses; and includes existing, expanded, and 

new site-specific management and recovery actions that emphasize habitat management. It 

estimates time and cost required for recovery, identifies partners and parties responsible for 

implementation of recovery actions, and identifies gaps in the information needed for 

management and recovery. 

Brief Overview/Status of the Species

Current Status of the Species

The Sonoran pronghorn subspecies is recognized by a number of federal, state, and international 

listings. The subspecies is currently listed as an endangered species throughout its range under 

the ESA. The subspecies was included on the first list of endangered species on 11 March 1967 

(Office of the Secretary 1967), under the Endangered Species Preservation Act of 15 October 

1966, a predecessor of the ESA. When the ESA was signed into law in 1973, the Sonoran 

pronghorn was placed on the list under section 4(c)(3) of the ESA as an endangered species

through the “grandfather clause”, which provides that: “(A)ny list in effect on the day before the 

date of the enactment of this Act of species of fish or wildlife determined by the Secretary of the 

Interior, pursuant to the Endangered Species Conservation Act of 1969, to be threatened with 

extinction shall be republished to conform to the classification for endangered species or 

threatened species, as the case may be, provided for in this Act, but until such republication, any 

such species so listed shall be deemed an endangered species within the meaning of this Act.” As 
Sonoran Pronghorn Recovery Plan, Second Revision

3

a consequence of the “grandfather” clause [Section 4(c)(3)] in the ESA, formal listing factors 

were never established or required for Sonoran pronghorn to be listed under the ESA. These 

factors were later described in the 2002 supplement to the 1998 recovery plan (U.S. Fish and 

Wildlife Service 2002). 

The species’ current recovery priority number is 3 (U.S. Fish and Wildlife Service 2010a), 

indicating the subspecies has a high degree of threat and a high potential for recovery (U.S. Fish 

and Wildlife Service 1983). A 5-year review that would result in recommendations concerning 

whether the species should remain listed as endangered, down-listed to threatened, or delisted 

has not yet been completed.

In addition to the U.S. ESA listing, the Secretaría de Medio Ambiente y Recursos Naturales

(Federal Ministry of the Environment and Natural Resource; SEMARNAT) lists the pronghorn 

as endangered in Mexico (Secretaría de Medio Ambiente y Recursos Naturales 2010). This 

listing is for the entire species and includes all subspecies within Mexico, including the Sonoran

pronghorn, peninsular pronghorn (A. a. peninsularis), and Mexican pronghorn (A. a. mexicana; 

SEMARNAT 2010). All subspecies of Antilocapra americana are listed on the Convention on 

International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix 1, but 

only populations in Mexico are included (Convention on International Trade in Endangered 

Species of Wild Flora and Fauna 2014).

Sonoran pronghorn in Arizona are also on AGFD’s list of “Species of Greatest Conservation 

Need” (Arizona Game and Fish Department 2012). The species is protected by Arizona state law 

(A.R.S. 17-314), and anyone convicted of unlawfully wounding or killing, or unlawfully 

possessing an endangered species of wildlife may be subject to civil action by the Arizona Game 

and Fish Commission in the form of license revocation and a minimum fine. 

Factors believed to have caused the decline of Sonoran pronghorn in the U.S. and Mexico 

include: unrestricted hunting; livestock grazing; prolonged drought; and habitat fragmentation by 

fences, railroads, highways, and canals (U.S. Fish and Wildlife Service 2010b), and possibly 

disease transmitted by livestock. The Arizona population of Sonoran pronghorn was nearly 

extirpated by a severe drought of 2002 when 80% of the collared pronghorn died (Bright and 

Hervert 2005). The Recovery Team and partners enacted emergency conservation measures for 

the Sonoran pronghorn in Arizona as a result of this drought. The measures included 

supplemental feeding, supplemental watering, and establishment of a captive breeding pen at 

Cabeza Prieta NWR. By 2011 FWS published a final rule to establish a second population in 

historical habitat on the Kofa National Wildlife Refuge (Kofa NWR) and the Barry M. 

Goldwater Range East (BMGR East) as a nonessential experimental population (U.S. Fish and 

Wildlife Service 2011a). Sonoran pronghorn were released into this nonessential experimental 

population on Kofa NWR in 2013, 2014, and 2015. Sonoran pronghorn were released into 

BMGR East (east of Highway 85) in 2015. Additional releases may occur in the future as 
Sonoran Pronghorn Recovery Plan, Second Revision

4

needed. Declines in the two Sonoran pronghorn populations in Mexico have also occurred, but 

have not been as severe and have not resulted in major management changes. 

Species’ Description and Taxonomy

Description

Pronghorn are endemic to western North America (O'Gara 1978) and are placed within the 

Family Antilocapridae in Order Artiodactyla, the even-toed ungulates. The Family

Antilocapridae, found only in North America, contains only one genus, Antilocapra, which in 

turn contains only one species, the pronghorn. The O’odham name for pronghorn is Ku:vid (or 

Kukuvid plural). Throughout this document we use the common name “pronghorn” for the 

species as a whole, including all subspecies, and “Sonoran pronghorn” for the subspecies

Antilocapra americana sonoriensis.

Pronghorn have slightly curved horns; the males usually have a single prong projecting forward. 

The horns have a straight bony core and sheaths of fused hairs, which are shed and replaced 

annually (Hoffmeister 1986). Coat color varies from yellowish to tan, with some white markings, 

except for black on the top of the nose (Hoffmeister 1986). Pronghorn are the only artiodactyls 

with pronged horns and horn sheaths that are shed annually (Hoffmeister 1986). The dental 

formula of pronghorn is I 0/3, c 0/1, p 3/3, m 3/3 (O'Gara 1978).In the field, pronghorn exhibit 

unique burnt apricot and white coloration, a spindle-legged silhouette, and long, pronged black 

horns in males (Brown and Ockenfels 2007). They are white on the underparts, and in patches on 

the lower face, throat, below the ears, rump, and in two triangular neck bands (Brown and 

Ockenfels 2007). Pronghorn are easily distinguished from other ungulates within their range. 

Bighorn sheep (Ovis canadensis) have massive coiled horns and do not have white bands across 

the throat; mule deer (Odocoileus hemionus) have black on the tail, and no white along sides; 

white-tailed deer (Odocoileus virginianus) do not have a white rump patch, and do not have

white along the sides (Arizona Game and Fish Department 2002). Pronghorn are the swiftest 

terrestrial mammals in the New World. Kitchen (1974) recorded herds moving at 64 to 72 

kilometers (km) per hour (40 to 45 miles per hour [mph]) with maximum speeds of 86.5 km per 

hour (54 mph). 

Morphology

The Sonoran pronghorn is one of four extant subspecies of pronghorn (Stephen et al. 2005). 

Other pronghorn subspecies are the American pronghorn (A. a. americana), Mexican pronghorn 

(A. a. mexicana), and the peninsular pronghorn (A. a. peninsularis). The Sonoran pronghorn was 

described in 1945 from morphological traits of primarily one specimen, the type specimen was 

an adult female skin and skull collected 40 miles north of Costa Rica, Sonora, Mexico. Goldman 

considered a second specimen, the skull of a female collected at Crittenden, near Sonoita, 

Arizona, which shared some characters with the type specimen, to be of the same form
Sonoran Pronghorn Recovery Plan, Second Revision

5

(Goldman 1945). However, he stated on geographic grounds individuals in southeastern Arizona 

would be expected to exhibit gradation towards A. a. mexicana. Original morphological analysis 

conferred subspecific status to the Sonoran Desert race of pronghorn based on smaller size and 

paler color of the type specimen compared to other subspecies (Goldman 1945). The Sonoran 

pronghorn skull is narrower than that of other subspecies in mastoidal, orbital, and zygomatic 

width; the rostrum is narrow; the frontal depression is not pronounced; and auditory bullae are 

small, but variable (Hoffmeister 1986). Paradiso and Nowak (1971) examined four males from 

near Carborca, Sonora, a female from Crittenden, Arizona, and the type specimen and concluded 

that the six individuals are more distinct from other subspecies of pronghorn than from each 

other. However, the morphological differences observed by Goldman may have been due 

primarily to the smaller-than-average size of the type specimen (Hoffmeister 1986). 

Genetics and Taxonomy

In recent genetic work, Stephen et al. (2005) did not find support for subspecies status for the 

Sonoran pronghorn in mitochondrial DNA sequence and microsatellite data, yet they found that 

all populations, including the Sonoran pronghorn, possessed unique haplotypes and 

microsatellite alleles not found in other populations. In addition, the combined (concatenated) 

dataset of mitochondrial DNA and microsatellite alleles showed differentiation of the two 

Sonoran populations and the remainder of the populations sampled for both FST and GST. FST is a 

test for subdivision between two subpopulations; GST is a similar measure but corrected for small 

and inbred populations. This difference between the two populations could be due to a series of 

bottlenecks rather than prolonged separation (Stephen et al. 2005). However, the study by 

Stephen et al. (2005) was limited due to a lack of species-wide sampling (they did not sample 

peninsular pronghorn), and they did not suggest alternative classifications for pronghorn. A 

sampling of all pronghorn populations from Canada to Mexico would be required to make 

subspecies-level taxonomic conclusions for this species. Further study of the taxonomy of this 

species is required, including more intensive sampling efforts and potentially the inclusion of 

genome-wide nuclear DNA markers, to resolve accurate taxonomic units below the species-level 

for pronghorn.

A recent publication of microsatellite markers isolated from Sonoran pronghorn (Munguia-Vega 

et al. 2013) included a comparison of Sonoran pronghorn to peninsular pronghorn, using a subset 

of 14 of these newly developed microsatellite markers. The data indicated a lower mean 

observed heterozygosity for peninsular pronghorn than for Sonoran pronghorn (0.31 and 0.48, 

respectively), and lower mean number of alleles per locus for peninsular pronghorn versus 

Sonoran pronghorn (2.050 and 4.86, respectively). These results suggest that of the two 

endangered pronghorn subspecies, the Sonoran pronghorn has retained a greater amount of 

genetic diversity. Further, analysis of these data indicates that the two subspecies have 

significant genetic divergence, based on microsatellite data sets (Klimova et al. 2014). 
Sonoran Pronghorn Recovery Plan, Second Revision

6

Populations Distribution and Trends

Distribution

Sonoran pronghorn historically occurred throughout most of southwestern Arizona, northwestern 

Sonora, and portions of southeastern California and northeastern Baja California (Figure 1). 

Because Sonoran pronghorn were not identified as a subspecies until 1945, historical records do 

not indicate if pronghorn observed were Sonoran pronghorn, American pronghorn, Mexican 

pronghorn, or peninsular pronghorn. Genetic analysis of museum specimens may clarify the

historical distribution of each subspecies. Pronghorn were observed in every open valley from 

Nogales, Mexico, to Yuma, Arizona, during the course of an international boundary survey from 

1892 to 1894 (Carr 1971). Many of those observed were likely Sonoran pronghorn. Early 

explorers and travelers also reported seeing pronghorn in almost every valley of Arizona and on 

all of the open foothills (Brown and Ockenfels 2007).

By 1907 pronghorn were described by E.A. Mearns as rare in the region (U.S. Fish and Wildlife 

Service 1998). Nelson (1925) stated that in 1923, “Papago Indians [O’odham] reported that a few 

pronghorn were still ranging in the Santa Rosa Valley in Pima County, Arizona.” From 1972 

until 2002, no Sonoran pronghorn were confirmed east of Highway 85 on Organ Pipe Cactus 

National Monument (Organ Pipe Cactus NM) (U.S. Fish and Wildlife Service 2006); however, 

in 2002, two collared Sonoran pronghorn independently crossed this highway, apparently in 

response to extreme drought conditions (U.S. Fish and Wildlife Service 2006). One of the 

animals returned west after the onset of rain in September 2002. The second apparently died 

from the drought (U.S. Fish and Wildlife Service 2006). Unconfirmed sightings were reported in 

1987 by a Border Patrol agent on the Tohono O’odham Nation (U.S. Fish and Wildlife Service

1998). More recently, some pen-released pronghorn have crossed Highway 85. With the 

exception of the recently established nonessential experimental population, Sonoran pronghorn 

have not been reported north of U.S. Interstate 8 since 1990 (U.S. Fish and Wildlife Service

1998).

The FWS reconstructed the limits of the historical distribution (Figure 1) of Sonoran pronghorn 

from historical accounts and summarized it as follows: 1) the eastern distributional limit of 

Sonoran pronghorn likely extended to the area between the Baboquivari Mountains and the Santa 

Cruz River; 2) the subspecies ranged northward into west-central Arizona, likely to the vicinity 

of present-day Interstate 10 and certainly no farther north than the Bill Williams River; 3) the 

southern limit of the historical range of Sonoran pronghorn followed the mainland coastline of 

the Gulf of California south to near Kino Bay and east to near Hermosillo, Sonora, Mexico; 4) 

westward, the range extended into the Imperial Valley of California and the northern Gulf of 

California coast of Baja California, Mexico (U.S. Fish and Wildlife Service 2010b). This 

reconstructed historical distribution encompasses an area of about 142,450 km2 (55,000 mi2

) 

(U.S. Fish and Wildlife Service 2010b). However, Brown et al. (2006) reviewed the historical 

distribution of pronghorn in California and Baja California and reported records indicating the 
Sonoran Pronghorn Recovery Plan, Second Revision

7

species’ range extended west to the Pacific coast from Monterey southward to Magdalena Bay, 

Baja California Sur, and on the Gulf of California side of the Baja peninsula to south of San 

Felipe, Baja California Sur. The authors did not specifically indicate the historical distributional 

limits of the Sonoran pronghorn subspecies as compared to the peninsular pronghorn subspecies. 

A genetic analysis of museum specimens representing animals collected from as far north as 

Fresno, California, and south to include the Baja Peninsula is currently being conducted, which 

may clarify which subspecies occurred in the areas of question in Southeastern California and 

Northeastern Baja California (M. Culver, University of Arizona, personal communication, 2014).

Presently, Sonoran pronghorn only occupy approximately 12 % of their historical range. Their 

current range (Figure 1) is limited to approximately 17,224 km2 (6,660mi2

), of which 4,057 km2

(1,566 mi2) are in Mexico and 13,167 km2 (5,094 mi2) are within the U.S. Five wild populations 

of the Sonoran pronghorn are now extant (Figure 1). Two of these populations, Pinacate and 

Quitovac, occur in northwestern Sonora, Mexico. The Cabeza Prieta, Kofa, and Sauceda 

populations occur in southwestern Arizona, U.S. Detailed descriptions follow: 

Population Name Description and Location

Cabeza Prieta An endangered population in southwestern Arizona, U.S. that generally 

occurs south of Interstate 8, west of Highway 85, and east of the Copper and 

Cabeza Prieta mountains. The Cabeza Prieta population is found primarily 

on federally-managed lands, including the Cabeza Prieta NWR; Organ Pipe 

Cactus NM; and the Barry M. Goldwater Range, a tactical aviation training 

range complex of which the eastern portion (Barry M. Goldwater RangeEast) is administered by the U.S. Air Force and the western portion (Barry 

M. Goldwater Range-West) is administered by the U.S. Marine Corps. The 

range of the Cabeza Prieta population also includes some Bureau of Land 

Management (BLM) land, private land, and state trust land.

Kofa A nonessential experimental population that is found primarily on federallymanaged lands, including the Kofa NWR; U.S. Army Yuma Proving 

Ground; and lands managed by the BLM. The population also ranges onto 

private and state lands and lands of the Colorado River Indian tribes. The 

2015 range is shown in Figure 1. The population occurs within the larger 

designated nonessential experimental population area which is located in 

southwestern Arizona in an area north of Interstate 8 and south of Interstate 

10, bounded by the Colorado River on the west and Interstate 10 on the east; 

and an area south of Interstate 8, bounded by Highway 85 on the west, 

Interstates 10 and 19 on the east, and the U.S.-Mexico border on the south 

(U.S. Fish and Wildlife Service 2011a).

Sauceda A nonessential experimental population initiated in December, 2015 by 

release of Sonoran pronghorn in the Barry M. Goldwater Range East, east of 

Highway 85. This population is too new to describe a current range; 

however, the area is bounded by Interstate 8 to the north, Highway 15 to the 
Sonoran Pronghorn Recovery Plan, Second Revision

8

east, Highway 85 to the west, and Highway 86 to the south. This population 

occurs within the larger designated nonessential experimental population 

area which is located in southwestern Arizona in an area north of Interstate 

8 and south of Interstate 10, bounded by the Colorado River on the west and 

Interstate 10 on the east; and an area south of Interstate 8, bounded by 

Highway 85 on the west, Interstates 10 and 19 on the east, and the U.S.-

Mexico border on the south (U.S. Fish and Wildlife Service 2011a). 

Quitovac A population occurring in northwestern Sonora, Mexico south and east of 

Mexico Highway 8 and west and north of Caborca, Sonora, near Quitovac, 

Sonora, Mexico.

Pinacate A population occurring in northwestern Sonora, Mexico, in the El Pinacate 

y Gran Desierto de Altar Biosphere Reserve of northwestern Sonora, 

Mexico.

These four populations are predominantly geographically isolated due to barriers, including 

roads and fences. Mexico Highway 2 and associated right-of-way fencing and a portion of the

international boundary fence (pedestrian fence only) act as barriers to movement between the

Pinacate and U.S. subpopulations (U.S. Fish and Wildlife Service 2002). Sonoran pronghorn 

habitat in Mexico is bisected by Highway 8 and associated fences; however, it is unknown how 

complete a barrier Highway 8 is to pronghorn movements (U.S. Fish and Wildlife Service 2002).

Historically these barriers were not present and genetic and demographic interchange between 

pronghorn in Sonora and Arizona likely occurred. 
^

Baja

California

Sonora

California

Arizona

§ ̈¦I-17

§ ̈¦I-19

§ ̈¦I-8

§ ̈¦I-10

Sonoyta

Puerto

Penasco

Caborca

q

Coordinate System: WGS 1984

UTM Zone: 12N

Projection:

Transverse Mercator

Linear Unit: Meter

Scale: 1:2,500,000

Basemap: Esri, DeLorme, 

USGS, NPS

Produced By: L. Urreiztieta, 

Harris Environmental Group, Inc.

June 2016

^ Sauceda Release Site - Dec 2015

Kofa Range as of Oct 2015*

Cabeza Prieta Range

Pinacate Range

Quitovac Range

Historical Range

0 25 50 75 100

Kilometers

GULF 

OF

CALIFORNIA

0 25 50 75 100

Miles

*Preliminary range anticipated to expand with increase in population.

£¤85

£¤86

§ ̈¦

§ ̈¦2

8

Figure 1. Current (2016) and historical ranges of Sonoran pronghorn in the U.S. and Mexico. The historical range is based on 

reconstruction by FWS (2010a). The current range is based on radio-collared pronghorn locations and other observations 

(current as of January 2016 for Pinacate, Quitovac, and Cabeza Prieta and October 2015 for Kofa). The December 2015 release site 

for the Sauceda population is depicted; however, as of May 2016, too few months of movement data exist for this population to depict 

its range.
Sonoran Pronghorn Recovery Plan, Second Revision

10

Historical Population Trends

Before European settlement, an estimated 35 million pronghorn inhabited North America, but by 

1924 the range-wide population of all pronghorn had decreased to less than 20,000 animals 

(O'Gara 1978). Associated with European settlement was widespread shooting of pronghorn for 

meat, recreation, and to reduce potential competition with domestic livestock (Brown and 

Ockenfels 2007). In 1540, a group of organized hunters near Pachuca Hidalgo, Mexico, reported 

the capture of 600 pronghorn and deer (Comisión Nacional de Areas Naturales Protegidas 2009). 

Four hundred years later, only 1,500 surviving pronghorn of three subspecies (A. a. sonoriensis, 

A. a. mexicana, and A. a. peninsularis) live in Mexico (Comisión Nacional de Areas Naturales 

Protegidas 2009). In Arizona, widespread decline of pronghorn began in the mid-to late-1800s. 

Domestic livestock competed with pronghorn for forage, and fencing to manage livestock 

introduced barriers to pronghorn movement throughout their range (Brown and Ockenfels 2007). 

Domestic livestock altered the vegetation of southeastern Arizona, causing changes in species 

composition and vegetation structure by increasing the abundance of shrubs such as mesquite 

(Prosopis spp.) (Bahr 1991). Brown and Ockenfels (2007) stated, “Indeed, the filling in of the 

land with mesquites, junipers, acacias, and other woody plants is the single-most reason why 

pronghorn are not widespread in Arizona today.” Severe, extended drought occurred throughout 

the region in the 1890s, when cattle numbers were at their peak, resulting in overgrazing (Bahr 

1991). 

By the 1920s, Sonoran pronghorn had declined to an estimated 100 animals in the U.S. (Table 1). 

No accurate data of Sonoran pronghorn populations exists prior to the 1920s to estimate the 

extent of the decline. The population oscillated between an estimated 50 to 100 animals from the 

1920s up through the mid-1980s. By 1994, the U.S. population of Sonoran pronghorn had 

rebounded to an estimated 280 animals (Table 2). The population in Sonora, Mexico, was about 

600 animals in 1925, but declined by almost half by 1993 (Table 1). 

Recent Population Trends - Arizona

Estimating population size of Sonoran pronghorn is inherently difficult due to a number of 

factors, including dense vegetation in some areas, large size of the survey area, and length of 

survey (multi-day surveys are required). The AGFD began conducting biennial aerial surveys for 

Sonoran pronghorn in 1992 in Arizona. The AGFD first began surveying populations in Sonora, 

Mexico, using the same techniques as in Arizona in 1993, but did not survey populations again 

until 2000. Initially, populations were estimated with DISTANCE, a computer program that 

constructs population estimates by adjusting counts by the probability that detecting a group of

animals decreases with distance from the surveyor (Laake et al. 1993). However, the coefficient 

of variation for these population estimates was considered too high (U.S. Fish and Wildlife 

Service 2002). From 1996 to 1998, the agencies used the Lincoln-Peterson Index, a mark-andrecapture method (Davis and Winstead 1980), to estimate the detection probability before 

adjusting counts. However, biologists observed that larger groups were more likely to be seen 
Sonoran Pronghorn Recovery Plan, Second Revision

11

than small groups or singletons and the estimator did not include a correction for this bias, and as 

a result, population estimates may have been inflated (U.S. Fish and Wildlife Service 2002). 

Population size and 95% confidence intervals were estimated using a sighting probability model 

(Samuel and Pollock 1981) previously developed for Sonoran pronghorn (Bright et al. 2001). In 

1998 a sightability model that could account for potential group-size bias was derived. This

sightability model was determined to be the best population estimator because it corrects for 

group size bias, is more conservative than the Lincoln-Peterson Index, and has a low coefficient 

of variation (U.S. Fish and Wildlife Service 2002). The Recovery Team used the sightability 

model to revise population estimates for 1992-2000 (Bright et al. 2001). Population estimates for 

1992 and later (Table 2) are based on this sightability model.

With the exception of 1994, Sonoran pronghorn in the U.S. declined from 1992 to 2000. The 

decline in numbers from 1992 to 2000 is supported by other survey data, including high adult 

mortality, low fawn survival and recruitment, and smaller average herd sizes (U.S. Fish and 

Wildlife Service 2002). A drought occurred between June 1995 and August 1997 during which 

23 of 27 months had below-average rainfall and nine of 16 collared pronghorn (56%) died 

(Bright and Hervert 2005). 

During the summer of 2002, between 1 June and 13 August, 4 out of 5 (80%) of collared 

pronghorn died. These animals were found intact, with no evidence of predation or scavenging. 

The authors suggested that because there was no evidence of predation and the rumens were full 

of chain fruit cholla fruits, the deaths were likely from malnutrition, starvation, and dehydration. 

The evidence supporting death by malnutrition was based on direct observations of deteriorating 

pronghorn health/condition in live animals and inspection of bone marrow, which was consistent 

with starving animals (J. Hervert, pers. com. 2015).The U.S. population declined from an 

estimated 99 animals in 2000, to an estimated 21 animals in 2002 (Table 2). In response to this 

decline, FWS and partners enacted instensive conservation measures. The measures included: 1) 

construction and operation of five forage enhancement (irrigation) plots (three on the Cabeza 

Prieta NWR, one on the BMGR East, and on BMGR West) to enhance fawn survival; 2) 

supplemental feeding; 3) construction of water sources; 4) establishment of a captive breeding 

pens at Cabeza Prieta and Kofa NWRs; and 5) initiation of the establishment of wild 

nonessential experimental populations on Kofa NWR and BMGR East (east of Highway 85). 

Since 2002, the wild endangered population in Arizona has rebounded to 202 animals in Arizona 

(as of December 2014). 

Recent Population Trends – Mexico

Populations in Mexico declined during the 2002 drought, but not as severely as the population in 

Arizona (Table 2). Addtionally, between 2004 and 2011, populations in Mexico declined from 
Sonoran Pronghorn Recovery Plan, Second Revision

12

683 animals to 241 animals (Bright and Hervert 2011, Bright et al. 2011). This estimate of 

population decline in Mexico was primarily influenced by declines in the Quitovac population, 

which declined from 625 in 2004 to 189 in 2011, while the Pinacate population remained stable 

during the same time period (Table 2). The specific cause of this decline is unknown, but drought 

is highly suspected. However, the estimate for the Quitovac population in December of 2013 had 

increased to 434 individuals, over double the 2011 estimate; and nearly doubled again to 862 in 

2015 (Table 2). In the Pinacate area, estimates have fluctuated widely and ranged from a low of 

25 in 2002 to a high of 122 in 2014 (Table 2).
Sonoran Pronghorn Recovery Plan, Second Revision

13

Table 1. Summary of population estimates from literature and field surveys for wild Sonoran pronghorn prior to use 

of standard aerial surveys and a sightability model.

Date Population estimate Source

Arizona, U.S. Sonora, Mexico

1925 105 595 in Sonora (Nelson 1925)

1941a 60 - (Nichol 1941) 

1957 <1,000 - (Halloran 1957)

1957 - >1,000 in NW 

Sonora (Villa 1958)

1968 50 - (Monson 1968)

1968-1974 50-150 - (Carr 1971)

1981 100-150

250-350 in 

Mexico (Arizona Game and Fish Department

1981)

1984 85-100 - (Arizona Game and Fish Department

1986)

1993 - 313 in Mexico (Snow 1994)

a Population estimate for southwestern Arizona, excluding Organ Pipe Cactus NM.
Sonoran Pronghorn Recovery Plan, Second Revision

14

Table 2. Wild and captive Sonoran pronghorn estimates after adoption of standard field surveys and sightability 

model for wild population estimations. Numbers in parentheses are 95% confidence intervals.

Year

Sonora, 

Mexico

(Pinacate)

Sonora, 

Mexico

(Quitovac)

Arizona, U.S.

(Cabeza wild)

Arizona, U.S. 

(Nonessential 

Experimental 

Population

wild)

Arizona,

U.S.

(Captive)a

1992 - - 179 (147-234)b -

1994 - - 282 (205-489)b -

1996 - - 130 (114-154)b -

1998 - - 142 (125-167)b -

2000 34 (27-48)c 311 (261-397)c 99 (69-392)b -

2001 - - - -

2002 25 (21-33)c 260 (216-335) c

21 (18-33)b -

2003 - - - -

2004 59 (32-171) c 624 (454-

2079)c

58 (40-175)b 7d

2005 - - - 15d

2006 67 (54-195)c 567 (445-

1530)c

68 (52-117)

b 25d

2007 50 (36-162)c 354 (327-852)c - 37d

2008 - - 68b 51d

2009 101 (57-321)c 381 (268-

1158)c

- 73d

2010 - - 76 (58-210)b 70e

2011 52 (32-183)f 189 (168-435)f - 75g

2012 - - 159 (111-432)h 98i

2013 No surveyf 434 (376-

1105)f

- 9j 117k

2014 122 (79-464) f 202 (171-334)h 30j 119l

2015 117 (98-224)f 862 (759-

2129)f

130m

2016 70 at Kofan

26 at Sauceda a including Cabeza Prieta NWR pen 2004-present; and Kofa NWR pen 2011- present; b

Bright and Hervert (2011);
Sonoran Pronghorn Recovery Plan, Second Revision

15

c

Bright et al. (2011); d U.S. Fish and Wildlife Service (2010b);

e Sonoran Pronghorn Recovery Team (2010); f

J. 

Bright, AGFD, personal communication, 2016; g Sonoran Pronghorn Recovery Team (2011);

h

J. Bright, AGFD, 

personal communication, 2016; i

Sonoran Pronghorn Recovery Team (2012); jSonoran Pronghorn Recovery Team 

(2015a); k Sonoran Pronghorn Recovery Team (2013);

l

Sonoran Pronghorn Recovery Team (2014); mSonoran 

Pronghorn Recovery Team (2015b). n Jim Atkinson, AGFD personal communication, 2016. 

Life Histor y and Ecology

Diet

Sonoran pronghorn forage on a variety of plant species. Fecal pellets collected from 1994-1998 

included 132 different plant taxa (Hervert et al. 2000). Sonoran pronghorn browse on palo verde

(Parkinsonia microphylla), mesquite (Prosopsis spp.), ironwood (Olneya tesota), chain fruit 

cholla (Cylindropuntia fulgida), an annual plantain (Plantago spp.), the lavender-flowered four 

o’clock (Ambronia villosa), and desert broom-rape, (Orobanche multiflora) (U.S. Fish and 

Wildlife Service 1998). Sonoran pronghorn also forage on white ratany (Krameria grayi), 

silverbush (Ditaxis spp.), spurge (Euphorbia spp.), marigold (Baileya spp.), noseburn (Stillingia 

linearifolia), wire-lettuce (Stephanomeria pauciflora), white bursage (Ambrosia dumosa), 

blazing star (Mentzelia spp), and ocotillo leaves (Fouquieria splendens) (U.S. Fish and Wildlife 

Service 1998). Other forage species include triangle-leaf bursage (Ambrosia deltoidea), mistletoe 

(Phoradendron spp.), false filaree (Erodium texanum), poverty weed (Monolepis nuttalliana), 

wooly plantain (Plantago insularis), wild carrot (Daucus pusillus), and Arizona blanket-flower 

(Gaillardia arizonica) (Hughes 1991). The following species are also heavily used: careless 

weed (Amaranthus palmeri), ragweed (Ambrosia spp.), astralgalus (Astragalus spp.), brome 

(Bromus spp.), and broom snakeweed (Guterrezia sarothrae) (U.S. Fish and Wildlife Service 

1998). Important forbs include buckwheat (Eriogonum spp.), milkvetch (Astragalus spp.), and 

borage (Borago spp.) species (Hervert et al. 2000). 

Diet composition varies between years and seasons. Fecal analysis completed from 1974 to 1977 

by AGFD indicated that the Sonoran pronghorn diet consisted of 69% forbs, 22% shrubs, 7% 

cacti, and 0.4% grasses (U.S. Fish and Wildlife Service 1998). In contrast, Hughes (1991a)

reported a diet with a much higher proportion of cacti (44%), and fewer forbs (33%), with 11% 

shrubs, 11% trees, and 0.4% grasses. Between 1994 and 1998, browse made up the highest 

percentage of pronghorn diets (43%-53%) in all seasons except wet summer, when they 

composed 28% of the diet (Hervert et al. 2000). Forbs made up the main component of the diet 

in wet summers (42%) when they were both available and succulent (Hervert et al. 2000). Forbs 

are a preferred diet item when they are available as they are highly nutritious and provide 

preformed water (Hervert et al. 2000). Cacti made up 7-14% of the diet, depending on the 

season, and grasses made up 3-13% of the diet, depending on season (Hervert et al. 2000). In 

Mexico, Sonoran pronghorn consume a diet based on 69% forbs, 22% shrubs, 7% cactus, and 

2% grasses (Comisión Nacional de Areas Naturales Protegidas 2009).
Sonoran Pronghorn Recovery Plan, Second Revision

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Water Use

Early accounts of Sonoran pronghorn stated that they can acquire all the water they need from 

preformed water contained in their forage and metabolic water (water produced as a by-product 

of metabolizing their food). However, a detailed analysis of preformed water and metabolic 

water available from the forage species of Sonoran pronghorn concluded that water intake from 

forage is not adequate to meet their minimum water requirements (Fox 1997, Fox et al. 2000a). 

Similarly, American pronghorn in the moister environment of grasslands of Perry Mesa, 

Arizona, were unable to meet water requirements through dietary water alone in any season 

(Tluczek 2012). Feeding at night and early in the morning when plant moisture is at its highest 

was also insufficient to meet water requirements (Tluczek 2012). However, the desert pronghorn 

(Sonoran and peninsular pronghorn) seem to get some water from morning dew in some areas 

(Brown and Ockenfels 2007). The use of morning dew by Sonoran pronghorn is an assumption 

made by early naturalists and not documented by scientific study. The assumption was made 

because Sonoran pronghorn occurred in good numbers along the Sonora and Baja California 

coasts without the benefit of free water (D. Brown, Arizona State University, personal 

communication, 2013). Sonoran pronghorn do obtain water from vegetation, and it has been 

hypothesized that they met their water requirements from cacti and morning dew in areas subject 

to coastal dew, such as along the Sonoran coast from Rocky Point Puerto Peñasco to Bahia Kino 

(D. Brown, Arizona State University, personal communication, 2013). Sonoran pronghorn 

subsistence in this area without water is mentioned in several old investigative reports, and this 

ability would only increase as one proceeded southward along the coast because humidity is 

higher (D. Brown, Arizona State University, personal communication, 2013). Alternatively, 

these pronghorn may have historically used the riparian areas along the Rio Sonoyta or 

ephemeral washes, and persisted under different climatic conditions than they do currently (J. 

Bright, AGFD, personal communication, 2014). Neither of these hypotheses has been tested, and 

it is unknown how Sonoran pronghorn historically survived in areas receiving so little 

precipitation per year. Sonoran pronghorn have been documented using man-made water sources 

(Morgart et al. 2005).

Home Range and Movement 

Home-range size for individual Sonoran pronghorn in Arizona estimated using locations of 

radio-collared pronghorn varied from 43-2,873 km2 (17-1,109 mi2

), with an average of 511 ± 

665.3 SD km2 (197 ± 257 mi2) (Hervert et al. 2005). These home range sizes are much larger 

than have been reported for other subspecies of pronghorn; the large home ranges estimated for 

Sonoran pronghorn likely indicate that resources are widely dispersed throughout the landscape 

(Hervert et al. 2005). Sonoran pronghorn in the northwestern part of their range in Arizona 

(Cabeza Prieta population) moved up to 130 km (81 miles [mi]) each year between hot-season 

habitats and cool-season habitats (Hervert et al. 2000). This study was conducted before many 

water sources and forage enhancement plots were constructed. It is unknown if the construction 

of these new water sources and forage enhancement plots have influenced seasonal movements. 
Sonoran Pronghorn Recovery Plan, Second Revision

17

Sonoran pronghorn have been documented to wander long-distances, particularly pen-raised and 

released individuals. This wandering behavior in is thought to occur in pen-raised animals 

because they do not have the landscape familiarty and social structure possessed by wild born 

animals. For example, one buck released in 2008, (#851) moved 217 miles from March 1 to 

June 10 (AGFD, unpublished data 2008).

While some monitoring of Sonoran pronghorn has occurred in Sonora, less is known about their 

home range and movements in Mexico. 

Social Structure

Pronghorn live in herds of mixed sexes, with group sizes largest in winter in populations that 

congregate on distinct winter ranges (Byers 1997). Herding is an adaptation to reduce the risk of 

predation, and may reflect eons of selection to detect predators, even those that are now extinct 

(Byers 1997). In years when succulent forage is more widespread, Sonoran pronghorn are 

generally in smaller, but more numerous and widespread groups. In years of poor and limited 

forage, pronghorn are in fewer, larger groups, concentrated in the few areas where green forage 

persists (Bright et al. 2011). Average group sizes of Sonoran pronghorn observed in winter 

survey transects in Arizona were 5.1 ±2.85 in 2006, 7.3 ± 7.97 in 2008, and 5.7 ± 3.23 in 2010 

(Bright and Hervert 2011). Group sizes ranging from 1-21 animals have been observed (Bright 

and Hervert 2011). Average group sizes of Sonoran pronghorn observed in winter survey flights 

in Mexico conducted between 2000 and 2009 ranged from 3.4 to 12.0 individuals (Bright et al. 

2011). In 2015, group sizes as large as 50 were observed in Sonora (C. Weise, FWS, personal 

communication, 2015); however, group sizes this large are exceptional and only follow years of 

above average rainfall. 

Recruitment

Pronghorn are polygamous. Females usually become sexually mature at 16 months of age but 

occasionally conceive at approximately 5 months of age (O'Gara 1978). Males become sexually 

mature at one year of age (O'Gara 1978). The gestation period in captivity averages 252 days

(O'Gara 1978). Twins are more common than single births (O'Gara 1978). 

Rut (the mating season of ruminant animals) in most pronghorn subspecies occurs during July, 

August, and September, and females primarily give birth from February through May (U.S. Fish 

and Wildlife Service 1998). Birthing appears to coincide with spring forage abundance (U.S. 

Fish and Wildlife Service 1998). Mating of Sonoran pronghorn was observed from 16 to 30 June 

in the Cabeza Prieta captive breeding pen (Wilson et al. 2008). In this pen, Sonoran pronghorn 

originally captured in Arizona gave birth from mid-February to early March, while those 

originally captured in Sonora, Mexico, gave birth in mid to late March (Wilson et al. 2008). 

Sonoran pronghorn observed in the wild typically give birth in mid-February to April (Bright and 

Hervert 2005). Sonoran pronghorn in Mexico breed in September and October.
Sonoran Pronghorn Recovery Plan, Second Revision

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The high maternal investment in development of offspring (i.e., lengthy gestation, twinning, high 

fetus biomass to female mass, rapid fawn growth, early weaning) may be an evolutionary 

adaptation to predation (Byers 1997). Pronghorn fawns suckle almost exclusively through the 

first month of life. The females initiate the weaning process as early as 4 weeks and by 12 weeks 

fawns are fully weaned, but nursing has been observed as late as September (Byers 1997). Most 

pronghorn fawns grow rapidly in the presence of nutritious forage and adequate moisture, and, 

by about 45 days of age, fawns are able to easily outrun even the fleetest of predators (Byers 

1997).

Estimates of Sonoran pronghorn fawn recruitment per 100 females varies from 0-78 fawns per 

100 females (Bright and Hervert 2005). Hervert et al. (2000) correlated years of high fawn 

recruitment with high forb production. The length of time between winter and summer rains was 

inversely correlated with fawn survival in Sonoran pronghorn (Bright and Hervert 2005). Most 

fawn mortalities did not occur until fawns were 3-5 months of age, during May and June (Bright 

and Hervert 2005). The authors suggested delayed onset of summer rains results in poor milk 

production, scarce forage, and increased mortality rates of fawns (Bright and Hervert 2005). 

Survivorship 

Longevity for pronghorn is reported as 10 years in the wild and 12 years in captivity (Carey and 

Judge 2000). Excluding the extreme year of 2002, annual mortality rates of collared adult 

Sonoran pronghorn in Arizona average 13% in wet years and 30% in dry years (Bright and 

Hervert 2005). During the extreme drought in summer of 2002, adult mortality was 83% in 

Arizona (Bright and Hervert 2005). From 1995 to 2002, adult mortality, including capturerelated mortality, averaged 28% annually, ranging from 11% to 83% (Bright and Hervert 2005).

Of 32 mortalities documented in Arizona from 1995-2002, 12 were from predation, 5 from 

capture-related mortality, 4 from drought-related factors (i.e., malnutrition, starvation, or 

dehydration), and 11 from unknown causes (Bright and Hervert 2005).

Habitat Characteristics

Soils

Sonoran pronghorn are associated with specific soil associations. Soil association affects 

moisture retention and vegetation growth. Soil association (Gunsight-Rillito-Chuckwalla) was 

one of the most important explanatory variables for Sonoran pronghorn in a classification and 

regression tree (CART) model and logistic regression analysis of Sonoran pronghorn use areas 

(O'Brien et al. 2005).
Sonoran Pronghorn Recovery Plan, Second Revision

19

Topography

Pronghorn are prey animals that rely on keen eyesight and swift running to escape from 

predators. These adaptations are most suited to terrain that is relatively flat and open. Sonoran 

pronghorn appear to prefer gentle slopes and hills, where the paloverde-chain fruit cholla 

vegetation association occurs, and use flat slopes in proportion to their availability (Hervert et al. 

2005). Hervert et al. (2005) found that Sonoran pronghorn avoided rugged slopes and mountains. 

However, more recently, Sonoran pronghorn have occassionally been observed in mountainous 

terrain. Of 3,219 radio-collared locations of Sonoran pronghorn in the U.S. collected from 1994-

2002, only 10% were in areas with slopes >20% (O'Brien et al. 2005).

Vegetation Communities and Structure

Sonoran pronghorn are found exclusively in the Sonoran Desertscrub Biome. Sonoran 

Desertscrub Biome is a relatively recent desert that has a bimodal rainfall pattern, which allows 

for greater structural diversity than in the Great Basin, Mojave, and Chihuahuan deserts (Turner 

and Brown 1994). The Sonoran Desert is in the western half of the state of Sonora, Mexico, and 

in large areas of southeastern California, southwestern Arizona, and the Baja California 

peninsula (Turner and Brown 1994). Sonoran pronghorn are in two of the five subdivisions of 

the Sonoran Desert: the Lower Colorado River Valley Subdivision and the Arizona Upland 

Subdivision (deVos and Miller 2005, Hervert et al. 2005). Historically, pronghorn may have

occurred in Gulf Coast and Plains of Sonora subdivisions in Sonora. Genetic analysis of museum 

specimens found in these subdivisions may help determine if these pronghorn were Sonoran or 

peninsular pronghorn.

The Lower Colorado River Valley Subdivision (Figure 2) is the largest and most arid subdivision 

of the Sonoran Desert extending from Palm Springs, California, in the west, to Needles, 

California, in the north; southeast to Tucson, Arizona, and around the Gulf of California to near 

the southern border of Baja California and south of Caborca, Mexico, in Sonora (Turner and 

Brown 1994). Within the Lower Colorado River Valley subdivision, Sonoran pronghorn are 

typically in the most widespread vegetation series of the subdivision, the Creosote-White 

Bursage series, which is characterized by low open stands of widely spaced creosotebush 

(Larrea tridentata) and white bursage (Turner and Brown 1994). The Creosote-White Bursage 

series offers sparsely-vegetated, flat, open spaces that are ideal for swift running and visual 

detection of predators. This series also supports numerous forbs in cool, wet seasons. Sonoran 

pronghorn prefer the Creosote-White Bursage series when abundant forage is available, such as 

during extremely wet years (deVos and Miller 2005, Hervert et al. 2005). Intermixed throughout 

this series are ephemeral desert washes that support the more diverse Mixed Scrub Series that 

includes blue palo verde, ironwood, desert lavender (Hyptis emoryi), and jojoba (Simmondsia 

chinensis) (Turner and Brown 1994). 
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 2. Sonoran pronghorn habitat in Lower Colorado River Valley Subdivision in the King Valley, Arizona, U.S. Photo 

courtesy Christa Weise, FWS.

In contrast to the Lower Colorado River Valley subdivision, the Arizona Upland Subdivision 

(Figure 3) is the best watered and least desert-like in North America (Turner and Brown 1994). 

The vegetation is largely arboreal and dominated by leguminous trees such as foothill paloverde,

ironwood, mesquites, and cat-claw acacia (Acacia greggii) (Turner and Brown 1994). The 

Paloverde-Cacti-Mixed Scrub Series is dominated by foothill paloverde and saguaro cactus 

(Carnegiea gigantea), the latter becoming more prevalent with increasing elevation. Ironwood is 

common in this series on bajadas (broad slopes at the foot of mountains) but excluded from cold

valley floors because of its frost intolerance. Creosotebush also occurs as a low, shrubby layer. 

Cacti form an important element, and Engelmann prickly pear (Opuntia engelmannii), saguaro,

cane cholla (Cylindropuntia imbricata), and chain fruit cholla are only a few of the cacti species 

found. Other plant species include whitethorn acacia (Acacia constricta), limber bush (Jatropha 

cardiophylla), ocotillo, jojoba, and fairy feather duster (Calliandra eriophylla) (Turner and 

Brown 1994). 
Sonoran Pronghorn Recovery Plan, Second Revision

21

Figure 3. Sonoran pronghorn habitat in Arizona Upland Subdivision in Arizona, U.S. Photo courtesy John Hervert, 

AGFD.

Within the Paloverde-Cacti-Mixed Scrub Series, Hervert et al. (2005) found Sonoran pronghorn 

prefer areas with chain fruit cholla, which they called a “palo verde chainfruit cholla 

association,” (Figure 4) in all seasons over other areas. This plant community consisted of 

creosote, palo verde, ironwood, saguaro, organ pipe cactus (Stenocereus thurberi), ocotillo, 

staghorn cholla (Cylindropuntia versicolor), buckhorn cholla (Cylindropuntia acanthocarpa), 

teddybear cholla (Cylindropuntia bigelovii), and chain fruit cholla. During the eight years of 

study from 1994 to 2002, Sonoran pronghorn used the “palo verde chainfruit cholla association”

in greater proportion than its availability in every season except the winter of 1997-1998, when 

rainfall was 11cm (4.3 inches [in]) above the long-term normal (Hervert et al. 2005). Sonoran 

pronghorn in the “palo verde chainfruit cholla association” had smaller home ranges than in 

other vegetation associations, indicating the habitat quality may be better and pronghorn do not 

need to travel as far to gain needed resources (Hervert et al. 2005). Hervert et al. (2005) 

attributed the preference for the “palo verde chainfruit cholla association” to the availability of 

chain fruit cholla fruits and the preformed water they provide.
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 4. "Palo verde chainfruit cholla association” in Arizona, U.S. Photo courtesy John Hervert, AGFD.

Sonoran pronghorn are also associated with washes more than expected based on availability 

during all seasons and all range conditions (Hervert et al. 2005). These washes support 

vegetation that is more structurally diverse than their surroundings regardless of vegetation type, 

and provide thermal cover (i.e., shade and cooler temperatures). They also retain quality forage 

longer than other areas. Washes are likely to be especially important to Sonoran pronghorn 

during the hot and dry season.

In Sonora, Mexico, the Sonoran pronghorn distribution is composed primarily of the Sonoran 

Desert Lower Colorado River Valley Subdivision (97%). Sonoran pronghorn are found in low 

dunes, sandy meadows, low hill areas, and basaltic areas (Comisión Nacional de Areas Naturales 

Protegidas 2009). Sonoran pronghorn in the Pinacate area inhabit the extensive sand flats and 

volcanic cinder flats, as well as the loose soil patches interspersed within the lava fields in 

Pinacate (Bright et al. 2011). The Quitovac area is characterized by arid granitic and volcanic 

mountain ranges and slopes, semi-stabilized interior and coastal dunes, and sandy plains with 

elevations from 12m to 999m (39 ft to 3277 ft) (Pate 2014). The most important landscape 

features for Sonoran pronghorn habitat in the Quitovac area are semi-stabilized dune fields 

("medanos" in Spanish) (Figure 5) which contain the highest diversity of annual plants, staple 

forage for pronghorn (Castillo 1999; Bright et al. 2011). Pate (2014) found terrain substrate was 

one of the best predictors of Sonoran pronghorn use in a habitat model constructed for the 
Sonoran Pronghorn Recovery Plan, Second Revision

23

Quitovac area; and of thirteen terrain substrate types, the four that most predicted suitability in 

the model were three medanos substrate types and sandy bajadas. Other terrain substrate types 

included bedrock/mountain, upper bajada, lower bajada, sandy flat, coastal dunes, mine, and 

non-medanos sand area (Figure 6). The Nature Conservancy Sonoran Desert Ecoregion 

Vegetation map depicts four vegetation associations for the Quitovac area: palo verde-mixed 

cacti desert scrub, torchwood-limber bush desert scrub, creosote bush-bursage desert scrub, and 

coastal/interior dunes and plains (Marshall et al. 2000; Pate 2014). Vegetation in the Pinacate 

and Quitovac areas is typical of the Sonoran Desert and includes creosotebush, bursage 

(Ambrosia spp.), saguaro cactus, paloverde, and chollas (Opuntia spp.) (Bright et al. 2011). Pate 

(2014) found presence of chain fruit cholla stands one of the most important predictors of habitat 

suitability in the Quitovac area during late spring.

Figure 5. Medano habitat in Sonora, Mexico. Photo courtesy Ami Pate, Organ Pipe NM.
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 6. Sonoran pronghorn in non-medanos habitat in Sonora, Mexico. Photo courtesy Ami Pate, Organ Pipe NM.

Sonoran pronghorn also use playas when forbs are abundant (U.S. Fish and Wildlife Service

1998). Some of the sandy areas within the range of Sonoran pronghorn, such as Pinta Sands, the 

Mohawk Dunes west of the Mohawk Mountains, and the west side of the Aguila Mountains, 

provide a greater variety of seasonal vegetation than other areas within their range. These areas 

are open and provide annuals, grasses, and shrubs for forage, particularly in the spring (U.S. Fish 

and Wildlife Service 1998). These dunes are important for forage in the spring when annuals are 

present, but become less important as summer approaches and the annuals desiccate. These areas 

lack sufficient woody vegetation to provide thermal cover in hot weather (U.S. Fish and Wildlife 

Service 1998). 

Sonoran pronghorn selection for vegetation communities varies with season, precipitation, and 

temperature. They prefer washes and areas with chain fruit cholla during dry conditions when the 

thermal cover and preformed water are necessary to escape heat and meet water needs (Hervert 

et al. 2000, 2005). Females with fawns are more selective for “palo verde chain fruit cholla

association” than females without fawns (Hervert et al. 2000). Although the taller and denser 

vegetation structure of these vegetation communities appears to provide more thermal cover, this 

same feature also likely makes it more difficult for pronghorn to detect predators and to run 
Sonoran Pronghorn Recovery Plan, Second Revision

25

swiftly to escape predation. As a result, adult pronghorn mortality is apparently greater in these 

dense vegetation communities. Hervert et al. (2005) tracked 35 radio-collared Sonoran 

pronghorn and documented that 75% of the predation mortality occurred in the “palo verde 

chainfruit cholla association” even though Sonoran pronghorn only used this habitat association 

48% of the time. In contrast, the collared Sonoran pronghorn used other vegetation communities 

52% of the time where only 25% of the mortality occurred (Hervert et al. 2005). Although the 

sample sizes in this study were small (12 mortalities) the results concur with the field 

observations of other biologists working with Sonoran pronghorn. In contrast, the “creosotebursage series” has more open vegetation structure, which provides greater opportunities to run 

from predators. It also appears to offer high quality forage in wet years. However, in hot seasons 

it does not provide cover from heat as do washes, or preformed water as does the “palo verde 

chainfruit cholla association.”

Forage Quality

Using information on plant species selected for foraging by Sonoran pronghorn from previous 

studies, Fox (1997) reported plant species selected by Sonoran pronghorn are higher in 

preformed water and some nutrients than those plants not selected for foraging. Sonoran 

pronghorn forage on plant species that have lower lipid content, and higher neutral detergent 

fiber and acid detergent fiber than non-forage species (Fox et al. 2000a). No difference in crude 

protein or nitrogen free extract between forage species and non-forage species was reported (Fox 

et al. 2000a). Fox et al (2000b) developed models of diets consumed by Sonoran pronghorn 

based on field collection of forage plants and published literature. Diet models for Sonoran 

pronghorn on the Cabeza Prieta NWR were deficient in 5 of 11 minerals (i.e., sodium, 

phosphorus, copper, zinc, selenium), and these mineral deficiencies could hinder growth and 

health of the population (Fox 1997, Fox et al. 2000b). 

Habitat disturbance may increase forage quality, at least temporarily. Sonoran pronghorn appear 

to be attracted to sites disturbed by military operations (Krausman et al. 2005), presumably 

because of increased production of forbs and other annual species in these areas. Areas burned 

from military activities are also used more than expected by Sonoran pronghorn (Krausman et al. 

2005). It is unknown if repeated burning from military activities would continue to provide a 

greater abundance or of forbs and grasses over time.

Succulent Foods

Forage containing large amounts of moisture is believed to be important to Sonoran pronghorn 

when free water is limited. Chain fruit cholla is considered a particularly important plant species 

in the Arizona Upland because the fruit has high quantities of preformed water (up to 85% water 

by weight) and cholla retain a high moisture content even during the hot dry summer when 

surface water is unavailable to pronghorn (Fox 1997). Fruits of the chain fruit cholla are a major 
Sonoran Pronghorn Recovery Plan, Second Revision

26

source of water during hot, dry conditions (Hervert et al. 2005). However, chain fruit cholla is 

low in protein (Hughes 1991a). Pronghorn that died during the drought of 2002 had rumens full 

of fruit of chain fruit cholla, indicating that the fruit was not meeting their nutritional 

requirements (Hervert et al. 2005). Cholla density was one of the most important variables 

contributing to a Sonoran pronghorn habitat model using Normalized Difference Vegetation

Index (NDVI) and locations of GPS-collared Sonoran pronghorn obtained in late spring in the 

Quitovac area (Figure 7) (Pate 2014). 

Figure 7. Sonoran pronghorn herd among chain fruit cholla on semi-stabilized sand dunes in Sonora, Mexico. Photo 

courtesy John Hervert, AGFD.

Water Availability and Access

Even in years with above-average rainfall, pronghorn select areas that are less than 10 km (6.2 

mi) from water (deVos and Miller 2005). Historically, rivers that flowed within Sonoran 

pronghorn habitat included the Gila River near the northern edge of their range, the Colorado 

River, the Rio Sonoyta in Mexico, and the Rio Sonora in Mexico. These rivers were potentially 

important in the survival of Sonoran pronghorn (U.S. Fish and Wildlife Service 1998). Historical 

descriptions of these rivers suggest a greenbelt existed that could have provided water and green 

forage during a time of year when food and water resources were limited in the rest of the range
Sonoran Pronghorn Recovery Plan, Second Revision

27

(U.S. Fish and Wildlife Service 1998). These rivers (except the Colorado) are now dry or 

ephemeral, and support little to no native riparian vegetation usable as forage by Sonoran 

pronghorn. Sonoran pronghorn have been unable to reach the Gila and Rio Sonoyta rivers since 

the construction of Interstate 8, State Route 85, and Mexican Highways 2 and 8 (U.S. Fish and 

Wildlife Service 2014). The drying of the Gila River in Arizona and other rivers in Sonora may 

have been a significant cause of the Sonoran pronghorn population decline (Carr 1972 in U.S. 

Fish and Wildlife Service 1998). 

Natural water sources 

Other natural water sources include playas (ephemeral lakes), springs, seeps, and tinajas 

(rainfall-recharged ephemeral catchments collected in depressions in rocks formed by scouring 

water). Morgart et al. (2005) reported natural water sources available to Sonoran pronghorn in 

southwestern Arizona include playas, tinajas, and ephemeral pools created by runoff from heavy 

rain. More than five dozen documented tinajas occur on Organ Pipe Cactus NM and additional 

tinajas occur on Cabeza Prieta NWR (U.S. Fish and Wildlife Service 2006, National Park 

Service 2010). Virtually all the tinajas on Cabeza Prieta NWR have been developed to hold more 

water, although some have filled with silt and no longer hold water (U.S. Fish and Wildlife 

Service 2006). Generally, tinajas hold water anywhere from a few days to many months and will 

run dry if there is no subsequent precipitation (J. Atkinson, FWS, personal communication, 

2013). Pronghorn will use these tinajas after rains have occurred, when they provide small pools 

of water in bajadas and similar habitats (hills, small drainages). Pronghorn likely use tinajas or 

any other source of standing water during the summer months if they are close and have access 

to them. However, most of the tinajas, especially the large, developed tinajas such as Heart Tank, 

are in mountainous areas unsuitable for pronghorn (J. Hervert, AGFD, personal communication, 

2013).

Quitobaquito pond and springs is by far the largest water source (natural or artificial) available to 

Sonoran pronghorn in the current endangered U.S. range. The springs are natural and feed the 

pond, which is a human "development" dating back to at least 1860. There are no records of 

pronghorn ever visiting the site although there are a few sight records and telemetry locations of 

pronghorn within 1.2 km (2 mi) from it. (T. Tibbitts, Organ Pipe Cactus NM, personal 

communication, 2013). Quitobaquito pond is in an area with suitable topography and vegetation 

for Sonoran pronghorn; immediately west of Quitobaquito are vast stands of chain fruit cholla. 

However, Mexico Highway 2 runs about 152 m (500 ft) south of the pond, and has heavy traffic,

which may repel pronghorn from the site (T. Tibbitts Organ Pipe Cactus N M, personal 

communication, 2013). Biologists at Organ Pipe Cactus NM operated camera traps at 

Quitobaquito in the late 1990s, and occasionally in 2010-2013, but no pronghorn have been 

photographed. In early 2015, a University of Arizona trail camera documented one pronghorn 

walking a road approximately 850 meters (0.52 mile) east of Quitobaquito. The animal was not 

documented at the pond, and within a day or two was about 15 km east of the area.
Sonoran Pronghorn Recovery Plan, Second Revision

28

There are other natural waters available to pronghorn, but they are ephemeral tinajas, in places 

like Acuna Valley, the margins of the Puerto Blanco and Bates Mountains, and Kino Tinaja, 

where pronghorn use was documented via game camera in 1997 (T. Tibbitts, Organ Pipe Cactus 

NM, personal communication, 2015). Ephemeral water sources such as these do not provide 

water during critical dry periods, however. Dripping Springs and Wild Horse Tank have water, 

but are located on rocky slopes where pronghorn are not likely to occur (T. Tibbitts, Organ Pipe 

Cactus NM, personal communication, 2013).

Springs on Cabeza Prieta NWR include Agua Dulce Spring, a natural seep in the southeast 

corner of Cabeza Prieta NWR, which was once thought to be perennial (U.S. Fish and Wildlife 

Service 2006). It is not known if Sonoran pronghorn used this area historically. Currently, the 

refuge believes the spring is no longer a source of surface water due to a reduction in the water 

table. Sonoran pronghorn are not known to range in that vicinity recently, which may be due to 

the frequent and likely heavy use of that area by cross border activities (J. Atkinson, FWS, 

personal communication, 2013).

There are no natural waters in the King Valley (Kofa population) that are accessible to 

pronghorn. The only natural waters are tinajas that are in areas considered too rugged for 

pronghorn to use (Christa Weise, FWS, personal communication, 2014).

Natural water sources in Mexico include Papagos stream and Tinajas de los Chivos stream on the 

west side of El Pinacate Biosphere Reserve, and the pond of Vidrios Viejos located on the 

northern part of the reserve. These have been used as a natural water source in the past (Federico 

Godínez Leal, El Pinacate Biosphere Reserve, personal communication, 2015). Notes from 

Sonoran pronghorn telemetry flights indicated that rain sufficient to cause the Rio Sonoyta to 

flow had fallen in July 2008, and there was rain water in several playas in September 2008 

(Bright et al. 2011). 

Developed waters

Man-made water sources include charcos (earthen livestock tanks), guzzlers, craters created by 

military activities, and water catchments (that feed water into a trough) created for Sonoran 

pronghorn and other wildlife. Within the Cabeza Prieta population area, as of 2016, 14 standalone developed waters and five waters associated with forage enhancement plots (three on 

Cabeza Prieta NWR and two on BMGR) have been developed for Sonoran pronghorn. However, 

only two of the five waters associated with the plots are reliably filled. Of the 14 stand-alone 

developed waters, 10 waters occur on Cabeza Prieta NWR including two within non-wilderness 

and eight within core pronghorn use areas in wilderness. Four developed waters occur on 

BMGR, two on the East and two on the West. Pronghorn have been observed routinely using 

these catchments and the FWS and Recovery Team believe they are essential components of 
Sonoran Pronghorn Recovery Plan, Second Revision

29

pronghorn recovery (U.S. Fish and Wildlife Service 2014). The standard storage capacity for 

newer water catchments for Sonoran pronghorn is at least 41,640 liters (11,000 gallons) (U.S. 

Fish and Wildlife Service 2014). In addition to these water sources designed for pronghorn, 

occasional pronghorn use is suspected at some of the waters developed for desert bighorn sheep,

including Heart Tank, Bassarisc, and possibly North Pinta on the Cabeza Prieta NWR (J.

Atkinson, FWS, personal communication, 2013). Over the years, Organ Pipe Cactus NM has had 

five "temporary" artificial water sources available to pronghorn. Pronghorn use has never been 

documented at any of them (T. Tibbitts, Organ Pipe Cactus NM, personal communication, 2013). 

The only one of these five currently functioning is "3-Jack Tank," which was established in April 

2013. It was placed in a pronghorn high-use area, based on many years of telemetry and visual 

monitoring. It consists of two 3,785 liter (1,000-gallon) tanks plumbed to a trough. 

Unfortunately, in late 2012 and early 2013, illegal roads were created passing near the site, 

which may have precluded use by pronghorn. As of May 2014, no pronghorn have been 

photographed at the tank (T. Tibbitts, Organ Pipe Cactus NM, personal communication, 2013).

Within the Kofa population area, five water sources for Sonoran pronghorn have been developed 

in the King Valley of the Kofa NWR since 2012. Additionally, Sonoran pronghorn have been 

documented using ponds in the King Valley on the Yuma Proving Ground. No permanent 

waters have been developed for Sonoran pronghorn within the Sauceda population area as of 

February 2016; however, three temporary waters for Sonoran pronghorn have been established 

and a number of waters for deer and sheep already exist. 

In Sonora, staff of the El Pinacate Biosphere Reserve installed nine water tanks (2 in the 

Quitovac and 7 in Pinacate population areas) for Sonoran pronghorn in 2015, although 

pronghorn use of these waters has not been documented likely due to cattle exclusion fences 

around the waters. The cattle fence is pronghorn-friendly, in that the bottom wire is sufficiently 

high for pronghorn to move under; however, it is thought that the fences may enclose too small 

of an area to allow pronghorn to escape from predators. Some tanks are installed at ground level 

and some are above the ground.

Habitat Area

To meet the home range and movement needs described in the life history section above, 

Sonoran pronghorn need large expanses of habitat. The amount of habitat needed has not been 

studied or estimated, but is likely to be thousands of km2 (thousands of mi2), considering homerange size for individual pronghorn in Arizona varies from 43-2,873 km2 (17- 1109 mi2

), with an 

average of 511 ± 665.3 km2 (197 ± 257 mi2) (Hervert et al. 2005). Patchy precipitation 

throughout the range of the subspecies results in a continuously shifting distribution of forage 

and water. Large expanses of habitat are needed for Sonoran pronghorn to have some area with 

seasonally suitable habitat available to them at any one time. 
Sonoran Pronghorn Recovery Plan, Second Revision

30

Habitat Connectivity 

Those large expanses of habitat required by pronghorn need to be free of barriers to enable 

pronghorn to move freely between areas as water and forage conditions change. Although the 

need for habitat connectivity has not been quantified, areas of pronghorn habitat need to 

incorporate a variety of vegetation communities and water sources. Maintaining habitat 

connectivity within each population is critical to the recovery of Sonoran pronghorn. Sonoran 

pronghorn would also likely benefit from creating habitat connectivity between or among 

populations. 

Areas with Modeling of Potential Habitat

O'Brien et al. (2005) used landscape level Classification and Regression Tree and logistic 

regression models to assess potential Sonoran pronghorn habitat in southwestern Arizona within 

their current and historical range as a means of identifying potential locations for establishing a 

second U.S. Sonoran pronghorn herd. The models did not include any areas of historical habitat 

outside of southwestern Arizona, such as southeastern California, Baja California, Sonora, or the 

far eastern historical distribution of Sonoran pronghorn in Arizona. Both models identified 

greater than 12,000 km2 (4,632 mi2

) of potential habitat (O'Brien et al. 2005). The largest blocks 

of potential habitat outside of the current range, which were identified by both models, were the 

Ranegras and Harquahala plains and King Valley at Kofa NWR north of Interstate 8; Sentinel 

Plain and other areas to the west between Interstate 8 and the Gila River; and areas south of 

Interstate 8 and immediately west of Highway 85. The models also identified a large potential

habitat block east of Highway 85 and south of Interstate 8. 

Clark et al. (2013) analyzed three areas in southeastern California and one area in Baja California 

as potential reintroduction sites for pronghorn. They evaluated 13 factors such as vegetation 

structure, water and forage availability, disturbance level and barriers, historical records of 

occurrence, and land protection status. The Chuckwalla Bench area in Imperial County 

California and the Tres Pozos area in Baja California ranked highest, with suitable amounts of 

forage, water, and land protection able to support a population of 50-150 pronghorn (Sonoran or 

peninsular pronghorn) in each area. 

Pate (2014) conducted a habitat suitability model for the Quitovac population using: 1) terrain 

substrate - thirteen terrain classes representing distinct habitat types and substrates for vegetation 

associations that acted as surrogates for detailed vegetation data; 2) Sonora vegetation 

associations from The Nature Conservancy Sonoran desert ecoregion map (Marshall et al. 2000); 

3) chain fruit cholla cactus stands; 4) terrain ruggedness; 5) road density; and 6) seasonal habitat 

quality data derived from remote sensing Normalized Difference Vegetation Index (NDVI); and 

7) habitat use data from locations recorded by aerial surveys and GPS telemetry (Figure 8). She 

used MaxEnt software version 3.3.3k (http://www.cs.princeton.edu/schapire/maxent/) to build a 

habitat suitability model from 2000-2013 pronghorn location data (314 points from aerial 
Sonoran Pronghorn Recovery Plan, Second Revision

31

surveys and 2,594 from GPS telemetry). The environmental variable that best predicted habitat 

suitability when used in isolation was terrain substrate, and out of the terrain substrate categories, 

the four that best predicted habitat suitability were the three categories of areas with semistabilized sand dunes and sandy bajadas. However, when variables were tested by omitting them

from models, cholla was determined to be the most important variable to the model fit. Pate

(2014) also created three seasonal models using a NDVI variable as a surrogate for habitat 

quality/forage availability for January 2006, August 29 - October 15, 2006, and March 22 - May 

8, 2006. The January 2006 and September/October 2006 models better predicted SPH habitat use 

than the non-temporal model.

Figure 8. Sonoran pronghorn habitat suitability model for Quitovac population in Sonora, Mexico. Numbers indicate 

probability of occurrence of Sonoran pronghorn (figure from Pate 2014).
Sonoran Pronghorn Recovery Plan, Second Revision

32

Key ecological attributes 

Key ecological attributes are the most important life history and habitat characteristics essential 

for the conservation of the Sonoran pronghorn. The Recovery Team developed a list of key 

ecological attributes based on published studies, reports, and expert judgment. The list was 

developed during an expert workshop held 25-28 June, 2013. The list of key ecological attributes 

is not an exhaustive list of all life history and habitat needs, but only those that the team felt are 

so important that if they are degraded, extirpation of a population may occur. The eleven key 

ecological attributes and justification for their inclusion are as follows:

 

Habitat attributes:

1. Amount of habitat. As discussed previously in home range and movement and habitat 

area, Sonoran pronghorn require large areas to make seasonal movements to meet their 

resource needs as environmental conditions and the availability of forage and water 

change.

2. Habitat connectivity. As discussed in habitat connectivity, a large amount of habitat 

would not benefit pronghorn if habitat gaps or barriers prevent them from moving

between areas as conditions change. Therefore the team determined habitat connectivity 

is also important to Sonoran pronghorn.

3. Forage quality. The expert team felt forage quality is one of the most important elements 

of Sonoran pronghorn habitat because Sonoran pronghorn need high quality forage to 

meet their diet needs. See the diet and forage quality sections above for information on 

vegetation species used by Sonoran pronghorn and factors influencing forage quality.

4. Succulent foods. Forage containing large amounts of moisture is believed to be 

important to Sonoran pronghorn when free water is limited. Chain-fruit cholla is 

considered a particularly important plant species in the Arizona Upland because the fruit 

has high quantities of preformed water (up to 85% water by weight) and cholla retain a 

high moisture content even during the hot dry summer when surface water is unavailable 

to pronghorn (Fox 1997).

5. Availability of water. As discussed in Water Use, Sonoran pronghorn require water and 

use water sources. As discussed in Water Availability and Access, drying of historical 

natural water sources in the current range of Sonoran pronghorn has limited the 

availability of water essential to the species survival.

6. Access to water. Physical barriers and human disturbance are preventing Sonoran 

pronghorn from using many natural and developed water sources. Sonoran pronghorn 

must be able to get to water in order to use it. 

7. Variety of vegetation communities and structure. Because different vegetation 

communities provide different advantages and disadvantages to pronghorn depending on 

conditions, the Recovery Team identified Sonoran pronghorn as needing a variety of 

vegetation communities, with a variety of vegetation structures, to meet their needs as 
Sonoran Pronghorn Recovery Plan, Second Revision

33

conditions change temporally and spatially. Having a variety of vegetation communities 

available to pronghorn enables them to move to different areas as precipitation, 

temperature, predation pressure, and forage availability change.

Population attributes (Please see the population viability analysis (PVA) (Appendix D) for a 

detailed analysis of the relationship of population attributes of each population to probability of 

extinction. The Recovery Team identified the following population attributes as most important 

in determining long-term survival of Sonoran pronghorn, and justifications are found in the 

PVA):

8. Population size.

9. Recruitment.

10. Survival.

Other attributes:

11. Low perceived threat from humans. The converse of this key ecological attribute, 

human disturbance, is discussed as a threat, below.

Critical Habitat

Critical habitat has not been designated for Sonoran pronghorn. Section 10(j)(2)(c)(ii) of the 

ESA precludes the designation of critical habitat for nonessential experimental populations. 

Reasons for Listing/Threats Assessment

Because most life history and habitat characteristics naturally vary over space and time, the 

Recovery Team subjectively determined an acceptable range of variation for each key ecological 

attribute. The Recovery Team determined, based on expert knowledge, which key ecological 

attributes are not within an acceptable range of variation and identified them as stressors to the 

Sonoran pronghorn. Next, the Recovery Team listed the past, present, and future sources of each 

stressor. The Recovery Team also developed conceptual models showing the relationships 

between the stressors and their sources (Appendix A). These relationships developed by the team 

form the basis of the threats discussion below.

The FWS uses five factors to determine threats to a species under Section 4(a)(1) of the ESA. 

The five factors are considered in determining if a species should be listed as threatened or 

endangered, and are also used to determine if the species should be downlisted or delisted. Those 

factors include: a) present or threatened destruction, modification, or curtailment of its habitat or 

range; b) overutilization for commercial, recreational, scientific, or educational purposes; c) 

disease or predation; d) inadequacy of existing regulatory mechanisms; and e) other natural or 

manmade factors affecting its continued existence. Because the Sonoran pronghorn was included 

on the list of endangered species under the ESA through the “grandfather clause”, no analysis of 
Sonoran Pronghorn Recovery Plan, Second Revision

34

the five factors was conducted when the species was listed. A five factor analysis was included 

in the 2002 supplement and amendment to the 1998 Recovery Plan and is updated here due to 

new information on threats to the species. To be consistent with listing, downlisting, and 

delisting procedures and terminology, the stressors to Sonoran pronghorn identified by the 

Recovery Team in the conceptual modeling effort are listed below by each of the five ESA 

listing factors (Table 3).

The stressors and sources of each stressor to Sonoran pronghorn are based on the expert opinion 

of the Recovery Team. The relationships of some of the stressors to Sonoran pronghorn are wellstudied. However, some have not yet been studied and need to be tested to determine to what 

degree the potential stressors are affecting Sonoran pronghorn. The relationships discussed 

below and shown graphically in Appendix A should be viewed as working hypotheses that are 

essential to develop recovery criteria and recovery actions, but in some cases are in need of 

testing.
Sonoran Pronghorn Recovery Plan, Second Revision

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Table 3. Summary of threats (stressors and sources) to Sonoran pronghorn by ESA Listing Factor.

ESA Listing Factor Stressor Source

A: Present or Threatened 

Destruction, Modification, or 

Curtailment of Its Habitat or 

Range

Habitat Loss Mining

Agriculture

Livestock Grazing

Renewable Energy

Habitat Fragmentation Habitat Conversion

Physical Barriers

Human Disturbance

Multiple stressors and 

contributing factor to multiple 

sources (Reduced availability 

of water, low annual rainfall, 

frequency and severity of 

drought, reduced forage 

quality, thermal stress)

Climate Change

Reduced Access to Water Physical Barriers

Human Disturbance

Inadequate Distribution

Reduced Availability of Water Low Annual Rainfall

Increased Frequency and 

Severity of Drought

Altered Runoff Patterns

Reduced Forage Quality Low Annual Rainfall 

Increased Frequency and 

Severity of Drought

Livestock Grazing

Extreme Heat

Altered Hydrology

Altered Fire Regimes

Increased Cover of 

Creosotebush 

Invasive Plants

Erosion

Lack of Pollination

Altered Habitat Structure Fire

Livestock Grazing

Military Training
Sonoran Pronghorn Recovery Plan, Second Revision

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ESA Listing Factor Stressor Source

Renewable Energy

Mining

Illegal Extraction

B: Overutilization for 

Commercial, Recreational, 

Scientific, or Educational 

Purposes

None N/A

C: Disease or predation Predation Native Predators

Disease Interaction with Cattle

Lack of Genetic Diversity Barriers to Dispersal and 

Small Population Size

D: Inadequacy of Existing 

Regulatory Mechanisms

None N/A

E: Other Natural or Manmade 

Factors Affecting Its 

Continued Existence

Human Disturbance Border Activities

Recreation

Military Activities

Land Management Activities

Mining, Ranching, and 

Agriculture

High Mortality Rates Drowning in Canals

Entanglement in Fences 

Vehicle Collision

Thermal Stress

Poaching

Capture -related mortality

Military Activities

Catastrophic Events Lack of Redundancy of 

Populations

Small Population Size

ESA Listing Factor A: Present or Threatened Destruction, Modification, or Curtailment of Its 

Habitat or Range
Sonoran Pronghorn Recovery Plan, Second Revision

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This listing factor includes most of the major stressors to Sonoran pronghorn, including habitat 

loss, habitat fragmentation, reduced forage quality, and changes in habitat structure. 

Habitat Loss

Historically, most of the habitat for Sonoran pronghorn has been lost, fragmented, or excluded 

from use as a result of urbanization, agriculture, railroad and highway development, and grazing 

practices (Appendix A). Presently, Sonoran pronghorn only occupy approximately 12% of their 

historical range. Because nearly all occupied Sonoran pronghorn habitat in the range of the 

Cabeza Prieta population is in federal ownership and therefore protected from destruction that 

would jeopardize the species’ existence by the ESA, current and future habitat loss is only a 

minor threat to this population. The habitat of the Pinacate population in Sonora is also protected 

from most sources of habitat loss by the Reserva de la Biosfera de El Pinacate y Gran Desierto 

de Altar (El Pinacate Biosphere Reserve). However, some land uses, such as agriculture, are 

allowed in the El Pinacate Biosphere Reserve that may result in loss and fragmentation of 

habitat. 

The Kofa population could be threatened by habitat loss, but most lands have some level of 

protection from habitat loss. Lands managed by FWS in the Kofa population area comprise 23% 

of the area, including Kofa NWR (2691.2 km2 [1,039.1 mi2

]), Imperial NWR (75.1 km2 [29.0

mi2

]), and Cibola NWR (45.6 km2 [17.6 mi2]; U.S. Fish and Wildlife Service 2010a). These FWS

lands are managed for wildlife habitat and are primarily protected from habitat loss. BLM lands 

are managed for multiple uses and comprise 43% of the Kofa area; they are managed by two 

offices: the Yuma Field Office in the Colorado River District and the Lower Sonoran Field 

Office in the Phoenix District (U.S. Fish and Wildlife Service 2010b). Department of Defense 

lands in the Kofa area comprise 27.1% of the area (U.S. Fish and Wildlife Service 2010b). State 

lands (4.6% of the Kofa area) include 9.1 km2 (3.5 mi2) of AGFD lands (Painted Rock Wildlife 

Area, managed for wildlife habitat) and 558.4 km2 (215.6 mi2) of State Trust Lands, managed to 

maximize revenue for state schools. Bureau of Reclamation lands, tribal lands, and private lands 

comprise only 2.8% of the area (U.S. Fish and Wildlife Service 2010b).

The Sauceda population could also be threatened by habitat loss, but has some level of 

protection. The majority of land (53%) in the Sauceda population area is managed by the Tohono 

O’Odham Nation (U.S. Fish and Wildlife Service 2010b). BLM lands are managed for multiple 

uses and comprise 23% of the Sauceda area; they are managed by the Lower Sonoran Field 

Office in the Phoenix District (U.S. Fish and Wildlife Service 2010b). Department of Defense 

lands in the Sauceda area comprise 21% of the area (U.S. Fish and Wildlife Service 2010b).

State of Arizona, county, and private lands comprise 3% of the area (U.S. Fish and Wildlife 

Service 2010b).
Sonoran Pronghorn Recovery Plan, Second Revision

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In contrast to the other three existing populations, the Quitovac population is entirely on lands 

with little protection from habitat alteration. Some of the land is private land and some of the 

land is ejidos (communally-owned lands). Habitat loss is the greatest stressor to this population, 

which is the largest of the five existing Sonoran pronghorn populations. 

Mining

Mining is probably the most significant current and potential source of habitat loss for the 

Quitovac population. There are two mining operations currently affecting this population. The

largest operation, La Herradura, is an open pit gold mine. When the La Herradura project was 

initiated in 2000, it was little more than 3.2 km2 (1.2 mi2

) on the southwest side of the Juan 

Alvarez Ejido. At that size, the project offered posed little risk to the conservation of the 

pronghorn and its habitat. The mine has expanded in a southeasterly and northwesterly direction

and currently occupies approximately 41.63 km2 (16.07 mi2) of Sonoran pronghorn habitat and 

continues to expand rapidly (Figures 9 and 10). The area occupied by the mine formerly 

contained habitat with a high probability of occupancy by Sonoran pronghorn (Figure 8). A

second open pit operation, a new mining project called Nochebuena, was initiated approximately 

15 km (9 mi) southeast of La Herradura in 2011. The mining operation removes all vegetation 

from the land (Figures 11 and 12). Sonoran pronghorn habitat use in 2006 was seasonally 

concentrated in areas around the La Herradura mine, within habitat that was converted to mining 

operations after 2006 (Pate 2014). However, the mine does practice restoration, and Sonoran 

pronghorn have been observed using areas replanted with cactus. The mining company has 

expressed an interest in working with Comisión de Ecologia y Desarrollo Sustentable del Estado 

de Sonora (CEDES) on conservation of Sonoran pronghorn (Cristina Melendez, CEDES, 

personal communication 2013). Factors leading to mine expansion include a high price of gold, 

improved mining technology, availability of materials, and lack of or weak regulations and/or 

enforcement of those regulations. Land protection laws favor economic uses over species 

conservation; this contributes to rapid expansion of the mines and loss of Sonoran pronghorn 

habitat. In addition, incentives to protect land in the area are lacking. The effects of this mine 

expansion have not been thoroughly evaluated due to limited information and limited access to 

the site. 
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 9. La Herradura Mine expansion and Sonoran pronghorn locations, Sonora, Mexico.
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 10. Additional mine (Nochebuena) near La Herradura in Sonora, Mexico.
Sonoran Pronghorn Recovery Plan, Second Revision

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Figure 11. La Herradura gold mine, Sonora, Mexico. Photo courtesy Ami Pate.

Figure 12. Mine tailings in Quitovac population area, Sonora, Mexico. Photo courtesy Ami Pate, Organ Pipe NM.
Sonoran Pronghorn Recovery Plan, Second Revision

42

Mining could also occur on BLM land, but only poses a minor threat to the populations at 

Cabeza Prieta, Kofa, and possibly Sauceda. Mining operations have the potential to cause habitat 

loss through vegetation clearing on the mine site, and construction of infrastructure in support of 

mining operations, such as roads, power lines, and water supplies. On BLM-managed lands, 

mining occurs pursuant to the Mining Law of 1872 (30U.S.C. 21 et seq.). Under this Act, U.S. 

citizens and businesses are free to prospect for hard rock (locatable) minerals, such as silver, 

gold, copper, and platinum, among others, on the public domain open to such activities. If in the 

course of exploration, a valuable mineral deposit is discovered, a mining claim can then be filed, 

giving the claimant the exclusive possessory right to develop that prospect. The BLM regulates 

surface activities associated with mining on BLM-administered lands, which are subject to 

federal laws, regulations, and policies. In addition to the 1872 Mining Law, overall guidance on 

the management of mineral resources is defined by: the Mineral Leasing Act of 1920, the 

Mineral Materials Act of 1947, the Domestic Minerals Program Extension Act of 1953, the 

Mining and Minerals Policy Act of 1970, the Federal Land Policy and Management Act of 1976, 

the National Materials and Minerals Policy, Research and Development Act of 1980, BLM’s 

Minerals Resources Policy of May 29, 1984, and the Energy Policy Act of 2005. Section 302 of 

Federal Land Policy and Management Act of 1976 directs the Secretary to manage public lands 

under the principles of multiple use and sustained yield in accordance with land use plans 

developed under the Act. Mining activities must generally conform to BLM Resource 

Management Plans (RMP), which are subject to the National Environmental Policy Act (NEPA). 

Notable exceptions from the NEPA process include casual use (e.g., hand tools) and notice level 

locatable minerals activities (e.g., mechanized earth moving equipment, less than 2 ha (5 ac) of 

surface disturbance and less than 1,000 tons of presumed ore) conducted pursuant to 43 Code of 

Federal Regulations (CFR) 3809. However, operations greater than casual use level conducted 

on lands or waters known to contain proposed or listed species or their proposed or listed critical 

habitat, require Plans of Operations [43 CFR 3809.11(c)(6)], which are subject to NEPA review. 

Exemption from the NEPA process for some mining operations does not extend to exemption 

from the ESA. 

According to BLM’s Land and Mineral Legacy Rehost 2000 System (LR2000), as of September 

2014 there were approximately 500 mining claims within the BLM-managed Sonoran pronghorn 

habitat. The majority of claims are casual use claims, but 29 of them are Notice Level claims: six

managed by the Lower Sonoran Field Office and 23 managed by the Yuma Field Office. These 

80 ha (197.63 ac) of Notice Level claims have been authorized under a Plan of Operation or 

Notice Level activity within the Kofa reintroduction area. In addition to these 29 claims, the 

Yuma Field Office also has had three pending Notice Level authorizations which total an 

additional 39 ha (96.5 ac). The current largest mining claim within Kofa population area totals 6 

ha (15 ac) and is run by Fancher-Luxor, but is not currently in operation. 
Sonoran Pronghorn Recovery Plan, Second Revision

43

Agriculture

Agriculture is a source of habitat loss for the Quitovac population, as the Quitovac area has much 

private and communal (ejido) land and very few regulations to prevent conversion of habitat to 

agriculture. Sonoran pronghorn habitat could also be lost to agriculture in the Pinacate 

population area, but to a much lesser extent than in the Quitovac area. Although the Pinacate 

population is in a biosphere reserve, some agriculture is allowed. Agriculture is prohibited in the 

nucleus zone of the bioreserve, but in the buffer areas outside the nucleus zone there is less 

habitat protection and agricultural activities occur on ejidos and private lands (Areas Naturales 

Protegidas 1995). Agricultural activities are expensive to operate due to the costs of pumping 

and transporting water, and operate at a subsistence level on ejidos and private farms (Areas 

Naturales Protegidas 1995). Ejidos and private farms obtain agriculture permits for planting 

areas that range between 30 and 40 ha (74 and 98 ac) for the production of livestock forage, 

including alfalfa, wheat, and other forage. However, lack of access to water and dysfunctional 

hydrologic infrastructure has limited development of agriculture in the bioreserve (Areas 

Naturales Protegidas 1995). The Cabeza Prieta, Kofa, and Sauceda populations occur primarily 

on public lands and are therefore protected from most major sources of habitat loss.

Livestock Grazing

Historical livestock grazing, and to a lesser extent current livestock grazing, has caused loss of 

habitat for Sonoran pronghorn. Historical livestock grazing was extensive and severe (causing 

erosion of soil, soil compaction, changes in composition of flora and fauna, and an increase of 

woody shrubs) and destroyed habitat for pronghorn throughout their range (Brown and 

Ockenfels 2007). Domestic livestock altered the vegetation of southeastern Arizona and 

northeastern Sonora, Mexico, causing changes in species composition and vegetation structure 

by increasing the abundance of shrubs such as mesquite (Bahr 1991). It is likely those changes 

also occurred in southwestern Arizona and northwestern Sonora in the range of Sonoran 

pronghorn. Cattle numbers were at their peak in the 1890s when severe, extended drought 

occurred throughout the region, which exacerbated the effects of the already severe overgrazing 

(Bahr 1991). Habitat alteration (caused in part by livestock grazing) was a leading cause in the 

decline in Sonoran pronghorn numbers (Wright and deVos 1986). Changes were so severe as to 

result in complete loss of habitat over a substantial portion of the Sonoran pronghorn’s historical

range. Accurate figures describing livestock numbers in the historical range of Sonoran 

pronghorn are sparse, but Rutman (1997) cites estimates of 1,000 head of burros and horses in 

1942 on the southern half of Organ Pipe Cactus NM, and as many as 3,000 cattle on the 

monument at one time. Current livestock grazing is not a continued source of habitat loss in most 

areas, but may reduce forage quality and habitat structure (see discussions under “reduced forage 

quality” and “altered habitat structure” sections below).
Sonoran Pronghorn Recovery Plan, Second Revision

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Renewable Energy

The Sonoran Solar project has been permitted on BLM land but has not been built because there 

is not a power purchase agreement in place. The project is outside the 2015 range of Sonoran 

pronghorn but is within the Sonoran pronghorn nonessential experimental population area. The 

Maricopa Solar Park also is outside the 2015 range of Sonoran pronghorn but is within the 

nonessential experimental population area. This project is pending a permit but has been put on 

hold by the applicant. Solar energy zones from the BLM National Solar Preliminary 

Environmental Impact Statement are areas now identified in BLM resource management plans

for utility scale solar development. The Preliminary National Solar Preliminary Environmental 

Impact Statement identified two Solar Energy Zones in Arizona (Brenda and Gillespie). One of 

these, the Gillespie, is within the nonessential experimental population area. These two proposed 

Solar Energy Zones in Arizona encompass 2,616 ha (6,465 ac) (Bureau of Land Management

2012b). There are no active applications or otherwise pending projects on any Arizona Solar 

Energy Zones at this time (Lane Cowger, BLM, personal communication, 2014). In addition, the 

Restoration Design Energy Project was an Arizona planning initiative. It identified an additional 

Solar Energy Zone (Agua Caliente) as well as 77,699 ha (192,000 ac) of renewable energy 

development areas, lands potentially suitable for renewable energy, not just solar (Bureau of 

Land Management 2012b). The Maricopa Solar Park mentioned above is mostly in one of these 

renewable energy development areas. There are no other active applications in renewable energy 

development areas.

Habitat Fragmentation

Sonoran pronghorn habitat may be fragmented by habitat conversion, physical barriers, and 

human disturbance. Physical barriers that fragment Sonoran pronghorn habitat include border 

infrastructure, fences along roads and for livestock management, paved roads, railroads, canals, 

transmission corridors, and mines. Human disturbance may also prevent pronghorn from using 

an area, and areas with extensive human use may function as a barrier to pronghorn despite 

otherwise suitable habitat conditions.

Fragmentation Caused by Habitat Conversion

Incompatible land uses such as mining or agriculture may fragment the Sonoran pronghorn 

habitat in the Quitovac area into isolated patches. Fragmentation is caused by the same sources 

as for “habitat loss” discussed above (mining, agriculture, and livestock grazing). The La 

Herradura mine, in particular, occupies approximately 25 square kilometers of formerly prime 

Sonoran pronghorn habitat for the Quitovac population. The band of high suitability habitat is 

narrow, and if the mine is expanded across this band, it may become a barrier between the high 

suitability habitat on the south end of the range and the high suitability areas farther north 

(Figure 8) (Pate 2014). In addition, the La Herradura and Nochebuena mines are connected by a 

10 m (33 ft) wide access road that causes habitat disturbance up to 20 m (66 ft) on either side of 

the road and divides the area of pronghorn habitat into two sections. These two mining projects 
Sonoran Pronghorn Recovery Plan, Second Revision

45

are located in a natural movement corridor for Sonoran pronghorn. If the Sonoran pronghorn 

population in this area were split into two populations by mining, each population would likely 

suffer from the deleterious effects of small, isolated population size such as loss of allelic 

diversity, inbreeding, and demographic losses due to random and catastrophic events. 

Additionally, the current population moves across its entire current range in search of forage that 

may shift locations from year to year and from season to season in response to sporadic rainfall 

patterns. If the area is further fragmented by the mines, pronghorn may no longer be able to 

make these movements resulting in reduced access to suitable habitat. 

Habitat for all the other populations could also be fragmented by conversion to other land uses;

however, because these populations primary occur on federally managed lands, land uses 

changes are more regulated. Pinacate population could also be fragmented by agriculture and 

livestock grazing and associated fences. Although each of these sources of habitat conversion is 

less severe than in Quitovac, the Pinacate population is smaller and less resilient to stressors such 

as habitat fragmentation. Although historical habitat conversion was one of the major causes of 

Sonoran pronghorn population declines throughout its range, currently very little habitat 

conversion occurs in the U.S. endangered population (Cabeza Prieta) because most of it is 

federally-owned and managed for Sonoran pronghorn under the ESA. The nonessential 

experimental population area is also mostly federally-owned and managed.

Fragmentation Caused by Physical Barriers

Physical barriers to pronghorn movement include fences, highways, canals, railroads, and 

transmission lines. Fences, in particular, are a barrier because pronghorn are reluctant to jump 

fences. If they do attempt to cross a fence, they normally will try to crawl under it. Fences with a 

bottom strand less than 41 cm (16 in) from the ground are impassible to pronghorn (Brown and 

Ockenfels 2007). A fence needs to have a smooth bottom wire, have the bottom wire at least 41 

cm (preferably 51-56 cm [20-22 in]), above the ground, and have no more than two stays

between posts to be passable for pronghorn (Brown and Ockenfels 2007). Many barbed-wire 

fences and all woven-wire (e.g., field fence or sheep fence) fences are impassable to pronghorn. 

Most fences within the range of Sonoran pronghorn are along roads or for livestock 

management. Fences occur within the range of all populations, but the Cabeza Prieta population 

is relatively contiguous (U.S. Fish and Wildlife Service 2006) and some former barriers (e.g., 

fencing between Organ Pipe Cactus NM, Cabeza Prieta NWR, BLM, and BMGR) have been 

removed or modified to allow passage by pronghorn. Fences have also been removed or 

modified in El Pinacate Biosphere Reserve. The international border fence between Mexico and 

Organ Pipe Cactus NM and Cabeza Prieta NWR is primarily a vehicle barrier fence that is 

passable by pronghorn.

Highways are also significant major barriers, particularly when accompanied by right-of-way 

fencing and high traffic volume. Pronghorn that succeed in crossing fences into right-of-ways 

may not easily cross fencing to exit the right-of-way and can become trapped and susceptible to 
Sonoran Pronghorn Recovery Plan, Second Revision

46

being hit by vehicles. Observations of Sonoran pronghorn crossing highways are rare, and those 

that do cross are at risk of being hit by vehicles, as documented along U.S. Interstate 8, Arizona 

Highway 85, and Mexico Highway 8 (see section Vehicle Collisions, below, for more 

information). 

Only one occurrence of a Sonoran pronghorn crossing U.S. Interstate 8 has been documented 

(Phelps 1981). Documentation of Sonoran pronghorn crossing Highway 85 was very rare prior to 

pronghorn releases from the captive breeding pen (just 1 occurrence was documented in 1996 

[U.S. Fish and Wildlife Service 1998, U.S. Fish and Wildlife Service 2002]). However, since 

2013 a number of collared pronghorn released from the pen have been documented to cross 

Highway 85 within Organ Pipe Cactus NM where no right-of-way fencing exists along the 

highway (Jim Atkinson, Cabeza Prieta NWR, personal communication 2016). In 2013, a release 

pen was constructed in the Valley of the Ajo on Organ Pipe Cactus NM about two miles west of 

Highway 85. Some animals released from this pen crossed Highway 85 to the east and 

subsequently returned to the west. Additionally, in 2008, a radio-collared buck (#851) recently 

released from the pen at Cabeza Prieta NWR crossed Highway 85 within BMGR where right-ofway fencing exists (U.S. Fish and Wildlife Service 2010b).

Documentation of Sonoran pronghorn crossing Mexico Highway 8 is rare. In January 1991 a 

pregnant Sonoran pronghorn female was found dead just a few hours after it had been killed by a 

mountain lion at the base of a small hill in the San Francisco Sierra foothills; this same animal 

had been radio collared in the El Pinacate Biosphere Reserve west of Mexico Highway 8 and the 

corpse was found east of Mexico Highway 8, indicating the individual must have successfully 

crossed the highway (Castillo 1999). Only two other reliable records of Sonoran pronghorn 

crossing Mexico Highway 8 were recorded prior to 1999 (Castillo 1999). Unconfirmed reports of 

Sonoran pronghorn crossing Mexico Highway 8 are occasionally received from residents of 

Puerto Peñasco (U.S. Fish and Wildlife Service 2002), although no radio-collared Sonoran 

pronghorn have ever been recorded crossing this highway (U.S. Fish and Wildlife Service 2002; 

J. Bright, AGFD, personal communication, 2015).

Mexico Highway 2 is also a barrier to Sonoran pronghorn movement, and documentation of 

Sonoran pronghorn crossing this highway is limited. In 1999 the El Pinacate Biosphere Reserve 

staff observed a group of five animals (three juveniles and two adults) crossing this highway 

(Castillo 1999). In 2008, one radio-collared buck (#851) recently released from the breeding pen 

at Cabeza Prieta NWR crossed Mexico Highway 2 multiple times (AGFD, unpublished data

2008). Construction of two underpasses along Highway 2 in 2013 is hoped to facilitate safe 

crossing by Sonoran pronghorn (for more details, see the Recent Conservation Programs and 

Management Efforts for Sonoran Pronghorn in Mexico section).
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47

While Sonoran pronghorn have not been documented to use underpasses, American pronghorn 

have been documented to use highway underpasses, but use is low (Plumb et al. 2003, Sawyer 

and LeBeau 2011). Sawyer and Rodgers (2015) found American pronghorn strongly preferred 

overpasses to underpasses in one study in Wyoming. Over three years of the study, 90 percent of 

pronghorn traveled over the highway (n=22,710) and only 10 percent moved under (n=2,546). 

Prior to overpass and underpass construction (2005 – 2012), the total number of mule deer and 

pronghorn wildlife vehicle collisions was 662, with an average of 85 per year. Of those, only 9 

percent involved pronghorn. By the third year following overpass and underpass construction, 

pronghorn-vehicle collisions were completely eliminated. Without overpasses, the Recovery 

Team considers highways to be barriers to Sonoran pronghorn movement.

Canals also pose significant major barriers, and those pronghorn that do attempt to cross canals 

may drown. Canals have been the cause of seven Sonoran pronghorn deaths since 2008 and pose 

significant barriers to the Cabeza Prieta and Kofa populations (see section Drowning in canals,

below, for more information). Railroads and transmission lines may also be barriers to Sonoran 

pronghorn movement, but their influence on Sonoran pronghorn movement has not been 

described. No estimates of the length of any barriers within any of the management units are 

available.

Habitat Fragmentation Created by Human Disturbance

Human disturbance may prevent Sonoran pronghorn from entering an area and therefore may 

essentially fragment habitat. For example, human disturbance may prevent pronghorn from 

reaching water sources. Actions that may cause human disturbance and evidence for their 

influence on Sonoran pronghorn are discussed further under Listing Factor E: Other Natural or 

Manmade Factors Affecting Its Continued Existence.

Climate Change

Our analyses under the ESA include consideration of ongoing and projected changes in climate. 

The terms “climate” and “climate change” are defined by the Intergovernmental Panel on 

Climate Change (IPCC). “Climate” refers to the mean and variability of different types of 

weather conditions over time, with 30 years being a typical period for such measurements, 

although shorter or longer periods also may be used (Intergovernmental Panel on Climate 

Change 2007). The term “climate change” thus refers to a change in the mean or variability of 

one or more measures of climate (e.g., temperature or precipitation) that persists for an extended 

period, typically decades or longer, whether the change is due to natural variability, human 

activity, or both (Intergovernmental Panel on Climate Change 2007). Various types of changes in 

climate can have direct or indirect effects on species. These effects may be positive, neutral, or 

negative and they may change over time, depending on the species and other relevant 

considerations, such as the effects of interactions of climate with other variables (e.g., habitat 
Sonoran Pronghorn Recovery Plan, Second Revision

48

fragmentation) (Intergovernmental Panel on Climate Change 2007). In our analyses, we use our 

expert judgment to weigh relevant information, including uncertainty, in our consideration of 

various aspects of climate change. 

For the Southwestern U.S., Garfin et al. (2013) predict the following influences of climate 

change:

1. Warming is expected to continue, with longer and hotter heat waves in summer. 

2. Average precipitation will decrease in the southern Southwest and perhaps increase in 

northern Southwest. 

3. Precipitation extremes in winter will become more frequent and more intense. 

Precipitation extremes in summer have not been adequately studied. 

4. Late-season snowpack will continue to decrease. 

5. Declines in river flow and soil moisture will continue. 

6. Flooding will become more frequent and intense in some seasons and some parts of the 

Southwest, and less frequent and intense in other seasons and locations. 

7. Droughts in parts of the Southwest will become hotter, more severe, and more frequent 

Strittholt et al. (2012) analyzed average annual temperature projections, seasonal summer 

temperature (July–September), and winter temperature (January–March) as simulated by the 

ECHAM5-driven RegCM3 models for the Sonoran Desert Ecoregion specifically. Results show 

that the ecoregion is expected to undergo general warming over the entire region with a > 2° 

Celsius increase by 2060 in some locations, particularly in the southwestern portion of the 

ecoregion. Average summer temperatures are expected to increase, but greater increases are 

projected to occur during the winter months.

Climate change is a likely contributor to the stressors of increased frequency and severity of 

drought, low annual rainfall, and extreme heat discussed in the sections on “reduced availability 

of water” and “reduced forage quality”. It is also a likely contributor to the stressor of thermal 

stress, a contributor to high mortality rates discussed under “ESA Listing Factor E: Other Natural 

or Manmade Factors Affecting Its Continued Existence.” 

Reduced Availability of Water

The most significant potential impact of global climate change on Sonoran pronghorn is its 

potential to increase the frequency and severity of drought. More dry days, warming 

temperatures, and increased evapotranspiration are expected to result in more severe drought in 

the Southwestern United States (Gershunov 2013). Future droughts are expected to become more 

frequent and severe, with 100-year droughts common in the second half of this century 

(Gershunov 2013). Drought was the factor causing extreme mortality of Sonoran pronghorn in 

2002, and as discussed in the life history section above, drought is the most important predictor 

of survivorship and recruitment. Similarly, global climate change could cause annual rainfall to 
Sonoran Pronghorn Recovery Plan, Second Revision

49

lessen. Precipitation is projected to drop by five percent by century’s end (relative to average 

precipitation over the last three decades of the 20th century) for much of Arizona and New 

Mexico, based on results from 18 global climate models (Seager et al. 2007). A ten percent 

decline could occur over the southern half of Arizona based on these estimates (Seager et al. 

2007). Winter storms could enter the western United States in a more northerly position, 

bypassing the Southwest more often than it currently does. Summer precipitation may also 

decrease, but is more difficult to predict (Lenart 2008). Specifically in the Sonoran Desert 

Ecoregion (the only ecoregion where Sonoran pronghorn occur) GCM-driven RegCM3 regional 

climate model projections show significant declines in annual precipitation during the time 

period of 2015 to 2030 with severe drought occurring in some areas (Strittholt et al. 2012). Over 

the 2045–2060 timeframe, precipitation is projected to slightly increase over historical levels in 

parts of the eastern portion of the ecoregion (the portion of the ecoregion where pronghorn are 

less likely to occur), particularly during the fall (October–December) (Strittholt et al. 2012). 

Other factors contributing to reduced availability of water include the historical drying of the 

Gila and Sonoyta Rivers following European settlement of the region. In addition, altered runoff 

patterns resulting from development, agriculture, soil compaction, and other anthropogenic 

influences on watersheds may cause flows to natural and surface-fed man-made water sources to 

be of greater intensity but occur less regularly. This pattern may result in water sources drying 

out between storms. 

The ability of current water developments to supply reliable water as the climate changes is 

unknown. Reductions in annual rainfall, coupled with hotter temperatures are likely to bring 

higher evaporation rates, much as they do during summer compared to winter. As a result, dry 

spells between rains can have more severe impacts on the landscape, especially in spring and 

summer (Lenart 2008). It is likely that some smaller existing water sources may dry out in spring 

and summer. While the region is expected to dry out, it paradoxically is likely to see larger, more 

destructive flooding. Because warm air holds more water vapor than cooler air, climate models 

project a future increase in atmospheric water vapor along with the increase in global 

temperature (Lenart 2008, Garfin 2013). This creates conditions that potentially could lead to 

bigger and more frequent floods by causing more intense, heavy rainfall events (Lenart 2008). 

Intense rainfall events are more likely to carry rainwater quickly away from the area in intense 

floods, with less water reaching the aquifers or remaining as semi-permanent water. MAPSS 

models for the Sonoran Desert Ecoregion predict surface runoff will slightly increase over the 

near term, and slightly decrease over the 2045–2060 time frame (Strittholt 2012). The decrease 

in runoff would result in less water in many water developments.
Sonoran Pronghorn Recovery Plan, Second Revision

50

Reduced Access to Water

Access to water is limited by two primary sources 1) barriers between Sonoran pronghorn and 

water sources, and 2) inadequate distribution of water, making it too far for individuals to travel 

to get to water. Physical barriers may exist due to the development of fences, paved roads, 

railroads, canals, transmission corridors, mines, border infrastructure, military infrastructure, 

dense stands of salt cedar (Tamarix ramossisima) along the Sonoyta River in Sonora, and human 

disturbance. Barriers between Sonoran pronghorn and water sources may have been a source of 

historical population declines as pronghorn were no longer able to access the Rio Sonoyta or 

Gila rivers. These rivers are now mostly dry. Current barriers exist between pronghorn and 

occasional flowing sections of the Rio Sonoyta, springs, or man-made water sources (see 

discussion of barriers under “Habitat fragmentation” above for more information on the types of 

physical barriers impenetrable by pronghorn). Human disturbance may also prevent Sonoran 

pronghorn from accessing water sources currently available (see “human disturbance” below for 

a discussion of human disturbance). In addition, the limited distribution of water sources force 

Sonoran pronghorn to travel long distances to get to water.

Reduced Forage Quality 

Sonoran pronghorn need quality forage to meet their nutritional needs and fawns are particularly 

vulnerable to low-quality forage. In years with poor winter rainfall, the nutritional quality of 

forage may be insufficient to keep fawns alive (Bright and Hervert 2005). Therefore, the 

Recovery Team has hypothesized that poor quality forage may be a stressor to Sonoran 

pronghorn. The Recovery Team has indicated that sources of reduced forage quality are an 

increase in the frequency and severity of drought, low annual rainfall, altered hydrology, extreme 

heat, erosion, fire, invasive plants, increase of creosotebush, lack of pollination of forage plants, 

and livestock grazing (Appendix A).

Since 2005, the Recovery Team has attempted to reduce the effects of reduced forage quality in 

the Cabeza and Kofa populations by providing irrigated forage, hay, and water. Reduced forage 

quantity was not determined to be a threat by the Recovery Team experts.

Low annual rainfall

Low annual rainfall reduces the amount of quality forage available to Sonoran pronghorn. Low 

winter precipitation results in sparse growth of forbs in the spring, which may negatively impact 

the condition of lactating females and their nursing fawns (Bright and Hervert 2005). The timing 

of precipitation may also affect forage quality. Bright and Hervert (2005) found the number of 

fawns recruited was inversely correlated to the number of days between the last winter rain and 

the first summer rain and suggested delayed onset of summer rains results in scarce forage and 

increases the mortality rates. 
Sonoran Pronghorn Recovery Plan, Second Revision

51

Changes in the magnitude, frequency, or timing of precipitation and increases in temperature and 

atmospheric concentrations of carbon dioxide as a result of global climate change will likely 

affect soil organisms, vegetation composition, and ecosystem processes in Southwestern deserts 

(Fleishman et al. 2013). These changes would affect the quantity and species composition of 

forage available to Sonoran pronghorn. Highly variable precipitation can also affect forage 

quality because it would result in large fluctuations of nutrients in soils and plants (Fleishman et 

al. 2013). Strittholt (2012) modeled changes to vegetation in the Sonoran Ecoregion that may 

occur with climate change. They used MAPSS models to predict the types of vegetation that 

would be supported under the given set of climate and soil conditions without human influence. 

MAPSS does not take into account human management of natural landscapes or its long term 

legacy (e.g., water management, logging, grazing, etc.). It only uses climate and soil data to 

simulate potential vegetation cover. The MAPSS models used by Strittholt (2012) indicate desert 

subtropical vegetation in the Sonoran Desert Ecoregion is likely to decreases in cover by 1934 ha 

(4,780 ac) from 2045-2060. They discussed potential effects of climate change on the Sonoran 

Desert Ecoregion:

The model projections show very dry annual and summer conditions during the 2020s, and 

slightly wetter conditions around 2050 (although still drier than historic mean). Winter 

precipitation increases slightly over both time periods. Winter and warm season rainfall 

influence germination and distribution of many Sonoran Desert plant species. With warmer, 

somewhat drier conditions, desert subtropical vegetation, such as creosotebush-white bursage in 

the Colorado Desert of California and southwestern Arizona, is projected to expand in the 2015–

2030 time period, but then recede in 2045–2060 replaced by an expansion of semi-desert C4 

grasses (see Glossary). Even this drought resistant community has limits. Creosotebush is 

susceptible to prolonged drought and its distribution is correlated with winter precipitation 

(Marshall 1995, Munson et al. 2011). Munson et al. (2011), in a study of the effects of climate 

variability on Sonoran Desert vegetation communities over the last century, found that the cover 

of creosotebush decreased with increased aridity and a decrease in winter precipitation (below 

135 mm). They also noted that in years with high temperatures the cover of foothills paloverde 

and ocotillo decreased and cacti increased in the Arizona Upland. Recent drought in the early 

2000s also caused nearly complete mortality of white bursage and other subshrubs in the 

California portion of the Sonoran and Mojave Deserts (McAuliffe et al 2010).

Increased frequency and severity of drought

Drought limits the availability of quality forage and water. During the extreme drought of 2002, 

four out of five (80%) of collared Sonoran pronghorn in Arizona died, and the population 

declined to 21 individuals (Bright and Hervert 2005). Nutritious forage was largely unavailable 

or dry, and the mortalities were likely due to lack of quality forage (Bright and Hervert 2005). In 

addition, drought may contribute to mortalities from predation because pronghorn use denser 

vegetation types to obtain moist vegetation and thermal cover during drought, but they are more 
Sonoran Pronghorn Recovery Plan, Second Revision

52

susceptible to predation in these areas (Bright and Hervert 2005). The primary source of 

increased frequency and severity of drought is climate change (see climate change and reduced 

availability of water sections above for discussion and citations). In the last 20 years, extreme 

drought (less than 50% of average annual rainfall) has occurred three times, with one event 

spanning two years (1995-1996), throughout the Arizona range of Sonoran pronghorn. Staff of 

Cabeza Prieta NWR evaluated rainfall averages from Organ Pipe Cactus NM, Ajo, and Tacna 

weather stations (Western Regional Climate Center 2014). Rainfall data from 1969 - 2003 

indicate average annual rainfall is 17.7 cm (6.97 in) for the three sites (Cabeza Prieta NWR

unpublished data). Annual rainfall was less than 50% of this average in 1995 (8.7 cm [3.43 in]), 

in 1996 (8.15 cm [3.21 in]), in 2002 (4.22 cm [1.66 in]), and in 2009 (6.76 cm [2.66 in]; Cabeza 

Prieta NWR unpublished data).

Livestock Grazing

Livestock grazing can cause reductions in forage quality by altering forage species abundance 

and composition. Cattle may compete with Sonoran pronghorn for forage; however, no studies 

have focused on dietary competition of cattle with the Sonoran subspecies of pronghorn, 

therefore we do not know the extent to which this may occur in areas where Sonoran pronghorn 

and cattle overlap. Yoakum (2004) reviewed the relationships of pronghorn (other subspecies) to 

livestock. Impact of livestock grazing on pronghorn habitat are complex, including modification 

of plant biomass, species compositions, and structure. He reviewed studies of dietary overlap of 

cattle with other subspecies of pronghorn (none were available for the Sonoran subspecies). Of 

these 13 studies, three found a high (>25%) overlap of forbs, and two found a high overlap of 

shrubs. Overlap of forbs ranged from 0.2 -19.0%, and overlap of shrubs ranged from 0-39%. 

Overlap of grasses (which are not reported to be a significant portion of Sonoran pronghorn 

diets) ranged from 0-46.3%, with only one study reporting overlap >10%. The vegetation and 

pronghorn diet in these study areas differ considerably from that in the range of the Sonoran 

pronghorn. Competition between pronghorn and cattle can potentially occur on a seasonal basis 

or during drought conditions and has been reported in New Mexico and Texas (Yoakum 2004). 

Kie et al. (1994) suggest indirect impacts include “ 1) gradual reductions in the vigor of some 

plants and in the amount and quality of forage produced, 2) elimination or reduction of the 

ability of forage plants to reproduce, 3) elimination of locally important cover types and 

replacement by less favorable types or communities, either by direct actions over time or by 

changing the rate of natural succession process, and 4) general alterations and reduction in the 

kinds, qualities and amounts of preferred or otherwise important plants through selective grazing 

or browsing or other activities.” Yoakum (2004) stated “Possibly the greatest impact of 

livestock grazing on pronghorn populations has been changes in plant succession and intensive 

foraging on fawning areas.” To what extent any of these effects reported in other pronghorn 

subspecies occur in the range of the Sonoran pronghorn species remains unknown.
Sonoran Pronghorn Recovery Plan, Second Revision

53

Displacement of pronghorn by cattle has not been studied in Sonoran pronghorn. Based on other 

subspecies, it appears possible but unlikely, as Yoakum (2004) reports most of nine studies 

focusing on pronghorn/cattle interactions have reported on nonaggressive association, although 

one study reported pronghorn avoid pastures with cattle. 

For more information on historical livestock grazing, which likely had severe impacts on forage 

quality, see the livestock grazing source of “habitat loss” above. Livestock grazing is no longer 

permitted on the Cabeza Prieta NWR, BMGR, Organ Pipe Cactus NM, or Kofa NWR. The 

BMGR was closed to livestock use in 1941 (Executive Order 8892), although trespass grazing 

occurred, at least sporadically, until the late 1970s (U.S. Fish and Wildlife Service 2006). Cattle 

were removed from Organ Pipe Cactus NM in 1978 (U.S. Fish and Wildlife Service 1998) and 

Cabeza Prieta NWR in 1981 when the last permit expired (U.S. Fish and Wildlife Service 2006). 

However, trespass cattle, horses, and burros from BLM, the Tohono O’odham Nation, private 

lands, and Mexico continue to graze the closed areas. 

Burros, in particular, appear to be expanding in numbers, particularly in the BMGR (east of 

Highway 85), and have caused observable damage to native vegetation (U.S. Department of the 

Air Force and U.S. Department of the Navy 2012). Competition for forage between burros and 

Sonoran pronghorn has not been studied, but diet of burros at Sheldon NWR in Nevada 

overlapped 25% with American pronghorn (6.8% overlap of shrubs, 8.8% overlap of forbs, and 

9.9% of grasses). Trespass burros in the area do not fall under Wild Free-Roaming Horses and 

Burros Act of 1971, as amended. To be considered "wild" and therefore covered under The Act, 

the animals had to have been documented in the area at the time The Act was passed. Because 

donkeys or horses were not observed in the area at that time, no herd area was established. 

Therefore, any cattle, horses, or donkeys not authorized under a grazing permit are in fact 

considered to be "estrays" and in trespass. Trespass livestock are covered under 43 CFR Subpart 

4150, which has provisions for their removal. Burros also occur in El Pinacate Biosphere 

Reserve mainly on the mountainous part of the area. The Bioreserve has been working to control

the population of these equines and is trying to eradicate them from the area.

Livestock grazing on BLM-administered land is an accepted and valid use under the Taylor 

Grazing Act of 1934, the Federal Land Policy and Management Act of 1976, and the Public 

Rangelands Improvement Act of 1978. Under these Acts public rangeland is managed to meet 

Standards of Rangeland Health (43 CFR 4180), and are subject to ESA Section 7 consultation 

with FWS. BLM livestock grazing allotments may be issued as perennial, ephemeral, or a 

combination of perennial-ephemeral. Perennial allotments have an authorized base herd stocking 

rate that may be grazed annually on the allotment. On ephemeral allotments, authorization for 

grazing is discretionary, based on forage conditions and other factors. Permittees with perennialephemeral allotments may graze their base herd each year, and apply to graze additional animals 

based on annual forage conditions. 
Sonoran Pronghorn Recovery Plan, Second Revision

54

Allotments within the range of the Cabeza Prieta pronghorn population are the Cameron, Coyote 

Flat II, and the Childs allotments. The Coyote Flat II and Childs allotments, which are east of the 

Cameron, are available for livestock grazing. The Coyote Flat II Allotment permits 31 cattle on a 

year-round basis, while the Childs Allotment authorizes 320 cattle on a year round basis. Both 

allotments are designated as perennial/ephemeral, which means that, when conditions warrant (a 

robust ephemeral bloom is present due to substantial rainfall) permittees can apply to turn out 

additional cattle for a limited time. In 2004, the BLM amended the Lower Gila South RMP to 

discontinue livestock grazing on the Cameron Allotment, which is directly east and adjacent to 

the Cabeza Prieta NWR, and manage it in a manner that emphasizes Sonoran pronghorn 

recovery (U.S. Fish and Wildlife Service 2004). The BLM upheld the closure of the Cameron 

Allotment to livestock grazing in its 2012 Lower Sonoran Record of Decision and Approved

RMP, and continues to coordinate efforts with Cabeza Prieta NWR to address and manage 

Sonoran pronghorn habitat on BLM lands (Bureau of Land Management 2012a). 

RMP revisions in 2010 for Yuma Field Office and 2012 for Lower Sonoran Field Office show 28 

BLM grazing allotments were included in the Kofa portion of the nonessential experimental 

population area: 20 active allotments, and 8 closed allotments (Bureau of Land Management

2010, 2012). All 28 allotments contained at least some potential habitat according to the CART 

model (O'Brien et al. 2005, U.S. Fish and Wildlife Service 2010a). About 27 % of the Kofa 

portion of the nonessential experimental population area (Area A in U.S. Fish and Wildlife 

Service 2010a) occurs within BLM livestock grazing allotments (Figure 13). RMP revisions in 

2012 for Lower Sonoran Field Office show portions of four open BLM ephemeral and 

perennial/ephemeral grazing allotments (Stout, Bighorn, Childs, and Santa Rosa) in the Sauceda 

portion of the nonessential experimental population area; other BLM managed lands within the 

Sauceda portion of the nonessential experimental population are not allocated for grazing 

(Sonoran Desert National Monument). About 8% of the Sauceda portion of the nonessential 

experimental population area occurs within BLM livestock grazing allotments. It is too soon to 

tell if Sonoran pronghorn recently released on the BMGR will disperse to these allotments.

Livestock grazing also occurs in the Quitovac area and the El Pinacate Biosphere Reserve. 

Although we have no estimate of the number of livestock in Quitovac, there are approximately 

250 cattle in the El Pinacate Biosphere Reserve. The Recovery Team is not aware of quantitative 

evaluations, but field observations suggest grazing impacts are severe in some areas occupied by 

the Quitovac population.
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MARIANI

GILA BEND

INDIANS

q Coordinate System: WGS 1984 | UTM Zone: 12N

Projection: Transverse Mercator

Linear Unit: Meter | Scale: 1:750,000

Basemap: Esri, DeLorme, USGS, NPS

Produced By: L. Urreiztieta, 

Harris Environmental Group, Inc. June 2016

Active BLM Grazing Allotments - Area A (831,171 acres/27%)

Kofa/Area A (3,066,641 acres)

BLM Field Office Boundaries

0 10 20 30 40

Kilometers

YUMA FIELD OFFICE

LOWER SONORAN FIELD OFFICE

0 5 10 15 20

Miles

Figure 13. BLM grazing allotments within the Kofa portion of the nonessential population area (Area A in FWS 2010a), Arizona, U.S.
Sonoran Pronghorn Recovery Plan, Second Revision

56

Extreme heat

Extreme heat can also kill quality forage or prevent growth of quality forage. Extreme heat is 

believed to be caused by climate change, as discussed in the “Climate Change” section above.

Extreme heat desiccates forage plants in washes and increases the potential for fire.

Altered hydrology

Changes in hydrology may reduce the water available to forage species even if precipitation is 

suitable. Hydrology may be altered by roads and development and other impervious surfaces. 

Hydrology may also be altered by trails and routes used by human and drug traffickers as well as 

by border enforcement efforts and recreational off-road driving, including off-road racing near 

Rocky Point in Sonora. By increasing soil compaction and altering runoff patterns, roads, 

building, trails, and routes may cause rainwater runoff to flow more quickly rather than penetrate 

the soil and provide for growth of forbs. They may also cause sheet flows to be redirected. 

Altered Fire Regimes

Fires burn creosotebush, which is a very competitive species, and create openings for plants that 

are more valuable as forage for pronghorn. On the other hand, in spring after average winter 

rains, growth of forbs (pronghorn forage) is typically tallest and most dense around and under 

creosote, because of the creosote’s shading effect creating a slightly cooler/moister microclimate.

In the first year or two after a fire, the remaining ash increases nutrient levels in the soil, 

resulting in higher quality forage, if it rains. These post-fire conditions may improve Sonoran 

pronghorn recruitment for a few years. 

Fire can be beneficial initially, but has the potential to become harmful in the long run by 

increasing invasive species (e.g., buffelgrass [Pennisetum ciliare], fountain grass [Pennisetum 

setaceum], and schismus grass [Schismus barbatus or S. arabicus]). Fire can also have adverse 

effects by causing mortality of ironwood, mesquite, paloverde, and other desertscrub 

trees/shrubs, which provide thermal cover and browse. The Sonoran desert is not considered a 

fire-adapted ecosystem and some of these invasive species provide fine fuels that may encourage 

more frequent and larger fires, perpetuating a cycle of fire and spread of invasive species 

(Arizona-Sonora Desert Museum 2013, 2014a, 2014b). 

However, the historical role of fire in the Sonoran Desert may have been underestimated. Early 

newspaper accounts documented large fires in Sonoran desertscrub areas in the eastern portion of 

the historical range of Sonoran pronghorn, such as the Avra Valley and near Redrock, prior to 

cattle being ubiquitous on the landscape (Bahr 1991, Brown and Glinski 2009). These fires were 

sporadic and made possible by the large flush of annual grasses and forbs after wet winters and

largely ceased after approximately 1890. The fires returned, again at infrequent intervals, after 

1975, when cattle were no longer ubiquitous in the desert and when winter rains brought a flush 

of spring annuals, such as an event along the Florence Highway that occurred in the 1980s (D. 

Brown, Arizona State University, personal communication, 2013). The first of these more recent
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57

fires was attributed to red brome, and a concern was raised that annual exotics were bringing a 

new threat to the Sonoran Desert. Since then, however, fires within the Sonoran Desert have 

been also been attributed to other annual plants, including native annuals such as plantains 

(Plantago sp.) and Hordeum sp. (D. Brown, Arizona State University, personal communication, 

2013). The AGFD consulted with the Tohono O’odham Nation prior to initiating the first 

Sonoran pronghorn forage plots for the Air Force. During these discussions tribal members 

described using fire as a tool to clear unwanted vegetation to facilitate planting crops (J. Hervert, 

AGFD, personal communication, 2013).These historical fires may have occurred in areas of 

creosotebush and in grassland areas within the Sonoran Desert. An old photo shows a fire in 

creosotebush-dominated landscapes taken on the stagecoach route between Gila Bend and Ajo 

(D. Brown, Arizona State University, personal communication, 2013). 

The role of fire in Sonoran pronghorn habitat is complex, and its beneficial or detrimental effects 

on forage and Sonoran pronghorn remain unknown. 

Increase in Creosotebush 

Creosotebush may be more dominant now compared to 100-200 years ago due in part to a lack 

of fire, coupled with cattle grazing (J. Hervert, AGFD, personal communication, 2013). Cattle 

grazing removed fine fuels such as grasses, contributing to the lack of fire. Creosotebush is not 

fire tolerant and the removal or reduction of grasses may have inhibited natural and human 

caused fires that would kill creosotebush. As a result, creosotebush dominance may be 

increasing, resulting in a conversion of vegetation to associations less favorable for pronghorn (J. 

Hervert, AGFD, personal communication, 2013).

Invasive plants

Invasive plant species that are currently established within the range of Sonoran pronghorn and 

which could compete with forage plants include Sahara mustard, Schismus grass, red brome, 

fountain grass and buffelgrass. Each of these invasive species could affect Sonoran pronghorn 

forage through direct competition, alteration of the fire regime, or by depleting soil fertility. 

As of 2016, invasive plants are not thought to be a significant threat to Sonoran pronghorn but 

monitoring is warranted to ensure this potential threat does not increase. Sahara mustard is most 

abundant in the Lower Colorado River Valley of Arizona. It grows very fast, smothering native 

herbaceous plants and competing with shrubs for light and soil moisture (Arizona-Sonora Desert 

Museum 2014b). However, although it may threaten native forage plants, it can be used as forage 

by Sonoran pronghorn. Sahara mustard has a high oxalic acid content (Arizona-Sonora Desert 

Museum 2014b), which may affect its nutritional value. Schismus grass is an annual grass native 

to southern Europe, northern Africa, and the Near East and now is widely distributed in areas 

with Mediterranean climates (California Invasive Plant Council 2014). In Sonoran pronghorn 

range it is abundant in the Lower Colorado River Valley. It is particularly abundant where 

grazing, off-road-vehicle use, or construction of linear corridors has reduced shrub cover and 

disturbed the soil (California Invasive Plant Council 2014). Red brome is an introduced, early 
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58

emerging annual grass that is native to the Mediterranean region; it is now widely distributed in

patches across Western States (U.S. Department of Agriculture 2012). It is not abundant in the 

Lower Colorado River Valley portions of the range, but is common in parts of Arizona Upland. 

Red brome is a fine-fuel source that decomposes slowly and greatly increases the fire potential, 

intensity, and burn speed in areas where it has invaded (U.S. Department of Agriculture 2012). 

As with red brome, fountain grass is most abundant in Arizona Upland, and less abundant in 

Lower Colorado River Valley. Fountain grass can form dense stands and aggressively competes 

with native species, especially perennial grasses and seasonal annuals, for space, water, and 

nutrients (Arizona-Sonora Desert Museum 2014a). Fountain grass is adapted to fire and provides 

fuel that can spread fire (Arizona-Sonora Desert Museum 2014a). 

Buffelgrass is most common along highways in the Arizona Upland areas in Arizona and 

Sonora, but is expanding into lower, hotter, drier desertscrub in the Lower Colorado River 

Valley to the west (Van Devender and Dimmit 2006). It was fairly well controlled in Organ Pipe 

Cactus NM from the mid-1990s to mid 2000s, but efforts were curtailed due to border-related 

security concerns and it has expanded since then. Also during that time, buffelgrass advanced 

from being established mainly on flat terrain with deep soils, to colonizing rocky slopes as well. 

Organ Pipe Cactus NM also has been conducting volunteer-run surveys for buffelgrass since the 

mid 1990s; in 2011, buffelgrass was reported at 208 sites and more than 11,000 plants were 

removed in the surveyed area (Rutman 2011). Most of these sites (48.1%) contained single plants 

or small patches of less than ten plants. A small percentage (2.4%) of sites were large, containing 

more than 1,000 plants (Rutman 2011). Large stands exist in some traditional pronghorn use 

areas like Acuna Valley, Pozo Nuevo area, and the west slopes of Bates Mountains (Tim 

Tibbitts, Organ Pipe Cactus NM, personal communication, 2015). On Cabeza Prieta NWR, 

buffelgrass is distributed sporadically, but one or two wet seasons will allow it to increase 

significantly. It is present along the Camino (Cholla Pass, Papago Well, and Growler Valley 

Trail) (Tim Tibbitts, Organ Pipe Cactus NM, personal communication, 2015). In Sonora, it is 

distributed continuously along Mexico Hwy 2, but is less common away from roads (Van 

Devender and Dimmit 2006).

This plant crowds out native plants of similar size and competes for water, which can weaken 

and kill larger desert plants (Arizona-Sonora Desert Museum 2013). This plant spreads fire 

rapidly through non-fire adapted ecosystems. There is also growing evidence that buffelgrass 

depletes soil fertility in a decade or so then dies and leaves behind a sterile wasteland (ArizonaSonora Desert Museum 2013). Current and historical planting of buffelgrass in Sonora for 

livestock has heavily altered some vegetation communities in the state. Van Devender and 

Dimmit (2006) found very little evidence of buffelgrass burning when it is interspersed in natural 

vegetation in Arizona, but found in Sonora, where roadside buffelgrass is typically much denser 

than in Arizona, roadsides burn intensely and often. Outside of roadside areas, heavy cattle 
Sonoran Pronghorn Recovery Plan, Second Revision

59

grazing appears to have effectively controlled buffelgrass in Sonora (Van Devender and Dimmitt 

2006).

Erosion

Erosion may damage or destroy forage. Sources of erosion include trails and routes, illegal offhighway vehicle use, off-highway races, highways, and land use changes within the same 

watersheds as Sonoran pronghorn habitat, as well as heavy grazing in Sonora.

Lack of pollination

The Recovery Team brainstormed potential causes of reduced forage while conducting 

conceptual modeling of threats (Appendix A). One hypothesized cause of reduced availability of 

forage species for Sonoran pronghorn may be lack of pollination. The Recovery Team also 

hypothesized that lack of pollination is caused by a reduction in the number of pollinators,

primarily insects. The existence, severity, and scope of this potential stressor across the range of 

Sonoran pronghorn are unknown.

Altered Habitat Structure

Vegetation structure is also critical to Sonoran pronghorn survival. While Sonoran pronghorn 

need open areas to visually detect predators, they also need areas of dense vegetation that 

provide hiding cover for fawning, and thermal cover to shelter them from the hottest 

temperatures of the year. Therefore a mosaic of open and densely vegetated areas is necessary to 

meet the needs of Sonoran pronghorn. That mosaic must provide the correct vegetation structure 

in the right places to support this highly nomadic species. In general, vegetation structure is 

becoming too dense due to invasion of shrubs in most places, although in some areas hiding 

cover and thermal cover have apparently become limiting (J. Hervert, AGFD, personal 

communication, 2014). 

Fire

As discussed in the reduced forage quality section above, the Sonoran Desert is widely believed 

to have evolved without fire (Arizona-Sonora Desert Museum 2013; 2014a; 2014b). Fire in 

Arizona Upland portions of the Sonoran Desert was considered historically uncommon due to 

the lack of fine fuels. Some Sonoran Desert plants, cactus in particular, and some perennial trees 

and shrubs are intolerant of fire and are killed wherever fire occurs. Nonnative perennial and 

annual plants that have increased fine fuels have allowed fire to become a much more frequent 

event in parts of the Sonoran Desert (Arizona-Sonora Desert Museum 2013;2014a;2014b). These 

fires create a more open vegetation structure, and reduce the vertical diversity of plants present 

(Krausman et al. 2005). In some areas, this opening of vegetation structure would benefit 

pronghorn by providing greater visual openness that enables detection and escape from 

predators. After large fires in 2005, staff of BMGR noticed pronghorn were using the burned 

areas, in part due to the increased visual openness caused by the fire, which enables detection of 
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60

predators from long distances (A. Alvidrez, BMGR, personal communication, 2014). Krausman 

et al. (2005) reported that Sonoran pronghorn used blocks that had some fire damage 

significantly more than they used unburned blocks, and 46% of l,203 locations of Sonoran 

pronghorn occurred in blocks that had been burned. 

However, fire could also be detrimental to pronghorn habitat by reducing or eliminating thermal 

cover and reducing or eliminating hiding cover for fawns and does. Sonoran pronghorn 

recruitment has been low in burned areas on the BMGR, and it has been hypothesized that the 

open vegetation structure of burned areas has increased predation pressure on fawns (J. Hervert, 

AGFD, personal communication, 2013). 

Fire can therefore be a threat or a benefit to vegetation structure depending on where and when it 

occurs. Careful consideration of the mosaic of vegetation structures needed for various seasonal 

needs of pronghorn are needed in evaluating the effects of fire. 

Livestock Grazing

Excessive livestock grazing can encourage shrub growth, which creates conditions where 

vegetation is too dense for pronghorn to be able to see predators (Brown and Ockenfels 2007). 

Cattle may compete with Sonoran pronghorn for preferred thermal cover; however, no studies 

have focused on this topic, therefore we do not know the extent to which this may occur in areas 

where Sonoran pronghorn and cattle overlap. In American pronghorn, cattle have been reported 

to displace does from fawning areas (McNay and O’Gara 1982), although it is not known if it is 

due to direct interference or alteration of vegetation. In one study on the effects of cattle 

exclusion on vegetation hiding cover for American pronghorn on the Anderson Mesa in Northern 

Arizona, areas where cattle were excluded had 8% more vegetation cover when measured 5m 

from random sample points, but no difference was found when cover was measured at 10m or 

25m from sample points. The vegetation in this study is different than that in Sonoran pronghorn 

range so it is uknown if cattle grazing affects hiding cover for Sonoran pronghorn fawning. For 

more information on where livestock grazing occurs in Sonoran pronghorn habitat, see the 

livestock grazing section under reduced forage quality, above.

Military training

Military training operations may cause fire or modify habitat. Removal of shrubby vegetation 

creates a more open habitat structure, which may be beneficial or detrimental to pronghorn 

depending on where it occurs. On all of BMGR East (including outside of current pronghorn 

range), about 5,594 ha (13,822 ac) have moderate to complete surface disturbance. About 48,995 

ha (121,069 ac) have negligible to low disturbance. The remaining 371,190 ha (917,230 ac) of 

BMGR East are undisturbed by military activities.
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61

Each year BMGR has wildland fires that are typically only associated with military training 

targets and the surrounding vegetation. In a given year, BMGR East has 15 to 30 fires and most 

are about approximately 0.04 ha (0.1 ac). These fires usually burn themselves out quickly (A. 

Alvidrez, BMGR, personal communication, 2014). However, in the summer of 2005, BMGR

East had two large complex fires that burned 15,974 ha (39,472 ac) of pronghorn habitat. After 

the wildland fires, BMGR staff noticed that pronghorn used the burned areas, likely for the postfire vegetation flush and the visual openness allowing detection of predators from long distances 

(A. Alvidrez, BMGR, personal communication, 2014).

Renewable energy

Although only large renewable energy developments are likely to remove significant habitat (see 

habitat loss section), installation of power lines and other structures associated with renewable 

energy creates visual barriers for pronghorn, altering the physiognomy of the habitat. These 

structures may limit the ability of pronghorn to detect and flee from predators. 

Mining

Conceptual modeling conducted by the Recovery Team hypothesized that mining can indirectly 

alter vegetation structure in Sonoran pronghorn habitat adjacent to the mines. The Recovery 

Team hypothesizes that mining may alter runoff patterns and create more dense vegetation in 

some areas. The Recovery Team conceptual models also hypothesize that pumping of 

groundwater for mines may lower water tables which will impact vegetation. In addition, mining 

activities often introduce invasive species through mineral transportation to and from the mine. 

An additional impact of mining is the salvage and relocation of individual plants to areas outside 

the mining footprint at La Herradura. These relocated plants may compete with the established 

plants in native vegetation communities for space and nutrients. The impact may be large 

because hundreds of thousands of individual plants have been introduced to thousands of 

hectares of habitat bordering the mine, resulting in modification of vegetation composition and 

structure.

Illegal extraction

Illegal extraction of native vegetation, particularly mesquite and ironwood, occurs frequently in 

the El Pinacate Biosphere Reserve. In some areas of Pinacate, arroyos have lost all xeroriparian 

(ephemeral drainage) vegetation and are now denuded (Areas Naturales Protegidas 1995). Cholla 

is also illegally exploited for fencing, and visitors to the biosphere reserve often illegally take 

cactus (Areas Naturales Protegidas 1995). These illegal extractions have altered the vegetation 

composition and structure of the biosphere reserve in some places.
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ESA Listing Factor B: Overutilization for Commercial, Recreational, Scientific, or 

Educational Purposes 

After listing in 1967, take of Sonoran pronghorn became a prohibited activity in the U.S. under 

the ESA. Additionally, Arizona state statutes, including A.R.S. 17-314 and Commission Rules, 

effectively prohibit recreational hunting of the Sonoran pronghorn. In Sonora it is illegal to hunt 

Sonoran pronghorn under the General Wildlife Law because they are listed as a species-at-risk 

under Norma Oficial Mexicana-059 (NOM-059-SEMARNAT-2010). Sonoran pronghorn are not 

hunted commercially or recreationally in either country. 

Both aerial and ground surveys are conducted for scientific purposes by agencies in both Mexico 

and the U.S. and may result in temporary disturbance to pronghorn. Additionally, both wild and 

pen-raised Sonoran pronghorn are periodically captured, restrained, have blood drawn, and 

outfitted with radio telemetry collars for research studies and relocations. Currently, wild 

pronghorn are infrequently captured. In contrast, pen-raised pronghorn are regularly handled, as 

they must be captured to release them from the breeding pens. Capture -related mortality has 

occurred during capture of wild and pen-raised pronghorn. As a result, changes to the capture 

protocol for both wild and captive animals have been implemented and capture -related mortality

has been greatly reduced. Research and management is strictly regulated pursuant to section 10 

of the ESA. 

No take of wild Sonoran pronghorn for educational purposes occurs.

ESA Listing Factor C: Disease or predation

Predation

Predation accounts for 37% of adult Sonoran pronghorn mortalities observed from 1995–2002 

(Bright and Hervert 2005). Of 12 mortalities attributed to predation, 6 were from coyotes (Canis 

latrans), three from bobcats (Lynx rufus), two from mountain lions (Puma concolor), and one

from an undetermined predator (Bright and Hervert 2005). Most predation has occurred in winter 

when coyotes hunt in packs (Bright and Hervert 2005). Fatalities from predation were more 

common in the “paloverde chainfruit cholla association”than would be expected based on 

availability of the associations. Of predation fatalities documented, 75% occurred in “paloverde 

chainfruit cholla association” This association has tall, dense vegetation that may place 

pronghorn at a disadvantage because they cannot easily see or flee from predators (Bright and 

Hervert 2005).

Coyote predation has been reported as a major cause of fawn mortality in other pronghorn 

subspecies, and coyotes are thought to prey heavily on Sonoran pronghorn fawns. The evidence 

for this is mostly inferred and consists primarily of several observations during aerial telemetry 

surveys of females with a newborn fawn(s) and one or more coyotes nearby. Subsequent surveys 
Sonoran Pronghorn Recovery Plan, Second Revision

63

one to two weeks later located the female but only one or no fawns (Arizona Game and Fish 

Department Sonoran pronghorn weekly radio telemetry forms, 1994-2001) (U.S. Fish and 

Wildlife Service 2006). However, it was not reported as a primary factor in mortality of Sonoran 

pronghorn fawns during the 1995-2002 investigation when nutritional factors appeared more 

important (Bright and Hervert 2005). Sonoran pronghorn females with fawns use washes, which 

are also preferred by bobcats primarily during dry conditions, but it has not been determined if 

bobcat predation is responsible for fawn fatalities (Bright and Hervert 2005).

Since 2005, the Recovery Team has noticed higher fawn mortality than expected. This is 

especially true in the burned areas of the Tactical Ranges where the cover fawns may use to 

avoid predation has been removed by fire. The causes of these fatalities have not been 

investigated; however, increases in fawn mortality may be due to a variety of factors, including 

reduced cover on the military tactical ranges due to wildland fires, reduced forage quality and 

environmental conditions due to climate change, increased cover of invasive vegetation, and 

increased predation rates.

Disease 

Diseases documented in Sonoran pronghorn include bluetongue and epizootic hemorrhagic 

disease (U.S. Fish and Wildlife Service 2010b). Blood samples from five Sonoran pronghorn 

captured in December 2000 were evaluated by the Arizona Veterinary Diagnostic Lab at the 

University of Arizona (UA) for evidence of epizootics. All five samples tested positive for 

bluetongue and epizootic hemorrhagic disease antibodies (U.S. Fish and Wildlife Service 2002). 

Bluetongue, or catarrhal fever, is caused by the pathogenic virus Orbivirus. The disease typically 

causes death only in cases where the infected animal is weak or stressed. Hosts include domestic 

cattle. It is transmitted by biting flies or gnats (Culicoides spp) (Thomas 1981). The Culicoides 

vector requires damp, humid substrates for larval development and adult emergence, a condition 

that may only exist in Sonoran pronghorn habitat around some dirt stock tanks or in wet years 

when water persists in playas and other natural collection basins for extended periods (U.S. Fish 

and Wildlife Service 2010b). Epizootic hemorrhagic disease is caused by a similar Orbivirus that 

is closely related to the bluetongue virus. Susceptible hosts include all ruminants, including 

white-tailed deer, which are highly susceptible to infection, and cattle, which rarely show signs 

of the disease (Thomas 1981). An adult male pronghorn fatality in the captive breeding pen at 

Cabeza Prieta NWR on 9 August 2007 during the monsoon season was attributed to epizootic 

hemorrhagic disease (Sonoran Pronghorn Recovery Team 2007). Like bluetongue, the vector for 

transmission of epizootic hemorrhagic disease are Culicoides biting flies or gnats, which require 

a humid substrate (e.g., weedy margin of a stock tank) to complete its life cycle. Adults emerge 

during the hot and humid monsoon season (Sonoran Pronghorn Recovery Team 2007).
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Potential disease transmission between cattle and pronghorn is possible where they coexist. Any 

Sonoran pronghorn that are handled (such as during capture operations) in the U.S. are 

vaccinated, but not in Mexico, where cattle and pronghorn have been observed using the same 

water sources.

Lack Of Genetic Diversity 

Effects of prolonged isolation, population crash, and ensuing bottleneck experienced by Sonoran 

pronghorn likely caused a loss of genetic diversity. While bottlenecks and loss of genetic 

diversity can negatively impact breeding success, recruitment, and survival, recent studies have 

indicated that the current genetic diversity of sampled Sonoran pronghorn populations is within 

acceptable parameters. 

In one older study, Sonoran pronghorn exhibited lower levels of genetic diversity than all other 

subspecies of pronghorn, except the peninsular pronghorn, which was not measured (Stephen et 

al. 2005). In that study, the Sonoran pronghorn population in the U.S. had lower diversity than 

the Sonoran pronghorn population in Mexico. Both populations exhibited low levels of 

haplotypic and allelic diversity (Stephen et al. 2005). Average number of alleles per locus 

measured by Stephen et al. (2005) was 4.4 for both Mexican and U.S. populations of Sonoran 

pronghorn. In contrast, the average number of alleles per locus for other pronghorn subspecies 

ranged from 4.6 to 8.6 (Stephen et al. 2005). Heterozygosity was 0.573 in Mexico and 0.502 in 

the U.S for Sonoran pronghorn; but ranged from 0.583 to 0.734 in other subspecies (Stephen et 

al. 2005). 

More recently, Munguia-Vega et al. (2013) analyzed microsatellite loci from Sonoran and 

peninsular pronghorn. The data indicated a lower mean observed heterozygosity for peninsular 

pronghorn than for Sonoran pronghorn (0.31 and 0.48, respectively), and lower mean number of 

alleles per locus for peninsular pronghorn versus Sonoran pronghorn (2.050 and 4.86, 

respectively). The data for Sonoran pronghorn indicated that all of the loci for Sonoran 

pronghorn were polymorphic (Munguia-Vega et al. 2013). The mean number of alleles per locus 

was 4.86 (range 2–8), and observed heterozygosity ranged from 0.13 to 0.78 (mean 0.48) 

(Munguia-Vega et al. 2013). They did not find significant linkage disequilibrium among loci 

pairs, and no loci deviated significantly from Hardy–Weinberg equilibrium (Munguia-Vega et al. 

2013). 

Culver and Vaughn (2015) of the Arizona Cooperative Fish and Wildlife Research Unit and the 

University of Arizona investigated genetic diversity, inbreeding, effective population size, and 

relatedness within both captive and recently re-established wild populations. They found 

observed heterozygosity for Sonoran pronghorn in 10 population segments ranged from 0.54 for 

scats collected from Barry M. Goldwater Range East to 0.68 for animals sampled during captures

in the South Pen at Cabeza Prieta NWR and at the Kofa NWR pen. Allelic richness ranged from 
Sonoran Pronghorn Recovery Plan, Second Revision

65

1.85 for scats collected from Barry M. Goldwater Range East to 3.77 for animal released at Kofa 

NWR. Eight samples were obtained from Mexico but may not have sampled both Quitovac and 

Pinacate populations. This study did not find evidence of significant inbreeding, but did find an 

increase in inbreeding in the captive population at Cabeza Prieta NWR from 2009-2012.

These studies indicate that although genetic diversity of Sonoran pronghorn is less than other 

subspecies in the U.S., the subspecies is more genetically diverse than the peninsular pronghorn, 

and genetic diversity in Sonoran pronghorn within the U.S. is not currently low enough to be an 

immediate concern. However, more samples are needed to adequately assess genetic diversity, 

particularly in the wild Arizona population and the Quitovac and Pinacate populations of 

Mexico. In addition, continued monitoring of the trend in genetic diversity is needed to 

determine if it is declining, and therefore a threat to the subspecies or individual populations.

ESA Listing Factor D: Inadequacy of Existing Regulatory Mechanisms 

The Sonoran pronghorn and its habitat are generally protected by numerous laws throughout its 

range. In some cases laws may not be adequate to prevent habitat loss and fragmentation; 

however, the larger threat is lack of funding and enforcement of existing laws. Therefore, the 

FWS generally does not consider lack of existing regulatory mechanisms a primary threat to 

Sonoran pronghorn. 

All subspecies of Antilocapra americana are listed on the Convention on International Trade in 

Endangered Species of Wild Fauna and Flora (CITES) Appendix 1, but only populations in 

Mexico are included (Convention on International Trade in Endangered Species of Wild Flora

and Fauna 2014). CITES is a treaty established to prevent international trade that may be 

detrimental to the survival of plants and animals. Generally, both import and export permits are

required from the importing and exporting countries before an Appendix I species may be 

shipped, and Appendix I species may not be exported for primarily commercial purposes. CITES 

permits may not be issued if the export will be detrimental to the survival of the species or if the 

specimens were not legally acquired. However, CITES does not itself regulate take or domestic 

trade.

Laws Protecting Sonoran Pronghorn In The U.S.

The Sonoran pronghorn has been federally protected in the U.S. since 1967 and is protected by 

the ESA. Pursuant to the ESA, it is unlawful to import or export, take, possess, or sell any 

endangered or threatened species. Under section 7 of the ESA, federal agencies must consult 

with U.S. Fish and Wildlife Service on their proposed actions that may affect the endangered 

Sonoran pronghorn. Any Sonoran pronghorn that occur outside of the nonessential experimental 

population in the U.S. are considered endangered. Habitat for the endangered population in the 

U.S. is primarily federally-owned and includes the Cabeza Prieta NWR, Organ Pipe NM, the 

BMGR, and BLM-administered lands.
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Sonoran pronghorn are also on AGFD’s list of “Species of Greatest Conservation Need” 

(Arizona Game and Fish Department 2012). The subspecies is protected by Arizona State 

Arizona state law (A.R.S. 17-314), and anyone convicted of unlawfully wounding or killing, or

unlawfully possessing an endangered species of wildlife may be subject to civil action by the

Arizona Game and Fish Commission in the form of license revocation and/or recovery of a 

minimum sum. 

Nonessential Experimental Populations

The reintroduced Sonoran pronghorn at Kofa and Sauceda are designated as a nonessential 

experimental population under section 10(j) of the ESA (U.S. Fish and Wildlife Service 2011a). 

Under section 10(j) of the ESA, the Secretary of the Department of the Interior can reestablish 

populations outside the species’ current range and designate them as ‘‘experimental.’’ With the 

experimental population designation, the relevant population is treated as threatened for purposes 

of section 9 of the Act, regardless of the species’ designation elsewhere in its range. Threatened 

designation allows discretion in devising management programs and special regulations for such 

a population. For the purposes of section 7 of the ESA, FWS treats members of a nonessential 

experimental population as a threatened species when the nonessential experimental population

is located within a National Wildlife Refuge or unit of the National Park Service, and section 

7(a)(1) and the consultation requirements of section 7(a)(2) of the Act apply. Section 7(a)(1) 

requires all federal agencies to use their authorities to carry out programs for the conservation of 

listed species. Section 7(a)(2) requires that federal agencies, in consultation with the Service, 

ensure that any action authorized, funded, or carried out is not likely to jeopardize the continued 

existence of a listed species. When nonessential experimental populations are located outside a 

National Wildlife Refuge or National Park Service unit, then for the purposes of section 7, FWS

treats the members of the population as proposed for listing, and only two provisions of section 7 

apply—section 7(a)(1) and section 7(a)(4). Section 7(a)(4) requires federal agencies to confer 

(rather than consult) with the Service on actions that are likely to jeopardize the continued 

existence of a species proposed to be listed. The results of a conference are in the form of 

conservation recommendations that are optional as the agencies carry out, fund, or authorize 

activities. Because the nonessential experimental population is, by definition, not essential to the 

continued existence of the species then the effects of proposed actions on the nonessential 

experimental population will generally not rise to the level of jeopardizing the continued 

existence of the species. As a result, a formal conference will likely never be required for 

Sonoran pronghorn established within the nonessential experimental population area. 

Nonetheless, the BLM has additional requirements in their policy manual (Manual 6840) that 

direct them to confer with the FWS on actions or activities that are likely to adversely affect the 

species. A map showing Sonoran pronghorn ESA status for section 7 consultation purposes is

shown in Appendix B.
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67

Laws Protecting Sonoran Pronghorn In Mexico 

In Mexico, there are a number of laws and regulations that directly or indirectly protect 

pronghorn. Some of these laws are discussed below. 

The Norma Oficial Mexicana NOM-059-SEMARNAT-2010, Protección ambiental-Especies 

nativas de México de flora y fauna silvestres-Categorías de riesgo y especificaciones para 

su inclusión, exclusión o cambio-Lista de especies en riesgo (NOM-059-SEMARNAT-2010), is 

a list of endangered species in Mexico. This law has no direct restriction regarding the protection 

of the listed species, but it includes the criteria for including, excluding, or changing the risk 

category for species or populations on the list, and it is related with other instruments of 

environmental protection. It has 4 categories:

• Probably extinct in the wild. (E – “Probablemente extinta en el medio Silvestre”)

• Endangered (P - “En Peligro de extinción”)

• Threatened (A - “Amenazadas”)

• Subject to special protection (Pr - “Sujetas a protección especial”)

The pronghorn is listed as Endangered on this list. This listing is for the entire species and 

therefore includes all subspecies within Mexico, including the Sonoran, peninsular, and Mexican 

pronghorn (Secretaría de Medio Ambiente y Recursos Naturales 2010).

In July 2014, the Priority Species List (ACUERDO por el que se da a conocer la lista de 

especies y poblaciones prioritarias para la conservación) of Mexico was published. It is not 

necessarily a list of species at risk, but rather a list of important species developed to promote 

efforts to maximize resources in conservation. Species may be considered important because, for 

example, they require large amounts of intact habitat, are charismatic, or are important to the 

public. Conservation of these species will enable conservation of many other associated species 

and biological communities. One of the priority species on this list is the pronghorn, including all 

the subspecies in Mexico. The list was created in accordance with the General Wildlife Law (see 

below) to promote the development of projects for the conservation and recovery of priority 

species. 

The General Wildlife Law (Ley General de Vida Silvestre [LGVS]; SEMARNAT 2000) has 

several restrictions that only apply to species at risk (i.e. species listed in the NOM-059-

SEMARNAT-2010), depending on their risk status. For example, it has strict provisions on the 

collection and capture of threatened and endangered species. It also contains general provisions 

on the sustainable use of wildlife; incentives for land owners; cooperation among federal, state, 

and municipal governments and private individuals; wildlife diseases; ethical use of wildlife; 

restrictions on exotic species, wildlife research and rehabilitation centers; wildlife use by 

indigenous people; environmental education; species at risk and their critical habitat; 

reintroduction and translocation protocols; scientific collection permits; control of nuisance 

species; and law enforcement investigations and citations (Valdez et al. 2006). Additionally, 
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68

under the LGVS, critical habitat for species at risk can be established. Critical habitat is habitat 

that requires special management and protection due to its importance to the survival of species 

at risk.

In addition, Federal Penal Law (Código Penal Federal) includes Artículo 420, which, among 

other things, assigns a fine and/or prison for illegally trafficking, capturing, transporting, or 

exporting species at risk (those listed in the NOM-059-SEMARNAT-2010) or species 

considered in international treaties signed by Mexico (i.e. CITES). Penalties increase in cases 

involving illegal activities in natural protected areas (e.g., El Pinacate Biosphere Reserve).

The General Act for Ecological Balance and Protection of the Environment (Ley General Del 

Equilibrio Ecológico y Protección al Ambiente [LGEEPA]) can protect habitat for pronghorn 

through ecological land zoning, environmental impact assessments, and establishment of natural 

protected areas. Exploration, extraction, and mining of minerals (as occurs at the La Herradura 

Mine) are among the activities requiring an environmental impact assessment (Szekely et al. 

2005). Natural protected areas can be one of eight types: biosphere reserves, national parks, 

natural monuments, areas for the protection of natural resources, areas for the protection of flora 

and fauna, sanctuaries, state parks and reserves, and ecological preservation zones in population 

areas. 

A recent federal law, Ley Federal de Responsabilidad Ambiental (Environmental Responsibility 

Law), recognizes damages to the environment and charges responsible parties for reparations and 

compensation of said damages. Its function is to protect, preserve, and restore the environment 

and ecological equilibrium, and to guarantee human rights to a healthy environment for the 

development and well-being of people. This law offers some opportunities to implement Sonoran 

pronghorn habitat restoration actions.

The State of Sonora also has a law that provides general protection for wildlife. The law of The 

Ecological Balance of The State of Sonora (Ley del equilibrio ecológico del estado de Sonora) 

aims to encourage sustainable development and provides some protection of wildlife and habitat.

ESA Listing Factor E: Other Natural or Manmade Factors Affecting Its Continued Existence

Human Disturbance

Human disturbance is defined here as the effects of the presence of humans, vehicles, and 

aircraft on Sonoran pronghorn. Human disturbance has the potential to affect the physiology, 

behavior, and ultimately, populations of Sonoran pronghorn. Available research evaluating 

physiological impacts of human stressors on wild animal populations indicates that the responses 

of species are variable (Manci et al. 1988, Larkin 1996, Radle 1998, Kaseloo and Tyson 2004, 

Stankowich 2008). For example, physiological effects of noise on wildlife can include stresses to 
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69

neural, endocrine, digestive, cardiovascular, and immune systems as well as reproductive 

function, causing changes such as increased blood pressure, available glucose, and blood levels 

of corticosteroids (Manci et al. 1988, Kaseloo and Tyson 2004, Keay et al. 2006). Sonoran 

pronghorn could experience physiological stress without exhibiting overt behavioral responses, 

making evaluation of human disturbance difficult. The occurrence of physiological stress in the 

absence of behavioral indicators of stress has been demonstrated in other species. For example,

investigators have recorded heart rate increases in wildlife in response to auditory or visual

disturbance in the absence of overt behavioral responses (Cherkovich and Tatoyan 1973). 

Behavioral responses to human disturbance can include flight and changes to activity budgets. It 

has been well documented that human presence can disturb animals, causing them to 

unnecessarily expend energy avoiding people (Kerley et al. 2002) or increasing the likelihood of 

fatal encounters with humans (Kerley et al. 2002). Range abandonment has been documented in 

response to human disturbance (Jorgenson 1988). Behavioral responses may also include altered 

time budgets; increased time spent fleeing or being vigilant reduces the time available for 

foraging or other important activities. For example, activity budgets of elk were altered during 

off-road recreation treatments, including increased travel time during most treatments, which

reduced time spent feeding or resting (Naylor et al. 2009). Responses to human disturbance are 

similar to predation risk in that both human disturbance and predation divert time and energy 

from other fitness-enhancing activities such as feeding, parental care, or mating displays (Frid 

and Dill 2002). The risk-disturbance hypothesis states that prey species may trade food for safety 

as they shift activity toward safer, but less rewarding food patches or heighten vigilance at the 

expense of feeding efficiency (Frid and Dill 2002). For example, mule deer have been observed 

to spend less time foraging, or abandon foraging in a patch before the forage is all utilized, and 

are more vigilant in risky areas (Altendorf et al. 2001). Human disturbance can also disturb 

social structure in some ungulates by decreasing group size and by causing groups to spend more 

time in vigilant behaviors and in larger groups than they would exhibit in the absence of human 

disturbance (Manor and Saltz 2003).

To have an effect on population size, physiological and behavioral responses to human 

disturbance must ultimately affect survival and productivity, and to date, no research efforts have 

supported or refuted population level impacts on Sonoran pronghorn from physiological stress. 

Bright and Hervert (2005) and deVos and Miller (2005) suggest that at some point, increased 

energetic costs resulting from a stress-related increase in metabolic rate, reduced foraging 

efficiency due to interrupted feeding, and alarm and flight responses could threaten survival and 

productivity if the disturbance is stressful enough and chronic.

Studies of captive pronghorn, other than the Sonoran subspecies, have reported that they are 

sensitive to disturbance such as human presence and vehicular noise. Human disturbance (e.g., a 

person walking or running past pronghorn in an enclosed pen, a motorcycle driving past, a truck 
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70

driving past, a truck blowing its horn while driving past, or a person entering a holding pen)

caused increased heart-rates in American pronghorn in 0.2 ha (0.5 ac) holding pens (Workman 

1992). The highest heart rates occurred in female pronghorn in response to a person entering a 

holding pen, or a truck driving past while sounding the horn. The lowest heart rates occurred 

when a motorcycle or truck was driven past their pen. Pronghorn were more sensitive to 

helicopters, particularly those flying at low levels or hovering, than fixed wing aircraft. Luz and 

Smith (1976) observed pronghorn reactions to overhead helicopter flights, which suggested mild

disturbance (muscle tensing and interruption of grazing) by helicopter noise levels at 

approximately 60 A-weighted decibels (dBA) and strong reaction (running) at approximately 77 

dBA. 

Sources of human disturbance in the Sonoran pronghorn range are varied. The primary sources

of human disturbance identified by the Recovery Team include border activities, military 

activities, mining, recreation, land management activities, ranching activities, and agricultural 

activities. Border activities, including both cross-border violator and U.S. Border Patrol (USBP)

activities, appears to be the most widespread source of increased human presence near the 

endangered U.S. population of Sonoran pronghorn. There is anecdotal evidence that pronghorn 

are avoiding areas of high cross-border violator traffic and law enforcement activities. For 

example, in spring of 2009, AGFD reported that they believe that three does with fawns 

abandoned the Granite Forage Enhancement Plot due to the high amount of USBP activity at the 

site (J. Hervert, AGFD, personal communication, 2009). The does were later observed at Organ 

Pipe Cactus NM; however, the fawns died (J. Hervert, AGFD, personal communication, 2009). 

Instances such as these are more likely to occur during periods of poor range conditions when the 

impacts are likely exacerbated, regardless of the source of disturbance or impact on the 

pronghorn. 

Staff at Organ Pipe Cactus NM observed potential disturbance events and pronghorn responses. 

Potential disturbance events were considered to be: 1) Fixed-wing aircraft flying within 1 mile 

laterally, below 1000 ft above ground level; 2) rotary-wing aircraft flying within 1.5 mile 

laterally, below 2000 ft above ground level; 3) motor vehicles approaching within 1 mile; 4) 

pedestrians approaching within 0.5 mile; or 5) predators noted within 500 ft. During this study 

they recorded six potential disturbance events and four visible responses by pronghorn (vigilance 

stance or running) during 1,500 minutes of observation in nine observation periods. By summing 

disturbances over all observation periods (1,500 minutes), Organ Pipe Cactus NM staff 

calculated the average rate of potential disturbances, and the average rate of pronghorn 

responses. During these observation periods, Sonoran pronghorn experienced some form of 

border-related potential disturbance once every 4 hours of observation. The pronghorn responded 

to the disturbances by running or becoming vigilant once every 6 hours 15 minutes of 

observation. Vehicles approaching within one mile occurred once every 12 hours 30 minutes of 

observation. Half of these vehicle approaches resulted in the pronghorn running, but for the other 
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half, the driver was contacted by radio and advised to drive slowly (< 16 km per hour [10 mph]) 

past the observation area. These observations led to speculation that the high levels of illegal 

border-related traffic in the area, and subsequent interdiction efforts, may have been sufficient to 

inhibit use of the area and 3-Jack Tank (a water development built for Sonoran pronghorn) by 

Sonoran pronghorn (Organ Pipe Cactus NM 2013).

Preliminary information from a study on the effects of human disturbance on Sonoran pronghorn 

indicates that pronghorn consistently exhibit visible responses to human activity, particularly to 

vehicles traveling on a road within several kilometers. Although some instances have been noted 

where a Sonoran pronghorn did not exhibit a visible response (for example, one buck did not 

appear disturbed by three vehicles driving at least 40 km per hour (25 mph) about 1.5 km [0.93 

mi] away); most observations indicate that Sonoran pronghorn stand vigilant or run from the 

stimulus. In some cases the response was to disturbances at a great distance. For example, eight 

Sonoran pronghorn were observed running a short distance and displaying vigilant behavior 

towards utility vehicle noise that was 3.4 km (2.1 mi) away. In other cases, the Sonoran 

pronghorn appeared to expend considerable energy fleeing from the disturbance. For example,

eight Sonoran pronghorn were observed running from several trucks traveling fast (> 25 mph). 

The pronghorn were initially vigilant when the vehicles were 1.3 km (0.8 mi) away but soon 

started running, travelling over 3.6 km (2.2 mi) in under five minutes until they were out of sight 

of the observers (S. Doerries, University of Arizona, personal communication, 2014).

Military activity is another source of human disturbance. Landon et al. (2003) evaluated whether 

Sonoran pronghorn used areas, as defined by noise levels produced by military aircraft, in 

proportion to their availability on the BMGR. Using 15% of the Arizona Sonoran pronghorn 

population, they studied pronghorn use of areas with varying sound pressure (ambient sound) 

levels and found that pronghorn did not use the areas with different ambient sound levels in 

proportion to their availability. In general, they found that Sonoran pronghorn select areas with 

the lower noise levels and avoid areas with the higher noise levels; however, they did not 

consider habitat in their analysis. Whether pronghorn avoid these areas because of the noise or 

because of some other human-related factor is unknown; however, the various potential factors 

(i.e. noise levels, human presence, reduced vegetation or cover, disturbance) are interrelated. 

Krausman et al. (2004) also examined effects of military aircraft and ground-based activities on 

Sonoran pronghorn at the North and South Tactical Ranges on the BMGR and concluded that 

military activities, both ground-based and aerial, were associated with some changes in behavior 

(e.g., from standing to trotting or running, or bedded to standing). On days with stimuli, adult 

pronghorn bedded more than they foraged (Krausman et al. 2004). On days without stimuli, adult 

pronghorn foraged more and bedded less. Ground stimuli including the presence of vehicles or 

people and comprised the majority (65%) of all anthropogenic stimuli. Ground stimuli were 

associated with 866 instantaneous changes in behavior (39%), with 56 of these changes to 

trotting or running (2.6%). During direct overflights (less than or equal to 100 m to the side of 
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animals), pronghorn changed behavior (e.g., from bedded to standing, walking to bedded, 

foraging to bedded) 45 times (41%) with 4 changes from any other activity to trotting or running 

(3.7 %). During overflights greater than 100 m to the side of animals, pronghorn changed 

behavior 105 times (34%), with 5 changes to trotting or running (1.6%). In response to stimuli, 

Krausman et al. (2004) only considered a change in behavior to trotting or running in response to 

stimuli as biologically significant. The authors concluded that these changes were not likely to be 

detrimental to the animals; however, sightings of Sonoran pronghorn were biased towards 

disturbed habitats on the TACs and other areas of military activities, which also corresponded to 

areas of favorable ephemeral forage production (Krausman et al. 2005). No specific conclusions 

could be drawn about effects of military activities on fawns during the Krausman et al. (2004) 

study, but the data suggests that fawns and their mothers may be more sensitive to anthropogenic 

stimuli than other pronghorn. In general, the study did not detect differences in the behavior of 

pronghorn with and without military stimuli; however, Krausman et al. (2004) recommends that 

all ground stimuli and activities that alerts or startles females and their fawns should be 

terminated. 

Pronghorn are also sensitive to the presence of roads, and spend more time vigilant and less time 

foraging near high traffic roads, indicating that they perceive these roads as risk (Gavin and 

Komers 2006). Sonoran pronghorn avoid roads, and use areas less than 1 km (0.62 mi) from 

roads less than expected and more than 5 km (3.1 mi) from roads more than expected (deVos and 

Miller 2005). Whether the avoidance is due to human or vehicle presence or the road itself is not 

known.

High Mortality Rates

Drowning in canals

Sonoran pronghorn occasionally drown when they enter irrigation canals and cannot climb back 

out the steep sides. Prior to 2002, two Sonoran pronghorn were pulled from the WelltonMohawk Canal on the northern end of their range (U.S. Fish and Wildlife Service 2002). Since 

2008, canals have been the cause of eight pronghorn deaths, including four from the Cabeza 

Prieta population and four from the Kofa population, all of which were pen-raised. Of the 

Cabeza Prieta population, three bucks drowned in the Palomas Canal in 2008, and one doe 

drowned in the Wellton Canal in 2010. Of the Kofa population, two bucks and two does died as a 

result of the Wellton Mohawk Canal. More specifically, two of nine Sonoran pronghorn released 

in January 2013 died due to canal-related incidents. One male was pulled out of the Wellton 

Mohawk Canal that runs from the SW to ENE between the southern Kofa boundary and 

Interstate 8 on May 16, 2013 and was found dead three days later nearby. Another dead buck 

was pulled out of the same canal 13.7 km (8.5 mi) east on May 17, 2013. A female was rescued 

alive from the Wellton Mohawk Canal on May 16, 2013 (along with the male that later died), 

and was rescued alive again from another canal near Texas Hill on June 20, 2013. She was later 

seen alive north of Dateland (Christa Weise, FWS, personal communication, 2013). On August 
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19, 2015, a dead Sonoran pronghorn doe was discovered floating by the Texas Hill 3.9 Pump lift 

gate of the Wellton Mohawk Canal. The doe was identified as 149.040, a 2-year old released into 

the Kofa population, from her ear tag and collar. Scratch marks were found along the concreted 

north side of the canal approximately 500 yards upstream (west) of TH-3.9 Pump lift which 

appeared to be from a hooved animal (Williford 2015). On April 26, 2016, a doe released from 

the Kofa breeding pen in January was found drowned in the Wellton Mowhawk Canal. 

Fence entanglement

Pronghorn try to go under barbed wire fences rather than jump over them and often get entangled 

in the bottom wire (Brown and Ockenfels 2007). However, this has not been observed for 

Sonoran pronghorn.

Vehicle collisions

Documented mortalities of Sonoran pronghorn due to vehicle collisions are sparse. An adult doe 

was hit and killed by a car on Mexico Highway 2, 5 miles west of Sonoyta (Phelps 1981).

Unconfirmed reports by ranchers and ejido landowners between 1989 and 1996 indicated some 

Sonoran pronghorn may have been hit crossing Mexico Highway 2 (Castillo 1999). In June 

1996, a dead, radio-collared Sonoran pronghorn was located approximately 400 m south of U.S. 

Interstate 8 that may have been struck by a vehicle (U.S. Fish and Wildlife Service 2002, Bright 

and Hervert 2005). An adult male Sonoran pronghorn was struck and killed by a vehicle near 

kilometer post 29 on Mexico Highway 8 in July 1996 (Castillo 1999, U.S. Fish and Wildlife 

Service 2002). A Sonoran pronghorn female and two fawns were observed crossing Highway 85 

in Organ Pipe Cactus NM in April 2015. Although not observed, one fawn was hit by 

southbound traffic on Highway 85 and the remains were found by Organ Pipe Cactus NM staff 

on April 21, 2015 (Coleman 2015). It is likely that more Sonoran pronghorn have been hit by 

vehicles, but their injuries or mortality went undetected.

Thermal Stress

Hyperthermia may occur in wild Sonoran pronghorn. Lack of thermal cover due to habitat 

alterations and warming climate are likely contributing factors.

Poaching

Even though pronghorn hunting has been illegal in Mexico since 1922, there is evidence that 

indicates that people continue to hunt them (locals continuously report hunting activities, there 

are empty bullets, and truck tracks that can be found in pronghorn habitat; Comisión Nacional de 

Areas Naturales Protegidas 2009). It is unknown how much poaching occurs in the Pinacate or 

Quitovac populations, but it could be significant in Quitovac. Lack of enforcement personnel, 

lack of land protection status, and lengthy travel from Hermosillo limits the ability of officials to 

enforce hunting laws. Presence of drug cartels limits vigilance by citizens and biologists.
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Bighorn sheep are hunted in the vicinity of Sonoran pronghorn populations in both countries. 

However, bighorn sheep occupy different habitat and fatalities due to misidentification are not 

suspected in either the U.S. or Mexico.

Military activities

To date, no pronghorn mortality from military activities has been documented since monitoring 

began (A. Alvidrez, BMGR East, personal communication, 2014). The BMGR East’s pronghorn 

monitoring program, initiated in 1997,provides standardized scheduling, monitoring, and 

reporting procedures for Sonoran pronghorn on the North and South Tactical Ranges and 

Manned Ranges 1, 2, and 4 of the BMGR East, and it establishes precautionary procedures for 

ground operations. If a pronghorn is detected (through telemetry or visual sighting) within 1.5 

km (0.9 mi) of a high explosive (live) target, that target will be closed to ordnance deliveries for 

the remainder of the day. No deliveries of any kind will be made to any other target within 1.0 

km (0.6 mi) of a pronghorn location (A Alvidrez, BMGR East, personal communication, 2014). 

Catastrophic Or Stochastic Events

Catastrophic or stochastic events have the potential to cause extirpation of Sonoran pronghorn 

populations. Although these events are impossible to predict, planning for and management of

multiple Sonoran pronghorn populations helps ensure loss of one population does not cause the 

entire species to go extinct.

Previous and Ongoing Conservation Effo rts

Sonoran pronghorn life history characteristics were poorly understood until the end of the last 

century. By 1998, there was an increase in the knowledge of basic life history characteristics, but 

even as late as 1992, the status of the Sonoran pronghorn population was not clear. As a result of 

this lack of basic information, early conservation efforts focused on gathering data on habitat, 

life history, and population status. In the U.S., more recent conservation efforts have focused on 

stabilizing and increasing the endangered population, as well as establishing new populations.

Conservation Efforts in the U.S.

Agencies Responsible For Sonoran Pronghorn And Their Habitat In The U.S. 

FWS

The primary programs within U.S. Fish and Wildlife Service responsible for Sonoran pronghorn 

include the National Wildlife Refuge System and Ecological Services. The National Wildlife 

Refuge System administers a national network of lands and waters for the conservation, 

management, and where appropriate, restoration of the fish, wildlife, and plant resources and 

their habitats within the United States. The Ecological Services Program provides national 
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75

leadership for the conservation of species and the habitats on which they depend, including 

species protected by the ESA, the Fish and Wildlife Coordination Act, the Coastal Barrier 

Resources Protection Act, and the Clean Water Act.

AGFD

The mission of Arizona Game and Fish Department is to conserve Arizona’s diverse wildlife 

resources and manage for safe, compatible outdoor recreation opportunities for current and 

future generations.

DOD

The mission of the Department of Defense (DOD) is to provide the military forces needed to 

deter war and to protect the security of our country. DOD installations provide safe and secure 

locations to realistically test equipment and train personnel to protect American interests. Natural 

resources and public use are managed to ensure no net loss in the capability of the installation to 

support its military purposes, and in a manner that is consistent with ecosystem management 

principles. 

BLM

The Bureau of Land Management is committed to manage, protect, and improve lands under 

their management authority in a manner to serve the needs of the American people for all times. 

Management is based upon the principles of multiple use and sustained yield of our nation’s 

resources within a framework of environmental responsibility and scientific technology. These 

resources include recreation, rangelands, timber, minerals, watershed, fish and wildlife, 

wilderness, air and scenic, scientific and cultural values.

NPS

The National Park Service preserves unimpaired the natural and cultural resources and values of 

the national park system for the enjoyment, education, and inspiration of this and future 

generations. The Park Service cooperates with partners to extend the benefits of natural and 

cultural resource conservation and outdoor recreation throughout this country and the world.

Other Federal Agencies

All federal agencies which conduct activities (including permitting and funding as well as land 

management) in the range of Sonoran pronghorn in the U.S. are subject to section 7 consultation 

under the ESA.

Early (1923-2002) Sonoran Pronghorn Conservation Efforts in the U.S.

The first conservation efforts initiated to protect Sonoran pronghorn occurred in 1923, when a 

special game warden was appointed to patrol the U.S. - Mexico international border to protect

pronghorn and bighorn sheep from poaching (Leopold 1959). More important conservation 

actions for Sonoran pronghorn were the creation of Organ Pipe Cactus NM in 1937, Cabeza 

Prieta Game Range (now Cabeza Prieta NWR) in 1939, and the creation of the BMGR in 1941
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(Phelps 1978). These areas are protected from development and encompass pronghorn habitat

within their current endangered range in the U.S. (Wright and deVos 1986, Hervert et al. 2000). 

Kofa NWR, established in 1939, encompasses 665,400 ac (269,278 ha) and now supports 

Sonoran pronghorn.

Following the listing of Sonoran pronghorn in 1967, the AGFD initiated a study to collect 

biological information on the subspecies (Arizona Game and Fish Department 1981). The 

Recovery Team first met in 1975 (U.S. Fish and Wildlife Service 1998) and produced the first 

recovery plan for Sonoran pronghorn in 1982 (U.S. Fish and Wildlife Service 1982). The 

recovery team set a recovery goal of maintaining an average population of 300 Sonoran 

pronghorn over a 5-year period in the U.S. Actions proposed in the 1982 recovery plan to 

maintain Sonoran pronghorn numbers included: population surveys, minimizing human 

disturbance and cattle trespass, understanding life history characteristics and limiting factors, and 

establishing a captive breeding population for transplant stock to reestablish Sonoran pronghorn 

into historical habitat. The 1982 recovery plan did not consider any areas outside the current U.S. 

range at the time. 

The first conservation action with the potential to increase Sonoran pronghorn numbers was the 

removal of cattle on most of the current range of Sonoran pronghorn that began in 1972 and 

continued into the early 1980s (O'Gara and McCabe 2004). Three studies on life history 

characteristics of Sonoran pronghorn also were conducted (Wright and deVos 1986, Hughes 

1991a, Hervert et al. 2000). In addition, all fences were removed from guzzlers and drinkers on 

Cabeza Prieta NWR to facilitate their use by pronghorn; and the first fulltime ecologist was 

employed at Cabeza Prieta NWR (U.S. Fish and Wildlife Service 1998). Two water catchments 

(Red-tail and Jose Juan charcos) were improved in 1956 for the benefit of Sonoran pronghorn on

Cabeza Prieta NWR (Morgart et al. 2005). The Red-tail and Jose Juan charcos were augmented 

in 1989 with 2,000 gallon tanks with waterlines connecting to newly-installed wildlife drinkers. 

However, they were not located in areas Sonoran pronghorn use in the summer and are also 

surrounded by dense mesquite, which inhibit Sonoran pronghorn use. Also in the 1980s an 

existing surface and trough tank (Charlie Bell) was renovated by the Arizona Desert Bighorn 

Sheep Society in an area Sonoran pronghorn use when moving to and from Child’s Valley and 

Growler Valley. Also during this period of time,various studies were conducted to determine 

what effects military operations on BMGR might have on pronghorn behavior and survival 

(Krausman et al. 2005).

In the late 1990s and early 2000s, Organ Pipe Cactus NM both removed and modified their 

fences separating NPS and BLM land. Where livestock grazing was removed from BLM 

(Cameron Allotment), the fences were removed. Elsewhere (Why/Coyote Flat Allotment), the 

fences were modified to AGFD standards to facilitate pronghorn movement yet still exclude 

cattle. In recent years (post-2010) pronghorn have been crossing these boundaries.A systematic 
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population monitoring program was initiated in 1992 to conduct biennial surveys (Snow 1994). 

Since then, the entire range of Sonoran-pronghorn in the U. S. has been surveyed biennially to 

obtain population estimates. In 1996, a population viability analysis (PVA) was used to model 

the probability of Sonoran pronghorn becoming extinct given the conditions in 1996 (Hosack et 

al. 2002). The PVA revealed that reduced fawn survival (i.e., less than 25%) might affect the 

population more than reduced adult survival (Hosack et al. 2002). 

In 1998, the 1982 Sonoran Pronghorn Recovery Plan was revised (U. S. Fish and Wildlife 

Service 1998). The 1998 revision updated the recovery criteria based on the results of the PVA 

and studies on Sonoran pronghorn life history. The recovery criteria in the 1998 plan state that 

Sonoran pronghorn will be considered for downlisting when there are 300 Sonoran pronghorn in 

the U.S. population, and a second population is established in the U.S. that remains stable over 5 

years, or when numbers are determined to be adequate to sustain a viable population (U.S. Fish 

and Wildlife Service 1998). In 2002, a supplement and amendment to the 1998 Recovery Plan 

was published that used the downlisting criteria from the 1998 plan and provided an explanation 

for why delisting criteria were not practicable at that time (see U.S. Fish and Wildlife Service 

2002 for a details). 

Recent (2003 to present) Programs and Management Actions in the U.S.

The 1998 recovery plan mentioned that captive breeding and the possibility of reintroductions to 

areas of historical range should be further investigated. By the end of 2002, these and other 

proposed recovery actions (e.g.. forage plots, water developments, land-use restrictions) were 

implemented or were being implemented in the U.S. because over 80% of the Sonoran 

pronghorn population in the U. S. perished after a severe drought in 2002 (Bright and Hervert 

2003).

Supplemental Feeding, Forage Enhancement Plots, and Waters

The 2002 drought prompted the creation of Sonoran pronghorn waters within the Cabeza Prieta 

population area, and as of 2016, 13 stand-alone developed waters and five waters associated with 

forage enhancement plots (three on Cabeza Prieta NWR and two on BMGR) have been 

developed for Sonoran pronghorn (Figure 14). In addition, to improve Sonoran pronghorn access 

to water, the BLM removed fences from around two earthen charcos. Within the Kofa population 

area, five water sources for Sonoran pronghorn have been developed in the King Valley of the 

Kofa NWR since 2012 (Figure 15). No permanent waters have been developed for Sonoran 

pronghorn within the Sauceda population area as of February 2016; however, three temporary 

waters for Sonoran pronghorn have been established. See the section on Water Availability and 

Access for detailed information on the aforementioned Sonoran pronghorn waters. 
Sonoran Pronghorn Recovery Plan, Second Revision

78

In 2009, supplemental feeding was implemented at three experimental sites on BMGR East 

(South Tactical Range) and one site on the Cabeza Prieta NWR (in Child’s Valley at the Charlie 

Bell forage enhancement plot), and Sonoran pronghorn quickly began feeding at these sites. 

Based on pronghorn use, one site on BMGR East (Uken Tank) was selected for continued use 

and the other two sites were discontinued. The Uken and the Child’s Valley sites are still active 

as of 2016. In 2010, AGFD also established two feed stations at developed waters on BMGR

West. In 2012, another feed station was developed on Cabeza Prieta NWR (in Child’s Valley at 

what is now Morgart Tank). Currently, there are five supplemental feeding sites for the Cabeza 

Prieta population that are not associated with the pen. These feeding sites are operated on a 

short-term duration, during the interval between winter and summer rains, and have a localized 

effect. No supplemental feed is provided for the Kofa, Quitovac, or Pinacate populations (with 

the exception of at the captive-breeding pen on Kofa NWR). The wild (free ranging) pronghorn 

learned to use the supplemental feed (baled alfalfa) from pronghorn released from the pen that 

had joined up with them. In 2009, use of supplemental feed by wild pronghorn was documented

within two months of feed station establishment. 

In addition to supplemental feeding, Hervert et al. (2001) suggested the creation of forage 

enhancement plots in key areas of Sonoran pronghorn habitat to increase fawn survival by 

providing lactating females and foraging fawns access to more succulent and nutritious forage 

during times of the year with limited rainfall. Since 2002, five forage enhancement plots (Adobe, 

Lower Well, Charlie Bell; Granite; Devil's Hills (Figure 14) have been established (one in 2002, 

three in 2005, and one in 2010). As of October 2015, two out of the five are working (Lower 

Well and Charlie Bell).Sonoran pronghorn took time to learn to use forage enhancement plots, 

but use them readily now. Each of the forage enhancement plots also provides a source of freestanding water for Sonoran pronghorn. Unfortunately, the Sonoran pronghorn water sources are 

being tapped for use by undocumented migrants and smugglers, and leakage along the lines 

prevents water from reaching the forage plots. In addition, the pumps stop working if not used 

frequently, so frequent maintenance is required.

Recovery actions (primarily water catchments) may be needed within wilderness because 

approximately half (50.3%) of the current Cabeza Prieta population range is designated 

wilderness. Within Cabeza Prieta NWR, approximately 93% of the refuge is designated 

wilderness, and within the Organ Pipe Cactus NM, approximately 95% is designated wilderness. 

There are few remaining opportunities within the southern half of the current range to implement 

meaningful recovery actions for Sonoran pronghorn outside of wilderness.

The Gila River was a reliable source of forage and water for Sonoran pronghorn prior to the 

early 1900s. Recovery actions such as water developments, forage plots, and supplemental 

feeding of alfalfa function in a similar manner ecologically as the Gila River historically did, 

however on a much smaller scale. Sonoran pronghorn likely used the river and the associated 
Sonoran Pronghorn Recovery Plan, Second Revision

79

riparian zone during periods of environmental stress (poor forage conditions and scarce free 

standing water); only to leave the vicinity of the river bottom after rain changed the 

environmental conditions. Similarly, Sonoran pronghorn do not use current water developments, 

forage plots, and supplemental feeding stations after substantial rains. Radio-telemetry data has 

shown that Sonoran pronghorn often move many miles into adjacent valleys as forage conditions 

improve. The movement patterns of Sonoran pronghorn remain dependent on forage conditions 

and have not changed substantially (e.g., they continue to have very large home ranges) since the 

initiation of active management. 

Sonoran pronghorn behavioral response to humans does not appear to have changed since 

waters, forage enhancement plots, supplemental feeding, and captive breeding have been 

implemented. Sonoran pronghorn continue to run from humans and do not appear to be

habituated to the sound of a truck delivering alfalfa. The Recovery Team suggests examination 

of survival rates among wild and released Sonoran pronghorn and pronghorn response to human 

stimuli. Anecdotal observation of pronghorn responses to human presence are subject to 

interpretation, consequently a more detailed experimental approach is needed.
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Figure 14. Location of captive breeding pen, waters, and forage enhancement plots in the range of the Cabeza Prieta 

population, Arizona, U.S.

Captive Breeding

Following the 2002 drought, plans were made to implement a captive-breeding program for 

Sonoran pronghorn (Arizona Game and Fish Department 2003); the first captive breeding pen 

(260 ha; 642 ac) was built in 2003 in Cabeza Prieta NWR. One goal of this facility was to 

produce animals for augmenting the population within the current range, establishing a second 

population in the U.S., and, upon request, providing return stock to Mexico. The pen was stocked 

with Sonoran pronghorn from Cabeza Prieta NWR and the Quitovac population in northwestern 

Sonora, Mexico. The captive breeding program at Cabeza Prieta NWR (Figure 14) is ongoing 

with 48 animals in the pen as of January 1, 2016 (after captures and before 2016 birthing 

season). In 2011 a captive breeding pen on Kofa NWR was established (Figure 15). The captive 

breeding program at Kofa NWR is ongoing with 29 adults in the pen as of January 10, 2016 

(after captures and before 2016 birthing season). The number of animals in each pen fluctuates 

frequently as animals are born and others are captured for releases. From 2006 to 2016, 205 
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81

Sonoran pronghorn have been released into the wild from the Cabeza Prieta and Kofa NWR pens 

(Table 4).

Figure 15. Location of captive breeding pen and waters in the range of the Kofa population, Arizona, U.S.
Sonoran Pronghorn Recovery Plan, Second Revision

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Table 4. Summary of Sonoran pronghorn releases from captive breeding pens at Cabeza Prieta and Kofa NWRs, Arizona.

a

Survival is defined by the Recovery Team as released animals surviving until the end of September after their release (about 9 months post-release), meaning 

they would have survived one summer season. The first release at Sauceda was in December 2015, so no survival information is yet available for that area. b The 

lower number of pronghorn released in 2011/12 reflects the fact that 13 pronghorn captured in the Cabeza Prieta pen were transported to the Kofa pen that year to 

serve as broodstock animals and were not therefore “released.” c No survival information available for 2015/2016 as of February 2016.

Year

Males Released Females

Released

Total Released to Each 

Management Unit

Total

Surviveda

Kofa Cabeza Sauceda Kofa Cabeza

2006/07 4 0 - 4 - - 4

2007/08 5 0 - 5 - - 2

2008/09 9 3 - 12 - - 7

2009/10 19 4 - 23 - - 10

2010/11 7 11 - 18 - - 11

2011/12b 7 4 - 11 - - 8

2012/13 11 7 9 9 - 6 7

2013/2014 22 14 24 12 - 24 10

2014/2015 15 17 21 11 - 15 9

2015/2016 22 25 19 2 26 NAc NAc

Total 121 85 72 107 26 45 68
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Nonessential Experimental Populations

A habitat evaluation was conducted to identify suitable areas for the second population (O'Brien 

et al. 2005). In 2008, an interdisciplinary team developed and applied screening criteria to

evaluate and compare the seven potential areas for establishing additional populations of 

Sonoran pronghorn (U.S. Fish and Wildlife Service 2010b). The screening criteria were:

1. Size of area (acreage);

2. Forage (quality of forage throughout the area, based on forage conditions current at the 

time and past rainfall patterns);

3. Water (rainfall patterns, condition and number of existing natural and manmade 

waters, and suitability for construction of new waters);

4. Degree of habitat fragmentation (by roads, railroads, fences, canals);

5. Degree of disturbance (human disturbance is the primary consideration, may result 

from recreation, military activities, Border Patrol activities, border crossing by 

undocumented migrants and smugglers);

6. Logistics (including considerations of access to area for building and maintaining a 

captive breeding or holding pen, waters, and forage enhancements, communications, and 

safety); and

7. Other factors (such as presence of predators, competitor abundance, and prevalence of

disease).

The seven potential areas for establishing additional populations of Sonoran pronghorn in the 

U.S. were ranked for each of the screening criteria by the interdisciplinary team, which 

deliberated as an expert panel. Ranking was conducted on a relative basis. The area with the best 

or highest qualitative value for a specific criterion was assigned a score of seven. The area with 

the poorest or lowest qualitative value for a specific criterion was assigned a score of one. The 

remaining five areas were then scored according to their rank relative to the highest and lowest 

scored areas. The Kofa area (Area A in FWS [2010]) ranked highest in this screening exercise, 

receiving 92% of possible points; followed by Sauceda area (Area D in FWS [2010]) with 79% 

of possible points (U.S. Fish and Wildlife Service 2010b). An environmental assessment was 

published in 2010 that examined alternatives and resulted in a Finding of No Significant Impact 

for the alternative including holding pens in both areas (U.S. Fish and Wildlife Service 2010a;

2011c).

A final rule establishing a nonessential experimental population was published in the Federal 

Register on May 5, 2011 (U.S. Fish and Wildlife Service 2011a). On Kofa NWR, a new captive 

breeding pen was established in 2011, as described above, and five permanent pronghorn water

catchments were built for released animals. In 2013, nine pronghorn were released into the wild 

at Kofa NWR for the first time; an additional 15 were released from Cabeza Prieta NWR pen and 

nine from the Kofa pen in January 2014. In January 2015, an additional 21 were released from 
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84

the Cabeza Prieta NWR pen. In January and February of 2016, 19 were released from the Kofa 

pen. Reproduction in the wild has been documented for this released population. In December 

2015 releases began at the Sauceda area within the nonessential experimental population 

boundary, with 26 animals released at BMGR East, east of Highway 85 (Figure 16).

Figure 16. Pre-release pen at Sauceda, Arizona, U.S. Mountain in the background is Hat Mountain. Photo by Jim 

Atkinson, FWS.
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Other Conservation Efforts 

Periodic (about twice a month) telemetry flights are conducted to locate collared Sonoran 

pronghorn in Arizona. These flights are designed to yield detailed information relative to 

movements of marked pronghorn, habitat selection, causes of mortality and survival. In addition, 

fawn survival and ultimately fawn recruitment for each year is estimated annually using data 

collected during these flights. Habitat condition is assessed, along with any new alterations to 

habitat that may be ongoing (new roads, trails, wild fires, construction activities, etc.) but 

unkown to managers. These flights also yield important information (water levels, condition of 

collection points, etc.) relative to pronghorn waters in remote locations. 

A relatively small number of pronghorn inhabit a very large area, consequently it is a challenge 

for a small work force to monitor and investigate the complex relationships associated with 

Sonoran pronghorn in a highly varied and complex habitat. Periodic telemetry fligths are 

extremely valuable to field biologist attempting to detect, describe, and observe patterns of 

Sonoran pronghorn behavior. 

Since 1997, the BMGR has required monitoring of Sonoran pronghorn before conducting 

munitions delivery missions and ground operations to prevent mortalities. As of March 2016

there have been no known pronghorn injuries or mortalities attributed to military training since 

this program began. Protocols for standardized biological monitoring are described in Luke Air 

Force Base’s Operating Instruction OI 13-01, Sonoran Pronghorn Monitoring (see Appendix 1 of 

U.S. Fish and Wildlife Service 2010c).

In 2004-2005, BLM closed 55,000 acres (Cameron Allotment) to livestock grazing to improve 

habitat conditions for pronghorn. From 2004-2008, Organ Pipe Cactus NM’s southern boundary 

(barbed-wire) fence with Mexico was replaced with a vehicle barricade fence. The vehicle 

barricade was configured to be pronghorn-passable, and included two wire strands to discourage 

cattle crossing. No pronghorn crossing of that fence has been documented in Organ Pipe Cactus 

NM, but radio-collared pronghorn have crossed through vehicle barricade fencing farther west, 

on Cabeza Prieta NWR.

Additionally, some recent research has been conducted on Sonoran pronghorn, including an 

ongoing (as of 2016) study led by the University of Arizona to investigate the effects of human 

activities on Sonoran pronghorn, and a genetic assessment of Sonoran pronghorn by the 

University of Arizona/U.S. Geological Survey (see the section on Lack Of Genetic Diversity for 

more information on this study). 
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Conservation Efforts in Mexico

Primary Agencies Responsible For Pronghorn and Habitat in Mexico 

Federal Ministry of the Environment and Natural Resources (Secretaría de Medio Ambiente y 

Recursos Naturales [SEMARNAT])

SEMARNAT is responsible for promoting the protection, restoration, and conservation of 

ecosystems, natural resources, and environmental goods and services in Mexico. To fulfill this 

mandate, SEMARNAT and its undersecretaries and decentralized agencies work in four priority 

areas, including the conservation and sustainable use of ecosystems and their biodiversity. 

Among other duties, SEMARNAT’s various agencies conduct wildlife law enforcement, 

management, and natural area protection. SEMARNAT was created from the federal Ministry of 

the Environment, Natural Resources, and Fish (Secretaría de Medio Ambiente, Recursos 

Naturales y Pesca [SEMARNAP]) in 2001. 

Federal Office of Wildlife (Dirección General de Vida Silvestre [DGVS])

DGVS, the Federal Office of Wildlife, an agency under SEMARNAT, is responsible for, among 

other things, approving hunting permits submitted by Unidades para la Conservación, Manejo y 

Aprovechamiento Sustentable de la Vida Silvestre (UMAs; Wildlife Conservation, Management, 

and Sustainable Utilization Units); determining extraction quotas; and regulating harvest of 

wildlife throughout the country. Wildlife regulation and administration was decentralized in the 

northern Mexican States, including Sonora and Baja California, meaning that the states now have 

authority for certain wildlife regulation such as approving some hunting permits submitted by 

UMAs. DGVS also has responsibility for issuing documents, agreements, permissions, or 

authorizations for conducting research on wildlife species when it involves managing or 

manipulating individuals. It also authorizes repopulation, relocation, and reintroduction of 

wildlife species, as well as permits for endangered species (NOM-059-SEMARNAT-2010).

Federal Agency of Environmental Protection (Procuraduría Federal de Proteccion del Ambiente 

[PROFEPA])

Wildlife and environmental law enforcement is under the jurisdiction of PROFEPA which is 

within SEMARNAT (Valdez et al. 2006). The principal function of PROFEPA, since its creation 

over 20 years ago, is to oversee the execution of all the legal dispositions, among them the 

General Wildlife Law, protecting the interest of the Nation in regards to the environment, and 

issuing sanctions to those who violate said legal precepts.

National Commission of Natural Protected Areas (Comisión Nacional de Areas Naturales 

Protegidas [CONANP]) 

CONANP is within SEMARNAT and is responsible for the protection, restoration, and 

sustainable use of natural resources, principally fauna and flora, within Protected Natural Areas 

(Valdez et al. 2006). 
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Branches of CONANP include, among others:

• Especies Prioritarias Para La Conservacion (Priority Species) manages the Programa de 

Conservacion de Especies en Riesgo (PROCER; Program for the Conservation of Species 

At Risk). Under PROCER, recovery programs for 60 at-risk species are developed and 

implemented. Currently, 40 of these recovery programs, called Programa de Acción para 

la Conservación de Especies (PACE; Species Conservation Action Program) have been 

developed. Pronghorn (including all subspecies) is a priority species in this program and 

the PACE for pronghorn is included in this recovery plan (Appendix C). 

• Areas Naturales Protegidas (ANP; Protected Natural Areas) manages protected areas, 

including the El Pinacate Biosphere Reserve. CONANP runs hundreds of conservation 

areas (177 federal protected areas) totaling more than 25,628,239 ha (63,328,757 ac), or 

12 % of the country's land.

According to Article 70 of the Reglamento Interior de Semarnat, CONANP has authority to 

implement activities to conserve priority species, such as the pronghorn, and their habitat both 

within a protected area and its zone of influence. For example, the Quitovac area is in the zone of 

influence for El Pinacate Biosphere Reserve. Therefore CONANP plays a role in the recovery of 

pronghorn in both the Pinacate and Quitovac populations. Since 2003 collaboration agreements 

have been established among CEDES, CONANP/El Pinacate Biosphere Reserve, and La 

Herradura Mine, which specifically include actions for Sonoran pronghorn conservation and 

recovery.

Federal Ministry of Livestock, Agriculture, Rural Development, Fisheries, and Foods (Secretaría 

de Agricultura, Ganaderia, Desarrollo Rural, Pesca, y Alimentación [SAGARPA])

SAGARPA is responsible for agricultural, livestock, and fish management throughout the 

country. Also SAGARPA is in charge of the zoo-sanitary and fito-sanitary law enforcement and 

regulation for international movements of wildlife (animal and plants). In the case of the 

pronghorn’s conservation, their direct participation is minimal.

The National Commission for Knowledge and Use of Biodiversity (Comisión Nacional para el 

Conocimiento y Uso de la Biodiversidad [CONABIO])

CONABIO is a permanent interdepartmental commission of Mexico, created in 1992. The 

mission of CONABIO is to promote, coordinate, support and carry out activities aimed at 

increasing awareness of biodiversity and its conservation and sustainable use for the benefit of 

society. CONABIO was conceived as an applied research organization, sponsoring basic 

research that generates and compiles information regarding biodiversity, developing capacity in 

the area of biodiversity informatics, and to act as a publicly accessible source of information and 

knowledge.
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Commission of Ecology and Development of the State of Sonora (Comisión de Ecologies y 

Desarrollo Sustentable del Estado de Sonora [CEDES])

CEDES is the state wildlife agency in Sonora. The Mission of CEDES is to establish 

environmental public policies that favor sustainable development, land ecological planning, and 

promote protection and care of the environment and natural resources. CEDES is responsible for 

the implementation and evaluation of environmental policy of the State of Sonora. CEDES 

promotes public participation and accountability in the formulation and implementation of 

environmental policy, collecting and monitoring environmental information, and other ecological 

actions taken by the State. CEDES is also responsible for conducting and promoting scientific 

studies and research of the natural environment, as well as promoting cultural and ecological 

values.

Ministry of Agriculture, Water Resources, Fisheries and Aquaculture (Secretaría de Agricultura, 

Ganadería, Recursos Hidráulicos, Pesca y Acuacultura [SAGARHPA]) 

SAGARHPA is an agricultural agency of the State of Sonora. Although it does not manage 

pronghorn or natural areas, its policies can affect pronghorn and their habitat. For example, 

because SAGARHPA is the permitting authority for hunting in Sonora, it can obligate UMAs to 

eliminate or modify barbed-wire fences that can negatively affect pronghorn movement. CEDES 

is the technical branch of SAGARPHA and both agencies work closely together. 

Environment Protection Minsitry of Baja California (Secretaría de Protección al Ambiente de 

Baja California [SPA]).

SPA is the state wildlife agency in the State of Baja California.

Past Pronghorn Conservation Efforts In Mexico

The first pronghorn conservation efforts in Mexico started in 1922, when President Álvaro 

Obregón banned the hunting of the pronghorn (Comisión Nacional de Areas Naturales 

Protegidas 2009). Later in 1952, the government created the Federal Hunting Law, which 

supports the banning of pronghorn hunting in Mexico (Comisión Nacional de Areas Naturales 

Protegidas 2009). The Norma Oficial Mexicana (NOM-059-ECOL-1994) and its updates in 2001 

and 2010, which classify the pronghorn populations in Mexico as an endangered species,

reiterated the legal protection of the species (Comisión Nacional de Areas Naturales Protegidas

2009). In 1999, the Technical Consulting Subcommittee for the Conservation, Management and 

Sustainable Use of the Pronghorn (Subcomité Técnico Consultivo para la Conservación, Manejo 

y Aprovechamiento Sustentable del Berrendo, órgano técnico consultivo) was formed, with the 

mission of proposing a national strategy for the conservation and management of the pronghorn. 

Recent Conservation Programs And Management Efforts for Sonoran Pronghorn In Mexico

Mexico's most ambitious wildlife conservation and management initiative is incorporated in the 

Wildlife Conservation and Production Diversification in the Rural Sector Program (Programa de 

Conservacion de la Vida Silvestre y Diversificacion Productiva en el Sector Rural) (Valdez et al. 

2006). The major objective of this program is to integrate environmental, economic, social, and 
Sonoran Pronghorn Recovery Plan, Second Revision

89

legal strategies to address wildlife needs while promoting broader societal participation and 

creating realistic economic incentives. This program includes: 1) the conservation and recovery 

of priority species, including pronghorn; and 2) the creation of a system of wildlife management 

units (Valdez et al. 2006). Wildlife Conservation, Management, and Sustainable Utilization 

Units (Unidades para la Conservación, Manejo y Aprovechamiento Sustentable de la Vida 

Silvestre [UMAs]) create economic incentives for the judicious management of wildlife 

resources by facilitating the integration of wildlife management programs in livestock, forestry, 

and agricultural schemes (Valdez et al. 2006). Wildlife uses (including plants) within UMAs 

include research, recreation, game parks, environmental education, game farms, and 

commercialization of wildlife byproducts (Valdez et al. 2006).

In 2007, the Program for the Conservation of At-Risk Species (Programa de Conservacion de 

Especies en Riesgo [PROCER]) was formed. Managed by CONANP, the PROCER’s main 

objective is to contribute to recovery of 60 species with the highest level of risk by implementing 

a recovery program developed for each species. Under the PROCER, Species Conservation 

Action Programs (Programa de Acción Para la Conservación de La Especie [PACE]) are 

developed, which are planning documents detailing the critical needs for the conservation of 

priority species, including all steps needed to be implemented in the short, mid, and long term to 

conserve a species. These PACEs are similar to recovery plans in the U.S. In 2009, CONANP 

produced a PACE for the pronghorn (Appendix C).

The Reserva de la Biosfera El Pinacate y Gran Desierto de Altar (El Pinacate Biosphere Reserve) 

is 714,556 ha (1764.3 ac). It was declared a reserve by the Mexican government in 1993, in part 

to protect Sonoran pronghorn. In parts of the El Pinacate Biosphere Reserve, CONANP is 

removing all old and unused fences. They are also educating ranchers how to create fences that 

exclude cattle, but allow the passage of pronghorn. Where fences are needed to delineate 

boundaries, CONANP is removing wires and leaving the posts for marking purposes. They are 

trying to reduce the effects of highways by installing information signs in the pronghorn corridor 

to reduce highway collisions. ). Fourteen wildlife underpasses were constructed in 2013 on 

Mexico Highway 2; two of these underpasses, each 45 ft long and 15 ft high, were constructed in 

the area occupied by Sonoran pronghorn (Horacio Alfonso Ortega Morales, CONANP, personal 

communication 2016). Fence adjustments are needed to make the underpasses more usable by 

Sonoran pronghorn, and the underpasses will be monitored with cameras if funding is received. 

They are seeking to reduce competition for forage and water by removing feral burros. In 

addition, CONANP is revising the management plan to restrict cattle to one zone. They installed 

nine water tanks for Sonoran pronghorn in 2015 (two in Quitovac and seven in Pinacate), 

although pronghorn use of these waters has not been documented likely due to cattle exclusion 

fences around the tanks. CONANP plans to continue experiment with the waters until pronghorn 

can successfully use them. CONANP is also working with the local communities to educate 

people about pronghorn.
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In addition, CONANP is seeking to acquire more land in the El Pinacate Biosphere Reserve. 

Currently, around 250,000 ha (617,763 ac) in the reserve are federal land (mostly in the core 

zone of the reserve) and 450,000 ha (1,111,974 ac) are communal land (ejidos) (mostly in the 

buffer zone of the reserve). CONANP is also currently revising the El Pinacate Biosphere 

Reserve management plan to try to limit changes in land use by not allowing developments or 

mining, and closing a well in the Sonoyta area.

CONANP staff from the El Pinacate Biosphere Reserve and staff from Espacios Naturales A.C., 

a nonprofit organization in Mexico, have been conducting Sonoran pronghorn studies and other 

conservation actions since 2014 under the PROCER. Their studies focus on behavior and habitat 

use in the Biosphere reserve and its area of influence, including the zone of the Herradura and 

Nochebuena mines, El Bajio, Juan Álvarez and El Indio ejidos, private land, and the comunity of 

Quitovac. In July 2015, they built towers to make behavioral observations of Sonoran pronghorn. 

In the Quitovac population area, CEDES is conducting Sonoran pronghorn surveys and working 

with the La Herradura mine and other landowners to reduce their impacts on pronghorn and their 

habitat. 

Biological Constraints and Needs

Sonoran pronghorn needs are primarily habitat based, and are discussed in the Habitat 

characteristics/ecosystem section above. In addition to sufficient quantity and quality of habitat, 

Sonoran pronghorn require vast areas of unencumbered open range to meet their annual needs 

for survival and reproduction. This includes the ability to freely travel long distances between 

localized, seasonally sporadic rainfall in search of sustenance (U.S. Fish and Wildlife Service

2002).

PART II. RECOVERY 

Recovery Strategy 

The recovery goal, as detailed below, is to ultimately delist the species. To achieve that goal, the 

recovery strategy is to secure a sufficient number of Sonoran pronghorn populations that are 

viable under appropriate management scenarios within select areas throughout their historical 

range. Both the number of individual Sonoran pronghorn in each population and the number of 

existing populations will need to be increased by: introducing Sonoran pronghorn to additional 

sites within their historical range; protecting, restoring, and enhancing habitat; maintaining and 

improving habitat connectivity; providing supplemental forage and water; minimizing or 

mitigating the effects of human caused disturbance; monitoring; conducting research to better 

understand habitat requirements and conservation needs; securing adequate funding to 
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91

implement recovery actions; enforcing existing laws; and maintaining and developing 

partnerships in the U.S. and Mexico.

The Recovery Team’s objective is to conserve Sonoran pronghorn in as natural a state as 

possible, meaning providing the least amount of human intervention required to recover the 

pronghorn. However, given the influences of anthropogenic factors (e.g., climate change, human 

population growth, land use changes), many of which are beyond the control of the Recovery 

Team, it is anticipated that Sonoran pronghorn populations will need to be managed with a 

variety of techniques. Some populations will need to be more intensively managed than others to 

ensure their viability, particularly during drought conditions and other catastrophic events. 

The Sonoran Pronghorn Recovery Plan has four overriding objectives.

1) Incorporate the important biodiversity principles of representation, resiliency and 

redundancy (Shaffer and Stein 2000) including:

a. representation: secure Sonoran pronghorn populations throughout their range to 

conserve genetic variation of the species to maintain its adaptive potential;

b. resiliency: ensure that each population is sufficiently large to withstand stochastic

(unpredictable, random) events; and

c. redundancy: secure multiple Sonoran pronghorn populations throughout their 

range so that this subspecies can withstand catastrophic events;

2) Summarize what is known about the status of the Sonoran pronghorn throughout its range 

and identify primary information gaps;

3) Identify threats to the species; and 

4) Describe in significant detail the actions necessary to restore and conserve Sonoran 

pronghorn populations in select portions of their range, including conservation units 

identified below. 

While the recovery plan and strategy considers the Sonoran pronghorn throughout its range, the 

FWS has little authority to implement actions needed to recover species outside the U.S. The 

management and recovery of listed species, including the Sonoran pronghorn, outside of U.S. 

borders are primarily the responsibility of the countries in which the species occur, with the 

provision, as appropriate, of available technical and monetary assistance from the U.S. However, 

the FWS and its partners can cooperate with partners in Mexico to focus efforts within respective

jurisdictions to conserve and recover the Sonoran pronghorn. In recognition of the binational 

distribution of the species, and the unique challenges and opportunities this presents, two 

conservation units for the species have been designated: one in the U.S. and one in Mexico. 

These conservation units, as well as their subset management units, discussed herein, are defined 

and described below. 
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Conservation units1 are subunits of the listed species that are 1) geographically identifiable by 

international boundaries, and as such, managed under the authorities of different countries; and 

2) important to the recovery of Sonoran pronghorn (e.g., constitute a substantial portion of the 

Sonoran pronghorn’s current and historical range). Conservation units are individually important

to conserve genetic and demographic robustness, which are key factors for ensuring long-term 

sustainability of the subspecies. Each designated conservation unit plays a significant role in

recovering the Sonoran pronghorn throughout its range. 

Management units, for the purposes of this recovery plan, are subunits of the conservation units 

that may require different management, are managed by different entities, and/or encompass 

different populations. For Sonoran pronghorn, each management unit is important to the 

recovery of the species and provides a function that benefits the overall conservation unit.

The U.S. Conservation Unit 

This conservation unit is located in Arizona and California and includes the historical range of 

Sonoran pronghorn in the U.S. In Arizona, it generally extends from the international border in 

the south to the Gila Bend and Kofa Mountains in the north. It is a logical conservation unit 

because the populations in the U.S. are 1) geographically identifiable from the populations in 

Mexico and managed under the authorities of the ESA, and 2) highly important to the recovery 

of the species because they are demographically and genetically robust and primarily occur 

within protected areas. Sonoran pronghorn in the U.S. are effectively geographically separated 

from Sonoran pronghorn populations in Mexico due to the physical barriers of Mexico Highway 

2 and associated fencing. 

Cabeza Prieta Management Unit

The Cabeza Prieta Management Unit (Figure 17) is defined to include the current range of the 

Sonoran pronghorn population in Arizona listed as endangered under the ESA. The current range 

of the Cabeza Prieta population was determined by radio-collared pronghorn locations and other 

observations. However, pronghorn from this population may occasionally occur outside of 

this boundary. Any pronghorn occurring outside the nonessential experimental population 

boundary are considered endangered. The Cabeza Prieta Management Unit generally extends 

 

1 In the Recovery Planning Guidance (National Marine Fisheries Service 2010), recovery and management units are 

defined; however, conservation units are not defined. For the purpose of recovery planning for Sonoran pronghorn, 

the Sonoran Pronghorn Recovery Team determined a need to separate pronghorn into two primary units (i.e., 

conservation units) separated by the international border, to reflect the significant differences in pronghorn 

management between countries. The Team, however, also determined that the definition of recovery and 

management unit did not accurately reflect the intent and functions of the units and therefore developed a new term 

“conservation unit.” 
Sonoran Pronghorn Recovery Plan, Second Revision

93

from BMGR West to Organ Pipe Cactus NM and is 8,161 km2 (3161 mi2) in area. It could 

expand if Sonoran pronghorn within the management unit expand their range to the west or 

slightly to the northeast. It is a logical management unit because it is managed under different 

regulations than the Arizona Reintroduction Management Unit (below). See Population Trends 

and Distribution for the current status of Sonoran pronghorn in the Cabeza Prieta Management 

Unit (referred to in the Background section as the Cabeza Prieta population).

Arizona Reintroduction Management Unit 

The Arizona Reintroduction Management Unit (Figure 17) includes the boundaries of the 

nonessential experimental population under section 10(j) of the ESA in Arizona and incorporates 

19,179 km2 (7,405 mi2) of potential habitat for Sonoran pronghorn mapped from a CART model 

(U.S. Fish and Wildlife Service 2010). The nonessential experimental population is located in 

southwestern Arizona in an area north of Interstate 8 and south of Interstate 10, bounded by the 

Colorado River on the west and Interstate 10 on the east; and an area south of Interstate 8, 

bounded by Highway 85 on the west, Interstates 10 and 19 on the east, and the United StatesMexico border on the south (Figure 17). It is a logical management unit because it is managed 

under different regulations than the Cabeza Prieta Management Unit. 

This management unit is further separated into two subunits: Kofa and Sauceda, which 

correspond to Areas A and D, respectively (Figure 17), in the final rule to establish a 

nonessential experimental population (U.S. Fish and Wildlife Service 2011a). Kofa ranked first 

and Sauceda ranked second among seven proposed reintroduction areas based on seven scoring 

criteria evaluated by an interdisciplinary team including members of the Recovery Team, the 

Tohono O’odham Nation, and representatives from land management agencies located in 

southwestern Arizona. The Kofa subunit is located in the King Valley on Kofa NWR, and 

adjacent portions of primarily Yuma Proving Ground (YPG) and BLM lands. The Sauceda 

subunit is located east of Highway 85 on the BMGR East, BLM lands, and a portion of the 

Tohono O’odham Nation. Within the Arizona Reintroduction Management Unit, additional 

subunits, as identified in the Sonoran Pronghorn Reestablishment Environmental Assessment 

(U.S. Fish and Wildlife Service 2010b) and Figure 17, may be considered for future 

reintroductions. However, there are no current plans to release animals outside of Kofa and 

Sauceda subunits.

California Reintroduction Management Unit

The California Reintroduction Management Unit is a potential unit for which feasibility planning 

is currently being conducted (Figure 17). There is an interest among the Recovery Team and 

partners to establish a nonessential experimental population under section 10(j) of the ESA in 

suitable remaining portions of the Sonoran Desert ecosystem of southeastern California. The 
Sonoran Pronghorn Recovery Plan, Second Revision

94

primary area of interest for Sonoran pronghorn reintroduction in California includes the 

Chuckwalla Bench (Clark et al. 2013). It is 5,166 km2 (1994 mi2

). It is a logical management unit 

because, although it would be a 10(j) population, it will be established under a different rule than 

the Arizona Reintroduction Management Unit and may require different management because it 

would be located in California and be managed by different agencies than the Arizona 

Reintroduction Management Unit. It is also geographically separated from the Arizona 

population by the Colorado River. 

Mexico Conservation Unit 

The Mexico Conservation Unit includes the historical range of Sonoran pronghorn primarily in 

the Mexican state of Sonora. The current range is estimated at about 4,057 km2 (1566 mi2). The

extent of the historical distribution of the Sonoran pronghorn subspecies, however, is currently 

under investigation, and will be determined by genetic analysis of museum specimens collected 

from the states of California and the extreme northeastern part of the state of Baja California. 

The current distribution of Sonoran pronghorn in Mexico includes the two current populations in 

Quitovac and Pinacate, Sonora (Figure 17). The Mexico Conservation Unit includes the ranges

of the two current populations and potential reintroduction sites within the historical range. The 

area of potential reintroduction sites has not been calculated and is not included in the acreages 

above. As stated above, the historical range is still under investigation; however, the Mexico 

Conservation Unit generally extends from Mexico Highway 2 roughly to Caborca, Sonora. In 

Mexico, pronghorn of all subspecies are listed as endangered under Mexican law (NOM-059-

SEMARNAT 2010), while only the Sonoran subspecies of pronghorn is listed as endangered 

under U.S. law (ESA). The Mexico Conservation Unit is a logical conservation unit because the 

populations in Mexico are: 1) geographically distinct from the populations in the U.S.; 2) 

managed under different laws, including the Ley General de Vida Silvestre y su Reglamento 

(Secretaría de Medio Ambiente y Recursos Naturales 2000) and other Mexican State laws; and 

3) highly important to the recovery of the species because they are demographically and 

genetically robust and partially occur within protected areas.

Pinacate Management Unit

The Pinacate Management Unit includes the current range of the Sonoran pronghorn population 

north of Mexico Highway 8 (Figure 17). The current range of the Pinacate population was 

determined by radio-collared pronghorn locations and other observations and is 1,959 km2 (756

mi2) in area (Jill Bright, AGFD, personal communication 2015). It could expand if Sonoran 

pronghorn within the management unit expand their range. It is a logical management unit 

because it occurs within the Reserva de la Biosfera El Pinacate y Gran Desierto de Altar (El 

Pinacate Bioreserve), a federal protected area (Area Natural Protegida) managed by the 

Comision Nacional de Areas Naturales Protegidas (CONANP). The El Pinacate Bioreserve

contains a mixture of federally owned and protected lands, as well as ejido and private lands. 
Sonoran Pronghorn Recovery Plan, Second Revision

95

Sonoran pronghorn in this management unit are geographically separated from pronghorn in the 

U.S. Conservation Unit and Quitovac Management Unit by Mexican Highways 2 and 8, 

respectively. As explained in the Background Section, pronghorn rarely cross these highways. 

See Population Trends and Distribution for the current status of Sonoran pronghorn in the 

Pinacate Management Unit (referred to in the Background section as the Pinacate population). 

This is a small management unit that receives little rainfall.

Quitovac Management Unit 

The Quitovac Management Unit includes the current range of the Sonoran pronghorn population 

south of Mexico Highway 8. It extends from Mexico Highway 8 to Caborca (Figure 17). The 

current range of the Quitovac population was determined by radio-collared pronghorn locations 

and other observations and is 2,098km2 (810 mi2) in area (Jill Bright, AGFD, personal 

communication, 2015). It could expand if Sonoran pronghorn within the management unit 

expand their range. It is a logical management unit because it entirely occurs within unprotected 

lands and therefore is managed differently than the Pinacate Management Unit. Sonoran 

pronghorn in this management unit are geographically separated from pronghorn in the Pinacate 

Management Unit by Highway 8, which is fenced along both sides. As explained in the 

Background section, pronghorn rarely cross this highway. The area contains a mixture of ejido 

and private lands. There are a number of UMAs within the Quitovac Management Unit. The 

UMAs in the Quitovac Management Unit are primarily for the management of bighorn sheep and 

mule deer. 

As of October 2015, this area supports 88% of the Sonoran pronghorn population in Mexico. See 

the Population Trends and Distribution for the current status of Sonoran pronghorn in the 

Quitovac Management Unit (referred to in the Background section as the Quitovac population). 

Sonora Reintroduction Management Unit

This is a potential management unit. There is an interest among the Recovery Team and partners 

to establish additional populations in the unoccupied historical range in Sonora, Mexico. Because 

this process is in the early phases, no boundaries have been developed. 
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Scale: 1:1,500,000

Basemap: Esri, DeLorme, USGS, NPS

Produced By: L. Urreiztieta, 

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Arizona Reintroduction Management Unit (Nonessential Experimental Population Area)

Kofa Subunit (Population Established in 2013)

Sauceda Subunit (Population Established in 2015)

California Reintroduction Management Unit (Proposed) Cabeza Prieta Management Unit

Pinacate Management Unit

Quitovac Management Unit

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Figure 17. Sonoran pronghorn management units and subunits in the U.S. and Mexico. Because the Cabeza Prieta, Pinacate, and Quitovac Management Units are based on Sonoran pronghorn locations, the management unit boundaries could expand if Sonoran pronghorn expand

their range in these areas. Because Sonoran pronghorn have not been documented outside of Cabeza Prieta Management Unit and south of I-8 and west of Hwy 85, there is an apparent gap in the map. Sonoran pronghorn could occasionally move outside of management units; 

any Sonoran pronghorn occurring outside the Nonessential Experimental Population area is considered endangered.
Sonoran Pronghorn Recovery Plan, Second Revision 

97

Recovery Goal , Objectives, and Criteria 

Recovery Goal

The recovery goal is to conserve and protect the Sonoran pronghorn and its habitat so that its 

long-term survival is secured, populations within the conservation units are capable of enduring 

threats, and it can be removed from the list of threatened and endangered species (delisted). As a 

species that is listed throughout its range in two countries, the Sonoran pronghorn presents some 

unique challenges and opportunities for recovery planning. The 1998 Sonoran Pronghorn 

Recovery Plan and the 2002 update to that plan focused primarily on the recovery of the U.S. 

population. Although our knowledge of the species in Mexico is currently more limited than in 

the U.S., this current plan revision addresses recovery of the Sonoran pronghorn range-wide.

Recovery Objectives 

Recovery objectives collectively describe the specific conditions under which the goal for 

recovery of the Sonoran pronghorn will be met throughout its range. The recovery objectives for 

Sonoran pronghorn are:

1) Ensure multiple viable populations of Sonoran pronghorn exist range-wide. 

2) Ensure that there is adequate quantity, quality, and connectivity of Sonoran pronghorn 

habitat to support populations. 

3) Minimize and mitigate the effects of human disturbance on Sonoran pronghorn. 

4) Identify and address priority monitoring needs.

5) Identify and conduct priority research.

6) Maintain existing partnerships and develop new partnerships to support Sonoran pronghorn 

recovery. 

7) Secure adequate funding to implement recovery actions for Sonoran pronghorn. 

8) Practice adaptive management in which recovery is monitored and recovery tasks are 

revised by the FWS in coordination with the Recovery Team as new information becomes 

available.

Recovery Criteria 

Recovery criteria are the values by which it is determined that an objective has been reached 

(National Marine Fisheries Service 2010). Recovery criteria must be objective and measurable. 

They provide a basis for determining whether a species can be considered for downlisting to 

threatened status, or removed from the list of threatened and endangered species. Because the 

same five statutory factors must be considered in delisting as in listing (16 U.S.C. § 1533 (a), (b), 

(c)), the objective, measurable criteria in this recovery plan address each of the five statutory 
Sonoran Pronghorn Recovery Plan, Second Revision 

98

delisting factors and provide a way to measure whether threats to the Sonoran pronghorn have 

been ameliorated (see Fund for Animals v. Babbitt, 903 F. Supp. 96 [D.D.C. 1995]). 

The recovery criteria in this plan are not binding, and it is important to note that meeting the

recovery criteria provided below does not automatically result in downlisting or delisting the 

species. Downlisting and delisting decisions are under the authority of the FWS Director and 

must undergo the rulemaking process and analyses. Both anthropogenic and non-anthropogenic 

threats to the Sonoran pronghorn must be acceptable in a five-factor analysis and adequate 

regulatory mechanisms must be in place to ensure that the species will persist into the 

foreseeable future. The management recommendations in this plan are believed to be necessary 

and advisable to achieve this goal, but the best scientific information derived from research, 

management experiments, and monitoring conducted at the appropriate scale and intensity 

should be used to test this assumption. Even if these criteria are achieved, continued management 

of the Sonoran pronghorn may be necessary to control the threats that otherwise might create a 

need to relist.

When considering downlisting or delisting the Sonoran pronghorn, the FWS will collaborate 

with Mexican partners, including CONANP and CEDES, and consider the requirements and 

scoring in Mexico’s “Método de evaluación del riesgo de extinción de las especies silvestres en 

México” (MER; Extinction Risk Evaluation Method in Mexico) (Sanchez et al. 2007).

The Recovery Team anticipates that management actions (e.g., providing water and forage, 

captive breeding) will be necessary to meet the recovery criteria both in the U.S. and Mexico. In 

particular, management actions will likely be required to achieve population stability indicated in 

the recovery criteria. Management scenarios should be appropriate for each population, taking 

into consideration the unique criteria, opportunities, and constraints for each population. 

Adaptive management should be practiced to stabilize and recover all Sonoran pronghorn 

populations. Recovery criteria may need to be adjusted if population stability is not achieved

after implementing relevant management actions. 

Downlisting Criteria 

Reclassification of Sonoran pronghorn from endangered to threatened may be considered when 

all six of the following criteria are met:

1. At least three free-ranging populations are viable. Two of these must be the Cabeza Prieta 

population and either the Quitovac or Pinacate population. The Recovery Team defines a 

viable population as one that has less than a 10% probability of extinction over 50 years and 

a growth rate that is stable or increasing. Furthermore, at least one new population must have 

been released, in addition to the Kofa subunit (e.g., Sauceda subunit). 
Sonoran Pronghorn Recovery Plan, Second Revision 

99

A population viability analysis (PVA) estimated abundance targets to meet the Recovery 

Team definition of viability, which is different for each management unit due to different 

environmental conditions. To be considered viable, a population estimate must meet or

exceed the abundance targets and demonstrate a population growth rate that is stable or 

increasing (r ≥0) for at least five of seven years1. Abundance targets for each management 

unit are estimated from the PVA to be: a) 225 in the Cabeza Prieta Management Unit; b) 150 

in the Kofa subunit or a new subunit (Sauceda or other future established subunit); c) 150 in 

the Pinacate Management Unit; and d) 450 in the Quitovac Management Unit. These 

population sizes must be estimated by monitoring (i.e., aerial surveys). 

Justification: This criterion is intended to ensure the Sonoran pronghorn subspecies has the 

representation, redundancy, and resiliency across its range to be successfully conserved. 

Representation of the subspecies in two conservation units would conserve the full range of 

genetic variability and different environments in which the subspecies now occurs. Conserving 

three redundant viable populations would decrease the chance that a single stochastic event 

would cause the entire subspecies to go extinct. Resiliency to stochastic events in each 

population is possible when populations are large and viable. The Recovery Team decided that 

other possible measures of viability, such as skewed male/female ratios, would be reflected in 

long-term growth rates. Due to differences in environmental conditions at each site, the PVA was 

conducted on a site-by-site basis. The Recovery Team placed more importance on having 

redundant, viable populations than the total number of individuals in the subspecies. 

To develop population criteria, the Recovery Team used a PVA, which simulated extinction risk 

and population growth rates as a function of demographic, life history, and environmental 

variables (Appendix D). Input variables included 19 demographic and environmental variables 

derived from field studies and expert opinion (Table 1 in Appendix D). Some of the PVA input 

variables still need to be tested in the field. Models will need to be adjusted as new data become 

available. Initial population size and carrying capacity estimates are two of the input variables 

that varied the most among populations (Table 5) (see Appendix D for information on how 

carrying capacities were estimated). Annual mortality by age class, percent of females breeding 

annually, drought frequency, and drought severity also varied among populations (Table 1 in 

Appendix D). 

 

1 As of 2016, aerial surveys to estimate Sonoran pronghorn population size alternate between the Cabeza Prieta 

population and the Mexico populations (Pinacate and Quitovac), so that each of these populations is surveyed every 

other year. Therefore, population estimates will be determined from surveys (in survey years) or the average 

between the previous and following year’s survey estimate (in non-survey years). For information on how 

population estimates and confidence intervals are calculated, please see the Recent Population Trends – Arizona

section of this plan. 
Sonoran Pronghorn Recovery Plan, Second Revision 

100

Sensitivity analysis was conducted as an initial step in the PVA; results indicated that population 

growth rate and, by extension, extinction risk, are most sensitive to changes in adult female 

mortality (Appendix D). Therefore, we chose to examine PVA models that used a range of adult 

female mortality rates (Appendix D). Other parameters input into the models are based on best 

available data (Appendix D).

Table 5. Inputs and results of Sonoran pronghorn PVA. 

Population Inputs to Baseline Model PVA model outputs

2012 

Population 

Size1

Carrying 

Capacity

Raw Abundance 

Target

Adjusted 

Abundance 

Target 2

Cabeza Prieta Wild 159 400 150 225 

Cabeza Prieta Pen 57 57 No targets 

calculated

No targets 

calculated

Kofa Wild 9 700 1003 150

Kofa Pen 22 25 No targets 

calculated

No targets 

calculated

Pinacate Wild 52 150 150 150

Quitovac Wild 189 700 300 450 1

Sonoran pronghorn population estimates from aerial surveys in 2012 (U.S.) and 2011 (Mexico). 

2

Adjusted abundance target is the raw abundance target plus a 50% buffer, and is the number used in the criteria. 3

Outputs apply to either of the Arizona Reintroduction Populations.

As a starting point in developing population criteria, the Recovery Team used raw population

abundance targets that, when achieved, could confer an acceptable level of long-term 

demographic stability according to the simulation models. In other words, populations that reach 

these raw abundance targets have the potential for a long-term positive growth rate and have a 

low probability of extinction (less than 10%) for 50 years after the target has been reached. The 

raw abundance targets (called “initial population sizes” in the PVA model scenarios because they 

are the population size used as a starting point in the model simulations) are the minimum 

number of Sonoran pronghorn individuals necessary for demographic stability and do not 

represent a maximum or long-term population goal. The Recovery Team assessed results for 

those model scenarios featuring 15% annual adult female mortality because this seems to be a 

threshold, all else being equal, above which long-term population growth becomes negative, 

leading to population decline. 

The Recovery Team evaluated model outputs for those models featuring a 15% drought 

frequency (one drought year out of every seven years) because drought is a major mortality 

factor for Sonoran pronghorn and has occurred at least this frequently over the past twenty years

(Cabeza Prieta NWR unpublished data). The Recovery Team picked the lowest raw population
Sonoran Pronghorn Recovery Plan, Second Revision 

101

abundance target that would confer less than a 10% probability of extinction. The Recovery 

Team also picked the lowest raw population abundance target that would confer a positive 

population growth rate. For any one population, if model results for growth rate suggested a 

different raw population abundance target than model results for extinction probability, the 

Recovery Team used the larger of the two raw abundance targets. These raw abundance targets 

are different for each population due to differences in environmental conditions at each site. 

Please see Appendix D for the detailed PVA process, assumptions, and results.

For the Quitovac population, the probability of extinction is 9.2% when the raw abundance target 

is 250 individuals. The probability of extinction modeled for other populations was much lower: 

Pinacate (6.1%), Kofa (1.4%), and Cabeza Prieta (0.6%). A 9.2% extinction risk is close to the 

threshold of 10%, so the Recovery Team decided to take additional precaution against 

uncertainty and use 300 individuals as a raw abundance target for the Quitovac population, 

which results in a much lower extinction risk of 5.9%. The larger target value for Quitovac 

reflects that population’s comparatively higher levels of instability, based on the judgment of 

species experts participating in this analysis. In summary, because of the following: 1) 

considerable fluctuations in population abundance; 2) relatively higher levels of demographic 

instability in its current habitat; and 3) higher levels of uncertainty regarding how the population 

will respond to threats such as climate change, the original 250 raw target abundance estimate for 

the Quitovac population was conservatively increased to 300.

The Recovery Team next added a 50% buffer to the raw abundance targets derived from PVA 

model results as a safeguard to offset possible underestimation of the raw abundance targets due 

to uncertainties in parameter estimation (e.g., demographic parameters) and the unknown effects 

of climate change. The adjusted abundance targets are shown in Table 5, and are as follows: 

• For the Cabeza Prieta Management Unit, the raw abundance target is 150 individuals. 

Adding the 50% buffer results in an adjusted abundance target of 225 individuals. 

• For the Arizona Reintroduction Management Unit, the raw abundance target is 100 

individuals. Adding the 50% buffer results in an adjusted abundance target of 150 

individuals. This criterion applies to either Kofa or a new Arizona subunit.

• For the Pinacate Management Unit, the raw abundance target is 150 individuals. 

Adding a 50% buffer is not possible because it would raise the adjusted target above 

the estimated carrying capacity of 150 individuals. On the other hand, the abundance 

target cannot be reduced because it would exceed our chosen extinction probability 

threshold (i.e., 10%). Therefore the adjusted abundance target remains at 150 

individuals.
Sonoran Pronghorn Recovery Plan, Second Revision 

102

• For the Quitovac Management Unit, the raw abundance target is 300 individuals. 

Adding the 50% buffer results in an adjusted population target of 450 individuals.

In addition to meeting adjusted abundance targets, it will be important that lower confidence 

intervals of population estimates meet or exceed the raw abundance targets (see Table 5 for raw 

abundance targets). This will help ensure that actual population numbers (estimated through 

surveys) are not below minimum viability levels. For information on how population estimates 

and confidence intervals are calculated, please see the Recent Population Trends – Arizona

section of this plan. 

The Recovery Team chose to evaluate population sizes over a seven year period because that 

timeframe approximates the average interval of drought. In the last 20 years, severe drought (less 

than 50% of average rainfall) has occurred in the Sonoran pronghorn range approximately every 

seven years (in 1995-1996, 2002, and 2009; Cabeza Prieta NWR unpublished data). If these 

population numbers can be maintained through at least one severe drought, we would know that 

the populations are less vulnerable to severe drought as a result of management actions taken to 

reduce other threats and the effects of drought. The Recovery Team decided population 

abundance targets need to be met for five out of seven years because populations naturally 

fluctuate and it is likely a drought may occur within the seven-year period and cause populations 

to temporarily decline due to lack of water or food resources. It may take two years to recover 

from such a drought.

These population targets do not include individuals in pens. Population augmentation has been 

implemented at Cabeza Prieta and Kofa Management Units and will likely be continued to 

achieve their respective population targets. This will likely be less necessary over time as the 

populations grow and become more stable. Population augmentation may be discontinued if 

populations continue to grow for at least three years. Population augmentation may be warranted 

in the Pinacate and Quitovac Management Units if it is feasible and appropriate. If population 

numbers cannot be maintained, additional management actions would likely be necessary, and 

the population recovery criteria may need to be re-examined by the Recovery Team. 

Using the seven year drought cycle, the PVA models explored impacts to the four populations 

and population growth rates. Although the Pinacate and Quitovac populations did not achieve 

population growth under the scenario of one drought every seven years, this is likely due to the 

high estimated mortality rates for these populations during severe drought. These populations in

Mexico have endured through drought cycles in the past, but information about the habitat, 

availability of water, and other factors affecting survival is lacking. It is not known how they 

have managed to survive historical droughts. To more accurately understand the dynamics of 

Sonoran pronghorn population fluctuations in Sonora in response to drought, the mortality 

estimates used in the PVA should be tested. Population growth rates should be monitored closely 
Sonoran Pronghorn Recovery Plan, Second Revision 

103

if drought continues to occur on average once every seven years. If growth rates are negative, 

recovery actions to increase survival would be implemented.

The Recovery Team anticipates that management actions (e.g., providing water and forage, 

captive breeding) will be necessary to meet the recovery criteria both in the U.S. and Mexico. In 

particular, management actions will likely be required to achieve population stability indicated in 

the recovery criteria. As referenced in this strategy, management scenarios should be appropriate 

for each population, taking into consideration the unique criteria, opportunities, and constraints 

for each population. Adaptive management should be practiced to stabilize and recover all 

Sonoran pronghorn populations. Recovery criteria may need to be adjusted if population stability 

is not achieved after implementing relevant management actions. 

In addition to ensuring current populations remain or become viable, this downlisting criteria 

calls for the release of one additional population (besides the Kofa subunit). This release will 

show progress toward establishing an additional population, which will provide additional 

redundancy to protect the Sonoran pronghorn subspecies if catastrophic loss should occur in one 

or more management units. 

2. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, a minimum of 90% of current Sonoran pronghorn habitat within each unit 

is retained and contiguous. This Sonoran pronghorn habitat is protected through agency 

policies, land use regulations and plans, landowner agreements, incentives, and/or other 

programs and agreements. The 90% of retained and contiguous Sonoran pronghorn habitat 

includes key habitat features such as water sources.

Justification: As indicated in the Reasons for Listing/Threats Assessment above, habitat loss and 

fragmentation (historical, present, and future) are two of the most significant stressors to Sonoran 

pronghorn. Sonoran pronghorn occupy 12% of their former range and occur in disjunct 

populations. The Quitovac population, in particular, is threatened by current and future habitat 

loss and fragmentation. In all management units, the areas with the best forage and water 

availability change seasonally and are dependent on recent precipitation patterns. Sonoran 

pronghorn rely on nomadic movements to use the areas that currently have the best forage and 

water available. Sonoran pronghorn require large areas of contiguous habitat to make these 

seasonal movements and to survive and reproduce successfully. A reduction in the amount of 

usable pronghorn habitat or any loss in habitat connectivity would reduce the resiliency of each 

population and increase the risk of extinction, especially during severe drought. In addition, large 

areas of contiguous habitat are efficient to maintain because they require less active management 

to meet recovery objectives. Therefore, recovery actions would attempt to conserve as much

contiguous habitat as possible. Contiguous habitat contains no barriers to Sonoran pronghorn 
Sonoran Pronghorn Recovery Plan, Second Revision 

104

movement, and is accessible to and inhabitable by Sonoran pronghorn throughout. Retaining 

contiguous habitat includes preventing and removing barriers to allow movement of Sonoran 

pronghorn. The baseline year for evaluation is 2016.

The population criteria and carrying capacity for the Pinacate population was based on the

amount of habitat that currently exists in the Pinacate Management Unit, so losing up to 10% of 

the habitat could reduce carrying capacity. However, implementation of actions such as 

developing pronghorn waters and removing fences could increase carrying capacity. Carrying 

capacities for other populations are well above the population criteria, so those populations may 

still be able to meet the targeted population criteria if some habitat is lost. 

3. Threats to Sonoran pronghorn habitat quality in three units are stabilized or decreasing as 

measured by indicators described in Appendix E. Threats must be stabilized or decreased in 

the three management units that correspond to the three populations that meet the population 

viability criteria in Recovery Criteria number 1. In particular, the threats of overgrazing;

unauthorized routes, roads and trails; invasive plant and animal species threatening Sonoran 

pronghorn habitat; and spread of shrubby vegetation are minimized through agency policies, 

land use regulations and plans, landowner agreements, incentives, and/or other programs and 

agreements.

Justification: Threats to habitat quality may occur at low levels without significant impact to 

Sonoran pronghorn, but at some unknown threshold, these threats may reduce the ability of 

habitat to provide sufficient resources for survival and reproduction. When severe, these threats 

to habitat quality may render the habitat unsuitable for use by Sonoran pronghorn, although 

thresholds are unknown. Sonoran pronghorn populations would remain vulnerable to extinction 

as long as threats to their habitat remain in place. Overgrazing, unauthorized or excessive offhighway routes and trails, invasive plant and animal species, and spread of shrubby vegetation 

are the most likely threats to Sonoran pronghorn habitat quality.

4. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit, and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, human disturbance is alleviated such that a minimum of 90% of Sonoran 

pronghorn habitat can be occupied by Sonoran pronghorn. 

Justification: Pronghorn are relatively shy animals (please see Factor E for background 

information) that are very sensitive to human disturbance and the presence of humans or human 

activity in otherwise suitable pronghorn habitat can render it unusable for pronghorn. As 

described in the threats assessment, human disturbance can prevent Sonoran pronghorn from 

occupying an area. The 90% of habitat that can be occupied by Sonoran pronghorn must include 

key habitat features such as water sources. Sonoran pronghorn occur in areas with human 
Sonoran Pronghorn Recovery Plan, Second Revision 

105

disturbance (e.g., tactical ranges); however, at certain levels, disturbance can lead to habitat 

exclusion or range abandonment. The Recovery Team wants to ensure that the level of 

disturbance is below the threshold that prevents Sonoran pronghorn from using habitat. Although 

this threshold is difficult to determine, the current study on the effects of human activity on 

Sonoran pronghorn should help us better understand human disturbance thresholds. The 

Recovery Team does not believe that current levels of authorized public use exclude pronghorn 

from habitat.

5. Genetic diversity for three populations, as measured by heterozygosity and allelic richness 

for nuclear DNA markers, has been retained from levels indicated in Culver and Vaughn 

(2015). These three populations must meet the threshold of viability as described in 

Downlisting Criterion 1. The minimum level of heterozygosity of any of the three 

populations must be 49% (i.e., within 20% of the average heterozygosity of population 

segments (10) estimated by Culver and Vaughn (2015)). The minimum level of allelic 

richness of any of the three populations must be 1.96 (i.e., within 20% of the average allelic 

richness of population segments (10) estimated by Culver and Vaughn (2015)). 

Justification: Heterozygosity is a measure of the proportion of individuals in a population having 

two different alleles of the same gene. As estimated by Culver and Vaughn (2015), average 

heterozygosity (across 16 microsatellite loci developed specifically for Sonoran pronghorn) of 10 

population segments is 62% (range 54 to 68%); this level of heterozygosity is not considered an 

immediate threat to the subspecies. Allelic richness is a measure of the average number of alleles 

that takes into account rarity and commonness of alleles and provides an additional measure of 

genetic diversity that complements heterozygosity. Average allelic richness of 10 population 

segments is 2.45 (range 1.84 to 3.77; Culver and Vaughn 2015). The 10 population segments 

used for calculations of average heterozygosity and average allelic richness are shown in Table 7 

of Culver and Vaughn (2015); however, Kofa NWR neonate and Kofa NWR pen were 

combined. Ideally, each population would regain the level of genetic diversity they possessed 

before bottlenecks occurred as a result of anthropogenic stressors and drought. An indication of 

pre-bottleneck diversity may be available by obtaining DNA from museum specimens. However, 

pre-bottleneck genetic diversity may not be achievable. Therefore, the goal is to retain as much 

diversity as possible, and if loss occurs, to have populations increase their genetic diversity to the 

level of the population that is the most diverse. The population segment with the highest overall 

genetic diversity is the Kofa Pen; observed heterozygosity (68%) and allelic richness (3.10) 

(Culver and Vaughn 2015). At a minimum for each population, however, heterozygosity must be 

maintained at 49% or above and allelic richness must be 1.96 or above. 

. 

This genetic criterion must be met in addition to achieving the population size criteria because 

captive breeding and other management efforts could result in an increase in population numbers 

without obtaining acceptable levels of genetic diversity. Translocations (immigration of 
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106

individuals) may be necessary to increase genetic diversity in some populations. If a single, or 

small number of, population(s) is observed to show a marked reduction in genetic diversity (5% 

or greater decline in heterozygosity and allelic richness over a 2-year period), then mixing 

populations (movement of individuals among populations within Arizona) to recover prior 

genetic diversity levels should be initiated. If all populations show a simultaneous decline in 

genetic diversity of 5% or greater over a 2-year period, then these declines should be 

investigated, minimized, and possibly mitigated.

6. Effective federal, state, tribal, and/or local laws are in place in the recovery conservation

units that ensure that killing of Sonoran pronghorn is prohibited or regulated such that viable 

populations of Sonoran pronghorn can be maintained and are highly unlikely to need the

protection of the ESA again.

Justification: The extent of the threat of poaching has not been examined and its extent is 

unknown. Ensuring laws are in place would enable enforcement response if poaching is 

determined to be negatively impacting pronghorn recovery. 

Delisting Criteria 

Removal from the list of threatened and endangered species may be considered when all six of 

the following delisting criteria are met:

1. At least three free-ranging populations are viable. Two of these must be the Cabeza Prieta 

population and either the Quitovac or Pinacate population. The Recovery Team defines a 

viable population as one that has less than a 10% probability of extinction over 50 years and 

a growth rate that is stable or increasing. Furthermore, at least one new population must have

been established, in addition to the Kofa subunit (e.g., Sauceda subunit). Established means 

that the population is stable and is no longer in need of augmentation from a captive breeding 

program. 

A population viability analysis (PVA) estimated abundance targets to meet the Recovery 

Team definition of viability, which is different for each management unit due to different 

environmental conditions. To be considered viable, a population estimate must meet or 

exceed the abundance targets and demonstrate a population growth rate that is stable or 

increasing (r ≥0) for at least 10 of 14 years1

. Abundance targets for each management unit 

 

1 As of 2016, aerial surveys to estimate Sonoran pronghorn population size alternate between the Cabeza Prieta 

population and the Mexico populations (Pinacate and Quitovac), so that each of these populations is surveyed every 

other year. Therefore, population estimates will be determined from surveys (in survey years) or the average 

between the previous and following year’s survey estimate (in non-survey years). For information on how 
Sonoran Pronghorn Recovery Plan, Second Revision 

107

are estimated from the PVA to be: a) 225 in the Cabeza Prieta Management Unit; b) 150 in 

the Kofa subunit or a new subunit (Sauceda or other future established subunit); c) 150 in the 

Pinacate Management Unit; and d) 450 in the Quitovac Management Unit. These population 

sizes must be estimated by monitoring (i.e., aerial surveys). 

Justification: Population numbers within each management unit are the same as those in the 

downlisting criteria, but must remain viable for a longer period of time for delisting to be 

considered. Removal from the list of threatened and endangered species requires greater 

confidence in the long-term persistence of the subspecies than downlisting requires. 

Demonstrating population abundance at target levels for a longer time provides greater 

confidence that adequate population numbers and positive growth rates are not temporary 

increases, but will remain sustainable over the long term.

All other delisting recovery criteria are the same as for downlisting:

2. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, a minimum of 90% of current Sonoran pronghorn habitat within each unit 

is retained and contiguous. This Sonoran pronghorn habitat is protected through agency 

policies, land use regulations and plans, landowner agreements, incentives, and/or other 

programs and agreements. The 90% of retained and contiguous Sonoran pronghorn habitat 

includes key habitat features such as water sources.

3. Threats to Sonoran pronghorn habitat quality in three management units are stabilized or 

decreasing as measured by indicators described in Appendix E. Threats must be stabilized or 

decreased in the three management units that correspond to the three populations that meet 

the population viability criteria in Recovery Criteria number 1. In particular, the threats of 

overgrazing; unauthorized routes, roads and trails; invasive plant and animal species

threatening Sonoran pronghorn habitat; and spread of shrubby vegetation are minimized 

through agency policies, land use regulations and plans, landowner agreements, incentives, 

and/or other programs and agreements.

4. Within the Cabeza Prieta Management Unit, Pinacate Management Unit, Quitovac 

Management Unit, and the Kofa and Sauceda subunits of the Arizona Reintroduction 

Management Unit, human disturbance is alleviated such that a minimum of 90% of Sonoran 

pronghorn habitat can be occupied by Sonoran pronghorn. 

5. Genetic diversity for three populations, as measured by heterozygosity and allelic richness 

for nuclear DNA markers, has been retained from levels indicated in Culver and Vaughn 

(2015). These three populations must meet the threshold of viability as described in 

 

population estimates and confidence intervals are calculated, please see the Recent Population Trends – Arizona 

section of this plan.
Sonoran Pronghorn Recovery Plan, Second Revision 

108

Downlisting Criterion 1. The minimum level of heterozygosity of any of the three 

populations must be 49% (i.e., within 20% of the average heterozygosity of population 

segments (10) estimated by Culver and Vaughn (2015)). The minimum level of allelic 

richness of any of the three populations must be 1.96 (i.e., within 20% of the average allelic 

richness of population segments (10) estimated by Culver and Vaughn (2015)). 

6. Effective federal, state, tribal, and/or local laws are in place in the recovery conservation

units that ensure that killing of Sonoran pronghorn is prohibited or regulated such that viable 

populations of Sonoran pronghorn can be maintained and are highly unlikely to need the

protection of the ESA again.

Recovery Action Outline and Narrative

The Recovery Team used the conceptual models of threats (Appendix A) to visually assess if 

each stressor was addressed with at least one recovery action and to assess if the factors 

contributing to each direct threat were considered. Recovery actions were developed to reduce 

the impact of each stressor, by addressing the stressor itself, minimizing the effect of the source, 

or by minimizing the indirect threats. Recovery actions are listed by stressor and source in the 

threats tracking table (Appendix F). 

The following is a list of the actions needed to recover the Sonoran pronghorn. The list is 

organized by objective, followed by threat type and broad recovery actions. Recovery actions are 

often broken down into sub-actions and underlined recovery actions represent the most steppeddown levels for the recovery program narrative. The narrative describes the actions in further 

detail and some of the reasons the action may be important for recovery. However, it is not 

intended to provide the detail necessary to implement each action; detailed plans will be 

developed prior to implementation as needed. Priorities, estimated costs, and responsible parties 

are listed for each underlined action in the Implementation Schedule, which follows this Outline. 

In some cases, as more information becomes available, the Recovery Team may determine an 

action is not necessary or not feasible.

In 2009, Mexico developed the PACE for pronghorn and is currently is implementing it. The 

FWS and Recovery Team acknowledge the significant contribution of the PACE to pronghorn

conservation. The FWS and Recovery Team will work with Mexico to ensure coordination in 

implementing actions from this plan and the PACE; these plans share many of the same recovery 

actions. See Appendix C for a translated version of the PACE.

Objective 1: Ensure multiple viable populations of Sonoran pronghorn exist range-wide.
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109

1.1. Stabilize, increase, or maintain the number of individuals within existing populations, 

range-wide, where there is adequate habitat. 

1.1.1. Maintain genetic diversity of Sonoran pronghorn. 

1.1.1.1. Transfer animals among Sonoran pronghorn populations to maintain 

diversity within each population as needed based on ongoing genetic 

evaluation (see research section). If genetic monitoring (see recovery action 

5.5 for details) demonstrates that the Arizona Sonoran pronghorn 

populations as a whole drop below 0.49 observed heterozygosity (see 

Recovery Criteria #5 and Culver and Vaughn 2015 for more information on 

observed heterozygosity in Sonoran pronghorn), this will trigger 

management actions such as considering translocations to Arizona from 

Mexico. If any single population in Arizona drops below 0.49 observed 

heterozygosity, this will trigger actions to move individuals among Arizona 

populations. If translocations are required, the number of individuals needed 

would be between 1-10 individuals; 1 individual will prevent differentiation 

between two populations and 10 individuals will make two populations 

panmictic. Translocations should occur every 5-10 years, based on need. If 

heterozygosity of Sonoran pronghorn in Sonora drops below acceptable 

levels, this will trigger management actions such as considering 

translocations from Arizona to Mexico, or among populations in Sonora. 

Specific thresholds and ideal translocation frequencies for Sonoran 

pronghorn in Sonora are not available; therefore, additional studies should 

focus on providing this information. Prior to transfers, conduct a 

cost/benefits analysis to determine if the benefit of increasing genetic 

diversity outweighs the risk of capture/moving animals, particularly with 

the significant delays at the international border associated with moving 

animals. The Recovery Team needs to ensure that animals moved will 

reproduce; therefore it may be most effective to move females, which are 

more likely to reproduce than males. On the other hand, the risk to the 

donor population of losing a female is greater. 

1.1.2. Reduce mortality caused by diseases.

1.1.2.1. Vaccinate against Epizootic Hemorrhagic Disease and Blue Tongue. 

Currently, vaccinations are limited to animals captured within the pens 

during annual capture and release operations. All captured pronghorn,

whether designated for wild release or returned to the pen, are vaccinated 

via hand-held syringe. Only pen-raised animals are vaccinated and only 

when they are being handled for other purposes. In the future there may be 

ways to vaccinate without handling. If that is the case, the Recovery Team

would expand vaccination program to free-ranging pronghorn.
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110

1.1.2.2. Vaccinate against other diseases that threaten Sonoran pronghorn if 

vaccination is available. Pronghorn could be vaccinated against other 

diseases during handling for other purposes if vaccines become available. In 

the future there may be ways to vaccinate without handling; if that is the 

case, the Recovery Team would expand vaccination program to freeranging pronghorn.

1.1.3. Decrease poaching (the level of effort needed for 1.1.3.2 to 1.1.3.6. will depend 

on the results of 1.1.3.1). 

1.1.3.1. Determine the extent of poaching. Poaching is not currently a threat in the 

U.S. populations. The amount of poaching that occurs in the populations in 

Mexico is unknown. The extent of poaching and its potential impact on 

Sonoran pronghorn needs investigation to determine if there is a need for 

anti-poaching programs.

1.1.3.2. Increase and maintain community vigilance programs in Mexico (an 

existing federal program in Mexico). Community vigilance programs to 

detect and report illegal pronghorn hunting are ongoing in Sonora, Mexico. 

These programs should be maintained and increased where feasible.

1.1.3.3. Promote the detection and denunciation of illegal hunting of pronghorn, 

including designing actions to reduce each kind of illegal hunting.

1.1.3.4. Promote and reinforce inspection and surveillance rounds in the areas where 

pronghorn are distributed during the seasons when hunting is allowed for 

other species that share habitat with pronghorn, with coordination of state 

and municipal governments. This action would target the source of 

poaching presumed to most likely, which is hunters for other species 

misidentifying or intentionally taking pronghorn.

1.1.3.5. Increase enforcement of existing wildlife protection laws. Laws to protect 

Sonoran pronghorn are in place in both countries. However, based on 

information from Recovery Team members from Mexico, enforcement is 

not adequate in Mexico and needs to be improved.

1.1.3.6. Monitor reductions in poaching. It is inherently difficult to monitor an 

illegal activity. However, as an estimate, community vigilance groups could 

provide the Recovery Team with records of poaching observations. These 

observations would be an incomplete count of the number of individual 

Sonoran pronghorn poached, but could be used as a rough index to assess if 

poaching is increasing or decreasing over time. Another rough index may 

be the number of poached animals or body parts confiscated by law 

enforcement officials.

1.1.4. Reduce predation by native, feral, and domestic predators 

1.1.4.1. Identify under what conditions, when, and where predator control is needed.

Predator control may be needed to achieve and maintain higher population 
Sonoran Pronghorn Recovery Plan, Second Revision 

111

levels of Sonoran pronghorn under certain conditions. Examples of such 

conditions include: a) when Sonoran pronghorn populations decline and 

high predation rates on fawns are documented, or b) when unacceptably 

high predation rates are occurring in special circumstances such as in the 

vicinity of the pens, or c) when predation rates, as documented by 

telemetry, are occurring on newly released animals that are determined to be 

unacceptably high by the Recovery Team. The amount, location, and type 

of predation would need to be assessed to determine when and where 

predator control would be implemented.

1.1.4.2. Implement predator control programs as needed. This action would occur 

when and where deemed necessary by the investigations and assessments 

described above.

1.1.5. Reduce mortality caused by canals.

1.1.5.1. Work with irrigation districts (i.e., those entities that manage canals) to 

develop possible solutions to prevent drowning in canals. Develop 

cooperative agreements and best management practices with irrigation 

districts. 

1.1.5.2. Fence or modify canals to prevent Sonoran pronghorn from entering and 

drowning in canals. Possible modifications that may prevent drowning 

include escape structures or fencing. 

1.1.5.3. Set criteria and conditions for response if pronghorn are approaching canals. 

A coordinated interagency response plan would outline which agencies, 

groups, or individuals would respond if pronghorn are detected in the 

vicinity of canals. This plan would describe procedures for actions such as 

intercepting pronghorn before they reach canals and removing pronghorn 

trapped in canals. The plan would include a contact list and determine 

which parties are responsible based on where and when pronghorn are 

detected in the vicinity of canals.

1.1.5.4. Monitor annual canal-related incidents (e.g., drowning, injury). Develop a 

reporting system and database of incidents. This database would be used to 

track the success of the above actions (1.1.5.1 – 1.1.5.3) in reducing canalrelated mortalities.

1.1.5.5. Monitor mi/km/m of canals rendered safe by fences or escape ramps. 

Develop a reporting system and database of fences, escape ramps, and other 

canal modifications. This database would be used to track these 

improvements as an indicator of our success at reducing canal-related 

threats.

1.2. Continue captive breeding program.
Sonoran Pronghorn Recovery Plan, Second Revision 

112

1.2.1. Maintain current captive breeding program, including care of Sonoran pronghorn 

and captive breeding infrastructure.

1.2.2. Evaluate and modify as needed methods of captive breeding, handling, transport, 

and transplant. Continuously update methods as new information becomes 

available. In particular: a) evaluate transplant holding requirements and protocol, 

b) evaluate and modify as needed the annual trapping and release plan, and c) 

continue to update handling/anesthesia protocols as needed with the help of 

veterinarians and other experts.

1.2.3. Define desired captive and released population structure. Sex ratios, age, etc. 

should be considered when defining the desired population structure. 

1.3. Establish additional populations within the historical range of Sonoran pronghorn.

1.3.1. Evaluate suitability and prioritize reintroduction sites. Determine if predator 

abundance, particularly of coyotes, is too high to support pronghorn. This analysis 

needs to be done near the time of reintroduction because drought cycles can affect 

predator densities. Determine if fences can be removed, or conversely, if hazards 

need to be fenced to protect pronghorn. Conduct vegetation sampling at 

reintroduction sites to determine forage composition and abundance. Determine if 

Sonoran pronghorn would be able to subsist on available forage. Evaluate 

number, accessibility, availability (permanent, ephemeral, seasonal etc.), and 

quality of water sources. Determine whether sources of water are present. If 

natural, determine if perennial or seasonal. If man-made, determine if they are 

maintained as reliable water sources all year or seasonally. Count water sources 

and measure dispersion of water. Field check water sources to determine if still 

functioning.

1.3.1.1. Evaluate legal aspects of reintroduction at each site. Determine whether 

reintroduction will be legal and supported. This may include considering 

establishment of a nonessential experimental population, conducting a 

NEPA analysis, and other steps.

1.3.2. Evaluate reintroduction techniques, taking into consideration site specific needs.

Investigate transfer and release techniques, particularly whether soft or hard 

releases are most effective. Evaluate and modify the trapping and release plan 

annually.

1.3.3. Establish new populations.

1.3.3.1. Release Sonoran pronghorn into Kofa and Sauceda subunits of the Arizona 

Reintroduction Management Unit. An Environmental Assessment for 

Sonoran pronghorn reestablishment was completed that analyzed potential 

reintroduction areas (U.S. Fish and Wildlife Service 2010). Seven potential 

areas were ranked using seven criteria (size, forage, water, fragmentation, 

disturbance, logistics, and other). The Kofa site (Area A) received the 
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113

highest total score and the Sauceda site (Area D) received the second 

highest total score (U.S. Fish and Wildlife Service 2010b). Release of 

Sonoran pronghorn in Areas A and D were each approved in a Finding of 

No Significant Impact (FONSI) for the Environmental Assessment (U.S. 

Fish and Wildlife Service 2011b). 

1.3.3.2. Establish additional populations in other sites already evaluated in the 

Arizona Reintroduction Management Unit. Establish additional populations 

at other sites evaluated in the Environmental Assessment for Sonoran 

pronghorn reestablishment (U.S. Fish and Wildlife Service 2010b).

1.3.3.3. Establish additional Sonoran pronghorn populations within unoccupied 

areas of its historical range in Sonora if the sites are determined to be 

appropriate for reintroduction. 

1.3.3.4. Determine by genetic analysis if pronghorn in the historical range of Baja 

California were A.a. sonoriensis. It would be inappropriate to consider 

introductions in Baja if a different subspecies (e.g., A. a. peninsularis) 

occurred there historically. 

1.3.3.5. If genetically appropriate as determined above, establish Sonoran pronghorn 

populations in Baja California where appropriate and feasible. Work with 

CONANP, SPA, and other Mexican Federal and State agencies to 

determine if reintroduction is compatible with their goals and budgets, and 

if so, proceed to determine feasibility as in 1.3.1 above. Clark and Brown 

(2013) have investigated the physical feasibility of some potential release

sites.

1.3.3.6. Determine by genetic analysis if pronghorn in the historical range of 

California were A.a. sonoriensis. An analysis of museum specimens from 

within the historical range of pronghorn in California is being conducted by 

the University of Arizona.

1.3.3.7. If genetically appropriate as determined above, establish Sonoran pronghorn 

populations in California where appropriate and feasible. Work with 

California Department of Fish and Wildlife, Palm Springs U.S. Fish and 

Wildlife Service Office, BLM, the Marines, and the peninsular pronghorn 

team to determine if reintroduction is compatible with their goals and 

budgets, and if so, proceed to determine feasibility as in 1.3.1 above. Clark 

and Brown (2013) have investigated the physical feasibility of some 

potential release sites. If a California Reintroduction Management Unit is 

established and a decision is made to reintroduce pronghorn, conduct a 

PVA or similar analysis to determine a viable population abundance target. 
Sonoran Pronghorn Recovery Plan, Second Revision 

114

Objective 2: Ensure that there is adequate quantity, quality, and connectivity of Sonoran 

pronghorn habitat to support populations.

2.1. Assess the quantity and quality of Sonoran pronghorn habitat.

2.1.1. Monitor and assess the quantity of habitat through aerial surveys annually. An 

initial assessment of the quantity of habitat available is necessary to determine the 

baseline for evaluating habitat loss and for determining if the habitat criterion has 

been met.

2.1.2. Conduct surveys through terrestrial and other methods (satellite images), as 

needed, to refine our understanding of vegetation changes. Understanding the 

spatial extent and magnitude of vegetation change (e.g., increases in shrubby 

plants, changes in distribution of plant communities) is necessary to determine 

how much habitat has become unsuitable for pronghorn.

2.1.3. Monitor and assess habitat quality (particularly greenness) through aerial surveys 

at least three times a year, and other methods as needed. Greenness is one of the 

best indicators of the nutritional quality of forage. Seasonal variation is extreme in 

the range of Sonoran pronghorn, therefore it is essential to measure several times 

per year to determine the range of variation. Development of quantitative 

indicator(s) of greenness and defensible, cost-effective methods is the first step in 

this recovery action.

2.1.4. Create maps seasonally (coinciding with data collected above) showing results of 

quality and quantities of habitat. Create Geographic Information System (GIS) 

layers that show the quality and quantity of habitat across the range of Sonoran

pronghorn. A spatial database would be valuable for planning where to implement 

restoration actions and for analyzing effects of proposed projects that may 

negatively affect Sonoran pronghorn habitat. 

2.1.5. Create a vegetation map for Sonoran pronghorn habitat throughout its range.

2.1.5.1. In Mexico. Create a vegetation map using the Brown et al. (1994) 

classification system for Mexico. The map should be at the sixth 

(Association) level of detail in Brown et al. (1994).The map will enable 

managers to determine which vegetation types are available and which ones 

are threatened by future land use changes.

2.1.5.2. In the U.S. Vegetation mapping has been completed for Organ Pipe Cactus 

NM, most of BMGR, and portions Cabeza Prieta NWR. Create vegetation 

maps for areas where none have yet been completed.

2.1.6. Assess impacts of unauthorized land use in Sonoran pronghorn habitat. Determine 

where, what type, and to what extent unauthorized or exempted land uses are 

occurring and whether those activities result in habitat impacts.

2.1.7. Install weather stations within Sonoran pronghorn habitat (to measure 

temperature, precipitation, dew point, relative humidity, etc.). Installing weather 

stations will enable the recovery team to assess the impacts of extreme 
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115

temperatures. It would also help determine where water is most limiting and 

where water developments are most needed. In Mexico, work with Comision 

Nacional de Agua (National Water Commission; a federal agency), Comision 

estatal de agua (State Water Commission a state agency), and the University of 

Sonora, as appropriate. In the U.S., work with Recovery Team partner agencies to 

determine number and placement of stations that would provide the most 

representative sample. Although there are a number of weather stations existing 

already, there is a need to link and standardize information so it is more of a 

network. Currently, the Arizona Meteorological Network has 5, BMGR East has 

30, BMGR West has 5, National Oceanic and Atmospheric Administration’s 

Cooperative Observer Network has 14, Cabeza Prieta NWR has 10, Kofa NWR 

has 22, the Flood Control District of Maricopa County has 30, Organ Pipe Cactus 

NM has 25, Pinacate has 3, private landowners have 2, and YPG has 21 weather 

stations. The details will be developed as needed for implementing the recovery 

action.

2.1.8. Update the information on land ownership of Sonoran Pronghorn habitat in 

Mexico. Obtain information on land ownership, preferably on a spatial database.

2.1.9. Monitor (document and track) the protection status of pronghorn habitat in each 

Sonora Management Unit.

2.1.9.1. In Pinacate (every two years). “Protection” means lands that are not at risk 

for conversion to development, mining, intensive agriculture, or other land

uses that would permanently destroy Sonoran pronghorn habitat. Track by 

reporting all new acres protected by category (e.g., UMAs, Areas Naturales 

Protegidas [ANPs], change in El Pinacate Biosphere Reserve core area, etc). 

2.1.9.2. In Quitovac (annually). “Protection” means lands that are not at risk for 

conversion to development, mining, intensive agriculture, or other land uses 

that would permanently destroy Sonoran pronghorn habitat. Track by 

reporting by category all new acres protected (UMA, Areas Naturales 

Protegidas [ANP], etc).

2.2. Protect and/or increase the amount of existing habitat range-wide.

2.2.1. Continue to acquire and protect more land for Sonoran pronghorn conservation in 

Mexico.

2.2.1.1. Expand the size of the core areas within the boundary of the El Pinacate 

Biosphere Reserve. Core areas have the most protection and management 

for Sonoran pronghorn. Expanding the core areas is a management action 

that is not a purchase and would not necessarily change land ownership.

2.2.1.2. Create protected reserve(s) for Sonoran pronghorn within the Quitovac 

Management Unit (e.g., UMA, State, private reserve). CEDES and 

CONANP could work with ejidos, private entities, and/or state or federal 
Sonoran Pronghorn Recovery Plan, Second Revision 

116

governments to create one or more reserves that include the protection of 

Sonoran pronghorn habitat. 

2.2.1.3. Identify and designate priority conservation areas (Área Prioritaria para la 

Conservación – CONANP/ CONABIO) or other State designation for the 

conservation of the Sonoran pronghorn. CEDES and CONANP could work 

with ejidos, private entities, and/or state or federal governments to create 

one or more reserves that include the protection of Sonoran pronghorn 

habitat. 

2.2.2. Acquire more land for Sonoran pronghorn conservation in the U.S. Although most 

Sonoran pronghorn habitat is already in federal ownership, some private lands 

could be acquired by federal or State agencies and put into status that is protected 

from conversion to other land uses. 

2.2.3. Protect, through appropriate laws, regulations, and policies, Sonoran pronghorn 

habitat in the U.S. Although most land currently occupied by Sonoran pronghorn 

in the U.S. is currently managed by the federal government, lands within

reintroduction units are not all federally-owned or in protected status. These lands 

could go into a status that would protect Sonoran pronghorn habitat from 

conversion to other land uses or degradation from current uses. This could include 

conservation easements or change in land use designation.

2.2.4. Restore highly degraded Sonoran pronghorn habitat.

2.2.4.1. Identify and prioritize areas where restoration is needed. Some areas are so 

highly degraded they no longer provide habitat for Sonoran pronghorn, but 

could be restored by planting native vegetation and other methods. Identify 

those areas through aerial imagery, telemetry flights, ground surveys, and 

other field work. 

2.2.4.2. Restore and protect potential Sonoran pronghorn habitat that is highly 

degraded. Restore habitat by planting native vegetation, restoring soils, 

removing hazards, and other methods. Restoration methods will be sitespecific.

2.2.4.3. Work with La Herradura and Noche Buena Mines to restore Sonoran 

pronghorn habitat.

2.2.4.3.1. Work with the Fresnillo mining company to encourage them to 

implement voluntary conservation measures. Fresnillo mining 

company owns the Noche Buena Mine. Fresnillo also co-owns La 

Herradura mine with Newmont Mining Company and operates La 

Herradura (Fresnillo PLC 2016, Wikipedia 2016). Provide technical 

assistance for implementing the restoration, including providing 

information about Sonoran pronghorn habitat needs and habitat 

restoration techniques. 
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2.2.4.3.2. Work with the Newmont Mining Company (based in Colorado) to 

become a corporate sponsor of Sonoran pronghorn recovery and 

implement voluntary conservation measures. Newmont Mining

Company owns 44% of La Herradura (Wikipedia 2016). This action 

provides an opportunity for agencies in the U.S. to facilitate 

conservation of habitat for the Sonoran pronghorn population in 

Quitovac.

2.2.5. Promote the conservation and protection of ANPs, Predios Certificados para la 

Conservación (Certified Properties for Conservation), communal and/or private 

reserves, and UMAs. Promote the establishment and conservation of these areas 

by working with responsible agencies, communities, and landowners. 

2.2.6. Ask the existing UMAs to incorporate Sonoran pronghorn in their list of protected 

and managed animals (free ranging pronghorn already occur within the UMAs).

2.3. Prevent or minimize the loss of Sonoran pronghorn habitat to land use impacts.

2.3.1. Cooperate with La Herradura Mine on their mining plan to prevent and minimize 

loss of Sonoran pronghorn habitat. Work with the mine on ways to minimize the 

footprint of the mine in Sonoran pronghorn habitat. 

2.3.2. Work with agencies and authorities (federal, state, municipal) to monitor, prevent, 

minimize, and/or mitigate habitat loss or future detrimental land use changes.

2.3.2.1. In Mexico SEMARNAT and SAGARHPA are responsible for monitoring, 

preventing, and/or mitigating these land use changes through implementing 

state and federal laws.

2.3.2.2. In the U.S. In the U.S. this coordination would occur primarily through 

ESA section 7 consultation on projects with a federal nexus. 

2.3.3. Monitor by land use type the area of Sonoran pronghorn habitat lost and extent of 

Sonoran pronghorn habitat fragmentation caused by all land uses. Land use 

activities include mines (e.g., La Herradura), agriculture, development, renewable 

energy, off-road races near Rocky Point, etc. Track the number of acres reported 

in consultation documents in the U.S. and by aerial imagery in Sonora. This 

includes tracking the spread of the La Herradura mine footprint and other mines 

in Sonora annually. Maintain information in a GIS database. Suitable habitat 

models for the Quitovac management unit could be created by incorporating data 

and suggested refinements from Pate (2014). Suitable habitat models/maps could 

be used to monitor area of suitable habitat available and determine if desert lost to 

agriculture, mines, etc. was within suitable habitat. Otherwise land use 

conversions would be tracked for the entire management unit.
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2.4. Implement environmental services, employment programs, and rural development 

programs in priority Sonoran pronghorn conservation areas in Sonora, and limit and/or 

regulate activities and infrastructure that can threaten those areas.

2.4.1. Work cooperatively with land owners within the ANPs and UMAs to adapt land 

management to benefit pronghorn. Work with these landowners and communities 

to provide information and to help them apply for federal programs to benefit 

ecosystem conservation.

2.4.2. Promote productive alternative low impact activities that benefit wildlife on 

ranches (wildlife management, ecotourism, etc.) These activities include, 

“Productive diversification,” a concept in the Mexican General Wildlife Law that 

refers to alternative low-impact activities that benefit wildlife on ranches. 

Examples include wildlife management and harvesting, ecotourism, and use of 

local plants in natural habitats.

2.4.3. Establish programs to organize and coordinate agricultural and livestock activities 

in or around important pronghorn habitat. Work with landowners and 

communities to improve cattle management so that it is compatible with Sonoran 

pronghorn conservation. Coordinate with SAGARPHA and La Union Ganadera 

Regional del Estado de Sonora (Cattle Union of Sonora) on this action. 

2.4.4. Promote coordinated actions regarding land use programs at the municipal and 

state levels, focused on avoiding changes in land uses in priority conservation 

areas for pronghorn.

2.5. Maintain and improve the quality of existing habitat (including an appropriate mix of 

vegetation types) range-wide.

2.5.1. Limit livestock grazing where it impacts Sonoran pronghorn habitat.

2.5.1.1. Reduce the amount of livestock grazing where it impacts Sonoran 

pronghorn habitat.

2.5.1.1.1. Coordinate with appropriate agencies to examine the need to reduce 

livestock numbers. In the U.S., BLM has specific procedures for 

reducing livestock numbers that would need to be followed. In 

Sonora, coordination would be with SAGARHPA and UMAs.

2.5.1.1.2. Reduce livestock numbers as determined by 2.5.1.1.1.

2.5.1.1.3. Provide financial incentives/ and other income opportunities to 

ranchers to reduce livestock grazing.

2.5.1.1.3.1. In Mexico. Incentives could come through programs such as 

Servicios Ambientales (environmental services) – CONAFOR

(Comisión Nacional Forestal); PROCODES (Programa de 

Conservacion para Desarollo Sustantable) – CONANP; or PROCER 

(Programa para la Conservacion de Especies en Riesgo) -

CONANP.
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119

2.5.1.1.3.2. In the U.S. Non-governmental organizations, such as TNC may be 

able to establish forage banks. This action may also include buying 

out allotment grazing privileges or land from willing sellers.

2.5.1.1.4. Develop and implement other strategies to reduce livestock grazing.

2.5.1.2. Track changes in the number of cattle. 

2.5.1.2.1. In Mexico. Develop an index with SAGARHPA or others.

2.5.1.2.2. In the U.S. This is already a requirement for allotments on BLM land 

in the U.S.

2.5.2. Reduce the impacts of livestock grazing where it will continue.

2.5.2.1. Coordinate with appropriate agencies to incorporate conservation measures 

to maintain or improve pronghorn habitat and forage availability. 

Coordinate with both U.S. agencies and Mexican agencies responsible for 

managing lands with livestock (e.g., BLM and SAGARPHA). Coordination 

will be to reduce the effects of livestock grazing on habitat quality, 

including, but not limited to, threats from reduced forage quality, increases 

in invasive and/or shrubby plants, and erosion. See Yoakum (2004, pages 

521-532) for general recommendations for design of grazing systems in 

areas with pronghorn, which could be adapted for the unique habitat 

requirements of Sonoran pronghorn.

2.5.2.2. Involve SAGARPA, SAGARHPA, and other agencies in improving 

management of areas for the Sonoran pronghorn in Sonora. These agencies 

are responsible for agricultural activities, including grazing, in Sonora.

2.5.2.3. Decrease livestock numbers or remove livestock from habitat during times 

of emergency (drought, fire, etc). Livestock grazing may increase the 

impact on availability and quality of forage during times that forage species 

are stressed, such as during drought. Emergency removal of livestock 

during times of emergency can be implemented by BLM with little lead 

time. Work with SAGARPA and SAGARHPA to develop similar protocols. 

2.5.2.4. Establish a utilization monitoring protocol and utilization thresholds, which 

if exceeded, would trigger the reduction or removal of livestock to maintain 

adequate forage and habitat for pronghorn.

2.5.2.4.1. In Mexico. SAGARPA provides recommendations on utilization 

thresholds to landowners in Sonora; however, they do not regulate 

the threshold. CEDES and CONANP could work directly with 

landowners to reduce livestock grazing through incentive programs 

as discussed above in 2.5.1.1.2.1.

2.5.2.4.2. In the U.S. Continue to monitor utilization within BLM-managed 

allotments, and adapt BLM protocols to include additional or revised 

measures that are more specific to Sonoran pronghorn habitat. Most 

other lands within Sonoran pronghorn habitat in the U.S. (e.g., 
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120

Cabeza Prieta NWR, BMGR, Organ Pipe Cactus NM) are not 

grazed.

2.5.3. Manage invasive species in Sonoran pronghorn habitat.

2.5.3.1. Remove feral burros, goats, cattle, and horses in Sonoran pronghorn habitat. 

Feral (unmanaged wild) livestock can damage Sonoran pronghorn habitat 

by spreading invasive plants, overgrazing forage, causing erosion, and 

compacting soil. Removal of feral livestock on Organ Pipe Cactus NM and 

Cabeza Prieta NWR has resulted in improved forage conditions and water. 

Feral burros can deny ungulates access to water sources and their urine and 

feces can rapidly degrade water sources, making them unsuitable for 

pronghorn (John Hervert, AGFD, personal communication, 2013). The 

Cabeza Prieta NWR staff observed a lone jack (male) burro successively 

drive three mature mule deer bucks away from one of the wildlife waters on 

the refuge, denying them access until they eventually departed the area. 

Pronghorn, being a smaller ungulate than a mule deer, would be likely

similarly affected at a water source that was frequented by burros.

2.5.3.2. Manage invasive, non-native plant species.

2.5.3.2.1. Identify distribution of invasive, non-native plant species that occur 

within Sonoran pronghorn habitat and assess the need to control 

them. Although some invasive, non-native plant species are known to 

occur within the range of Sonoran pronghorn, the extent of their 

distribution has not been fully investigated. Efforts have been made 

to map some species, such as bufflegrass, but maps showing overlap 

of their distribution with Sonoran pronghorn habitat have not been 

produced. The geographic scope of this stress, and resulting need for 

management, will remain unknown until the distribution has been 

identified. Monitor area of spread by species.

2.5.3.2.2. Control invasive, non-native plants if they are determined to be 

detrimental to Sonoran pronghorn habitat and if the benefit of 

controlling the species outweighs the potential risks to pronghorn. As 

the recovery team gains more knowledge about the distribution and 

impact of non-native plants, the priorities for which species and 

locations to conduct control will evolve. Those species that do cause 

significant alteration of structure or composition of Sonoran 

pronghorn habitat should be controlled using mechanical, manual, 

chemical, or biological methods. However, in some cases the impact 

of the control on Sonoran pronghorn (e.g., forage loss, toxicity, or 

human disturbance) may exceed the impact of the non-native plant. 

2.5.3.2.3. Ensure herbicide use within Sonoran pronghorn habitat does not 

negatively affect Sonoran pronghorn or habitat. Herbicide may be 
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121

applied to benefit agriculture or native species or ecological 

communities other than Sonoran pronghorn. Ensuring such herbicide 

use does not impact Sonoran pronghorn or their habitat would 

involve coordination with land management agencies, agricultural 

agencies, or other groups. It may also involve landowner agreements 

or agreements with ejidos, agricultural groups, or other interested 

groups.

2.5.4. Avoid and minimize impacts (contamination, fugitive dust, noise, lights, off-road 

vehicle use, changes in runoff patterns etc.) on Sonoran pronghorn habitat quality 

from adjacent projects and activities. Work with developers, mining companies, 

farms, energy facilities, and others to ensure their projects do not spread dust, 

cause erosion, or otherwise impact Sonoran pronghorn habitat outside the 

footprint of the development. These edge effects could effectively reduce the size 

of habitat patches available to pronghorn. 

2.5.5. Minimize and mitigate impacts of border-related activity on Sonoran pronghorn 

habitat.

2.5.5.1. Work with Customs and Border Protection (CBP) and USBP to minimize 

and mitigate, to the greatest extent possible, operation of off-road vehicles 

in Sonoran pronghorn habitat. Off-road vehicle use contributes to erosion 

and altered hydrology which can affect forage and availability of water.

2.5.5.2. Work with USBP to minimize road dragging that is currently occurring in 

Sonoran pronghorn habitat. These roads affect hydrology, erosion, and 

vegetation of Sonoran pronghorn habitat. Work with USBP to find ways to 

minimize their creation and use or minimize their impacts on habitat.

2.5.5.3. Work with USBP to identify and implement alternative methods of crossborder violator detection that are less destructive than road dragging to 

Sonoran pronghorn habitat. Identify methods that minimize soil and water 

erosion and do not change vegetation structure or composition. One 

example would be integrated fixed towers.

2.5.5.4. Work with USBP to minimize, to the greatest extent possible, impacts of 

other border operations on Sonoran pronghorn habitat quality. In particular, 

work with USBP to limit the use of existing roads to the ones that are most 

critical to Border Patrol and explore alternatives to reduce the creation of 

new roads. Restore unnecessary roads. 

2.5.5.5. Document number/miles of new drag roads, and undesignated vehicle 

routes and trails created. Documenting the amount of roads and trails will 

enable monitoring of the effectiveness of strategies listed above.

2.5.5.6. Monitor extent of erosion and changes in hydrologic patterns resulting from 

new roads and routes.
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2.5.6. Reduce the impacts of mines (e.g., La Herradura) on Sonoran pronghorn habitat 

quality.

2.5.6.1. Assess the effects of La Herradura mine on Sonoran pronghorn habitat 

quality (contamination, fugitive dust, noise, lights, off-road vehicle use, 

etc.). The effects of mining can extend beyond the footprint of the mine. It 

is important to know if the La Herradura mine is having a negative impact 

on Sonoran pronghorn habitat surrounding it. 

2.5.6.2. Work with La Herradura mine and provide technical assistance to minimize 

and mitigate the effects of the mine on Sonoran pronghorn habitat. 

Technical assistance would be aimed at ensuring all areas outside the 

footprint of the mine are minimally impacted. Assistance could be provided 

to minimize dust, runoff, lights, and contamination that penetrate into 

Sonoran pronghorn habitat as well as reducing off-road vehicle use in 

Sonoran pronghorn habitat surrounding the mine.

2.5.6.3. Identify and work with other mines that impact Sonoran pronghorn habitat. 

Technical assistance would be similar to that described for La Herradura 

mine above.

2.5.7. Reduce the negative impacts of agriculture on Sonoran pronghorn habitat quality.

2.5.7.1. Identify where agriculture impacts Sonoran pronghorn habitat quality.

2.5.7.2. Work with agricultural representatives to minimize and mitigate the effects 

of agriculture on Sonoran pronghorn habitat.

2.5.8. Establish Best Management Practices (BMPs) for U.S. projects on BLM land, to 

minimize the impacts of projects on Sonoran pronghorn habitat quality. BLM will 

work with the Recovery Team to create recommendations for BMPs and potential 

mitigation for all actions that may impact Sonoran pronghorn and their habitat.

2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran pronghorn habitat. 

This would include evaluating impacts and if detrimental impacts are occurring, 

assemble a team to develop and implement strategies to minimize and mitigate the 

impacts.

2.6. Protect and/or improve the connectivity of existing Sonoran pronghorn habitat rangewide.

2.6.1. Improve Sonoran pronghorn habitat connectivity where it is impeded by barriers 

(e.g., highways, fences, canals).

2.6.1.1. Monitor the number of barriers in miles. Existing and planned barriers are 

likely documented by Arizona Department of Transportation and La 

Secretaria de Infraestructura y Desarrollo Urbano (the Sonora, Mexico road 

agency), railroad companies, and canal companies. Data (including 

geospatial data) on existing and planned fences could be obtained from land 

management agencies, ejidos, and SAGARPHA.
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123

2.6.1.2. Identify potential travel ways across existing barriers and other 

impediments to Sonoran pronghorn movement. Using telemetry data and 

field observations, identify areas where pronghorn would be most likely to 

attempt to cross highways, canals, fences, and railroads. 

2.6.1.3. Remove or modify existing barriers and impediments to allow for Sonoran 

pronghorn passage (e.g., remove/modify fences, railroad tracks, roads, 

install overpasses). Prioritize areas based on data gathered in 2.6.1.1 for 

fence removal and modification projects. Also install overpasses for 

highways, canals, and railroad tracks. Modify the fences along Mexico 

Highway 2 to funnel pronghorn to safe crossings. Current information 

suggests overpasses would be more successful than underpasses.

2.6.1.4. Monitor (document) number or miles of barriers eliminated or modified to 

allow safe passage by pronghorn. Track the progress by maintaining a 

database of number of miles of barriers eliminated or modified.

2.6.1.5. Protect existing Sonoran pronghorn habitat corridors used frequently for 

movement between seasonal habitat use areas. Some areas are used 

frequently for travel between seasonal use areas. These travel areas should 

be protected from habitat loss, modification, or creation of barriers. 

2.6.2. Prevent creation and/or minimize impacts of new barriers/impediments (e.g., 

roads, fences, transmission lines) to Sonoran pronghorn movement.

2.6.2.1. Work with appropriate authorities and stakeholders to prevent creation of 

new barriers/impediments to Sonoran pronghorn movement. Work 

cooperatively with stakeholders to find ways to achieve their goals without 

creating barriers to Sonoran pronghorn movement.

2.6.2.2. Where new barriers will be constructed, work with appropriate authorities 

and stakeholders to minimize the impacts of those barriers on Sonoran 

pronghorn movement. Effects of barriers can be minimized by altering 

fence design; altering placement of barriers; or providing alternative 

passage routes for pronghorn. 

2.6.3. Minimize current and avoid future Sonoran pronghorn habitat fragmentation (see 

section 2.6.2 for actions pertaining to barriers).

2.6.3.1. Work with mine companies within the Sonoran pronghorn range to avoid 

and minimize habitat fragmentation.

2.6.3.1.1. Work with mine companies operating in Mexico. The La Herradura 

mine could threaten to fragment the area occupied by the Quitovac 

population into two smaller and isolated areas that are not likely to 

provide for the long-range movements and habitat diversity 

necessary for Sonoran pronghorn to persist. It is extremely important 

to ensure any expansion of the mine does not split Sonoran 

pronghorn habitat into two isolated blocks or otherwise restrict 
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124

movement of the population between different areas of its current 

range. It would also be important to ensure any future mines do not 

create similar fragmentation. 

2.6.3.1.2. Work with mine companies operating in the U.S. 

2.6.3.2. Work with authorities to enforce environmental laws pertaining to mining 

to prevent habitat fragmentation. 

2.6.3.3. Work with authorities to enforce environmental laws pertaining to other 

sources of habitat fragmentation (e.g., new paved roads).

2.6.3.4. Establish BMPs for U.S. projects on BLM land, to minimize habitat 

fragmentation.

2.7. Enhance forage quality and availability to support viable populations of Sonoran 

pronghorn range-wide.

2.7.1. Continue forage enhancement plot program in the U.S.

2.7.1.1. Evaluate the effectiveness of existing forage enhancement plots. Develop 

and implement studies to determine if forage enhancement plots are 

effective at: 1) increasing adult survival; or 2) increasing reproductive 

success, primarily fawn survival.

2.7.1.2. Maintain existing forage enhancement plots, including periodic irrigation. 

Maintain plots unless determined ineffective in 2.7.1.1. , above.

2.7.1.3. Evaluate the need for additional forage enhancement plots. 

2.7.1.4. Develop additional plots, if they are determined to be necessary and are 

demonstrated to be successful. 

2.7.2. Continue the supplemental feeding program in the U.S.

2.7.2.1. Evaluate the effectiveness of supplemental feeding of Sonoran pronghorn. 

Develop and implement studies to determine if supplemental feed is 

effective at: 1) increasing adult survival; or 2) increasing reproductive 

success, primarily fawn survival.

2.7.2.2. Provide supplemental feed to Sonoran pronghorn. Continue to provide 

supplemental feed as needed during the spring and summer months to 

enhance the survival of fawns as the pronghorn populations increase to 

target levels. Reevaluate if not determined to be effective. 

2.7.3. Evaluate feasibility of and initiate a food plot program in the U.S.

2.7.3.1. Convert current agriculture to alfalfa for Sonoran pronghorn forage. This 

may include purchasing agricultural lands and using them as additional 

forage enhancement plots or converting to Sonoran pronghorn habitat. 

Arizona State Heritage funds may be available to buy private lands that 

Sonoran pronghorn may use in the future; however, they could only be used 

to purchase land once Sonoran pronghorn use of the area is confirmed 

(Kofa region).
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2.8. Maintain and improve availability of and access to water (both natural and humanmade) range-wide.

2.8.1. Assess availability, amount, and accessibility to current and potential future 

Sonoran pronghorn waters. Monitor availability, amount, and accessibility of 

water seasonally

2.8.2. Map and monitor existing water sites available to Sonoran pronghorn or that could 

be available with some modification. Reduced availability and access to water are 

two of the most significant stressors to Sonoran pronghorn. Mapping water 

sources would provide information on how far apart usable water sources are on 

the landscape and if the distribution of water is adequate considering distance 

between waters and barriers such as paved roads and fences.

2.8.3. Maintain water sources for Sonoran pronghorn. Reduced availability of water is 

one of the most significant stressors to Sonoran pronghorn and is expected to 

worsen with climate change. Maintaining water sources is an action to counter 

this effect of climate change.

2.8.4. Modify existing water sources to make them available to Sonoran pronghorn as 

needed. This may include actions such as removing fences, fixing damaged water 

sources, and taking over abandoned wells to use the water for pronghorn.

2.8.5. Create new water sources for Sonoran pronghorn. Construct new water sources for 

Sonoran pronghorn that the Recovery Team recommends at sites determined 

through consultation between the site specific land management agency and the 

Recovery Team. Construction may include self-filling systems (catchments) or 

drilling wells. Ensure water sources will have certainty of being maintained 

before constructing. Some areas may require pronghorn-safe fencing, grids on top 

of the water, or other devices to exclude livestock. Water catchments may be 

needed within wilderness because approximately half (50.3%) of the current 

Cabeza Prieta population range is designated wilderness. Within Cabeza Prieta 

NWR, approximately 93% of the refuge is designated wilderness, and within the 

Organ Pipe Cactus NM, approximately 95% is designated wilderness. There are 

few remaining opportunities within the southern half of the current Cabeza Prieta 

range to implement meaningful recovery actions for Sonoran pronghorn outside 

of wilderness.

2.8.5.1. In the U.S. New waters sources for Sonoran pronghorn will be considered 

for construction based upon the recommendation of any land management 

representative on or associated with the Recovery Team. Any decision to 

proceed with construction will follow consultation and coordination 

between the site-specific land management agencies involved, AGFD, 

FWS, and Recovery Team. Coordinatation with other entities and 

acquisition of necessary permits may also be required. 
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2.8.5.2. In Mexico. New waters were constructed at El Pinacate Biosphere Reserve 

and in the Quitova area in 2015. Investigate reasons these waters are not 

being used and make any adjustments needed to encourage use. Construct 

new waters where feasible and beneficial to Sonoran pronghorn.

Objective 3. Minimize and mitigate the effects of human disturbance on Sonoran 

pronghorn.

3.1. Minimize and mitigate the impact of border-related activities on Sonoran pronghorn.

3.1.1. Complete study of effects of human disturbance on Sonoran pronghorn. As of 

2016, a study is ongoing that is examining the effects of human activity on 

Sonoran pronghorn. 

3.1.2. Monitor an index of border-related human disturbance. The index may be 

recommended by the human disturbance study. It may be most meaningful to 

monitor disturbance at important habitat features such as water sources and forage 

plots. It may also be effective to monitor an index of human disturbance based on 

the number of border crossers and CBP/USBP activities (obtain documentation 

from CBP). 

3.1.3. Continue to work with CBP/USBP to minimize and mitigate the impacts of their 

operations on Sonoran pronghorn. Work with CBP/USBP to find solutions to 

enable effective operations while protecting Sonoran pronghorn from human 

disturbance, including disturbance from vehicles and low-level helicopter 

operations as well as foot patrols. Continue educating agents about the status of 

the subspecies and the sensitivity of Sonoran pronghorn to human disturbance. 

Measures to avoid and minimize human disturbance impacts resulting from CBP 

operations have been included in biological opinions. The FWS, Recovery Team, 

and CBP need to continue to collaborate to ensure the effectiveness of these 

measures, and develop new measures as needed.

3.2. Minimize and mitigate the impact of recreational activities on Sonoran pronghorn.

3.2.1. Work with off-highway vehicle (OHV) groups to inform them about Sonoran 

pronghorn and ways to minimize disturbance to the species. This could include 

presentations to OHV groups or meeting with group leaders.

3.2.2. Evaluate impacts of off-road races near Puerto Peñasco (Rocky Point), Sonora and 

the need to develop measures to minimize their impact on Sonoran pronghorn.

Measures, if needed, may include regulating or developing BMPs with racing 

groups to minimize disturbance to pronghorn.

3.2.3. Work with other recreational users to inform them about Sonoran pronghorn and 

ways to minimize disturbance to the species. This could include presentations to 

hiking, biking, hunting, or other recreational groups or meeting with group 
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127

leaders. The Cabeza Prieta NWR staff members currently conduct outreach 

presentations. This action should continue to encourage the groups to care about 

Sonoran pronghorn conservation, recognize if their actions may disturb 

pronghorn, and utilize practices that minimize disturbance.

3.2.4. Consider closing some areas of El Pinacate Biosphere Reserve to recreational 

activity.

3.2.5. Consider closing select roads and trails to public use during times of the year 

when Sonoran pronghorn are under stress. This would be determined by the 

Recovery Team on an annual basis, including identifying which roads and the 

timing of the closure. These could be emergency closures or ongoing annual 

closures as needed for times of extreme population decline or other extreme 

circumstances.

3.3. Minimize and mitigate the impact of military activities on Sonoran pronghorn.

3.3.1. Continue to work with the military partners in the U.S. (BMGR [MCAS Yuma

and Luke Air Force Base], Army National Guard, Yuma Proving Ground) to 

minimize the impact of military activities on Sonoran pronghorn. On BMGR East, 

this would be a continuance of the near-daily monitoring for presence of 

pronghorn in vicinity of targets. When pronghorn are detected, targets within 

specified distances are closed for the day.

3.3.2. Update the Memorandum of Understanding between the Department of Defense 

and Department of Interior Relating to the Cabeza Prieta NWR. It was signed in 

1994 and at some point, will need to be updated.

3.4. Minimize and mitigate the impact of public land management agency activities on 

Sonoran pronghorn.

3.4.1. Continue to work with land management agencies in the U.S. to minimize the 

impact of their activities on Sonoran pronghorn. Work with land management 

agencies to ensure they have policies in place to inform employees, volunteers, 

and contractors of ways to avoid disturbing pronghorn when conducting field 

activities.

3.5. Minimize and mitigate the impact of mining activities on Sonoran pronghorn.

3.5.1. Identify sources of disturbance to Sonoran pronghorn from mining activities. 

Sources of disturbance could include vehicles, personnel, and other human 

activities in the vicinity of mines. The Recovery Team needs further information 

to determine which activities associated with mining are disturbing to Sonoran 

pronghorn and how far from the mines these disturbances affect pronghorn.

3.5.2. Work with mining authorities to minimize and mitigate human disturbance. Work 

with mining companies to ensure they have policies in place to inform employees 
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128

and contractors of ways to avoid disturbing pronghorn and minimize human 

activities in areas surrounding the mines.

3.6. Minimize and mitigate the impact of other activities on Sonoran pronghorn.

3.6.1. Identify sources of disturbance to Sonoran pronghorn from other activities. These 

activities may include agriculture and ranching, and other sources that have not 

yet been identified.

3.6.2. Work with authorities regulating these other activities to minimize and mitigate 

human disturbance when and where feasible. Work with companies to ensure they 

have policies in place to inform employees and contractors of ways to avoid 

disturbing pronghorn and minimize human activities.

Objective 4. Identify and address priority Sonoran pronghorn population monitoring 

needs.

4.1. Aerially survey Sonoran pronghorn populations annually to determine abundance.

4.2. Monitor Sonoran pronghorn populations to determine, among other things, population 

structure (e.g., sex ratios, recruitment, and age), mortality, and distribution.

4.2.1. Continue to monitor using periodic telemetry flights.

4.2.2. Monitor using other methods. Use methods such as hilltop surveys and cameras in 

addition to telemetry flights where they may add additional information.

Investigate use of fecal DNA to improve population estimates. Fecal DNA can be 

used to estimate population size and survival (Woodruff, et al, in press), as well 

as to monitor movement of individuals.

4.2.3. Identify sources of Sonoran pronghorn mortality when possible. 

4.3. Continue to mark (e.g., ear tags, collars) captive-raised Sonoran pronghorn released 

from pens. Marking captive-raised pronghorn when they are released from a pen is 

relatively safe and inexpensive when compared to capturing and marking wild animals 

and provides an effective means to use mark-recapture monitoring methods. 

4.4. Evaluate the need to capture and mark (e.g., ear tags, collars) wild Sonoran pronghorn 

and implement as needed. Evaluate if additional wild Sonoran pronghorn need to be 

tagged or collared for population monitoring enhancement to be accurate.

4.5. Monitor effectiveness of predator control if and when implemented. If predator control 

is implemented, conduct monitoring to determine its effectiveness; if and when the 

objectives have been achieved; and if the effort is worthwhile or needs to be modified,

changed, or discontinued. 
Sonoran Pronghorn Recovery Plan, Second Revision 

129

4.6. Ensure adequate training, personnel, and infrastructure are available to monitor 

Sonoran pronghorn.

4.6.1. Ensure adequate training, personnel, and infrastructure are available for 

monitoring Sonoran pronghorn in Mexico.

4.6.1.1. Train personnel in Mexico for monitoring Sonoran pronghorn. 

4.6.1.2. Provide equipment (e.g., radio collars) to personnel in Mexico. 

4.6.1.3. Establish a biological station in or near the Quitovac Management Unit. 

4.6.1.4. Ensure adequate numbers of personnel are available to monitor Sonoran 

pronghorn in Mexico.

4.6.2. Ensure adequate training, personnel, and infrastructure are available for 

monitoring Sonoran pronghorn in the U.S. 

4.6.2.1. Train personnel for monitoring Sonoran pronghorn. 

4.6.2.2. Provide equipment (e.g., radio collars).

4.6.2.3. Ensure adequate numbers of personnel are available to monitor Sonoran 

pronghorn.

4.6.3. Report regularly on Sonoran pronghorn status.

4.6.3.1. Provide periodic (monthly or as needed) Sonoran pronghorn status updates.

4.6.3.2. Notify appropriate agencies and personnel of Sonoran pronghorn fatalities.

4.6.4. Identify additional Sonoran pronghorn monitoring needs.

Objective 5. Identify and address priority research needs.

5.1. Research the extent of disease within Sonoran pronghorn populations. The Recovery 

Team can develop a good herd health profile by sampling both wild and captive 

animals when handled. Random, captive and wild fecal samples can provide additional 

health information. The diseases of most concern to date are Blue tongue and 

Epizootic Hemorrhagic Disease in both groups and coccidia in the captive pens. If 

Sonoran pronghorn are exposed to livestock in the future, other communicable 

diseases will be of concern depending upon which livestock are present and their

geographical location.

5.2. Continue to research the impact of human disturbance on Sonoran pronghorn 

populations. Continue to support the study “Effects of human activities on Sonoran 

Pronghorn” and determine if additional research is necessary.

5.3. Investigate ways to optimize Sonoran pronghorn survey techniques. Consider using 

data from concurrent pronghorn monitoring efforts (e.g., cameras placed at waters, 

data collected by the BMGR range monitors, and use of fecal DNA) to corroborate 

data collected from aerial surveys.
Sonoran Pronghorn Recovery Plan, Second Revision 

130

5.4. Research and evaluate genetic diversity, gene flow, and potential founder effects of 

Sonoran pronghorn wild populations. Utilize feces, blood, hair, or other types of 

samples such as opportunistic tissue samples. Collect samples yearly, if feasible and 

budgets allow.

5.5. Continue conducting periodic evaluation of genetic diversity of captive Sonoran 

pronghorn populations. Monitor genetic diversity (heterozygosity, allelic richness, and 

number of unique haplotypes) from fecal pellets and blood samples, including 

collections from a variety of locations (some at waters and some free range) until 50 

samples are obtained per population. Monitor every four years.

5.6. Determine if Baja and California reintroduction sites should have Sonoran pronghorn 

or peninsular pronghorn through genetic analysis of museum specimens. CONANP is 

working on genetic analysis of peninsular and Chihuahuan pronghorn. Plan a meeting 

among researchers to share information on genetic analysis results.

5.7. Investigate Sonoran pronghorn subspecies differentiation relative to other pronghorn 

subspecies. This could include genetic, epigenetic, and/or morphometric 

investigations. 

5.8. Research the impact of predation on Sonoran pronghorn fawns. Determine if predation 

on fawns is occurring at high enough levels to have an effect on populations.

5.9. Investigate effects of cattle grazing on Sonoran pronghorn habitat. Determine extent of 

competition for forage between cattle and Sonoran pronghorn. Determine if cattle 

grazing is affecting Sonoran pronghorn forage species composition or abundance. 

Determine whether cattle grazing is impacting vegetation structure in ways that are 

detrimental to pronghorn (e.g., reducing thermal cover or fawning cover).

5.9.1. In Mexico.

5.9.2. In the U.S.

5.10.Investigate interactions and competition between deer and Sonoran pronghorn. The 

primary focus should be on mule deer. This investigation would be especially 

appropriate in the eastern portions of BMGR and Organ Pipe Cactus NM where 

pronghorn observations have declined since 1940 and mule deer observations have 

increased. The relationship could be due to habitat changes, water provision, or 

competition.

5.11.Investigate the effects of fire on Sonoran pronghorn.
Sonoran Pronghorn Recovery Plan, Second Revision 

131

5.11.1. Research Sonoran pronghorn fawn recruitment as it relates to the relationship 

between burned areas and predation. Although burned areas provide improved 

forage, they provide less cover and seem to have greater fawn predation. Research 

is needed to determine if greater predation in burned areas is a consistent pattern.

5.11.2. Evaluate effects of fire on forage availability and vegetation structure.

5.11.3. Monitor the area of Sonoran pronghorn habitat with fire frequencies outside the 

natural range of variation. Work with plant ecologists to determine the natural 

range of variation in fire frequencies.

5.12. Research the effects of supplemental water sources on Sonoran pronghorn adult 

survival and fawn recruitment. Supplemental water is instrumental in increasing adult 

survival and fawn recruitment. Validating this assumption is crucial for determining if 

the priority placed on supplying water is justified. This research should also include 

the influence of other variables on survival and recruitment.

5.13.Investigate Sonoran habitat use and preferences, including identifying critical use 

areas.

5.14. Investigate the effects of helicopters on Sonoran pronghorn. The study should focus 

on the intensity and frequency of helicopter use by USBP in their interdiction effort. 

USBP helicopter flight patterns are different than military flight patterns. USBP 

helicopter use involves slow back and forth and hovering movements that are 

hypothesized to impact Sonoran pronghorn more than military flights, which fly higher 

and in more direct paths.

5.15.Describe demography and reproductive biology of Sonoran pronghorn in Sonora.

Little information is available currently on demography and reproductive biology in 

Sonora. Differences between Sonoran populations and U.S. populations need to be 

understood before recovery actions that are based on field data collected in the U.S. 

can be assumed appropriate for pronghorn populations in Sonora.

5.16.Determine extent of Sonoran pronghorn distribution in Mexico.

5.17.Revise PVA in ten years, or earlier if determined necessary due to new information.

5.18.Coordinate among individuals conducting field work within Sonoran pronghorn 

management units. Ensure coordination among researchers, biologists, managers, and 

citizen scientists to optimize research efforts, staffing, and funding. 
Sonoran Pronghorn Recovery Plan, Second Revision 

132

5.19.Centrally manage Sonoran pronghorn data. Ensure historical and current data 

collected on Sonoran pronghorn ecology, recovery, and management (of biotic and 

abiotic elements) by researchers, biologists, managers, and citizen scientists is shared 

with appropriate groups and organized and managed in a database. The purpose of this 

database is to facilitate data management, archiving, and inquiries. 

Objective 6. Maintain existing partnerships and develop new partnerships to support 

Sonoran pronghorn recovery.

6.1. Continue the work of the Recovery Team. The Recovery Team is vital for sharing 

information among partners and developing cooperative projects.

6.2. Continue and promote coordination between Mexico and the U.S. to recover Sonoran 

pronghorn. 

6.2.1. Establish a binational agreement or letter of intent (Mexico-U.S.) to implement 

binational recovery actions in the Sonoran Pronghorn Recovery Plan and PACE. 

A letter of intent between CONANP and the FWS would help Mexico and the 

U.S. coordinate on implementing joint recovery actions. 

6.2.2. Establish a binational steering committee for the Sonoran pronghorn that could 

facilitate and support the tasks of the Recovery Team, exchange between 

ministries in the Mexican Government, and the commitment of resources (both 

human and economic) towards the Plan. Information exchange should occur 

annually and meetings should be held as necessary, or at least every 5 years. 

Information to be exchanged should include progress in implementing state and 

federal Sonoran pronghorn recovery and conservation plans in the U.S. and 

Mexico, including updates on implementation of actions from both the PACE and 

the U.S. recovery plan as well as their effectiveness in recovering Sonoran 

pronghorn. Agencies in Mexico could include: CONANP, DGVS, PROFEPA, 

state wildlife agencies, and other agencies as necessary. Agencies in the U.S. 

could include: FWS, AGFD, and other agencies as necessary.

6.2.3. Coordinate to secure funding to recover Sonoran pronghorn.

6.3. Develop a Sonora State PACE for Sonoran pronghorn to, among other things, faciliate 

recovery actions between Sonora and Arizona.

6.4. Expand partnerships with interested groups to implement Sonoran Pronghorn recovery. 

Expand partnerships to include groups that may support Sonoran pronghorn recovery. 

Also partner with groups that may be opposed to recovery actions to develop mutuallyagreeable actions.
Sonoran Pronghorn Recovery Plan, Second Revision 

133

6.5. Increase public support for the Sonoran pronghorn recovery program. Public support can 

be increased through public presentations and media. 

6.6. Promote active social participation in the protection of Sonoran pronghorn and habitat in 

Mexico. 

6.7. Increase and maintain community vigilance programs in Mexico (Programa de 

Vigilancia is the existing federal program in Mexico). Increase support of the program

and expand the program outside of Pinacate. 

6.8. Engage universities and other interested parties (e.g., zoos) in priority research of 

Sonoran pronghorn. Communicate Sonoran pronghorn research needs to universities 

through symposia (e.g., Sonoran desert symposium), and communication with individual 

professors, research teams, and students.

6.9. Conduct education and outreach to promote Sonoran pronghorn recovery. Include 

information on the loss of natural water sources and importance of supplemental water to 

counter effects of climate change. Specific education and outreach programs and 

materials (e.g., videos, pamphlets, posters) for those who live in the range of Sonoran 

pronghorn should be developed in Spanish and English and disseminated.

6.10.Work with governments (federal, state, and municipal) to recover Sonoran pronghorn. 

6.11.Work to improve and maintain partnerships with ranchers in Mexico to conserve 

Sonoran pronghorn. Develop specific information (videos, pamphlets, posters) for those 

that live in the pronghorn areas and/or support the recovery plan.

6.12.Develop, maintain, and disseminate a directory of specialists and working groups that 

conduct studies or implement actions for the management, recovery, conservation, and 

protection of the Sonoran pronghorn at the regional, national, and international level. 

Develop and maintain the directory as part of Recovery Team duties.

6.13.Ensure sufficient personnel are trained and resources (e.g., vehicles) are available to 

adequately monitor, manage, and protect Sonoran pronghorn in Mexico. An evaluation 

of the current and needed levels of personnel should be conducted. 

Objective 7. Secure adequate funding to implement recovery actions for Sonoran 

pronghorn.

7.1. Explore U.S.-based funding source options; secure and manage funds acquired from 

those sources.
Sonoran Pronghorn Recovery Plan, Second Revision 

134

7.2. Explore Mexico-based funding source options; secure and manage funds acquired 

from those sources.

7.3. Secure and manage mitigation and compensation funding in the U.S.

7.4. Secure and manage mitigation and compensation funding in Mexico.

7.5. Manage the environmental impact mitigation fund in Mexico to ensure that funds are 

applied specifically to Sonoran pronghorn conservation. Regardless of the species 

being impacted by a project, mitigation funds for that project go into a general 

conservation fund and are not necessarily used to mitigate impacts to the species 

affected by the project. Language should be added to that fund for the conservation of 

pronghorn, when pronghorn are impacted by projects.

7.6. Secure and manage funding from other funding sources (e.g., nongovernmental 

organizations, international funds, corporate sponsors). 

Objective 8. Practice adaptive management, in which recovery is monitored and recovery 

tasks are revised by the FWS in coordination with the Recovery Team as new 

information becomes available.

8.1. Use adaptive management principles in the context of structured decision making (e.g., 

The Open Standards for the Practice of Conservation by the Conservation Measures 

Working Group [http://cmp-openstandards.org/] and the Department of Interior’s 

Technical Guide to Adaptive Management) to evaluate this recovery effort on an 

ongoing basis.

8.1.1. Conduct monitoring of Sonoran pronghorn populations, habitat, and threats.

Monitoring that is needed is listed in sections above. Monitoring populations will 

provide information on success towards reaching population criteria. Monitoring 

habitat and threats is also important because large populations would still be 

vulnerable if threats persist. Habitat and threats monitoring indicators will need to 

be refined and methods and monitoring plans developed. It may be important to 

respond to a rapidly-growing threat before its effects are shown in Sonoran 

pronghorn population sizes or demographics because by the time effects are 

shown in populations the threat may have already reached an irreversible 

threshold. 

8.1.2. Analyze and share results of monitoring.

8.1.2.1. Compile (FWS) and discuss Sonoran pronghorn recovery accomplishments 

and updates (via email, conference call, or meeting) with the Sonoran 
Sonoran Pronghorn Recovery Plan, Second Revision 

135

Pronghorn Recovery Team at least two times per year. Discuss formal 

monitoring results and informal observations as well as successes and 

failures with recovery implementation.

8.1.2.2. Exchange information annually and hold meetings as necessary, or at least 

every two years, between agencies and universities in Mexico and the U.S.

to discuss progress in implementing Sonoran pronghorn recovery in the 

U.S. and Mexico. Agencies in Mexico include: CONANP, CEDES, DGVS, 

PROFEPA, and other agencies as necessary. Agencies in the U.S. include: 

FWS, AGFD, Organ Pipe Cactus NM, and other agencies as necessary.

8.1.2.3. Report regularly on Sonoran pronghorn status. See 4.6.3 above for 

population status. Also report regularly on status of habitat and threats.

8.1.3. Revise recovery actions and tasks using monitoring results (Adaptive 

Management Plan). If actions are not effective, revise or eliminate. Increase 

efforts if actions are effective but not broad enough in scope.

8.1.4. Revise recovery criteria, if warranted, following new PVA or if other new 

information becomes available that suggests the recovery criteria in the document 

are not sufficient for recovering Sonoran pronghorn (in 10 years or earlier if 

determined necessary).
Sonoran Pronghorn Recovery Plan, Second Revision 

136

PART III. IMPLEMENTATION SCHEDULE

The implementation schedule that follows outlines the recovery actions and estimated costs for 

the recovery program for Sonoran pronghorn, as set forth in this recovery plan. It is a guide for 

meeting the recovery goals outlined in this plan. This schedule includes recovery action 

numbers, action descriptions, action priorities, duration of actions, the parties responsible for 

actions (either funding or carrying out), and estimated costs. The actions that will incur costs (the 

most stepped-down recovery actions) are indicated by underlining of the action name in the 

implementation schedule. Priorities, responsible parties, and costs are shown for each of these 

actions. For clarity, they are organized by objective and grouped by similar actions as in the 

recovery action outline and narrative. Objectives are indicated in bold. Objective and other 

category headings are not underlined, do not incur costs, and were not prioritized by the team. 

Priorities are based in part on the immediacy and severity of specific threats, as determined by

the threats assessments presented above and in Appendix A, and how each recovery action 

would ameliorate those threats. Action priorities in the implementation schedule are assigned as 

follows:

Priority 1: An action that must be taken to prevent extinction or to prevent the species from

declining irreversibly in the foreseeable future.

Priority 2: An action that must be taken to prevent a significant decline in species

population/habitat quality or some other significant negative impact short of extinction.

Priority 3: All other actions necessary to provide for full recovery of the species.

Action duration is the estimated length of time to complete the recovery action. If the action will 

be continuous throughout the recovery of the species and is currently underway, it is described as

“ongoing.” The Recovery Team expects recovery to take 20 years. Some actions may be 

continuous throughout the recovery period but not currently underway, and are described as

“continuous.” Other actions are of a definite duration, such as research projects, and in these 

cases the estimated number of years to complete the action is provided.

Costs for each recovery action are estimates, and actual budgets will have to be determined when 

each recovery action is undertaken. Cost estimates were rounded from original workbook and 

may not add up due to rounding differences. Cost estimates do not commit funding by any

agency. Section 4(f) of the ESA requires the time and cost to be estimated to reach the plan’s 

goal (usually delisting). For any actions listed as “Ongoing” in duration, costs were calculated 

for 20 years, the time period the Recovery Team estimated to recover the species. To determine 

if an action’s costs should be included, the Recovery Team evaluated if the costs are incurred 

because the species is listed and the action is necessary for recovery (i.e., if they wouldn’t be 

incurred “but for” the recovery action for the listed species). If the costs are due to the species 
Sonoran Pronghorn Recovery Plan, Second Revision 

137

being listed, the Recovery Team included them in the implementation schedule. If, on the other 

hand, the action truly would take place regardless of the involvement of the listed species, the 

Recovery Team did not include the costs. The total estimated cost of recovery, by priority, 

calculated from the information in this implementation schedule is provided in the executive 

summary. In addition to total cost of recovery, annual costs for the first five years are also shown 

in the executive summary.

Responsible parties are the parties with authority, responsibility, or expressed interest to 

implement a specific recovery action. The listing of a party in the Implementation Schedule does 

not require the identified party to implement the action(s) or to secure funding for implementing 

the action(s).

Responsible Party Acronyms Used in the Implementation Schedule:

• ADOT: Arizona Dept. of Transportation

• AESO: AZ Ecological Services Office (FWS)

• All AZMUs: All applicable land and wildlife management agencies in the US 

Conservation Unit, including: DOI (BLM-LSFO, BLM-YFO, CPNWR, 

OPCNM, KOFA), DOD (BMGR-EAST, BMGR-WEST, YPG), AGFD

• All CAMU: All applicable land and wildlife management agencies in the 

California Management Unit including: CDFW. BLM, DOD/CMGR

• All Sonora MUs: All applicable land and wildlife agencies in the Sonora

Management Units: CEDES, CONANP (Pinacate), SAGARHPA

• APHIS: Animal & Plant Health Inspection Service

• AGFD: Arizona Game and Fish Department

• AZMU: all management units in Arizona

• BLM: Bureau of Land Management

• BMGR-EAST: Barry M Goldwater Range-East (Luke Air Force Base)

• BMGR-WEST: Barry M Goldwater Range-West (Marine Corps Air Station 

Yuma)

• CAMU: California Management Unit

• CBP: US Customs and Border Protection

• CDFW: California Department of Fish and Wildlife

• CDPCG: CA Desert Pronghorn Coordination Group
Sonoran Pronghorn Recovery Plan, Second Revision 

138

• CEDES: Commission of Ecology and Development of the State of Sonora 

(Comisión de Ecologies y Desarrollo Sustentable del Estado de Sonora)

• CMGR: Chocolate Mountain Gunnery Range (U.S. Marine Corps)

• CONANP (Pinacate): National Commission of Natural Protected Areas 

(Comisión Nacional de Areas Naturales Protegidas), El Pinacate Biosphere 

Reserve

• CONANP (Priority Species): National Commission of Natural Protected Areas 

(Comisión Nacional de Areas Naturales Protegidas), Priority Species (Especies 

Prioritarias Para La Conservacion)

• CPNWR: Cabeza Prieta National Wildlife Refuge (USFWS)

• DGVS: Mexican Federal Office of Wildlife (Dirección General de Vida 

Silvestre)

• DOD: Department of Defense

• FWS: Fish & Wildlife Service

• ID: Irrigation Districts

• Luke AFB: Luke Air Force Base

• MCAS: Marine Corps Air Station

• OPCNM: Organ Pipe Cactus National Monument

• PROFEPA: Mexican Federal Agency of Environmental Protection (Procuraduría 

Federal de Proteccion del Ambiente)

• SAGARHPA: State of Sonora Ministry of Agriculture, Water Resources, 

Fisheries and Aquaculture (Secretaría de Agricultura, Ganadería, Recursos 

Hidráulicos, Pesca y Acuacultura) 

• SAGARPA: Mexican Federal Ministry of Livestock, Agriculture, Rural 

Development, Fisheries, and Foods (Secretaría de Agricultura, Ganaderia, 

Desarrollo Rural, Pesca, y Alimentación)

• SCT: Mexico Highway Department (Secretaría de Comunicaciones y 

Transportes)

• Sonora CU: Sonora Conservation Unit

• SPA: Environment Protection Minsitry of Baja California (Secretaría de 

Protección al Ambiente de Baja California)
Sonoran Pronghorn Recovery Plan, Second Revision 

139

• SPRT: Sonoran Pronghorn Recovery Team

• U of A: University of Arizona

• UMAs: 

• USCU: U.S. Conservation Unit

• USGS: U.S. Geological Survey

• YPG: Yuma Proving Ground
Sonoran Pronghorn Recovery Plan, Second Revision 

140

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

Na 1 Ensure multiple viable 

populations of Sonoran 

pronghorn range wide.

1 NA NA NA NA NA NA NA NA NA NA

NA 1.1 Stabilize, increase, or maintain 

the number of individuals within 

existing populations, range 

wide, where there is adequate 

habitat 

1 NA NA NA NA NA NA NA NA NA NA

1.1.1 Maintain genetic diversity of 

Sonoran pronghorn 

1 NA NA NA NA NA NA NA NA NA NA

3 1.1.1.1. Transfer animals among 

Sonoran pronghorn populations 

to maintain genetic diversity 

within each population as 

needed based on ongoing 

genetic evaluation (see 

research section 5). 

1 4 SPRT No 100.00 0.00 0.00 0.00 0.00 25.00 Costs include vet costs, helicopters or ground 

transfer; collars. This action may only be 

needed every 5 years starting in 2019.

NA 1.1.2 Reduce mortality caused by 

diseases 

1 NA NA NA NA NA NA NA NA NA NA

2 1.1.2.1 Vaccinate against Epizootic 

Hemorrhagic Disease and Blue 

Tongue. 

1 Ongoing AZGFD, 

CDFW

No 28.00 1.40 1.40 1.40 1.40 1.40 Note, for all ongoing actions, costs are 

calculated for 20 years, the estimated time to 

recovery. Estimated costs based on current 

vaccination program. 

3 1.1.2.2 Vaccinate against other 

diseases that threaten Sonoran 

pronghorn if vaccination is 

available. 

1 Ongoing AZGFD, 

CDFW

No 32.20 1.61 1.61 1.61 1.61 1.61
Sonoran Pronghorn Recovery Plan, Second Revision 

141

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1.1.3 Decrease poaching (the level 

of effort needed for 1.1.3.2 to

1.1.3.6 will depend on the 

results of 1.1.3.1)

1 NA NA NA NA NA NA NA NA NA NA

3 1.1.3.1 Determine the extent of 

poaching

1 Ongoing PROFEPA, 

CEDES, 

SAGARPHA

No 87.00 4.36 4.36 4.36 4.36 4.36 Cost estimates based on an average wage of 

$1000 per month or $45.45 per day (salary and 

benefits) for Mexican Patrol Officers. Minimum 

of two officers needed to patrol the two 

populations during the fall and winter months (6 

months) at least eight days per month.

3 1.1.3.2 Increase and maintain 

community vigilance programs 

in Mexico (an existing Federal 

program in Mexico).

1 Ongoing CONANP,

CEDES

No 19.00 0.93 0.93 0.93 0.93 0.93 Cost estimates based on an average wage of 

$1700 per month or $77.27 per day (salary and 

benefits) for Mexican Biologists. Minimum of 

one biologist needed to increase community 

vigilance at least one day per month.

3 1.1.3.3 Promote detection and 

denunciation of illegal hunting 

of pronghorn, including 

designing actions to reduce 

each kind of illegal hunting.

1 Ongoing PROFEPA, 

CONANP, 

CEDES, 

SAGARPHA

No 37.00 1.85 1.85 1.85 1.85 1.85 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed to increase community vigilance at 

least two days per month.
Sonoran Pronghorn Recovery Plan, Second Revision 

142

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 1.1.3.4 Promote and reinforce 

inspection and surveillance 

rounds in the areas where 

pronghorn are distributed, 

during the seasons when 

hunting is allowed for other 

species that share the habitat 

with the pronghorn, with 

coordination of state and 

municipal governments.

1 Continuous PROFEPA, 

CONANP, 

CEDES, 

SAGARPHA

No 131.00 6.54 6.54 6.54 6.54 6.54 Cost estimates based on an average wage of 

$1000 per month (salary and benefits) for 

Mexican Patrol Officers. Minimum of two 

officers needed to patrol the two populations 

during the fall and winter months (6 months) at 

least 12 days per month. Costs calculated for 

20 years. 

3 1.1.3.5 Increase enforcement of 

existing wildlife protection laws

1 Continuous PROFEPA No 22.00 1.09 1.09 1.09 1.09 1.09 Cost estimates based on an average wage of 

$1000 per month (salary and benefits) for 

Mexican Patrol Officers. Minimum of two 

officers needed to increase enforcement of 

existing wildlife protection laws during the fall 

and winter months (6 months) at least 2 days 

per month. Costs calculated for 20 years.

3 1.1.3.6 Monitor reductions in poaching 1 Continuous PROFEPA No 5.00 0.27 0.27 0.27 0.27 0.27 Cost estimates based on an average wage of 

$1000 per month (salary and benefits) for 

Mexican Patrol Officers. Minimum of one 

officer needed to monitor reduction in poaching 

during the fall and winter months (6 months) at 

least 1 day per month. Costs calculated for 20 

years.
Sonoran Pronghorn Recovery Plan, Second Revision 

143

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1.1.4 Reduce predation by native, 

feral, and domestic predators 

1 NA NA NA NA NA NA NA NA NA NA

1.1.4.1 Identify under what conditions 

and when and where predator 

control is needed

1 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below.

2 In AZMUs 1 Continuous All AZMUs No 4.00 0.20 0.20 0.20 0.20 0.20 A shared function between the AZGFD and 

land managers. Unknown frequency of need 

depending on circumstances and predator 

populations. On the average, 1 day per year 

and a minimum of two staff devoted to this. 

Costs calculated for 20 years.

2 In Sonora MUs 1 Continuous Pinacate, 

CEDES

No 3.0 0.15 0.15 0.15 0.15 0.15 A shared function between the CEDES and 

CONANP staff. Unknown frequency of need 

depending on circumstances and predator 

populations. On the average, 1 day per year 

and a minimum of two staff devoted to this. 

Costs calculated for 20 years.

1.1.4.2 Implement predator control 

programs as needed

1 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below.

2 In AZMUs 1 2 APHIS, 

AZGFD

No 30.00 0.00 0.00 0.00 0.00 15.00 Small scale around or within pen; unknown 

frequency needed but estimate once per 5-10 

years. Aphis contract.
Sonoran Pronghorn Recovery Plan, Second Revision 

144

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 In Sonora MUs 1 2 CEDES, 

UMAs

No 50.00 0.00 0.00 0.00 0.00 10.00 This would be controlling wild populations of 

coyotes if needed within Mexico. The estimate 

frequency would be once every 10 years for an 

average cost of $10,000 per operation.

1.1.5 Reduce mortality caused by 

canals

1 NA NA NA NA NA NA NA NA NA NA

3 1.1.5.1 Work with irrigation districts 

(i.e., those entities that manage 

canals) to develop possible 

solutions to prevent drowning 

in canals 

1 Ongoing FWS, 

AZGFD,

BLM, BMGR

Yes 3.60 0.18 0.18 0.18 0.18 0.18 At least one staff biologist may work 

occasionally on this action every year. 

3 1.1.5.2 Fence or modify canals 

(provide escape structures, or 

provide food and water next to 

canals) to prevent Sonoran 

pronghorn from entering and 

drowning in canals

1 5 AZGFD No 50.00 0.00 0.00 10.00 0.00 10.00 Includes staff time to write grants to get projects 

funded. Estimating 5 total projects needed @ 

an average of $10,000 per project. Fencing 

projects occur once, but food and water would 

be provided as needed. 

3 1.1.5.3 Set criteria and conditions for 

response if pronghorn are 

approaching canals

1 Continuous FWS, 

AZGFD,

BLM, BMGR

Yes 5.60 0.28 0.28 0.28 0.28 0.28 Handled on a case by case basis. May occur 

at least three times per year involving at least 

two staff biologists. Costs calculated for 20 

years.
Sonoran Pronghorn Recovery Plan, Second Revision 

145

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 1.1.5.4 Monitor annual canal-related 

incidents (e.g. drowning, injury)

1 Ongoing FWS, 

AZGFD,

BLM, BMGR

Yes 5.60 0.28 0.28 0.28 0.28 0.28 Handled on a case by case basis. May occur 

at least three times per year involving at least 

two staff biologists. 

3 1.1.5.5 Monitor miles/km/m of canals 

rendered safe by fences or 

escape ramps

1 Continuous FWS, 

AZGFD,

BLM, BMGR

Yes 0.00 0.00 0.00 0.00 0.00 0.00 Handled on a case by case basis. May occur 

at least three times per year involving at least 

two staff biologists. Costs included in 1.1.5.4 

above.

1.2. Continue captive breeding 

program

1 NA NA NA NA NA NA NA NA NA NA

1 1.2.1 Maintain current captive 

breeding program, including 

care of Sonoran pronghorn and 

captive breeding infrastructure

1 10 AZGFD, 

FWS

No 3900.00 390.00 390.00 390.00 390.00 390.00 Costs include Cabeza Prieta and Kofa pens, 

and are based on current cost of operating 

pens. 

3 1.2.2 Evaluate and modify as needed 

methods of captive breeding, 

handling, transport, and 

transplant

1 10 SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Ongoing; costs covered in 1.2.1

3 1.2.3 Formulate captive and released 

population structure 

1 10 SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Ongoing; costs covered in 1.2.1

1.3. Establish additional populations 

within the historical range of 

Sonoran pronghorn 

1 NA NA NA NA NA NA NA NA NA NA

1.3.1. Evaluate suitability and 

prioritize reintroduction sites

1 6 SPRT Yes 0 0 0 0 0 0 Costs included in action 1.3.1.1. below
Sonoran Pronghorn Recovery Plan, Second Revision 

146

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1.3.1.1.

Evaluate legal aspects of 

reintroduction at each site.

1 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below.

3 In U.S. 1 6 All AZMUs, 

All CAMU

No 2.40 0.40 0.40 0.40 0.40 0.40 Mostly completed within the U.S. Prioritization 

and planning requires at least three days per 

year and at least four staff. These activities 

should be completed by 2021 within the U.S.

3 In Mexico 1 1 All Sonora 

MUs, SPA

No 13.00 0.00 0.00 13.00 0.00 0.00 Estimate for evaluating and prioritizing site 

suitability within Mexico would involve a 

minimum of 12 staff biologists/managers at 

least 14 days out of a year. Should only need 

doing once.

3 1.3.2. Evaluate reintroduction 

techniques, taking into 

consideration site specific 

needs.

1 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Ongoing; part of existing positions

1.3.3. Establish new populations 1 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

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Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 1.3.3.1. Release Sonoran pronghorn 

into Kofa and Sauceda 

subunits of the Arizona 

Reintroduction MU

1 6 SPRT Yes 138.00 23.00 23.00 23.00 23.00 23.00 Cost includes holding pen construction and 

transoprt of pronghorn. Pen materials in stock. 

Pen crew is already employed in other 

capacities. In-kind support is estimated at about 

40 staff people per year, ranging from 

volunteers to people with $100K salaries. 

Estimate 4 days per year. 

3 1.3.3.2 Establish additional populations 

in other sites already evaluated 

in the Arizona Reintroduction 

MU

1 6 SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs included in the estimates above for 

1.3.3.1. The effort in any one location would 

take place for at least three years.

3 1.3.3.3 Establish additional Sonoran 

pronghorn populations within 

unoccupied areas of its 

historical range in Sonora if the 

sites are determined to be 

appropriate for reintroduction 

1 3 CONANP 

(Priority 

Species), 

CEDES, 

DGVS

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs not estimated due to high level of 

uncertainity in timing, location, and effort 

needed to accomplish this action. 

3 1.3.3.4 Determine by genetic analysis 

if pronghorn in the historical 

range of Baja California were 

A.a. sonoriensis.

1 2 SPRT,

CDPCG

No 0.00 0.00 0.00 0.00 0.00 0.00 Already funded nearly completed. 
Sonoran Pronghorn Recovery Plan, Second Revision 

148

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 1.3.3.5 If genetically appropriate as 

determined above, establish 

Sonoran pronghorn populations 

in Baja California where 

appropriate and feasible. 

1 3 CONANP 

(Priority 

Species), 

CEDES, 

DGVS, SPA

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs not estimated due to high level of 

uncertainity in timing, location, and effort 

needed to accomplish this action.

3 1.3.3.6 Determine by genetic analysis 

if pronghorn in the historical 

range of California were A.a. 

sonoriensis.

1 2 SPRT,

CDPCG

No 0.00 0.00 0.00 0.00 0.00 0.00 Already funded and nearly completed. 

3 1.3.3.7 If genetically appropriate as 

determined above, establish 

Sonoran pronghorn populations 

in California where appropriate 

and feasible. 

1 3 SPRT,

CDPCG

Yes 0.00 0.00 0.00 0.00 0.00 0.00 Cost not estimated due to high level of 

uncertainity in timing, location, and effort 

needed to accomplish this.

2. Ensure that there is adequate 

quantity, quality, and 

connectivity of Sonoran 

pronghorn habitat to support 

populations

2 NA NA NA NA NA NA NA NA NA NA

2.1. Assess the quantity and quality 

of Sonoran pronghorn habitat.

2 NA NA NA NA NA NA NA NA NA NA

2 2.1.1. Monitor and assess the 

quantity of habitat through 

aerial surveys annually

2 Continuous AZGFD No 28.50 0.00 1.50 1.50 1.50 1.50 Costs include costs of one monitoring flight per 

year ($1000 for the plane and $500 for the staff 

time associated annually); however, other 

techniques such as use remote sensing may be 

preferred in the future.
Sonoran Pronghorn Recovery Plan, Second Revision 

149

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.1.2. Conduct surveys through 

terrestrial and other methods 

(satellite images), as needed, 

to refine our understanding of 

vegetation changes 

2 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 2 4 AZGFD No 200.00 0.00 0.00 0.00 0.00 50.00 Based on $18,000 for veg analysis contract for 

just the Cabeza Prieta NWR alone. Should be 

repeated once every five years rangewide.

3 In Mexico 2 4 All Sonora 

MUs

No 120.00 0.00 0.00 0.00 30.00 0.00 Based on $18,000 for veg analysis contract for 

just the Cabeza Prieta NWR alone. Should be 

repeated once every five years rangewide.

2 2.1.3. Monitor and assess habitat 

quality (particularly greenness) 

through aerial surveys at least 

three times a year, and other 

methods as needed

2 Ongoing AZGFD No 90.00 4.50 4.50 4.50 4.50 4.50 Same unit cost as for 2.1.1 above multiplied by 

three surveys.

3 2.1.4. Create maps seasonally 

(coinciding with data collected 

above) showing results of 

quality and quantities of 

habitat. 

2 Continuous AZGFD No 30.00 0.00 3.00 1.50 1.50 1.50 AZGFD staff time to create map, estimated @ 

$500.00. Costs for 2017 doubled to account for 

greater amount of time needed to create initial 

map.
Sonoran Pronghorn Recovery Plan, Second Revision 

150

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2.1.5. Complete a vegetation map for 

Sonoran pronghorn habitat in 

throughout its range.

2 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 2.1.5.1 In Mexico 2 10 CEDES No 200.00 20.00 20.00 20.00 20.00 20.00 Estimate extrapolated from known costs in the 

U.S. applied to pronghorn range within Sonora.

3 2.1.5.2 In the U.S. 2 5 OPCNM, 

CPNWR, 

BMGR, 

AZGFD

No 110.00 22.00 22.00 22.00 22.00 22.00 Estimate provided for portions of the CPNWR 

that remain to be mapped. Adjacent areas 

within pronghorn range have already been 

completed.

3 2.1.6. Assess impacts of 

unauthorized land use in 

Sonoran pronghorn habitat

2 4 OPCNM, 

CPNWR,

BMGR, 

CONANP

Yes 300.00 0.00 75.00 75.00 75.00 75.00 Each land area would likely be assessed 

separately. $75K estimated for each

3 2.1.7. Install weather stations within 

Sonoran pronghorn habitat (to 

measure temp, precipitation, 

dew point, RH, etc.)

2 4 All AZMU, 

All Sonora 

MUs

No 10.00 0.00 2.50 2.50 2.50 2.50 Aprroximately $2,500.00 per station.

3 2.1.8. Update the information on land 

ownership of Sonoran 

Pronghorn habitat in Mexico

2 2 All Sonora 

MUs, 

CONANP 

(Priority 

Species)

No 10.00 5.00 5.00 0.00 0.00 0.00 5 coastal municipalities

2.1.9 Monitor (document and track) 

the protection status of 

pronghorn habitat in each 

Sonora MU

2 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

151

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.1.9.1. In Pinacate every two years 2 10 CONANP 

(Pinacate)

No 15.50 0.00 1.55 0.00 1.55 0.00 Costs include costs for 2 Mexican biologists, 10 

days per year, every other year. 

1 2.1.9.2. In Quitovac annually 2 20 CEDES No 31.00 0.00 1.55 0.00 1.55 0.00 Costs include costs for 2 Mexican biologists, 10 

days per year annually.

2.2. Protect and/or increase the 

amount of existing habitat 

range wide 

2 NA NA NA NA NA NA NA NA NA NA

2.2.1. Continue to acquire and protect 

more land for Sonoran 

pronghorn conservation in 

Mexico

2 NA NA NA NA NA NA NA NA NA NA

2 2.2.1.1. Expand the size of the core 

areas within the boundary of 

the Pinacate Biosphere 

Reserve

2 5 CONANP 

(Pinacate)

No 30.00 6.00 6.00 6.00 6.00 6.00

2 2.2.1.2. Create a protected reserve for 

the Sonoran pronghorn within 

the Quitovac Management Unit 

(e.g. UMA, State ANP, private 

reserve)

2 5 CEDES, 

SAGARHPA

No 30.00 6.00 6.00 6.00 6.00 6.00

2 2.2.1.3 Identify and designate priority 

conservation areas (Área 

Prioritaria para la Conservación 

– CONANP/CONABIO) or 

other State designation for the 

conservation of the Sonoran 

pronghorn

2 4 CONANP 

(Priority 

Species)

No 8.00 0.00 2.00 0.00 0.00 0.00 Update every five years
Sonoran Pronghorn Recovery Plan, Second Revision 

152

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.2.2. Acquire more land for Sonoran

pronghorn conservation in the 

U.S.

2 5 All AZMUs, 

All CAMU

No 250.00 0.00 0.00 50.00 0.00 50.00 Costs will vary by locality and size of parcel. 

Estimate provided based on the known asking 

price for 0.5 section of land within current range 

in Arizona.Will likely occur at intermittent 

intervals, costs calculated for 5 purchaes over 

20 years.

1 2.2.3. Protect, through appropriate 

laws and regulations, Sonoran 

pronghorn habitat in the U.S. 

by changing or maintaining 

land use designations

2 2 All AZMUs, 

All CAMU

Yes 200.00 0.00 0.00 0.00 0.00 0.00 Costs of maintaining designations part of 

existing agency budgets; costs of changing 

land use designations would include NEPA and 

other analyses. Not anticipated more frequently 

than once every 10 years. 

2.2.4. Restore highly degraded 

Sonoran pronghorn habitat

3 NA NA NA NA NA NA NA NA NA NA

3 2.2.4.1. Identify areas where restoration 

is needed 

3 4 SPRT No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in 2.1.6 above

3 2.2.4.2. Restore and protect potential 

Sonoran pronghorn habitat that 

is highly degraded

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 1 All AZMUs, 

All CAMU

No 1750.00 1750.00 0.00 0.00 0.00 0.00 Cost estimates based on restoration work 

within OCPNM and CPNWR in 2015.

3 In Mexico 3 1 All Sonora 

MUs

No 580.00 0.00 0.00 0.00 0.00 580.00 Cost estimates based on restoration work 

within OCPNM and CPNWR in 2015.
Sonoran Pronghorn Recovery Plan, Second Revision 

153

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.2.4.3. Work with La Herradura and 

Noche Buena Mines to restore 

Sonoran pronghorn habitat.

3 NA NA NA NA NA NA NA NA NA NA

2 2.2.4.3.1 Work with the Fresnillo Mining 

Company to encourage them to 

implement voluntary 

conservation measures. 

3 Ongoing CEDES No 140.00 7.00 7.00 7.00 7.00 7.00 The action will require annual engagement with 

the mine company.

2 2.2.4.3.2 Work with the Newmont Mining 

Company (based in Colorado) 

to become a corporate sponsor 

of Sonoran pronghorn recovery 

and implement voluntary 

conservation measures. 

3 Continuous CEDES, 

FWS

No 140.00 7.00 7.00 7.00 7.00 7.00 This action provides an opportunity for 

agencies in the U.S. to facilitate conservation of 

habitat for the Sonoran pronghorn population in 

Quitovac and the action will require annual 

engagement with the mine company.

2 2.2.5. Promote the conservation and 

protection of ANPs, Predios 

Certificados para la 

Conservación (Certified 

Properties for Conservation), 

communal and/or private 

reserves, and UMAs.

2, 3 Ongoing CONANP 

(Priority 

Species and 

Pinacate), 

CEDES

No 37.00 1.85 1.85 1.85 1.85 1.85 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed to promote conservation and protection 

at least two days per month.
Sonoran Pronghorn Recovery Plan, Second Revision 

154

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.2.6 Ask existing UMAs to 

incorporate pronghorn in their 

list of protected and managed 

animals.

2,3 5 SAGARHPA

,CEDES

No 3..90 0.00 0.00 0.77 0.00 0.00 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. A minimum of one biologist 

may work on this about 10 days every four 

years. 

2.3. Prevent or minimize the loss of 

Sonoran pronghorn habitat to 

land use impacts

2, 3 NA NA NA NA NA NA NA NA NA NA

1 2.3.1. Cooperate with La Herradura 

Mine on their mining plan to 

prevent and minimize loss of 

Sonoran pronghorn habitat.

2, 3 Ongoing CEDES No 200.00 10.00 10.00 10.00 10.00 10.00

2 2.3.2. Work with agencies and 

authorities (federal, state, 

municipal) to monitor, prevent, 

minimize, and/or mitigate future 

detrimental land use changes

2, 3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 2.3.2.1 In Mexico 2, 3 Ongoing All Sonora 

MUs

No 200.00 10.00 10.00 10.00 10.00 10.00 Cost estimate provided by CEDES.
Sonoran Pronghorn Recovery Plan, Second Revision 

155

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.3.2.2 In US 2, 3 Ongoing All AZMUs, 

All CAMU

Yes 2400.00 120.00 120.00 120.00 120.00 120.00 Incremental costs for section 7 consultation 

specifically on pronghorn are totaled here for 

both USFWS and technical experts helping 

USFWS (150 days) and action agencies. 

1 2.3.3 Monitor area of Sonoran 

pronghorn habitat lost 

2, 3 Ongoing All AZMUs, 

All CAMU, 

All Mexico 

CU

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in 2.1.6 above

2.4. Implement environmental 

services, employment 

programs and rural 

development programs in

priority Sonoran pronghorn 

conservation areas in Sonora, 

and limit and/or regulate 

activities and infrastructure that 

can threaten those areas.

2, 3 NA NA NA NA NA NA NA NA NA NA

3 2.4.1. Work cooperatively with the 

landowners of the Natural 

Protected Areas (Areas 

Naturales Protegidas) and 

UMAs to adapt land 

management to benefit 

pronghorn.

3 Ongoing CONANP 

(Priority 

Species and 

Pinacate), 

CEDES, 

SAGARHPA

No 37.00 1.85 1.85 1.85 1.85 1.85 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed to work with landowners at least two 

days per month.
Sonoran Pronghorn Recovery Plan, Second Revision 

156

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.4.2. Promote productive alternative 

low impact activities that 

benefit wildlife on ranches 

(wildlife management, 

ecotourism, etc.) 

3 Ongoing CONANP 

(Priority 

Species and 

Pinacate), 

CEDES, 

SAGARHPA

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in 2.4.1 above

3 2.4.3. Establish programs to organize 

and coordinate agricultural and 

livestock activities in or around 

important pronghorn habitat.

3 3 CONANP 

(Priority 

Species and 

Pinacate), 

CEDES, 

SAGARHPA

No 5.60 0.00 0.00 1.85 1.85 1.85 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per month for at least three 

years to establish programs beneficial to 

pronghorn.

2 2.4.4. Promote coordinated action 

among municipal and state 

agencies to decree the state 

land use program which is 

focused on avoiding changes in 

land uses in priority areas. 

3 3 CONANP 

(Priority 

Species and 

Pinacate), 

CEDES, 

SAGARHPA

No 5.60 0.00 0.00 1.85 1.85 1.85 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per month for at least three 

years for this action.

2.5. Maintain and improve the 

quality of existing habitat 

(including an appropriate mix of 

vegetation types) range wide 

3 NA NA NA NA NA NA NA NA NA NA

2.5.1. Limit livestock grazing where it 

impacts Sonoran pronghorn 

3 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

157

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

habitat

2.5.1.1. Reduce the number of livestock 

grazing in Sonoran pronghorn 

habitat in the Mexico CU, 

Cabeza Prieta MU and the 

A10jMU 

3 NA NA NA NA NA NA NA NA NA NA

3 2.5.1.1.1

. 

Coordinate with appropriate 

agencies to examine the need 

to reduce livestock numbers

3 1 SAGARHPA

, BLM

No 1.90 0.00 0.00 1.86 0.00 0.00 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per month for at least one 

year for this action.

2.5.1.1.2

. 

Reduce numbers when 

necessary.

3 Continuous SAGARHPA

, BLM

No 4.00 0.20 0.20 0.20 0.20 0.20 Estimate based on at least five days per year to 

implement this action. Costs calculated for 20 

years.

2 2.5.1.1.3 Provide financial incentives/ 

and other income opportunities 

to ranchers to reduce livestock 

grazing

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See below

2 2.5.1.1.3

.1

In U.S. 3 Continuous BLM No 62.80 3.14 3.14 3.14 3.14 3.14 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Position. Minimum of one biologist needed at 

least ten days per year to coordinate this 

action. Costs calculated for 20 years.
Sonoran Pronghorn Recovery Plan, Second Revision 

158

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.5.1.1.

3.2

In Mexico 3 Continuous SAGARHPA No 15.50 0.77 0.77 0.77 0.77 0.77 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed at least ten days per year to coordinate 

this action. Costs calculated for 20 years.

2.5.1.1.4

 

Develop and implement other 

strategies to reduce livestock 

grazing.

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See below

2 In U.S. 3 3 All AZMUs, 

All CAMU

No 9.42 0.00 3.14 3.14 3.14 0.00 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of one biologist needed at 

least ten days per year for at least three years 

to coordinate this action.

2 In Mexico 3 5 All Mexico 

CU

No 3.90 0.77 0.77 0.77 0.77 0.77 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed at least ten days per year for at least 

five years to coordinate this action.

3 2.5.1.2 Track changes in the number 

of cattle

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See below
Sonoran Pronghorn Recovery Plan, Second Revision 

159

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In U.S. 3 10 BLM No 9.40 0.94 0.94 0.94 0.94 0.94 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Position. Minimum of one biologist needed at 

least three days per year for at least 10 years to 

compile livestock numbers from allotments in 

pronghorn range.

3 In Mexico 3 Continuous SAGARPHA No 15.50 0.77 0.77 0.77 0.77 0.77 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed at least ten days per year to compile 

livestock numbers on ejidos. Costs calculated 

for 20 years.

2.5.2. Reduce the impacts of 

livestock grazing where it will 

continue

3 NA NA NA NA NA NA NA NA NA NA

3 2.5.2.1. Coordinate with appropriate 

agencies to incorporate 

conservation measures to 

maintain or improve pronghorn 

habitat and forage availability

3 Ongoing FWS,BLM, 

SAGARPHA

, CONANP 

(Priority 

Species), 

CEDES

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs included in action 2.3.2.2 above
Sonoran Pronghorn Recovery Plan, Second Revision 

160

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.5.2.2. Involve SAGARPA, 

SAGARHPA, and other 

agencies in improving 

management of areas for the 

Sonoran pronghorn

3 Ongoing All Mexico 

CU

No 3.10 0.15 0.15 0.15 0.15 0.15 Minimum of two, one day meetings per year to 

coordinate this action. Assumes an average 

wage of $1700 per month (salary and benefits) 

for Mexican Biologists.

2 2.5.2.3. Decrease livestock numbers or 

remove livestock from habitat 

during times of emergency 

(drought, fire, etc).

3 4 BLM No 3.76 0.00 0.94 0.00 0.00 0.00 Minimum of three days per year once every five 

years to coordinate this action. Assumes an 

average wage of $314 per day (salary and 

benefits) for a GS-11 position.

2.5.2.4. Establish utilization monitoring 

protocol, including utilization 

thresholds, which if exceeded 

would trigger the need for 

reducing or removing livestock 

to maintain adequate forage 

and habitat for pronghorn.

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See below

3 In Mexico 3 Continuous SAGARPHA No 15.70 0.00 1.70 0.78 0.78 0.78 First year of costassumes an average wage of 

$1700 per month (salary and benefits) for one 

Mexican Biologist to develop the protocol. 

Subsequent costs assume rate of $850 per 

month ($39 per day) for techs. 2 techs 10 days 

per year to monitor. Costs calculated for 19

years.
Sonoran Pronghorn Recovery Plan, Second Revision 

161

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In the U.S. 3 Continuous BLM No 34.00 0.00 1.57 1.80 1.80 1.80 Costs are for adapting utilization monitoring 

plan and for collecting any additional data that 

is solely for Sonoran pronghorn habitat. Costs 

calculated for GS11 5 days to develop 

measures and two GS7 techs 5 extra days 

(each) annually on top of regular allotment 

management monitoring. GS7 calculated at 

$181 (salary + benefits) per day; GS11 at $314 

per day. Costs calculated for 19 years.

2.5.3. Manage invasive species in 

Sonoran pronghorn habitat

3 NA NA NA NA NA NA NA NA NA NA

1 2.5.3.1. Remove feral burros, goats, 

cattle, and horses in Sonoran 

pronghorn habitat 

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

1 In U.S. 3 Ongoing All AZMUs, 

All CAMU

No 128.00 6.40 6.40 6.40 6.40 6.40 One annual meeting involving at least 15 

agency participants in addition to the annual 

estimated cost of control.

1 In Mexico 3 Ongoing All Mexico 

CU

No 40.00 2.00 2.00 2.00 2.00 2.00 At least one annual coordination meeting and 

the estimated cost of controlling feral livestock.

2.5.3.2. Manage invasive, non-native 

plant species

3 NA NA NA NA NA NA NA NA NA NA

3 2.5.3.2.1

. 

Identify distribution of invasive, 

non-native plant species that 

occur within Sonoran 

pronghorn habitat and assess 

the need to control them

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

162

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In U.S. 3 Ongoing All AZMUs, 

All CAMU

No 112.00 5.60 5.60 5.60 5.60 5.60 Estimated to require at least 60 staff days per 

year (assumes a field crew of at least two) to 

complete annually in priority areas throughout 

pronghorn range.

3 In Mexico 3 Ongoing All Mexico 

CU

No 36.40 1.82 1.82 1.82 1.82 1.82 Estimated to require at least 20 staff days (at 

$45.45 per day) per year (assumes a field crew 

of at least two) to complete annually in priority 

areas throughout pronghorn range.

3 2.5.3.2.2

. 

Control invasive, non-native 

plants if they are determined to 

be detrimental to Sonoran 

pronghorn habitat and if the 

benefit of controlling the 

species outweighs the potential 

risks to pronghorn 

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 Ongoing All AZMUs, 

All CAMU

No 200.00 10.00 10.00 10.00 10.00 10.00 Costs depend on control technique and extent 

of infestation; however, annual estimated costs 

are provided.
Sonoran Pronghorn Recovery Plan, Second Revision 

163

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In Mexico 3 Continuous All Mexico 

CU

No 100.00 5.00 5.00 5.00 5.00 5.00 Costs depend on control technique and extent 

of infestation; however, annual estimated costs 

are provided. Costs calculated for 20 years.

3 2.5.3.2.3

. 

Ensure herbicide use within 

Sonoran pronghorn habitat 

does not negatively affect 

Sonoran pronghorn or habitat

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 Ongoing All AZMUs, 

All CAMU

Yes 1.80 0.09 0.09 0.09 0.09 0.09 One annual meeting per year required per 

proposed control project involving at least four 

participants.

3 In Mexico 3 Continuous All Mexico 

CU

No 1.00 0.05 0.05 0.05 0.05 0.05 One annual meeting per year required per 

proposed control project involving at least four 

participants. Costs calculated for 20 years.

3 2.5.4. Avoid and minimize noise and 

lights associated with projects, 

actions, and/or activities within 

Sonoran pronghorn habitat 

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 Ongoing All AZMUs, 

All CAMU

Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs included in action 2.3.2.2 above.
Sonoran Pronghorn Recovery Plan, Second Revision 

164

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In Mexico 3 Ongoing All Mexico 

CU

No 6.00 0.30 0.30 0.30 0.30 0.30 Will require coordination meetings. Anticipate 

at least two staff at least three times per year to 

propose mitigation measures for proposed 

activities in pronghorn range.

2.5.5. Minimize and mitigate impacts 

of border related activity on 

Sonoran pronghorn habitat

3 NA NA NA NA NA NA NA NA NA NA

1 2.5.5.1. Work with CBP/USBP to 

minimize and mitigate, to the 

greatest extent possible, 

operation of off-highway 

vehicles in Sonoran pronghorn 

habitat

3 Ongoing SPRT Yes 94.20 4.71 4.71 4.71 4.71 4.71 Estimated to involve at least five resource 

agency staff (assuming GS-11 level) for a least 

three days per year to coordinate.

2 2.5.5.2. Work with USBP to minimize 

road dragging that is currently 

occurring in Sonoran 

pronghorn habitat

3 Ongoing SPRT Yes 94.20 4.71 4.71 4.71 4.71 4.71 Estimated to involve at least five resource 

agency staff (assuming GS-11 level) for a least 

three days per year to coordinate.

3 2.5.5.3. Work with USBP to identify and 

implement alternative methods 

of cross-border violator 

detection that are less 

destructive than road dragging 

to Sonoran pronghorn habitat 

3 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Estimated costs covered in 2.5.5.2 above
Sonoran Pronghorn Recovery Plan, Second Revision 

165

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1 2.5.5.4. Work with USBP to minimize, 

to minimize, to the greatest 

extent possible, impacts of 

other border operations on 

Sonoran pronghorn habitat 

quality. 

3 Ongoing SPRT Yes 94.20 4.71 4.71 4.71 4.71 4.71 Estimated to involve at least five resource 

agency staff (assuming GS-11 level) for a least 

three days per year to coordinate.

2 2.5.5.5 Document number/miles of 

new drag roads and 

undesignated vehicle routes 

and trails created

3 1 OPCNM, 

BMGR, 

CPNWR, 

BLM

No 800.00 0.00 0.00 0.00 0.00 0.00 Estimate based on a recent project led by 

OPCNM to document the extent of UVR's. 

Each land area would likely be assessed 

separately. This activity would likely be 

conducted once during the recovery period.

3 2.5.5.6 Monitor extent of erosion and 

changes in hydrologic patterns 

resulting from new roads and 

routes.

3 2 OPCNM, 

CONANP 

(Pinacate)

No 0.00 0.00 0.00 0.00 0.00 0.00 Would likely be done regardless of pronghorn 

ESA status, so no costs included.

2.5.6. Reduce the impacts of mines 

(e.g. La Herradura) on Sonoran 

pronghorn habitat quality

3 NA NA NA NA NA NA NA NA NA NA

3 2.5.6.1. Assess the effects of La 

Herradura mine on Sonoran 

pronghorn habitat quality 

(contamination, fugitive dust, 

noise, lights, off-road vehicle 

use, etc.)

3 5 CEDES No 10.00 2.00 2.00 2.00 2.00 2.00
Sonoran Pronghorn Recovery Plan, Second Revision 

166

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.5.6.2. Work with La Herradura mine 

and provide technical 

assistance to minimize and 

mitigate the effects of the mine 

on Sonoran pronghorn habitat. 

3 Ongoing CEDES No 120.00 6.00 6.00 6.00 6.00 6.00

2.5.6.3. Identify and work with other 

mines that impact Sonoran 

pronghorn habitat 

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 Ongoing BLM, 

AZGFD

No 40.00 2.00 2.00 2.00 2.00 2.00 Costs will vary depending on the size, duration 

and number of proposed mines. Estimated 

costs includestaff time (at least four staff for at 

least two days per year) per mine. 

3 In Mexico 3 Ongoing All Mexico 

CU

No 200.00 10.00 10.00 10.00 10.00 10.00 Costs will vary depending on the size, duration 

and number of proposed mines. Estimated 

costs include staff time (at least four staff for at 

least 8 days per year) per mine. 

2.5.7. Reduce the negative impacts of 

agriculture on Sonoran

pronghorn habitat quality

3 NA NA NA NA NA NA NA NA NA NA

3 2.5.7.1. Identify where agriculture 

impacts Sonoran pronghorn 

habitat quality (once every 5 

years)

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 3 4 All AZMUs, 

All CAMU

No 60.00 0.00 0.00 15.00 0.00 0.00 Will require aerial imagery to track new 

agricultural areas adjacent to BLM lands and 

BMGR. 

3 In Mexico 3 4 All Mexico 

CU

No 60.00 0.00 0.00 15.00 0.00 0.00 Will require use aerial imagery to track new 

agricultural areas. 
Sonoran Pronghorn Recovery Plan, Second Revision 

167

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 2.5.7.2. Work with agricultural 

representatives to minimize 

and mitigate the effects of 

agriculture on Sonoran 

pronghorn habitat

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below.

3 In U.S. 3 Continuous BLM, 

AZGFD, 

BMGR, 

CADFW

No 62.80 3.14 3.14 3.14 3.14 3.14 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of two biologists needed at 

least five days per year annually to coordinate 

this action. Costs estimated for 20 years. 

3 In Mexico 3 Continuous All Mexico 

CU

No 37.00 1.86 1.86 1.86 1.86 1.86 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per month to coordinate this 

action. Costs estimated for 20 years.

3 2.5.8 Establish Best Management 

Practices for U.S. projects on 

BLM land, to minimize habitat 

loss. 

3 1 SPRT No 2.80 2.80 0.00 0.00 0.00 0.00 Based on best management practices and 

standard operating proceedures outlined in the 

2012 lower Sonoran RMP and 2010 Yuma 

RMP. 

1 2.5.9 Minimize impacts of off-road 

racing in Sonora on Sonoran 

pronghorn habitat.

2 Continuous CONANP, 

CEDES

No 34.00 1.70 1.70 1.70 1.70 1.70 Costs based on 2 biologists for 2 weeks per 

year to evaluate impacts. No cost estimates are 

provided for assembling a team because the 

extent of the issue is not currently known. Costs 

estimated for 20 years.

2.6. Protect and/or improve the 

connectivity of existing 

Sonoran pronghorn habitat 

range wide 

2 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

168

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2.6.1. Improve Sonoran pronghorn 

habitat connectivity where it is 

impeded by barriers (e.g., 

highways, fences, canals)

2 NA NA NA NA NA NA NA NA NA NA

2 2.6.1.1 Monitor number of miles of 

barriers

2 Continuous All AZMUs, 

All CAMU, 

All Mexico 

CU

No 18.80 0.94 0.94 0.94 0.94 0.94 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Position. Minimum of one biologist needed at 

least three days per year to monitor the number 

of miles of barriers in pronghorn habitat. Costs 

estimated for 20 years.

2 2.6.1.2 Identify potential travel ways 

across existing barriers and 

other impediments to Sonoran 

pronghorn movement

2,3 1 SPRT No 15.00 0.00 0.00 15.00 0.00 0.00 This action would involve modeling using 

telemetry data and should only need to be done 

once.

2 2.6.1.3 Remove or modify existing 

barriers and impediments to 

allow for Sonoran pronghorn 

passage (e.g. remove/modify 

fences, railroad tracks, roads, 

install overpasses) 

2, 3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 In U.S. 2,3 Ongoing All AZMUs, 

All CAMU,

ADOT

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs not estimated because they will vary 

according to the scope of the proposed project. 

Although no projects are currently proposed, 

efforts to identify such projects are ongoing.

2 In Mexico 2,3 Ongoing All Mexico 

CU, SCT

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs not estimated because they will vary 

according to the scope of the proposed project. 

Although nNo projects are currently proposed, 

efforts to identify such projects are ongoing..
Sonoran Pronghorn Recovery Plan, Second Revision 

169

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.6.1.4 Monitor (document) number or 

miles of barriers eliminated or 

modified to allow safe passage 

by pronghorn

2,3 2 SPRT No 18.60 0.00 0.00 0.00 0.00 9.30 Will likely be assessed at least once every ten 

years. Estimated costs include four biologists

for 10 days, plus mileage.

2 2.6.1.5 Protect existing Sonoran 

pronghorn habitat corridors 

used frequently for movement 

between seasonal habitat use 

areas.

2,3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 In U.S. 2,3 Ongoing All AZMUs, 

All CAMU,

ADOT

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs included in action 2.3.2.2 above

2 In Mexico 2,3 Ongoing CEDES, 

CONANP 

(Pinacate)

No 3.0 0.15 0.15 0.15 0.15 0.15 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per year to coordinate this 

action.

2.6.2. Prevent creation and/or 

minimize impacts of new 

barriers/impediments (e.g. 

roads, fences, transmission 

lines) to Sonoran pronghorn 

movement

2,3 NA NA NA NA NA NA NA NA NA NA

1 2.6.2.1. Work with appropriate 

authorities and stakeholders to 

prevent creation of new 

barriers/impediments to 

Sonoran pronghorn movement

2,3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

170

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1 In Mexico 2,3 Ongoing CEDES,

CONANP 

(Pinacate 

and Priority 

Species)

No 3.0 0.15 0.15 0.15 0.15 0.15 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of two biologists 

needed at least one day per year to coordinate 

this action.

1 In U.S. 2,3 Ongoing All AZMUs, 

All CAMU

Yes 25.20 1.26 1.26 1.26 1.26 1.26 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of four biologists needed at 

least one day per year annually to coordinate 

this action.

1 2.6.2.2. Where new barriers will be 

constructed, work with 

appropriate authorities and 

stakeholders to minimize the 

impacts of those barriers on 

Sonoran pronghorn movement 

2,3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

In U.S. 2,3 7 SPRT Yes 8.82 0.00 0.00 1.26 0.00 0.00 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of four biologists needed at 

least one day every three years to coordinate 

this action.

In Mexico 2,3 Ongoing CEDES, 

CONANP 

(Pinacate 

and Priority 

Species)

No 6.0 0.30 0.30 0.30 0.30 0.30 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of two biologists 

needed at least two days per year to coordinate 

this action.

2.6.3. Minimize current and avoid 

future Sonoran pronghorn 

habitat fragmentation 

NA NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

171

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2.6.3.1. Work with mine companies 

within the Sonoran pronghorn 

range to avoid and minimize 

habitat fragmentation 

2,3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

1 2.6.3.1.1

. 

In Mexico 2,3 Ongoing All Mexico 

CU

No 200.00 10.00 10.00 10.00 10.00 10.00 Costs copied from similar actions estimated by 

CEDES

3 2.6.3.1.2

. 

In the U.S. 2,3 Ongoing All AZMUs, 

All CAMU

No 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.5.6.3 above

1 2.6.3.2. Work with authorities to enforce 

environmental laws pertaining 

to mining to prevent habitat 

fragmentation 

2 Ongoing All AZMUs, 

All CAMU

No 25.20 1.26 1.26 1.26 1.26 1.26 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of four biologists needed at 

least one day per year annually to coordinate 

this action.

1 2.6.3.3 Work with authorities to 

enforce environmental laws 

pertaining to other sources of 

habitat fragmentation (e.g. new 

roads) 

2,3 Ongoing All AZMUs, 

All CAMU

No 25.20 1.26 1.26 1.26 1.26 1.26 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of four biologists needed at 

least one day per year annually to coordinate 

this action.

2.6.3.4. Establish Best Management 

Practices for U.S. projects on 

BLM land, to minimize habitat 

fragmentation.

2 1 SPRT No 0.00 0.00 0.00 0.00 0.00 0.00 No costs included because this action would be 

coordinated with 2.5.8 above to reduce costs 

associated with additional meetings.

2.7. Enhance forage quality and 

availability to support viable 

populations of Sonoran 

pronghorn range wide 

3 NA NA NA NA NA NA NA NA NA NA

2.7.1. Continue forage enhancement 

plot program in the U.S.

3 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

172

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 2.7.1.1. Evaluate the effectiveness of 

existing forage enhancement 

plots 

3 1 AZGFD,

FWS, BMGR 

East and 

West

No 346.00 346.00 0.00 0.00 0.00 0.00 The costs reflects the actual cost of a project 

coordinated by the AZGFD.

2 2.7.1.2. Maintain existing forage plots,

including irrigation

3 10 AZGFD,FW

S,BMGR

No 180.00 18.00 18.00 18.00 18.00 18.00 The costs reflect the actual current costs of 

maintaining plots. 

2 2.7.1.3. Evaluate the need for 

additional forage enhancement 

plots 

3 Ongoing SPRT Yes 25.20 1.26 1.26 1.26 1.26 1.26 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of four biologists needed at 

least one day per year annually to implement

this action.

2 2.7.1.4. Develop additional plots 3 1 All AZMUs, 

All CAMU

Yes 220.00 0.00 0.00 0.00 0.00 220.00 The costs cover the addition of one plot. 

2.7.2. Continue the supplemental 

feeding program in the U.S.

3 NA NA NA NA NA NA NA NA NA NA

3 2.7.2.1 Evaluate the effectiveness of 

supplemental feeding of 

Sonoran pronghorn 

3 3 SPRT No 346.00 0.00 115.00 115.00 115.00 0.00 Estimate based on 2.7.1.1 which is similar in 

scope

1 2.7.2.2 Provide supplemental feed to 

Sonoran pronghorn 

3 Ongoing AZGFD, 

FWS

No 50.00 5.00 5.00 5.00 5.00 5.00 Approximately $2,100 for the alfalfa hay bales 

needed, Additional staff time to distribute hay 

annually, approximately $5,000

NA 2.7.3. Evaluate feasibility of and 

initiate a food plot program in 

the U.S.

3 NA NA NA NA NA NA NA NA NA NA

3 2.7.3.1. Convert current agriculture to 

alfalfa for Sonoran pronghorn 

forage 

3 3 All AZMUs, 

All CAMU

No 75.00 25.00 25.00 25.00 0.00 0.00 Likely a small scale effort of not more than 5 -

10 acre plots in six locations. Estimate based 

on the cost of annual irrigation at the feps
Sonoran Pronghorn Recovery Plan, Second Revision 

173

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

NA 2.8. Maintain and improve 

availability of and access to 

water (both natural and humanmade) range wide 

3 NA NA NA NA NA NA NA NA NA NA

3 2.8.1. Assess availability, amount of, 

and accessibility to current and 

potential future Sonoran 

pronghorn waters

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In the U.S. 3 Ongoing AZGFD No 160.00 8.00 8.00 8.00 8.00 8.00 AZGFD and CPNWR do this on an ongoing 

basis

3 In Mexico 3 Ongoing CONANP 

(Pinacate 

and CEDES)

No 80.00 4.00 4.00 4.00 4.00 4.00 Pinacate staff are currently monitoring waters 

for pronghorn

3 2.8.2. Map and monitor existing water 

sites available to Sonoran 

pronghorn or that could be 

available with some 

modification

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In the U.S. 3 Ongoing AZGFD No 0.00 0.00 0.00 0.00 0.00 0.00 Mapping is done. Monitoring is ongoing and 

costs are covered in 2.8.1.1.

3 In Mexico 3 Ongoing CEDES No 10.00 5.00 5.00 0.00 0.00 0.00 Mapping is complete for Pinacate, incomplete 

for Quitovac. Cost estimate provided to 

complete mapping for Quitovac over 2 years.

Monitoring is ongoing and costs are covered in 

2.8.1.2.

1 2.8.3. Maintain water sources for 

Sonoran pronghorn

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

174

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1 In the U.S. 3 Ongoing All AZMUs, 

All CAMU

Yes 376.80 18.84 18.84 18.84 18.84 18.84 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of two staff needed at least 

30 days per year annually to coordinate this 

action.

1 In Mexico 3 Ongoing All AZMUs, 

All CAMU

No 100.00 5.00 5.00 5.00 5.00 5.00 Costs based on an ongoing effort to provide 

water (via temporary waters) for Sonoran 

pronghorn at Pinacate.

1 2.8.4. Modify existing water sources 

to make them available to 

Sonoran pronghorn as needed

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

1 In the U.S. 3 4 All AZMUs, 

All CAMU

No 30.00 0.00 0.00 0.00 7.50 0.00 Estimate that four existing waters will be 

modified for pronghorn over a 20 year period at 

$7,500 each.

1 In Mexico 3 2 CEDES No 6.00 3.00 0.00 0.00 0.00 3.00 Estimate that two existing waters will be 

modified for pronghorn over a 20 year period at 

$3,000 each.

1 2.8.5. Create new water sources for 

Sonoran pronghorn

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

1 In U.S. 3 10 AZGFD No 400.00 40.00 40.00 40.00 40.00 40.00 Two large 18,000 gallon capacity catchments 

per year for the next 10 years at $20,000 each.

1 In Mexico 3 5 CONANP 

(Pinacate)

No 17.00 3.40 3.40 3.40 3.40 3.40 Two above ground 1000 gallon capacity 

systems per year for the next five years at 

$1,700 each
Sonoran Pronghorn Recovery Plan, Second Revision 

175

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

NA 3. Minimize and mitigate the 

effects of human disturbance 

on Sonoran pronghorn

4 NA NA NA NA NA NA NA NA NA NA

Na 3.1. Minimize and mitigate the 

impact of border-related 

activities on Sonoran 

pronghorn

4 NA NA NA NA NA NA NA NA NA NA

2 3.1.1. Complete study of effects of 

human disturbance on Sonoran 

pronghorn

4 1 CBP, UofA, 

FWS

No 482.00 482.00 0.00 0.00 0.00 0.00 Cost includes cost of actual study that will be 

completed by Feb, 2017.

2 3.1.2. Monitor an index of borderrelated human disturbance4 6 FWS,CBP, 

OPCNM

Yes 33.60 5.60 0.00 0.00 5.60 0.00 Costs included above in 3.1.1.

1 3.1.3. Continue to work with 

CBP/USBP to minimize and 

mitigate the impacts of their 

operations on Sonoran 

pronghorn 

4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs included 2.5.5.2 - 2.5.5.5 above

NA 3.2. Minimize and mitigate the 

impact of recreational activities 

on Sonoran pronghorn

4 NA NA NA NA NA NA NA NA NA NA

3 3.2.1. Work with OHV groups to 

inform them about Sonoran 

pronghorn and ways to 

minimize disturbance to the 

species

4 6 SPRT No 1.90 0.00 0.00 0.31 0.00 0.00 Costs include 1 day of a GS-11 biologist to 

meet with OHV groups every 3 years over 20 

years. 
Sonoran Pronghorn Recovery Plan, Second Revision 

176

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 3.2.2. Evaluate impacts of off-road 

races near Puerto Penasco 

(Rocky Point), Sonora and 

develop measures to minimize 

their impact on Sonoran 

pronghorn. 

3,4 Ongoing CEDES, 

CONANP 

(Priority 

Species)

No 40.00 2.00 2.00 2.00 2.00 2.00 Costs estimated from costs provided by 

CEDES below in 3.6.2 for a similar action.

3 3.2.3. Work with other recreational 

users, as needed, to inform 

them about Sonoran pronghorn 

and ways to minimize 

disturbance to the species

4 Ongoing SPRT No 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

3 3.2.4 Evaluate recreational activity 

within Pinacate Bioreserve and 

close areas as necessary to 

protect Sonoran pronghorn 

during fawning season or other 

periods of vulnerability (e.g., 

dry years).

4 Ongoing CONANP 

(Priority 

Species and 

Pinacate), 

CEDES, and 

others in 

Sonora

No 3.10 0.15 0.15 0.15 0.15 0.15 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of one biologist 

needed two days per year to coordinate this 

action.

3 3.2.5. Close select roads and trails to 

public use during times of the 

year when Sonoran pronghorn 

are under stress. 

4 Ongoing All AZMUs Yes 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

NA 3.3. Minimize and mitigate the 

impact of military activities on 

Sonoran pronghorn 

4 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

177

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 3.3.1. Continue to work with the 

military partners in the U.S. 

(Luke AFB, MCAS, ARNG, 

YPG) to minimize the impact of 

military activities on Sonoran 

pronghorn 

4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

3 3.3.2. Update MOU between military 

and USFWS-CPNWR, as 

needed

4 2 FWS, DOD Yes 12.52 0.00 0.00 6.28 0.00 0.00 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of two biologists needed at 

least 10 days per year, once every 10 years to 

coordinate this action.

NA 3.4. Minimize and mitigate the 

impact of land management 

agency activities on Sonoran 

pronghorn

4 NA NA NA NA NA NA NA NA NA NA

2 3.4.1. Continue to work with land 

management agencies in the 

U.S. to minimize the impact of 

their activities on Sonoran 

pronghorn 

4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

3.5. Minimize and mitigate the 

impact of mining activities on 

Sonoran pronghorn

4 NA NA NA NA NA NA NA NA NA NA

3 3.5.1. Identify sources of disturbance 

to Sonoran pronghorn from 

mining activities

4 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

178

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In U.S. 4 6 BLM,

AZGFD

No 18.80 0.00 0.00 0.00 6.28 0.00 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of two biologists needed at 

least 10 days per year, once every three years 

to coordinate this action.

3 In Mexico 4 20 All Mexico 

CU

No 40.00 2.00 2.00 2.00 2.00 2.00 Cost estimate provided by CEDES

2 3.5.2. Work with mining authorities to 

minimize and mitigate human 

disturbance 

4 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 In U.S. 4 Ongoing BLM,AZGFD

,FWS

No 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

2 In Mexico 4 Ongoing All Mexico 

CU,CONAN

P (Priority 

Species)

No 80.00 4.00 4.00 4.00 4.00 4.00 Cost estimate provided by CEDES

NA 3.6. Minimize and mitigate the 

impact of other activities on 

Sonoran pronghorn

4 NA NA NA NA NA NA NA NA NA NA

3 3.6.1. Identify sources of disturbance 

to Sonoran pronghorn from 

agricultural activities

4 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below
Sonoran Pronghorn Recovery Plan, Second Revision 

179

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 In U.S. 4 Continuous All AZMU; 

mostly 

BMGR and 

BLM N of I8

No 25.20 1.26 1.26 1.26 1.26 1.26 Landscape level analysis. Cost estimates 

based on an average wage of $314 per day 

(salary and benefits) for a GS-11 Biologist. 

Minimum of four biologists needed at least one 

day per year annually to coordinate this action.

3 In Mexico 4 Continuous All Mexico 

CU

No 6.20 0.31 0.31 0.31 0.31 0.31 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of two biologists 

needed at least two days per year to coordinate 

this action. Costs estimated for 20 years. 

3 3.6.2. Work with authorities regulating 

other activities to minimize and 

mitigate human disturbance 

4 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In U.S. 4 Ongoing All AZMUs, 

All CAMU

Yes 0.00 0.00 0.00 0.00 0.00 0.00 Cost estimates included in 2.3.2.2 above

3 In Mexico 4 Ongoing All Mexico 

CU

No 40.00 2.00 2.00 2.00 2.00 2.00 Cost estimate provided by CEDES

NA 4. Identify and address priority 

Sonoran pronghorn 

population monitoring needs

NA NA NA NA NA NA NA NA NA NA NA

1 4.1. Aerially survey Sonoran 

pronghorn populations annually 

to determine abundance

1 Ongoing AZGFD, 

FWS

No 400.00 20.00 20.00 20.00 20.00 20.00 Costs based on current actual costs of surveys. 
Sonoran Pronghorn Recovery Plan, Second Revision 

180

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

NA 4.2. Monitor Sonoran pronghorn 

populations to determine, 

among other things, population 

structure (e.g., sex ratios, 

recruitment, and age), 

mortality, and distribution

1 NA NA NA NA NA NA NA NA NA NA

1 4.2.1. Continue to monitor using 

periodic telemetry flights 

1 Ongoing AZGFD No 300.00 15.00 15.00 15.00 15.00 15.00

2 4.2.2. Monitor using other methods 

such as hilltop surveys and 

cameras 

1 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 In U.S. 1 Ongoing All AZMU No 653.20 32.66 32.66 32.66 32.66 32.66 Cost estimates based on an average wage of 

$314 per day (salary and benefits) for a GS-11 

Biologist. Minimum of two biologists needed at 

least one day per week (=104 GS11 days per 

year) to do hilltop surveys and maintain 

cameras.

2 In Mexico 1 Ongoing All Mexico 

CU

No 74.20 3.7 3.7 3.7 3.7 3.7 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of two biologists 

needed at least two days per month to monitor 

pronghorn from the ground via telemetry and 

maintain cameras.

2 4.2.3. Identify sources of Sonoran 

pronghorn mortality when 

possible. 

1 Ongoing SPRT No 44.00 2.20 2.20 2.20 2.20 2.20 Minimum of four biologists involved on an 

average of six days per year to locate and 

investigate pronghorn remains.
Sonoran Pronghorn Recovery Plan, Second Revision 

181

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1 4.3. Continue to mark (e.g., ear 

tags, collars) captive-raised 

Sonoran pronghorn released 

from pens

1 10 AZGFD, 

FWS

No 120.00 12.00 12.00 12.00 12.00 12.00 In addition to the costs associated with the 

annual captured summarized above in 1.3.3.1, 

annual radio collar and ear-tag costs are 

approximately $12,000.

3 4.4. Evaluate the need to capture 

and mark (e.g., ear tags, 

collars) wild Sonoran 

pronghorn and implement as 

needed 

1 Ongoing SPRT No 90.00 0 0 10.00 0 10.00 Evaluation is ongoing and conducted at 

Recovery Team meeitings (costs of which are 

covered in action 4.6.4.). Capturing is done 

about every three years in U.S. and about 

every 5 years in Mexico.Therefore, about 6 

captures in the U.S. and 3 in Mexico would 

occur during the recovery period. Wild 

captures cost approximately $10,000 per event.

2 4.5. Monitor effectiveness of 

predator control when and if 

implemented 

1 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

2 In U.S. 1 Ongoing USCU No 402.00 20.10 20.10 20.10 20.10 20.10 Would require a predator monitoring program 

involving at least two biologists at least two 

days per week for at least four months per year 

(64 GS11 days). GS-11 rate.

2 In Mexico 1 Ongoing Mexico CU No 98.00 4.90 4.90 4.90 4.90 4.90 Would require a predator monitoring program 

involving at least two biologists at least two 

days per week for at least four months per year. 

Mexican biologist rate.

NA 4.6. Ensure adequate training, 

personnel, and infrastructure 

are available to monitor 

Sonoran pronghorn 

1 NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

182

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

NA 4.6.1. Ensure adequate training, 

personnel, and infrastructure is 

available for monitoring 

Sonoran pronghorn in Mexico

1 NA NA NA NA NA NA NA NA NA NA

2 4.6.1.1. Train personnel in Mexico for 

monitoring Sonoran pronghorn 

1 6 AZGFD, 

CONANP, 

CEDES

No 30.00 5.00 5.00 5.00 5.00 5.00 Cost estimates provided by CEDES.

2 4.6.1.2. Provide equipment (e.g. radio 

collars) 

1 4 All AZMUs No 16.00 4.00 0.00 0.00 0.00 0.00 Need approximately 10 collars every five years

at $400 per VHF collar.

3 4.6.1.3. Establish a biological station in 

Quitovac MU 

1 3 CEDES No 50.00 10.00 20.00 20.00 0.00 0.00 Cost estimates provided by CEDES.

3 4.6.1.4. Ensure adequate number of 

personnel are available to 

monitor Sonoran pronghorn in 

Mexico

1 Ongoing CEDES,

CONANP 

(Pinacate)

No 100.00 5.00 5.00 5.00 5.00 5.00

NA 4.6.2. Ensure adequate training, 

personnel, and infrastructure is 

available for monitoring 

Sonoran pronghorn in the U.S. 

1 NA NA NA NA NA NA NA NA NA NA

2 4.6.2.1. Train personnel for monitoring 

Sonoran pronghorn 

1 6 All AZMUs, 

All CAMU

No 55.80 9.30 0.00 0.00 9.30 0.00 Estimated the involvement of at least 10 

resource and biologist staff for at least 10 days 

per year, approximately every three years. Staff 

could vary from GS11 to interns. Actual costs 

will vary annually depending on training needs.
Sonoran Pronghorn Recovery Plan, Second Revision 

183

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 4.6.2.2. Provide equipment (e.g. radio 

collars) 

1 Ongoing AZGFD, 

FWS

No 0.00 0.00 0.00 0.00 0.00 0.00 $400 for VHF; $2500 for GPS collars. Will 

mostly be using VHF collars from now on. 

Costs are included in 4.3 above.

3 4.6.2.3. Ensure adequate numbers of 

personnel are available to 

monitor Sonoran pronghorn 

1 Ongoing All AZMUs No 100.00 5.00 5.00 5.00 5.00 5.00 In the absense of positions dedicated solely to 

pronghorn monitoring, this action would be 

absorbed by existing positions with time 

allocations accordingly.

NA 4.6.3. Report regularly on Sonoran 

pronghorn status

1 NA NA NA NA NA NA NA NA NA NA

3 4.6.3.1. Provide periodic (monthly or as 

needed) Sonoran pronghorn 

status updates

1 Ongoing AZGFD No 150.60 7.53 7.53 7.53 7.53 7.53 Approximately two days per month at the GS11 rate to produce and distribute the Sonoran 

Pronghorn Update.

3 4.6.3.2. Notify appropriate agencies 

and personnel of Sonoran 

pronghorn fatalities

1 Ongoing SPRT No 12.40 0.62 0.62 0.62 0.62 0.62 Approximately two days per year at the GS-11 

rate to prepare and distribute notices of 

pronghorn mortalities.

2 4.6.4. Identify additional Sonoran 

pronghorn monitoring needs

1 Ongoing SPRT No 628.00 31.40 31.40 31.40 31.40 31.40 Discussed quarterly at Recovery Team 

Meetings. Recovery Team Meetings average 

25 agency staff at a GS-11 rate

NA 5. Identify and address priority 

research needs 

NA NA NA NA NA NA NA NA NA NA NA

2 5.1. Research the extent of disease 

within Sonoran pronghorn 

populations 

1 3 SPRT 

(AZGFD)

No 360.00 0.00 0.00 120.00 120.00 120.00 Three year study estimated at $360,000
Sonoran Pronghorn Recovery Plan, Second Revision 

184

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 5.2. Continue to research the 

impact of human disturbance 

on Sonoran pronghorn 

populations.

3 4 SPRT, UofA No 500.00 0.00 0.00 0.00 125.00 125.00 Costs of a followup study would be similar to 

those of the current study.

3 5.3. Investigate ways to optimize 

Sonoran pronghorn survey 

techniques

1 3 SPRT 

(AZGFD)

No 360.00 0.00 0.00 120.00 120.00 120.00 Estimated three year study at approximately 

$360,000

2 5.4. Research and evaluate genetic 

diversity, gene flow, and 

potential founder effects of 

Sonoran pronghorn wild 

populations.

1 5 USGS/UofA No 500.00 25.00 25.00 25.00 25.00 25.00

2 5.5. Continue conducting periodic 

evaluation of genetic diversity 

of captive Sonoran pronghorn 

populations

1 5 USGS/UofA No 100.00 0.00 0.00 0.00 0.00 20.00 Estimated cost approximately $20,000 every 

four years. ($100 per sample * 50 per 

population* 4 populations)

3 5.6. Determine if Baja and 

California reintroduction sites 

should have Sonoran 

pronghorn or peninsular 

pronghorn through genetic 

analysis of museum specimens 

1 1 SPRT, 

CDPCG, 

CONANP 

(Priority 

Species), 

SPA

No 0.00 0 0 0 0 0 Already funded and begunnearly completed. 

3 5.7. Investigate Sonoran pronghorn 

subspecies differentiation 

relative to other pronghorn 

subspecies

1 4 USGS/UofA No 100.00 25.00 25.00 25.00 25.00 0.00 Estimated cost approximately $100,000

1 5.8. Research the impact of 

Sonoran pronghorn fawn 

predation 

3 3 AZGFD, 

CEDES

No 360.00 0.00 120.00 120.00 120.00 0.00 Estimated three year study at approximately 

$360,000
Sonoran Pronghorn Recovery Plan, Second Revision 

185

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 5.9. Determine if cattle grazing is 

affecting Sonoran pronghorn 

forage species composition or 

abundance. 

3 See below See below See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

See 

below

Costs covered below

3 In Mexico 3 3 SPRT No 150.00 0.00 0.00 0.00 0.00 50.00 Estimated three year study by full-time two 

biologists and expenses for transportation and 

materials.

3 In the U.S. 3 3 SPRT No 360.00 0.00 0.00 0.00 0.00 120.00 Estimated three year study at approximately 

$360,000.

3 5.10. Investigate interactions and 

competition between deer and 

Sonoran pronghorn 

3 3 SPRT No 360.00 0.00 0.00 0.00 0.00 0.00 Estimated three year study at approximately 

$360,000

NA 5.11. Investigate the effects of fire on 

Sonoran pronghorn.

NA NA NA NA NA NA NA NA NA NA NA

3 5.11.1 Research Sonoran pronghorn 

fawn recruitment as it relates to 

the relationship between 

burned areas and predation 

3 3 AZGFD No 360.00 0.00 120.00 120.00 120.00 0.00 Estimated three year study at approximately 

$360,000

3 5.11.2 Evaluate effects of fire on 

forage availability and 

vegetation structure. 

3 3 AZGFD No 180.00 0.00 60.00 60.00 60.00 0.00 Additional cost tiered off of 5.11.1 above
Sonoran Pronghorn Recovery Plan, Second Revision 

186

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 5.11.3 Monitor the area of Sonoran 

pronghorn habitat with fire 

frequencies outside the natural 

range of variation. 

3 3 SPRT No 180.00 0.00 0.00 60.00 60.00 60.00 Could be tiered off of existing vegetative 

community monitoring conducted by agency 

personnel within BMGR, CPNWR and OPCNM 

but at additional cost as estimated at left

1 5.12. Evaluate the effects of 

supplemental water sources 

and feed on the survival and 

recruitment of both wild and 

pen raised Sonoran pronghorn.

3 3 AZGFD, 

CEDES

No 360.00 0.00 120.00 120.00 120.00 0.00 Estimated three year study at approximately 

$360,000

1 5.13. Investigate Sonoran habitat 

use and preferences, including 

identifying critical use areas. 

3 Ongoing AZGFD No 0.00 0.00 0.00 0.00 0.00 0.00 Costs above in 4.2.1 and 4.2.2.

3 5.14. Investigate the effects of 

helicopters on Sonoran 

pronghorn. 

4 3 SPRT No 360.00 0.00 0.00 120.00 120.00 120.00 Estimated three year study at approximately 

$360,000

3 5.15 Describe demography and 

reproductive biology of 

Sonoran pronghorn in Sonora.

1 3 CEDES,

CONANP, 

AZGFD

No 360.00 0.00 0.00 120.00 120.00 120.00 Estimated three year study at approximately 

$360,000

3 5.16 Determine extent of Sonoran 

pronghorn distribution in 

Mexico.

1 3 CEDES,

CONANP, 

AZGFD

No 360.00 0.00 0.00 120.00 120.00 120.00 Estimated three year study at approximately 

$360,000
Sonoran Pronghorn Recovery Plan, Second Revision 

187

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 5.17 Revise PVA in ten years, or 

earlier if determined necessary 

due to new information.

1 2 SPRT Yes 60.00 30.00 0.00 0.00 0.00 0.00 Estimated cost of the PVA and agency staff 

participants is approximately $30,000 per 

event.

3 5.18 Coordinate among individuals 

conducting field work within 

Sonoran pronghorn 

management units

1,2,3,4,5,

6

Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in other coordination actions, 

primarily 4.6.4.

3 5.19 Centrally manage Sonoran 

pronghorn data.

1,2,3,4,5,

6

Continuous SPRT Yes 195.00 100.00 5.00 5.00 5.00 5.00 Estimated cost of $100,000 to develop and 

organize data into a central database. 

Estimated $5,000 to manage the database 

annually after it is developed.

NA 6. Maintain existing 

partnerships and develop 

new partnerships to support 

Sonoran pronghorn recovery

NA NA NA NA NA NA NA NA NA NA NA

2 6.1. Continue the work of the 

Sonoran Pronghorn Recovery 

Team 

1,2,3,4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs calculated above in 4.6.4

NA 6.2 Continue and promote 

coordination between Mexico 

and the U.S. to recover 

Sonoran pronghorn. 

NA NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

188

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

1 6.2.1 Establish a binational 

agreement or letter of intent 

(Mexico-U.S.) to implement 

binational recovery actions in 

the Sonoran Pronghorn 

Recovery Plan and PACE

1,2,3,4 1 SPRT, FWS, 

CONANP

No 1.57 1.57 0.00 0.00 0.00 0.00 Costs calculated using one GS11 to write 

agreement for 1 week. Coordination included in 

6.2.2., below.

1 6.2.2 Establish a binational steering 

committee for the Sonoran 

pronghorn that could facilitate 

and support the tasks of 

several members of the 

recovery team, have more 

weight in the exchange 

between ministries in the 

Mexican Government and 

facilitate the flow of resources 

(both human and economic) 

towards the Plan. 

1,2,3,4 Ongoing SPRT, FWS, 

CONANP

No 20.00 1.00 1.00 1.00 1.00 1.00

1 6.2.3 Coordinate to secure funding to 

recover Sonoran pronghorn.

1,2,3,4 Ongoing SPRT, FWS, 

CONANP

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered above in 4.6.4

1 6.3 Develop a Sonora State PACE 

for Sonoran pronghorn to, 

among other things, faciliate 

recovery actions between 

Sonora and Arizona.

1,2,3,4 1 CEDES, 

CONANP 

(Priority 

Species and 

Pinacate)

No 20.40 0.00 0.00 0.00 0.00 20.40 Two Mexican Biologists at half time for one 

year.

3 6.4 Expand partnerships with 

interested groups to implement 

Sonoran Pronghorn recovery 

1,2,3,4 Ongoing SPRT Yes 12.60 0.63 0.63 0.63 0.63 0.63 Two staff attending partner meetings once per 

year. GS-11 standard salary. 
Sonoran Pronghorn Recovery Plan, Second Revision 

189

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 6.5 Increase public support for the 

Sonoran pronghorn recovery 

program 

1,2,3,4 Ongoing SPRT Yes 37.60 1.88 1.88 1.88 1.88 1.88 Recovery staff involvement in public seminars 

and symposia, 6 days per year estimated.

3 6.6 Promote active social 

participation in the protection of 

Sonoran pronghorn and habitat 

in Mexico

1,2,3,4 Ongoing SPRT 

(CEDES and 

CONANP 

(Priority 

Species))

No 22.00 1.10 1.10 1.10 1.10 1.10 Mexico biologist staff involvement in education 

and outreach to the public. At least five days 

per year for 3 biologists.

3 6.7 Increase and maintain 

community vigilance programs 

in Mexico (existing Federal 

program in Mexico) 

1,2,3,4 Ongoing SPRT 

(CEDES and 

CONANP 

(Priority 

Species))

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered above in 6.4

3 6.8 Engage universities and other 

interested parties (e.g. zoos) in 

research of Sonoran pronghorn

1,2,3,4 Ongoing SPRT Yes 31.40 1.57 1.57 1.57 1.57 1.57 Annually coordinate with science group.GS-11 

standard salary. Minimum of five staff days per 

year.

3 6.9 Conduct education and 

outreach to promote Sonoran 

pronghorn recovery 

1,2,3,4 Ongoing SPRT No 31.40 1.57 1.57 1.57 1.57 1.57 Recovery staff involvement in education and 

outreach to the public. At least five days per 

year. GS-11 salary standard.

1 6.10 Work with governments 

(federal, state, and municipal) 

to recover Sonoran pronghorn

1,2,3,4 Ongoing SPRT Yes 62.80 3.14 3.14 3.14 3.14 3.14 Costs partially covered above in 4.6.4. 

Additional five days per year of at least two GS11 staff required annually for follow through.

2 6.11 Work to improve and maintain 

partnerships with ranchers in 

Mexico to conserve Sonoran 

pronghorn 

1,2,3,4 Ongoing CEDES, 

CONANP

(Priority 

Species and 

Pinacate)

No 22.00 1.10 1.10 1.10 1.10 1.10 Cost estimates based on an average wage of 

$1700 per month (salary and benefits) for 

Mexican Biologists. Minimum of two biologists 

needed at least 10 days per year to coordinate 

this action.
Sonoran Pronghorn Recovery Plan, Second Revision 

190

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 6.12 Develop, maintain, and 

disseminate a directory of 

specialists and working groups 

that conduct studies or 

implement actions for the 

management, recovery, 

conservation, and protection of 

the Sonoran pronghorn at the 

regional, national, and 

international level

1,2,3,4 Continuous SPRT Yes 6.28 0.31 0.31 0.31 0.31 0.31 One GS-11 staff day per year required to 

update and distribute annually. Costs estimated 

for 20 years. 

3 6.13 Ensure sufficient personnel and 

resources (e.g., vehicles) are 

trained and available to 

adequately monitor, manage, 

and protect Sonoran pronghorn 

in Mexico. 

1,2,3,4 Ongoing CEDES, 

CONANP 

(Priority 

Species and 

Pinacate)

No 15.40 0.77 0.77 0.77 0.77 0.77 Costs partially covered above in 4.6.1.4. 

Additional five days per year of at least two staff 

(one from CEDES and one from CONANP) 

required annually for follow through.

NA 7. Secure adequate funding to 

implement recovery actions 

for Sonoran pronghorn

NA NA NA NA NA NA NA NA NA NA Na

1 7.1. Explore U.S.-based funding 

source options; secure and 

manage funds acquired from 

those sources.

1,2,3,4 Ongoing SPRT Yes 100.00 5.00 5.00 5.00 5.00 5.00 Requires the involvement of at least three GS11 staff for 16 days per year.

1 7.2. Explore Mexico-based funding 

source options; secure and 

manage funds acquired from 

those sources.

1,2,3,4 Ongoing SPRT No 100.00 5.00 5.00 5.00 5.00 5.00 Requires the involvement of at least three staff, 

for at least 16 days per year.
Sonoran Pronghorn Recovery Plan, Second Revision 

191

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

2 7.3. Secure and manage mitigation 

and compensation funding in 

the U.S. 

1,2,3,4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs included in 2.3.2.2 above.

2 7.4 Secure and manage mitigation 

and compensation funding in 

Mexico.

1,2,3,4 Ongoing CONANP, 

CEDES

No 7.70 0.39 0.39 0.39 0.39 0.39 Costs partially covered above in 3.5.2 and 3.6.2 

above. At least an additional five staff days per 

year may be required to implement this action.

3 7.5 Manage the environmental 

impact mitigation fund in 

Mexico to ensure that funds are 

applied specifically to Sonoran 

pronghorn conservation

1,2,3,4 Ongoing SPRT 

(CEDES and 

CONANP 

(Priority 

Species))

No 50.00 2.50 2.50 2.50 2.50 2.50 Would require state and national agency staff 

participation to implement and manage. 

Estimate at least $2,500 per year in staff 

involvement to implement this action. 

3 7.6 Secure funding from other 

funding sources (e.g., 

nongovernmental 

organizations, international 

funds)

1,2,3,4 Ongoing SPRT Yes 6.58 0.94 0.00 0.00 0.94 0.00 Occasional, not anticpated every year. 

Estimate two GS-11 staff working with an NGO 

to coordinate at least three days per year, at 

least every three years.

NA 8. Practice adaptive 

management in which 

recovery is monitored and 

recovery tasks are revised by 

the USFWS in coordination 

with the Sonoran Pronghorn 

Recovery Team as new 

information becomes 

available

NA NA NA NA NA NA NA NA NA NA NA
Sonoran Pronghorn Recovery Plan, Second Revision 

192

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

NA 8.1. Use adaptive management 

principles in the context of 

structured decision making 

(e.g. The Open Standards for 

the Practice of Conservation 

and the DOI Technical Guide to 

evaluate this recoery effort on 

an ongoing basis. 

1,2,3,4 NA NA NA NA NA NA NA NA NA NA

3 8.1.1. Conduct monitoring of Sonoran 

pronghorn populations, habitat, 

and threats.

1,2,3,4 Ongoing All AZMUs, 

All CAMU, 

Mexico CU

No 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in monitoring actions above. 

Specifically, 2.1, 2.3, 4.2 and 4.5

8.1.2. Analyze and share results of 

monitoring 

1,2,3,4 NA NA NA NA NA NA NA NA NA NA

3 8.1.2.1. Compile (FWS) and discuss 

Sonoran pronghorn recovery 

accomplishments and updates 

(via email, conference call, or 

meeting) with the Sonoran 

Pronghorn Recovery Team at 

least two times per year

1,2,3,4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 Costs covered in recovery team meeting cost 

estimates above in 4.6.4

3 8.1.2.2. Exchange information annually 

and hold meetings as 

necessary, or at least every 

two years, between agencies 

and universities in Mexico and 

the U.S to discuss progress in 

implementing Sonoran 

pronghorn recovery in the U.S. 

and Mexico

1,2,3,4 Ongoing SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 This would be done at recovery team meetings 

(costs calculated above in 4.6.4), as well as at 

the Sonoran Desert symposium every two 

years; however this meeting would occur 

regardless of the Sonoran pronghorn's listed 

status, so no costs are included. 
Sonoran Pronghorn Recovery Plan, Second Revision 

193

Recovery 

Criterion 

Number

Action 

Duration 

(Years)

Responsibility

Cost Estimate by FY (by 

$1,000s)

Prior

-ity 

Action 

Number

Action Description

Parties

Is 

FWS 

Lead?

Total 

Cost 

($1,000s) 2016 2017 2018 2019 2020 Comments

3 8.1.2.3. Report regularly on Sonoran 

pronghorn status (see 4.6.3.1 

above)

1,2,3,4 Ongoing SPRT No 0.00 0.00 0.00 0.00 0.00 0.00 Cost covered above in actions 4.6.3.1 and 

8.1.2.2.

3 8.1.3. Revise recovery actions and 

tasks using monitoring results

1,2,3,4 3 SPRT Yes 9.20 0.00 0.00 0.00 0.00 2.30 This only includes costs of revising the recovery 

actions, if needed, every 5 years with the 

recovery team, it does not include the cost of 

implementing revised actions. Anticipate at 

least a one day meeting with at least 25 

participants every five years for recovery action 

revision.

3 8.1.4. Revise recovery criteria, if 

warranted, following new PVA 

or if other new information 

becomes available that 

suggests the recovery criteria 

in the document are not 

sufficient for recovering 

Sonoran pronghorn (revise in 

ten years; or earlier if 

determined necessary).

1,2,3,4 3 SPRT Yes 0.00 0.00 0.00 0.00 0.00 0.00 No costs included because this action would be 

coordinated with 8.1.3 above to reduce costs 

associated with additional meetings.
Sonoran Pronghorn Recovery Plan, Second Revision 

194

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APPENDICES
207

Appendix A. Conceptual Models of Threats
208

stressor

source

Indirect 

threat

The green ovals are the key ecological attributes. A 

degraded key ecological attribute is a stressor. For 

example, a key ecological attribute may be “habitat 

connectivity.” “Habitat fragmentation” is a stressor.

A direct threat is a proximate activity or 

process that directly has caused, is 

causing, or may cause stress. It is the 

source of the stressor.

An indirect threat is the cause of a 

direct threat. There can be many 

indirect threats.

KEY

Note: conceptual models are for all existing populations (Cabeza Prieta, Kofa, 

Pinacate, and Quitovac) unless noted otherwise.
209
210
211
212
213
214
215
216
217
Baja

California

Sonora

California

Arizona

§ ̈¦I-17

§ ̈¦I-19

§ ̈¦I-8

§ ̈¦I-10

§ ̈¦8

§ ̈¦2

Sonoyta

Puerto

Penasco

Santa Cruz

Pima

S

a

nta 

Cru

z

C

o

c

h

si e

Gila

Maricopa

Gila

Graham

Gila

Pinal

La 

Paz

Riverside

L

a 

P

a

z

M

aric

op

a

La Paz

Yuma

La 

P

a

z

Imperial

Riverside

Imperial

M

aric

op

a

Yu

m

a

Maricopa

Pinal

Maricopa

Pima

Gra

h

a

m

P

ni al

Graham

Cochise

Yu

m

a

mI p

erial

Yu

m

a

P

mi a

Pinal

Pima

Pim

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C

o

c

h

si e

q

Coordinate System: WGS 1984

UTM Zone: 12N

Projection:

Transverse Mercator

Linear Unit: Meter

Scale: 1:1,250,000

Basemap: Esri, DeLorme, 

USGS, NPS

Produced By: L. Urreiztieta, 

Harris Environmental Group, Inc.

April 2016

Cabeza Prieta Management Unit

Arizona Reintroduction Management Unit

 Kofa Sub-Unit (Population Established in 2013)

 Sauceda Sub-Unit (Population Established in 2015)

0 50 100 150 200

Kilometers

GULF 

OF

CALIFORNIA

0 25 50 75 100

Miles

Bureau of Land Management

Barry M. Goldwater Range

Buenos Aires NWR

Cabeza Prieta NWR

Kofa NWR

Organ Pipe Cactus National Monument

Tohono O'odham Tribal Lands

Yuma Proving Ground

£¤85

£¤86

Endangered

Threatened

Proposed (All other areas within AZ MU)

ESA STATUS FOR SECTION 7 CONSULTATION
219

Appendix C. PACE
220

Species Conservation Action Program

Pronghorn (Antilocapra americana)

2009 Year of the Pronghorn

Mexico

Federal Government

SEMARNAT

August 2009

Translated to English

March 2013
221

I. Introduction

Natural resources represent one of the most important assets of a nation because of its environmental 

contribution and direct use. In northern Mexico, the diversity of hoofed species is relatively low compared with 

other bioregions around the world; and in most cases, populations have dramatically decreased, contributing to 

and even accelerating the extinction process in that area. Extinction in this case refers to the loss of the species’

population and its genetic variability.

This destructive and recurrent process can presents itself in desert areas and has become more prevalent and at a 

faster rate during the last 50 years. This rapid increase in the destruction of the species is mainly due to the 

deforestation, destruction of animal species, increased rate of pasture lands for domestic animals, and aquifer 

reduction.

At the same time, the dysfunction of the ecosystem in desert areas is having a snowball effect on itself, by 

making the desert ecosystems even more arid. We should be concerned with the rapid increase in the extinction 

rate of the desert species and should pay more attention to the natural resources in our desert areas, which

represent 60% of their area and are key for the future of the human communities which they inhabit, since these 

are reaching their limit, to a point of no return. Unfortunately, the actions needed to stop this dangerous process 

are generally perceived, in our uninformed society, as untrue and even alarmist.

This is the reason why in February in 2007, Mexican president Felipe Calderon Hinojosa presented the 

Programa de Conservacion de Especies en Riesgo – PROCER (Program for the Conservation of At Risk

Species), and part of his five presidential commitments for conservation. This program is managed by the 

Conservación de la Comisión Nacional de Áreas Naturales Protegidas (Conservation of the National 

Commission of Protected Natural Areas) of SEMARNAT. The main objective of this program is to recover the 

30 most at risk species during 2007-2012, by implementing a recovery program developed for each species 

Programas de Acción para la Conservación de Especies (Species Conservation Action Program).

This program is the result of collaboration between the Dirección de Especies Prioritarias Para la 

Conservación (Directive of Species Prioritized for Conservation) and a group of experts, who have been 

working on the pronghorn for several years and belong to or have been working with the Subcomité Técnico 

Consultivo Para la Conservación Manejo y Aprovechamiento Sustentable del Berrendo en México (Technical 

Consulting Subcommittee for the Conservation, Management and Sustainable Use of the Pronghorn in Mexico). 

This document summarizes the combined efforts of the experts along with the recommendations of the 

subcommittee, detailing the critical needs for the conservation of the species and details all steps needed to be 

implemented in the short, mid, and long term.

Following an information gathering process with information provided by the specialists and the contribution 

and participation of the Comisión Nacional de Áreas Naturales Protegidas (National Commission of Protected 

Natural Areas), they initiated the integration of the Action Plan for the Conservation of the Pronghorn in 

Mexico. This phase includes the integration, communication and reinforcement of local, regional, national, and 

international efforts. These efforts have been taking place in the country by several civil organizations, 

academic and research programs, government institutions, and public, social and private entities interested in 

collaborating in the conservation of the pronghorn.

Currently the pronghorn PACE is the most viable strategy to aid this species to continue its opportunity to 

recover. Without a doubt, the pronghorn can be rescued with the existing knowledge about how to manage this 

species, however with the current knowledge along with the technology developed, it will be necessary to 
222

double the efforts required in order to persuade SEMARNAT, in a timely manner, to guarantee the available 

habitat for wildlife as a natural treasure and make it a national treasure with high value with a significant 

meaning to the Mexican people.

Another key component to the success of this program will be to continuously incorporate landowners to 

conservation programs, along with the proper financial programs, combined with the development of 

environmental education and local conservation. 
223

II. Background

Barely known in Mexico, the pronghorn (Antilocapra americana) is considered the only “antelope” of the new 

world. It belongs to the Artiodactyla class and it is the only living representative of the Antilocapridae family on 

the planet. Besides being the fastest mammal in America and the second fastest in the world, it is a species 

highly sought after as an endemic game animal in North America. Up until 1945, there were five described 

subspecies, of which three can be found in Mexico (A. a. mexicana, A. a. peninsularis and A. a sonoriensis)

Before the European colonization, it is estimated that the pronghorn population was around 50 million 

individuals on the North American plains. Four hundred years later, the population is estimated to be around 

1,500 individuals of the three subspecies that live in Mexico. Mexican history mentions how this valuable 

natural resource, the pronghorn, was mismanaged and over exploited. It is historically relevant that there was an 

organized hunting trip, close to Pachuca Hidalgo, for the first Virrey don Antonio de Mendoza in 1540, in 

which Torquemada reported the capture of 600 pronghorn and deer. This was just the beginning of what 

repeated itself during the following four decades. In other words, in four hundred years, humans, directly or 

indirectly, destroyed 50 million pronghorn. It is a different situation in the United States of America, where the 

healthy pronghorn population is over 750,000 individuals. In Mexico, the number of pronghorn and their 

distribution has been heavily affected by significant habitat destruction and fragmentation, along with hunting

pressures. Besides the fact that the pronghorn in Mexico is being geographically isolated and the number of 

free-range individuals is diminishing, their genetic load is diminishing as well, making the pronghorn in Mexico 

an endangered species.

Some international organizations like Union Internacional Para la Conservación de la Naturaleza

(International Union for the Conservation of Nature), classifies the pronghorn as Low Concern (LC) (Hoffmann, 

et. al. 2008). However, several of the pronghorn populations in Mexico are in a different situation as compared 

to pronghorn in the United States. The circumstances that have made the Mexican pronghorn become an 

endangered species are anthropogenic, because the pronghorn have been exterminated by free land ownership 

and its habitat has been fragmented because of economic development in Mexico. For over a decade, biologists 

and naturalists have raised their voices in alarm without being able to produce a significant change. On the other 

hand, the United States and Canada implemented actions and laws allowing them to recover pronghorn 

populations that on their lands.

The United States has control of over one million individuals, and they could increase this number, but they 

lack additional available habitat. On the other hand, the pronghorn in Mexico is about to disappear even though 

there is sufficient habitat available to increase the population.
224

III. Description and Species Classification

The pronghorn looks like a cross between an antelope and a deer. Males are bigger in size with an approximate 

weight of 45-60 Kg (99-133 lbs.), and females weight 35-45 Kg (77-99 lbs.). Their body length is 1.30-1.50 

meters (4.25-5 feet), and they are 70-80cm (2.3-2.6 feet) tall from shoulder to feet, the length of their tail is 

approximately 10cm (4 in), and their ears are approximately 15cm (6 in) long.

Pronghorn have a relatively robust body, with black perpendicular horns, for both sexes, with the tip curved 

towards the inside. Pronghorn replace their horns every year like deer replace antlers. Males’ horns are bigger in 

size (125-450mm (5-18 in)) and are branched. Females’ horns are usually straight, short spikes about 25-

150mm (1-6 in) long. Both males and females have a crown of hair at the bottom of the horns and black mane 

along the neck. Males have glands under their ears and rump area, but females do not.

The pronghorn has a deer-like body that also reminds us of an antelope. Its back is higher than its shoulder 

blades, with long skinny legs. It has a tan to reddish brown body. Its cheeks, belly, rump, chest and inner legs 

are white. Males have a broad black mask that runs from their eyes down their snout to their nose, and black 

neck patches. The females do not have black markings.

An element that characterizes this species is the white hair on their rump, which can be seen from far distances. 

Pronghorn rump hairs will stand up, like bristles, to signal danger and it is used as an alarm signal amongst their 

group. The pronghorn taxonomy is detailed in the table below:

Kingdom Animalia

Phylum Chordata

Class Mammalia

Order Artiodactyla

Suborder Ruminantia

Infraorder Pecora

Family Antilocapridae

Genus Antilocapra

Species Antilocapra americana
225

IV. Evolution

Antilocaprids belong to a family in the endemic order of Artiodactyla in North America, and its origin is 

estimated to be 19 million years old. There is no evidence of its presence in any fossils found in the paleoarctic 

region, and until now nobody has found evidence showing that antilocaprids may have crossed the Bering 

Strait. During this period, the family diversified into 18 genera. Each one showing variation in horn structure, 

making horn design a specific characteristic of each family. The genus Antilocapra originated in the middle of 

the Pleistocene, a little less than a million years ago, in a time when forests and grasslands rapidly grew 

throughout the world. This family developed a high level of adaptation to the hypsodont dentition (molars with 

high crests and deep valleys, which allow the pronghorn to mill their food) since the new grasses and shrubs

were hard and abrasive. As a species, it is well adapted to the big plains covered by grasslands and/or xeric 

shrublands. Up until 1945 there were five subspecies described, of which two can be found in shrubland areas 

(A. a. peninsularis and A. a. sonoriensis) and three can be found in grassland areas (A. a. americana, A. a. 

mexicana and A. a. oregona).

The natural history of this family indicates that during the Pliocene, this family experienced their more 

extensive adaptive propagation, and by the end of the Pleistocene, only the antilocaprids survived. However, the 

pronghorn has perfectly adapted to desert habitats and its extreme drought conditions. Hence, there is no 

intrinsic biological reason that could influence the endangered status that some populations are facing.
226

V. Reproduction

Polygamy is the characteristic reproductive behavior of the pronghorn. Females generally reach sexual maturity 

at 16-17 months of age, even though there have been records indicating some females who reached their 

reproductive stage at the age of 5 months (Mitchel, 1967). Males generally reach sexual maturity at the end of 

their first year, however, dominant adult males generally exclude the young individuals from the reproductive 

process. The males in reproductive age compete amongst themselves to win the right of reproduction. Contrary 

to many other ungulate species, males do not abandon the herds of females and young after the reproductive 

period is over; to the contrary, they stay close to them during this period.

Gestation lasts 250 days. For the first birth, females generally give birth to only one fawn, but after that they 

generally give birth to two fawns and in rare instances to three. Fawns are light brown and weigh 2-4 Kg (4.4-9 

lbs.). Immediately after giving birth, females hide their fawns in the shrubbery and stay away from them in 

order to protect them from predators, even though they stay vigilant in the surroundings and go to their fawns 

regularly to nurse them. 

Reports show that both males and females continue to reproduce until they are 10 years old and approximately 

25% of females who are in reproductive capacity do not give birth every year (Mitchell, 1967).

The breeding period varies according to geographic distribution of the different populations. Peninsular 

populations breed in June and July (Cancino et al., 1995), Sonoran populations breed in September and October 

(Castillo, 1993), and Mexican populations breed in November and December (Treviño, 1978).
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VI. Diet

Pronghorn eat throughout most of the day, grazing on grasses, forbs, herbs, moss, and a large variety of tender 

plants and on some occasion even cactus. The peninsular population consumes a diet based on 44% shrubs, 

22% herbs, 4% grasses, and 30% non-identified material with reproductive structures (Cancino, 1994). The 

Sonoran populations consume a diet based on 69% herbs, 22% shrubs, 7% cactus, and 2% grasses.

Pronghorn satisfy their water needs through their physiological adaptation, by taking the water in the form of 

dew or the water contained inside the foliage that they consume (O’Gara, 1978). During the drought season, 

pronghorn reduce their water requirements by significantly reducing their food consumption, by staying in 

shady areas, reducing their mobility, and by reducing other activities that require the use of high levels of 

energy (Yoakum, 1990).
228

VII. Habitat

Pronghorn live in habitats characterized by open space such as grasslands, shrublands, plains with low hills, 

riverbeds and plateaus. Pronghorn prefer the wide riverbeds during the drought seasons. Generally, they avoid 

forests and areas with dense shrubs (O’Gara, 1978). The elevation range where pronghorn live varies according 

to the population. A. a. peninsularis and A. a. sonoriensis can be found between sea level and 200 msnm, while 

A. a. mexicana can be found between 1,400 and 1,600 msnm (González-Romero y Lafón, 1993). The peninsular 

population is found in areas characterized by xeric shrubs located in the biosphere reserve “El Vizcaíno”. 

Vegetation more frequently consumed includes shrubs from the dunes, halophilic shrubs, and microphilic 

shrubs (Cancino et al., 1995). Pronghorn of the Sonoran populations are distributed in the following habitats: 

low dunes, sandy plains, low hill areas, and basaltic areas. The foot of low mountains represents a typical 

habitat, along with low granite mountains and sandy plains (Arizona Game and Fish Department, 1981). The 

Mexican population typically lives in grasslands with yucca, and these species dominate the area: Bouteloua 

hirsuta, B. curtipendula, B. eriopoda, B. gracilis and Dalea citrina (Treviño, 1978).
229

VIII. Ecology and Behavior

One of the functions of the pronghorn is the passive cultivation of the substrate and vegetation in the desert 

areas. Hence, it is an important contributor to the persistence and structure of the flora of its habitat. This 

happens through multiple interactions with its environment: the mechanic action that it produces with its hoof 

prints in the soil, the transportation and propagation of plant seeds that it digests, as well as the excrement and 

urine it deposits on the soil serves as organic fertilizer.

Pronghorn move in groups, whose members of these herds are females with their fawns and young males. Adult 

males are generally solitary or live in small groups, even though they sometimes form small herds with only 

male individuals. They are active during night and day; however there have been records of high level of 

activity registered at sunrise and sunset, with less frequency at sunset (Byers, 1998).

The establishment of territory is basically determined by the sexual behavior of the males. During the 

reproductive period, dominant males delineate their territories with urine, excrement, and secretions from the 

glands located in the ear areas. During this time, territories are defended by using antagonistic behaviors such 

as: staring, vocalizations, puffing up, drawing near, interactions and persecutions. This territorial behavior 

allows the stronger and more aggressive males to reproduce with the females, preventing the young males from 

reproducing. The size of the territory varies according to the availability of food, number of animals per group, 

and environmental conditions. The young males of one or two years of age and the non-reproductive adults 

form groups that do not defend territories. The reproductive-age females establish their own groups within and 

around the territories already established by the dominant males. It has been reported that the descendants of 

these groups become active members of the same groups after 6 weeks old and represent their own hierarchy 

within the group (Byers, 1998).
230

Map on Page 14
231

IX. Distribution

The historical distribution of the pronghorn covers from the south-central part of Canada, the central and west 

plains of the United States, through the south-central and northwest of Mexico, including the Baja California 

peninsula.

In the specific case of A. a. mexicana, distribution is from the southeast of Arizona, southwest of New Mexico, 

and west of Texas, in the United States, and in Mexico, includes Chihuahua, Durango, Coahuila, parts of Nuevo 

León, and Tamaulipas, extending towards the south at least to the state of Hidalgo. A. a. peninsularis was 

distributed historically in a wide region in the Baja California peninsula, from the San Felipe and San Quintín 

bay areas through the north of Magdalena bay (Nelson, 1925). Finally, A. a. sonoriensis was distributed 

historically from the south of Arizona through the desert plains of the center and west of Sonora (May, 1980; 

Leopold, 1959).

Currently, the Mexican subspecies can be found in some areas in the Chihuahua region, mainly in “La Perla”, 

“La Gregoria”, “San Luis”, “Terraceño”, “El Sueco- Moctezuma”, “Janos-Ascención” y “Coyame”, as well as 

in the “Valle de Colombia” and rancho “El Novillo”, Coahuila (Pallares, 1999). In the peninsula the pronghorn 

lives in an area of approximately 362,385 ha. Within the Biosphere Reserve of “El Vizcaíno”, pronghorn live in 

the plains located at the parallel 28o North, 113o 18” East, 26o 47” South y and 114o 30” West (PHVA, 1994). 

In the Sonora region, the habitat is limited to the northwest of the state, including Caborca, Puerto Peñasco, 

Plutarco Elías Calles, and San Luis Río Colorado.
232

X. Threats

Experts believe that the main causes of the rapid decline of pronghorn populations are the reduction and 

fragmentation of their habitat, uncontrolled hunting, and predation. Another cause is the increase of free-range 

domestic species in pronghorn habitat (CES, 1992). It has been reported in the southwestern United States, that 

the forage required to feed one domestic animal is equivalent to the forage required to feed 47 to 220 pronghorn

(Yoakum y O’Gara, 1990).

Even though pronghorn hunting has been forbidden in Mexico since 1922, there is evidence that indicates that 

people continue to hunt them (locals continuously report hunting activities, there are empty bullets, and truck 

tracks that can be found in pronghorn habitats). Illegal pronghorn hunting is a fact in Mexico, and it obviously 

makes the recovery of this species even more difficult.

Predation is another cause that hinders the recovery process. In Mexico, the coyote (Canis latrans), is the most 

important predator, because it can cause a high level of mortality to pronghorn fawns.

Natural factors such as extensive drought periods are also high risk factors that affect pronghorn populations. 

These factors mainly affect the reproduction rate and the survival rate of the fawns (Yoakum y O ́Gara, 1990).
233

XI. Conservation of Pronghorn in Mexico

Due to the rapid decrease of pronghorn populations in Mexico, governmental and non-governmental entities 

have developed action plans to aid the conservation of the pronghorn. The first efforts started back in 1922, 

when president Álvaro Obregón banned the hunting of the pronghorn. Later in 1952, the government created the 

Federal Hunting Law, which supports the banning of the hunting of the pronghorn in Mexico. The Norma 

Oficial Mexicana (NOM- 059-ECOL-1994) reiterated the legal protection and its update in 2001, which 

classifies the pronghorn populations in Mexico as endangered species.

During the 70s and 80s, there were several projects developed with the idea of starting to build the theoretical 

and practical foundation to initiate the recovery of the pronghorn in Mexico (Ramírez, et al., 1999).

With the creation of the Secretary of the Environment, Natural Resources and Fish (Secretaría de Medio 

Ambiente Recursos Naturales y Pesca [SEMARNAP]) in 1994, one of the areas that experimented the most 

development was the Protected Natural Areas (Áreas Naturales Protegidas [ANP]), focusing on the

conservation of the habitat and the species in most endangered situations. This is the case of the Biosphere 

Reserve “El Vizcaíno” (ReBiVi) with an area of 2’546,790.00 ha and the Biosphere Reserve “El Pinacate y 

Gran Desierto de Altar” (ReBiPi) with an area of 714,556 ha. Such areas represent, without a doubt, significant 

habitats for the conservation of the pronghorn and other species.

The Wildlife Conservation and Productive Diversification Program in the Rural Sector (Programa de 

Conservación de Vida Silvestre y Diversificación Productiva en el Sector Rural 1997- 2000) (SEMARNAP, 

1997) included among its strategies, the Priority Species Recovery Program (Proyectos para la Recuperación de 

Especies Prioritarias [PREP]) and the establishment of the Unions System for the Conservation of Wildlife 

(Sistema de Unidades para la Conservación de la Vida Silvestre [SUMA]). This program created strategies to 

help develop and maintain the natural process of the ecosystems, and promote the conservation of the habitats 

and the wildlife, reducing the extinction rate of species and increasing the development of endangered species.

The success of these strategies motivated lawmakers to include them in the General Wildlife Law (Ley General 

de Vida Silvestre [LGVS]) and the General Law for Sustainable Rural Development (Ley General de 

Desarrollo Rural Sustentable), which allowed the continuance to protect affected species. In 1999, they formed 

the Technical Consulting Subcommittee for the Conservation, Management and Sustainable Use of the 

Pronghorn (Subcomité Técnico Consultivo para la Conservación, Manejo y Aprovechamiento Sustentable del 

Berrendo, órgano técnico consultivo) of the Secretary of the Environment and Natural Resources (Secretaria de 

Medio Ambiente y Recursos Naturales [SEMARNAT]), with the mission of proposing a national strategy for 

the conservation and management of the pronghorn by developing the PACE, which established the foundation 

and rules to promote the joined participation of the federal government, state government, and local society, 

with the objective to help preserve the species in Mexico. The plan included an evaluation of the situation, the 

control of the main threats in its habitat and population, and the implementation of the actions listed in the 

Conservation, Management and Sustainable Use Project for the Pronghorn in Mexico (Proyecto para la 

Conservación, Manejo y Aprovechamiento Sustentable del Berrendo en México [PREPBe]).
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XI. 1. Peninsular Pronghorn (A. a. peninsularis)

In 1978, through the Dirección General de Fauna Silvestre (DGFS), a program for the conservation of the Baja 

California region, was initiated along with the program for the preservation of the aquatic migrating birds of the 

Laguna Ojo de Liebre. Later, the protection program was extended to the pronghorn in the desert of “El 

Vizcaíno” because of the agreements established between the DGFS and the Servicio de Pesca y Vida Silvestre 

de Estados Unidos (FWS). The program received financial support from the Comité Conjunto México-Estados 

Unidos para la Conservación de la Vida Silvestre. Later, the Denver Wildlife Research Center provided funds 

for the establishment of a wildlife laboratory in La Paz, B.C.S., an aerial census, and the assessment of a group 

of predator’s experts who will conduct the first evaluation and management of the coyote population, which 

was affecting the pronghorn population. The DGFS authorized five areas to form the team to work in the 

Estación de Aprovechamiento de Vida Silvestre (EAVS) en Guerrero Negro, BCS. Later, through the Dirección 

General de Parques Nacionales (1984), they conducted the first technical study that justified the establishment 

of the Biosphere Reserve “El Vizcaíno” (Sànchez, et. al., 2006).

In 1988 the Reserve was decreed, however they did not have enough resources to implement and manage the 

decree. Some institutions volunteered to conduct basic studies in the Reserve. Among them was the Centro de 

Investigaciones Biológicas del Noreste (CIBNOR), the Universidad Autónoma de Baja California Sur and the 

Instituto de Biología de la UNAM, who developed a study of the flora and fauna of the Reserve, including the 

pronghorn.

In 1993, they received the first financial support from the Banco Mundial through the Fondo Mundial para el 

Medio Ambiente (GEF) and they allocated the first significant resources to the El Vizcaíno. However, it was 

not until 1997 that a donation was received for the GEF I project, through the Fondo Mexicano para la 

Conservación de la Naturaleza, A.C., and the El Vizcaíno had a permanent annual budget.

In 1994, organized by the CIBNOR, in La Paz, B.C.S., they conducted the first Taller de Evaluación de la 

Población Peninsular del Berrendo y su Hábitat, in which 30 specialists participated and created the first 

Programa de Recuperación del Berrendo Peninsular (Program for the Recovery of the Peninsular Pronghorn), 

which was the beginning of the conservation program that was continued through the Biosphere Reserve El 

Vizcaíno.

By 1997, the Secretaría de Medio Ambiente, Recursos Naturales y Pesca, the Ford Motor Co. and the Espacios 

Naturales y Desarrollo Sustentable, A.C., signed a five year agreement to finance and manage the campaign 

“Salvemos al Berrendo”, which was later renewed by the Comité Cívico de la Asociación Mexicana de 

Distribuidores Ford and is still in place today. In addition, the Fondo Mexicano para la Conservación de la 

Naturaleza approved additional resources to complement the cost of the program, and helped with the 

consolidation of the infrastructure needed. Since 2001, the L.A. Zoo has provided support by providing medical 

equipment and consulting to the project. In 2003 the REBIVI and the L.A. Zoo signed an agreement. To 

continue supporting this effort, the La Campania Exportadora de Sal S.A de C.V. has generously contributed 

and supported this cause since 1983.

Until today, we have observed positive results in the conservation and reproduction of the peninsular 

pronghorn. We currently have a ranch with 450 individuals, with a reproduction rate of 100 individuals a year, 

in addition to the wild individuals. Together we estimate a population of 600 pronghorn. The first reintroduction took place in December of 2006 and the second one in 2007, and we have observed positive results 

from the first introduction of the “ranch raised” individual into the wilderness.
235

After almost 14 years since this project started and more than 25 years of work in this pronghorn population, 

one can observe the positive results of this program, including the positive adaptation of the “ranch raised” 

pronghorn raised in a natural but controlled environment, then being introduced to the wild population. It is 

important to highlight that the objective of this program is to help in the recovery of the peninsular pronghorn 

wild population to help it live and develop freely in its natural way, without any intensive management.

Increasing the pronghorn population is the main objective of this project, hoping that the pronghorn can 

establish two or more permanent populations that will allow them to overcome any future environmental 

challenges that constantly affect their population. If we can reach this in the future, then the management

required to protect and help the wild population will be minimal, and the raising of pronghorn in captivity will 

be a way of helping this species reach this point.
236

XI. 2. Sonoran Pronghorn (A. a. sonoriensis)

In the United States of America, the A. a. sonoriensis population has been protected by the Arizonan 

government since 1967, when this pronghorn was included in the federal list of endangered species, and it 

became part of the Mexican list in 1984. In addition, a significant part of the pronghorn’s habitat in Arizona is 

legally protected.

Between 1987 and 1989, the Sonora government, through the Centro Ecológico de Sonora (CES), conducted a 

series of surveys on the northwest of the state, to implement their long-term project “Estrategias para la 

recuperación del berrendo sonorense”. This project focused on educating and raising awareness in Sonora about 

the critical situation of the pronghorn and its biological, social, and cultural relevance in the area. At the same 

time, a patrol/surveillance program was implemented in the area.

Since 1988, the Sonora Government, through the El Centro Ecológico de Sonora del IMADES, currently 

Comisión de Ecologies y Desarrollo Sustentable del Estado de Sonora (CEDES), and in conjunction with the 

Arizona Game and Fish Department (AGFD) andU.S. Fish and Wildlife Service (FWS), have been evaluating 

and following the Sonoran pronghorn populations in the regions of the Biosphere Reserve of El Pinacate and El 

Gran Desierto de Altar, as well as the Enid Juan Álvarez, located 60 kilometers south of the reserve. Based on 

the interest that Mexico and the United States had in preserving and recovering the Sonoran pronghorn 

population, in April of 1992 the Core Working Group (Group Central de Trabajo de Berrendo Sonorense) was 

created. This group had members from the AGFD and theFWS, theNational Park Service, the Bureau of Land 

Management, the US Air Force, Tohono O’odham Nation and the Centro Ecológico de Sonora. This group 

conducted the first phase of aerial surveys within the project called Prospecciones de Pruebas Binacionales, 

directed by the Cabeza Prieta National Wildlife Refuge, Arizona. 

Afterwards, this group changed its name to the Sonoran Pronghorn Recovery Team (Equipo de Recuperación 

del Berrendo Sonorense), and became part of the Biosphere Reserve El Pinacate and the Instituto del Medio 

Ambiente y el Desarrollo Sustentable del Estado de Sonora (IMADES, currently CEDES) continuing the efforts 

for the recovery of this subspecies.

With the decree of the Biosphere Reserve of El Pinacate y Gran Desierto de Altar, Sonora, in 1993 a significant 

area (714,556.5 hectares) was established as habitat for the conservation of the pronghorn, and it became an 

important area for its study and conservation. During the years of 1990, 1992, 1993, 1996, 2002, 2006, and 

2007 the project captured 46 pronghorn and placed radio telemetry collars on them within the Sonora area.

In 2002, the team conducted a census of pronghorn in the Cabeza Prieta NWR in the United States, where the 

team was able to observe only 20 animals. This situation raised an alarm signal to those organizations interested 

in recovering this subspecies, and indicated the need to create a semi captivity reproduction program in the 

United States, similar to the one created in Mexico in the Biosphere of El Vizcaíno.

During February 2004, the Dirección General de Vida Silvestre de la SEMARNAT, gave to the AGFD and 

FWS, the permit to capture five pronghorn (four females and one male) to be exported from Sonora to the 

United States to initiate the semi captivity reproduction program in the Cabeza Prieta NWR. The capture was 

not successful, and 4 out of the five individuals died after the capture. Later in 2006, they conducted a new 

initiative with positive results. This time they captured 1 male and 3 females, with the objective of reinforcing 

the group of pronghorn in the encierro de Cabeza Prieta and increase the genetic variability of the population.

The implementation of some of the strategies contained in the Programa de Conservación de la Vida Silvestre y 
237

Diversificación Productiva en el Sector Rural 1997-2000, in particular the implementation of the UMA in the 

South and East of the Reserve El Pinacate, that contained actions for the surveillance, habitat conservation, and 

management of population of species of interest to the UMA, such as mule deer, bighorn sheep, and the collared 

peccary, have indirectly benefitted the pronghorn, as it was planned, just by implementing a conservation 

mindset. In the last census conducted in Sonora in 2007, they counted 360 individuals, estimating the 

population as 404 with a 95% reliability rate. Such population is located on the outskirts of the Reserve 

(CEDES - AGFD, 2008).
238

XI. 3. Mexican Pronghorn (A. a. mexicana)

In 1978, the first study in the distribution of the pronghorn in Chihuahua was conducted (Treviño, 1978). 

Chihuahua was the only state that still had native populations of grassland pronghorn. The author reported ten 

isolated locations and an estimated population of 533 pronghorn. In 1993, González y Lafón reported a 

minimum population of 214 individuals, with an estimate of 307.

With the objective of updating the information about the distribution of the pronghorn in Chihuahua, 

researchers from the Unidos para la Conservación A.C. (UPC), the Universidad Autónoma de Chihuahua and 

the Dirección General de Vida Silvestre, SEMARNAP, in 1996 conducted a study that found that in at least two 

of the ten locations reported by Treviño —el Berrendo y Benavides— there was no presence of any pronghorn. 

It was not until in 2006, that the Comisión Nacional de Áreas Naturales Protegidas, published the “Estudio 

Previo Justificativo para el establecimiento del Área Natural Protegida: “Reserva de la Biosfera Janos, 

Chihuahua, México”, with the objective of protecting the habitat and a population of 30 wild individuals, and a 

plan for future allocation of pronghorn to the grasslands of rancho “El Uno”, administered by The Nature 

Conservancy (TNC).
239

XII. Background of the Translocation for the Repopulation in Mexico

XII. 1. Isla Tiburón

One of the first attempts at management and reintroducing the pronghorn in Mexico took place in 1967, when a 

group of 22 individuals from Colorado (USA) were transferred to the Isla Tiburón en Sonora, México, with the 

intention of implementing a population that could be managed under isolating conditions, that will allow its 

rapid growth, since there was no competition for the pronghorn on the island. Unfortunately, the drought

conditions that prevailed in the island during those years, along with the abundant number of coyotes in the 

area, destroyed the efforts in no more than three years.

XII. 2. San Luís Potosí

The pronghorn disappeared from this region in the 50s. In 1972, Mexico and the state of New Mexico (USA), 

decided to exchange wild species for the development of some experimental work. Mexico exchanged five 

bighorn sheep individuals for a small herd of pronghorn from New Mexico. The herd contained 52 individuals, 

19 males and 33 females, and it was sent to the Rancho Guadalupe, located in the municipio de Ramos, San 

Luís Potosí.

The main objective of this project was the establishment of a viable population of pronghorn, to then aid the 

reproduction, repopulation, and possible future use. However, the group of pronghorn disappeared in 1991 

regardless of all the efforts that took place to maintain the population. Long drought periods during the first 

years after the introduction, the wide spread of some of the individuals in the vast territory, along with the 

predations of fawns by local coyotes, were some of the factors that contributed to the failure. However, this 

project served as the foundation for the knowledge and capacitation of most of the people that later participated 

in the design and implementation programs that now develop successfully in Mexico and some places in the 

United States of America.

XII. 3. Coahuila

The pronghorn disappeared from the state of Coahuila at the end of the 50s, beginning of the 60s. In 1993, the 

Unidos para la Conservación, A. C. and Agrupación Sierra Madre initiated negotiations with the New Mexico 

Department of Game and Fish (NMDGF), in USA, with the objective of establishing a collaboration program in 

the short and long term, for the reintroduction and recovery of the pronghorn in Coahuila. This program 

proposed the repopulation, in a big scale, of the empty areas in the state.

Its implementation was approved in 1994, by the Dirección General de Aprovechamiento Ecológico de los 

Recursos Naturales del Instituto Nacional de Ecología, SEMARNAP, and then later renewed by the Dirección 

General de Vida Silvestre; to be developed first in a meadow area of 75 thousand hectareas, divided in five 

private ranches, in an area known as the “Valle Colombia”. Such place had the right foliage conditions, fences 

and surveillance needed, besides the right habitat – water, food, and protection against human activity, to be 

able to host at least a thousand pronghorn individuals.

In February of 1996, in Carrizozo Nuevo México, they captured a herd of 65 individuals that were transported 

and released in the ranch “El Cimarrón”, en Valle Colombia, Coahuila.

During the first year, some individuals or small groups of pronghorn moved out of the areas where they were 

first introduced, reducing the size of the herd to 54%. In 1998, with the objective of reinforcing the first 
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introduction, they conducted a second introduction with a herd of 85 individuals. The reintroductions have 

allowed the establishment of a herd in the wild, whose population is estimated at 45 pronghorn, and new 

reinforcements may be required in the future to aid in the recovery of this species in this region. The ranches 

involved in this region are “La Palma”, “Buenavista”, “El Cimarron”, and “La Gorriona”, all of them located in 

the Municipio de San Buenaventura, and they have a UMA registry, which is part of the objective and strategy 

of the Programa de Conservación de la Vida Silvestre y Diversificación Productiva en el Sector Rural 1997-

2000. Similarly, the Instituto Nacional de Ecología de la SEMARNAP, coordinated with the support of the 

NMGFD, a visit to the area UMA “El Novillo” en el Municipio de Guerrero, Coahuila, with the objective of 

evaluating the infrastructure and habitat available to free up one of the ranches that were raising the pronghorn. 

In 1998, they freed in this new location 14 pronghorn (9 males and 5 females).

On the other hand, during 2005 and 2006, there was a noticeable increase in interest to support the “return of the 

pronghorn” to places where it had extinguished, especially in the different plains in the Altiplano Mexicano.

This is how CIBOR, in coordination with WGFD and the BFA, conducted a first effort to try to repopulate these 

areas with individuals captured in the BFA installations, to be transported, hand raised and then weaned in the 

area where they were to be released. This effort, that took place in 2005, was supported by the participation of 

the Asociación de Manejadores de Vida Silvestre, A. C. (AMAVISI) and the rancho “El Bonito”, Municipio de 

Acuña, Coahuila. 47 fawns were transported and 54 more in 2006. From the first group they weaned 24 

individuals, 12 males and 12 females; while from the second group there are only 16 males and 17 females left. 

With the surviving animals from 2005, in August of 2006 there were two reproductive groups formed with 2 

males and 6 females each, the rest of the males were kept segregated. Unfortunately, a bear attacked one of the 

reproductive groups and all the individuals died. Currently we only have one of the reproductive groups and the 

rest of the males, and we have already accomplished the birth of 20 fawns in the area in 2008.

XII. 4. Nuevo León

In 1999, the first request to transfer pronghorn from Wyoming to Mexico was approved. This first effort took 

place in the year 2000, and it involved the Dirección General de Vida Silvestre (DGVS), the Centro de 

Investigaciones Biológicas del Noroeste (CIBNOR, and the Bioparque Estrella from Mexico). While from the 

USA the participating entities were the Wyoming Game and Fish Department (WGFD), and the Air Force Base 

Francis E. Warren (BFA). In that year they provided 12 individuals to the BioParque Estrella de Nuevo León, 

leaving open the opportunity of reinforcing the project with a later transfer. The experience ended in the first 

attempt, and concluded with the extinction of all the pronghorn transferred four years later. However, during 

those four years many people had the opportunity to observe the animals and had the chance to get to know the 

species.

XII. 5. Zacatecas

In 2006, there were some pronghorn transferred from the BFA and the WGFD with the intent of having a first 

experience and training the personnel that would later manage the program on the ranches that would be 

participating in the repopulation program of that state. The objective was to use the same raising technique that 

had been used successfully in other areas in Mexico. In June 2007, there were 159 fawns captured (76 males 

and 83 females) and transported by plane by the SEDENA, with the support of the Gobierno del Estado de 

Zacatecas, the UAZ, the CIBNOR, the DGVS, and the Espacios Naturales y Desarrollo Sustentable, A. C.

The previous transfers (2005 and 2006) were based on annual transfers, showing the need to develop a short and 

a long-term project proposal presented to the BFA and the WGFD, requesting multi-annual transfers. 

Consequently, the request was accepted for the 2007-2011 period, with a limit of 250 young individuals 

captured per year. Even though there have been some health issues amongst the young individuals, it is still too 
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early to issue a conclusion about this initiative. However, it is important to notice the high participation level 

amongst Mexican and North American institutions.

XII. 6. Regional Program for the Reintroduction and Conservation of the Pronghorn (Antilocapra americana) in 

the Northwest of Mexico.

During 2008, the state government of Coahuila and Nuevo León, began the development of the Regional 

Program for the Reintroduction and Conservation of the Pronghorn (Antilocapra americana) in the Northwest 

of Mexico (“Programa Regional de Reintroducción y Conservación del Berrendo (Antilocapra americana) en el 

Noreste de México”). The main objective of this program is to promote the reintroduction and the management

of the pronghorn in private UMA in the states of Coahuila and Nuevo León, as areas where they can initiate the 

reproduction of the pronghorn, to then use the young individuals to repopulate areas where there were 

pronghorn in the past. This plan will allow, in the short and long term, to contribute to the financial 

opportunities of the local communities, by benefiting from the return of pronghorn to areas where it became 

extinguished 30 years ago.

The program will begin in 2009 with the reintroduction of the first group of pronghorn, to be distributed in the 

UNA of El Rincón de la Madera – La Mesa, located in the municipio de Cuatro Ciénegas; in the El Valle de 

Colombia y Maderas del Carmen, and the UMA San Rafael y Rancho Pilares, respectively. Management will be 

done on a semi-extensive basis, with hopes of a short period of adaptation to then release groups in the region. 

These pronghorn will come from New Mexico, and some of the captured groups will be allocated to El Valle de 

Colombia, and Maderas in the UMA San Rafael y Rancho Pilares, respectively.
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XIII. Objectives

XIII. 1. General Objectives

The objectives begin with the identification of the critical needs for the conservation of the species, and the 

planning of the actions needed to cover these needs in the short and long term. In addition, objective will 

include to execute, unify, and consolidate the different initiatives and strategies that have been developed for the 

conservation of this species presented in the Proyecto para la Conservación, Manejo y Aprovechamiento 

Sustentable del Berrendo en México (PREPBe), as well as other ones considered relevant to help recover and 

preserve the populations of this species in Mexico.

XIII. 2. Specific Objectives

• Generate the biological, ecological, and social information about the pronghorn, as an input for the 

decision making process that will issue effective actions for the management, recovery, conservation, 

and protection of this species and its habitat.

• Promote and generate the social participation from different areas as a strategy focused on the 

management, recovery, conservation, and protection of the pronghorn populations.

• Promote the consolidation of a group of specialists, through the continuous use of their technical 

knowledge as consultants in the process, as well as providing resources (mainly financial) for the 

management, recovery, conservation, and protection of the pronghorn.

• Strengthen the protection and surveillance for the conservation of the pronghorn populations.

• Increase the number of individuals in the different populations classified as low management, as well as, 

increase the number of areas with actual population where there used to be pronghorn populations 

historically in Mexico.

• Generate the right conditions for successful implementation of the strategies developed in this program 

for the management, recovery, conservation, and protection of the pronghorn.
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XIV. Goals

XIV. 1. General Goals

• Establish a program with prioritized actions focused on the management, recovery, conservation, 

protection, and sustainable benefit of the pronghorn at the national and regional level.

• Rely on updated technical and scientific information to determine the true state of the pronghorn 

populations, to then efficiently take actions on the management, recovery, conservation, protection, and 

sustainable benefit of the pronghorn.

• Preserve, and even increase, the areas considered as important habitat for the conservation of the 

species, to facilitate the recovery of the biological and ecological processes, with the objective of 

helping this species to recover.

• Consolidate a process for the participation of all the agencies and institutions that participated in this 

project, in order to keep the communication channels open to facilitate the protection and conservation 

of the populations of the species.

• Manage and facilitate the resources needed for the enforcement of the actions needed for the 

conservation and management of the species and its habitats.

• Boost the active participation of academic institutions, ONG, government, and the general society, in 

steps to help the conservation of the pronghorn and its habitats.

XIV. 2. 2012 Goals

• Have a solid group of specialists that will work along with other groups in the conservation of species 

that share a habitat, with the objective of developing strategies and actions that will focus on the 

ecosystem, helping to continue the natural ecologic and evolution processes.

• Have a solid database with data from national projects, monitoring projects, recovery, conservation, 

protection, and sustainable benefit projects done in the areas of historical distribution of the species.

• Establish, along with the Procuraduría Federal de Protección al Ambiente (PROFEPA), the outline for 

the reinforcement of the surveillance and protection of the pronghorn, its habitat and species that share

the same habitat. Furthermore, have specific projects with surveillance committees that will focus on 

communities where there are areas with pronghorn presence.

• Increase the size of the areas considered as pronghorn habitats, under a conservation scheme (ANP, 

UMA, Institutes with conservation certificates, ecological organizations, programs for the environmental 

services, etc.) by promoting conservation proposals or agreements with institutions in the environmental 

areas at any governmental level, as well as, private sector.

• Increase the number of pronghorn populations and individuals by at least 30%, by taking advantage of 

the collaborations between Mexico and the international entities, as well as, utilizing the progress of the 

current projects.

• Generate and distribute informational materials about the pronghorn.

• Complete at least 100% of the activities detailed in this document (PACE: Pronghorn), by conducting a 

follow up and evaluation of the program and its link to the Programa de Conservación de las Especies en 

Riesgo PROCER, and all of its subprograms.
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XV. General Conservation Strategies

XV. 1. Protection Components 

XV. 1. 1. Habitat Protection Components

• Reinforce, coordinate, and implement the mechanisms to protect the distribution areas for the 

pronghorn.

XV. 1. 1. 1. Activities

• Promote the conservation and protection of the priority areas for the conservation of the pronghorn and 

its habitat. Such areas include Áreas Naturales Protegidas (Protected Natural Areas), Predios 

Certificados para la Conservación (Certified Properties for the Conservation), Reservas comunales y/o 

privadas (Common and/or private reserves), as well as, Unidades de Manejo para la Conservación de la 

Vida Silvestre (UMA).

• Achieve the incorporation of properties where there currently exist activities related to the conservation 

of the pronghorn and its habitat, for the benefit of the Pago por Servicios Ambientales (PSA - Captura 

de carbono, Hidrológicos y para Conservación de Biodiversidad), Programas de Conservación para el 

Desarrollo Rural Sustentable (PROCODES) and all of those who help with the productive activities.

• Promote the productive activities within the zones classified as priority.

• Promote the steps that will help reduce the risks and threats for the pronghorn populations, such as, 

exclusion of free-range cattle that may compete for the same habitat as the pronghorn’s, stimulation of 

the habitat, and management or even control the predators in those areas.

• Promote through an institutional coordination, the Ordenamientos Territoriales Municipales (Municipal 

territory laws) in the areas with conservation priorities for the pronghorn.

• Consolidate, along with the authorities, the outline for the participation of different sectors to avoid the 

destruction of the pronghorn habitat, due to changes in the use of the land.

XV. 1. 2. Components of the Protection Plan for Pronghorn Populations and its Grazing Areas

• Reinforce the existing mechanisms for the protection and recovery of the pronghorn populations and 

their habitat, especially those in rehabilitation process.

XV. 1. 2. 1. Activities

• Contribute with the recovery of the pronghorn populations through mechanisms of breeding more 

fawns, repopulation, reallocation, and sustainable benefit.

• Contribute with the implementation of mechanisms of inspection and surveillance in order to detect 

and prevent any damage to the pronghorn populations and their habitats.

• Categorize and prioritize the action needed to guarantee the protection of the pronghorn and its 

habitat.

• Design and implement strategies for the protection of specific pronghorn populations and their 

habitats, based on their situation and specific problems.

XV. 1. 3. Legal Components
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• Conduct the necessary efforts to ensure the proper legal actions required to ensure the management, 

protection, conservation, and sustainable benefit of the pronghorn in Mexico.

XV. 1. 3. 1. Activities

• Promote and spread the information amongst the institutions involved in the conservation, protection, 

and management of the evaluation mechanisms and in some instances, the modification of the current 

laws.

• Establish the general guidelines for the implementation of prevention and impact mitigation actions that 

may generate as projects to be developed are implemented in the distribution areas for the pronghorn. 

• Propose mechanisms to strengthen the compliance of the environmental rules and regulations in the 

national territories, including the close monitoring of the relationship with the countries involved in the 

existing International projects.

• Promote evaluation mechanisms to evaluate the management projects in the ANP where pronghorn are 

distributed.

• Provide technical information about the species, to help those local authorities, which request such 

information, to make the right decisions.

XV. 1. 4. Inspection and Surveillance Component

• Avoid and detect illegal activities related with hunting and poaching, trade, and possession of any 

specimen, parts, or by-product of any pronghorn, and the destruction or illegal modification of its 

habitat.

XV. 1. 4. 1. Activities

• Create an efficient system for the uptake and processing of complaints to the pertinent authorities 

that will require an immediate set of actions with the objective of stopping and discouraging any 

illegal attempts that may be taking place in those areas designated for pronghorn.

• Promote social participation strategies for the environmental surveillance, with different approaches 

that will target several sectors, for the conservation of areas designated for pronghorn.

• Promote, closely with the Procuraduría Federal de Protección al Ambiente (PROFEPA), the timely 

processing of any complaints that are related with affecting, directly or indirectly, the pronghorn and 

its habitat.

• Recognize and involve the legal hunting departments, to request their assistance in spreading the 

regulations and conservation efforts for the species, with the objective of reducing any pronghorn 

hunting by designing actions for each kind of identified hunting.

• Promote inspection and surveillance rounds in the areas where pronghorn are distributed, during the 

seasons when hunting is allowed for other species that share the habitat with the pronghorn.

• Collaborate with the Procuraduría Federal de Protección al Ambiente (PROFEPA), in training 

federal inspectors and the community surveillance group, whose main objective is to help prevent 

and detect pronghorn illegal hunting and any activities related to the destruction and fragmentation 

of its habitat.

• Reinforce inspection and surveillance activities with state and municipal governments.
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• Promote amongst the general society the detection and denunciation of illegal hunting of the 

pronghorn.
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XVI. Recovery Strategies

XVI. 1. Recovery Component for Populations and Habitat

• Promote the recovery of the population and areas disturbed and that are located within the priority areas 

for the pronghorn conservation, with emphasis in the Natural Areas and areas of historical distribution.

XVI. 1. 1. Activities

• Identification of “critica” (critical) zones within the current pronghorn distribution areas that are key for 

the continuation of the genetic flow of this species and to promote the fixing or removal of the fences 

built to contain the livestock.

• Determine the possibility and mechanisms necessary for the recovery of the populations and the 

identification of critical areas.

• Coordinate, across and within institutions, actions to implement the recovery of populations and 

improvement of disturbed areas identified as “critical”.

• Implement actions for the restoration of critical areas identified as distribution areas for the pronghorn 

along with the ANP.

XVI. 2. Impact Mitigation and Prevention Components 

• Reduce the impact generated by the property fencing, changes in the use of the land, and other factors, 

in the pronghorn populations and their habitats.

XVI. 2. 1. Activities

• Establish preventive and corrective actions, in coordination with the local authorities and property 

owners, to prevent the fencing needed for the cattle, thus allowing the free flow of pronghorn between 

different areas.

• Monitor the effect that the main risk factors identified may have in the pronghorn populations.

• Periodically evaluate the impact of the main risk factors in the pronghorn populations.

• Establish mechanisms, within the institutions, that will guarantee the prevention of impacts in the 

pronghorn population and its habitat.

Management Strategies

XVII. 1 Habitat Management Component

• Develop and implement actions and activities that will guarantee the existence of enough habitats to be 

able to maintain viable pronghorn populations in the areas of distribution of this specie.

XVII. 1. 1. Activities

• Promote and manage payment programs for environmental services with the Comisión Nacional 

Forestal (CONAFOR) for the areas with pristine habitat for the pronghorn.

• Promote the creation of new federal, state, or governmental natural areas, the certification of the 

properties for the conservation and establishment of the Unidades de Manejo para la Conservación de la 
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Vida Silvestre, in distribution areas for the pronghorn, as a tool for the conservation and restoration of 

the habitat for the species.

• Accomplish the implementation of the properties where conservation efforts for the pronghorn and its 

habitat are taking place, with the benefits from the Pago por Servicios Ambientales (PSA), Programas de 

Empleo Temporal (PET), and Programas de Conservación para el Desarrollo Rural Sustentable 

(PROCODES), in priority areas that may be under any protection status or that may have been identified 

as important for this species, as well as, limit and/or regulate the productive activities and the 

infrastructure that can threaten such areas.

• Promote the review and follow up of the management programs of the ANP and UMA located in the 

distribution areas with the objective of proposing adaptations and improvements, in an agreeable way 

with the property and landowners in these areas.

• Promote and follow up the Programas de Ordenamiento Territorial in the elected municipality and 

communities settled in regions with conservation priority for the pronghorn, with the objective of 

promoting the continuity of the habitat that will allow the genetic flow of the species.

• Promote the productive diversification in areas located within the pronghorn distribution areas, with low 

impact activities that will benefit the conservation of the wildlife and their habitats.

• Establish, organize and coordinate agricultural and livestock activities in, or around, the important 

habitat for the pronghorn.

• Promote the recovery of the habitat throughout the implementation of sustainable tourism programs that 

will increase the interest of the pronghorn in the society (showing live individuals, guided tours, 

camping, nature tourism through the protected areas, etc).

XVII. 2. Species Management Component

• Determine and standardize the procedures for the management of individuals and populations.

XVII. 2. 1. Activities

• Elaborate a standard manual of procedures for the management of individuals, focused on reproduction, 

and of populations, focused on recovery and sustainable benefit.

• Continue with the reproduction, breeding, and translocation for the creation of new populations.

• Develop regional diagnosis with the objective of promoting intersectional meetings according to the 

priority to be addressed.

• Coordinate the Programa de Fomento Ganadero (PROGAN) de la SAGARPA, mainly in the natural 

areas located in the distribution areas for the pronghorn, with the objective of organizing the livestock 

activity.

• Subscribe the production organizations to the Sistema- Producto Ganadería Diversificada SAGARPA, 

with the objective of financing the recovery, repopulation, and reproduction projects for the pronghorn.

• Promote an agreement between SEMARNAT and SAGARPA, for the implementation of an 

improvement program for cattle management in the distribution areas for the pronghorn.

• Promulgate a directory of specialists and working groups that will conduct studies or actions for the 

management, recovery, conservation, and protection of the pronghorn at the regional, national, and 

international level.
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XVII. Strategies to Develop Knowledge

XVIII. 1. Components in the Priority Areas

• Generate information about the distribution and abundance of the pronghorn in the priority areas for its 

conservation that will support the management, recovery, conservation and protection efforts of this 

species and its habitat within the conservation priority areas in Mexico.

XVIII. 1. 1. Activities

• Identify the critical sites for the recovery of the pronghorn in Mexico, particularly the main populations 

and the dynamics between populations, through a monitoring and population density study at the 

national level.

• Identify the priority areas (actual and potential) for the distribution, repopulation, and reproduction of 

the pronghorn.

• Estimate the populations of pronghorn in the priority areas.

• Estimate the availability of the habitat for the pronghorn in the priority areas.

• Promote, in a coordinated way, technical assessments in the livestock subject amongst communities 

within the influential areas.

• Promote coordinated action for the territorial laws at the municipal and state level, focused on avoiding 

changes in the use of the land in the priority areas for the conservation of the pronghorn.

• Promote the active social participation in the protection of the pronghorn and its habitat, beginning by 

acknowledging the cultural and environmental heterogeneity existing in each region.

XVIII. 2. Scientific Research Component

• Promote, support, and direct solid researches about the biology and ecology of the pronghorn, as 

well as, the risks that their populations are facing in the national territory, that will support the 

decision making process and the establishment of actions in the management, recovery, 

conservation, protection, and sustainable benefit.

XVIII.2.1 Activities

• Create a geographic information system with information regarding the geographic location of the 

pronghorn’s habitats, the physical and biological characteristics of the area and the changes 

tendencies of the land.

• Review the availability of areas in zones with habitat potential.

• Review the availability of food source areas within the potential habitats.

• Boost the generation of maps that will include the main risk factors that affect the different 

pronghorn populations in Mexico.

• Describe the demography and reproductive biology of the pronghorn in Mexico (with emphasis in 

the reproduction rate, the survival of the fawns, and more)

• Determine the actual distribution of the pronghorn in Mexico, with emphasis on the identification of 

the priority areas for its conservation.

• Estimate the size of the pronghorn population in Mexico, with emphasis on the priority areas for its 

conservation.

• Describe the genetic structure of the pronghorn populations in Mexico.
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• Evaluate the real and potential effect that competition for food with the cattle has on the pronghorn 

populations.

• Identify the priority areas for the conservation of the habitat of the pronghorn.

• Define the best techniques for the controlled reproduction, population management, capture, 

translocations, and follow up of the populations.

• Manage the search for financial support for the identified projects, as a key strategy for the 

conservation of the species.

XVIII.3 Biological Monitoring Component

• Periodically monitor the pronghorn populations at the national level, with the objective of getting to 

know the tendencies of the populations of the species (density, abundance, recruitment, etc.) inside and 

outside of the natural areas.

XVIII.3.1 Activities

• Systematically follow up the pronghorn populations and its reproductive activities.

• Conduct longitudinal demographic analysis in the different pronghorn populations.

• Monitor the quality of the habitat in the critical locations for the distribution of the pronghorn.

• Periodically recollect and analyze the information about demographic tendencies for the pronghorn 

populations, the availability of its habitat, and its relation with the identified risk factors.

• Design, in coordination with the ANP and institutions involved, a protocol for the monitoring of the 

pronghorn, to unify the criteria for all the priority areas and initiate the creation of a database for the 

CONANP and the participating institutions.

• Systematically implement national census for the pronghorn every three years, with the objective of 

knowing the changes and pressures that the populations are been exposed to.

• Monitor the distribution, feeding, and influence areas in the critical locations for its distribution.

• Periodically gather and analyze the information regarding the demographic tendencies of the pronghorn 

populations and their relation with the risk factors identified.

• Determine the dispersion of the pronghorn populations through the use of known techniques.
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XVIII. Cultural Strategies

XIX. 1. Environmental Education Component

• Develop a conservation and management culture for the pronghorn and its habitat amongst the 

Mexicans, based on the acknowledgment of its cultural and biological value, risk situation of the 

species, and its potential for sustainable rural development.

• Promote the knowledge about biology, ecology, and financial potential of the species and its habitat in 

the Mexican society, with emphasis on the people living in the distribution areas of the pronghorn.

• Promote the understanding of the problems of the pronghorn and its habitat in Mexico.

XIX.1.1 Activities

• Identify the sectors that directly influence the pronghorn populations and its habitat, in order apply the 

environmental education strategies.

• Define the priorities, focus, and diffusion methods necessary for the conservation of the pronghorn and 

its habitat, in the general population.

• Update the information regarding the pronghorn and its habitat, included in the basic school education 

programs in the country.

• Design a manual for the environmental educator about the pronghorn in Mexico, and distribute it 

amongst professors and environmental educators.

• Provide training to professors and environmental educators about the biology of the pronghorn, its 

habitat, problematic, and potential use.

• Promote the presence of individuals of the species in zoos, with the objective of educating the 

population about the pronghorn and the problems that are affecting them, hoping that people will 

become sensitive about it.

• Build a data base including information about people, institutions, organizations, interest groups, and 

facilities, that can support and influence the environmental education, research, management, protection, 

conservation, recovery, and diffusion activities about the biology and problematic of the pronghorn and 

its habitat.

XIX. 2. 1. Communication and Diffusion Component

• Boost a communication and diffusion campaign that will allow the ability to position the pronghorn 

as a key species in the general population, and reinforce that historical value of the species, to 

recover its high cultural value and belonging to the Mexicans.

• Develop communication strategies oriented to specific subjects and people.

• Develop the appropriate subjects and materials to deploy such strategies.

• Establish a signaling program for the sites identified as critical for the conservation of the species.

XIX. 2. 2. Activities

• Spread the scientific information about the pronghorn to the different areas of the society in an 

appropriate language for their comprehension, awareness, and higher participation.

• Design the definition of the contents and optimal communication media, with a regional emphasis.

• Promote and manage events for pronghorn conservation.
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• Make available educational materials about the species to institutions involved and guarantee the 

availability of the materials.

• Spread the importance of the pronghorn and its habitat for the ethnical groups.

• Spread the importance of the influence of the society in the protection, conservation, and recovery of 

the pronghorn and its habitat.

• Establish technical and financial synergies amongst the different communication resources for the 

development and distribution of informational material.

• Develop a proposal to make a year, like “The Year of the Pronghorn”.

• Develop a program of activities about the species for the year designated as “The Year of the 

Pronghorn”.

• Promote the integration, diffusion, and participation of all the responsible parties involved; in the 

activation of a web site for the consulting of general people and specialists, with the objective of 

developing the interest and participation in the conservation of the pronghorn at the national and 

international level.

• Promote and manage a communication strategy to sensitize the population at two levels:

1. In the rural sector, to promote the coexistence, convenience, and respect of the species, by 

using speeches, conferences, videos, radio, television, and brochures.

2. In the urban sector, utilize mass communication with explicit messages and accessible to the 

entire population.

XIX. 3. Social Capacitation Component

• Diminish the activities with potential to destroy habitat and individuals, and/ or pronghorn populations 

in the Áreas Prioritarias de Conservación, through the finding and promotion of social participation, 

represented by a higher level of information, participation, and involvement of the locals, and property 

owners of lands located in these areas.

• Involve the different sectors and responsible entities to collaborate in the activities created for the 

recovery, protection, and conservation of the pronghorn.

XIX. 3. 1. Activities

• Promote best practice exchanges amongst communities, with the objective of sensitizing and educating 

the locals about their importance in the cultural recovery of the pronghorn and its importance for the 

ecosystems, as well as, developing educational forums focused on:

o Promoting the productive activities that are compatible with the conservation of the pronghorn 

and its habitat.

o Environmental regulations.

o Biological monitoring of the species.

• Educate and sensitize the locals about the importance of the conservation of the habitat, as a resource 

with ecological value.

• Educate the people in local rural communities, who are culturally linked to the pronghorn, to obtain their 

assistance on the monitoring, surveillance, and environmental education.

• In coordination with the sectors involved, create a technical manual with the recommendations for the 

installation of pronghorn friendly fences and structures.

• Educate personnel in the CONANP, and other federal, and state institutions, organizations, technicians, 

and property owners in the identification of the pronghorn habitat, in the monitoring procedures for the 

areas that the species visits, and the protection and surveillance strategies.
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XIX. Management

XX. 1. Components of the Responsible Parties Involved

• Create the organization, administration, and financing conditions that will guarantee accomplishing the 

objectives of this program.

• Identify the different working groups that will conduct the investigation, management, protection, 

conservation, and recovery of the pronghorn.

• Integrate the identified people and organizations that will conduct the investigation, management, 

protection, conservation, sustainable benefit, and recovery of the pronghorn in one group.

• Promote the collaboration of the different working groups related to the pronghorn population, to align 

strategies, efficiently utilize resources, create synergy in the investigations, management, protection, 

conservation, repopulation, and recovery.

• Obtain financial support, as well as materials and logistics materials for the implementation and 

continuity of the actions and activities included in this program.

• Establish working networks with Subcomités Técnicos Consultivos and other working groups for other 

species that share the habitat with the pronghorn, to incorporate their activities to preserve the 

ecosystem.

XX.1.1 Activities

• Establish a schedule for regular meetings for the evaluation and follow up of PACE, with the 

participation of the Subcomité Técnico Consultivo para la Conservación, Manejo y Aprovechamiento 

Sustentable of the pronghorn and subject experts.

• Establish a communication mechanism for the continuous communication between the members of the 

Subcomité Técnico Consultivo para la Conservación, Manejo y Aprovechamiento Sustentable of the 

pronghorn in addition to the web site.

• Establish a collaboration program and meeting agenda for the working groups and committees of the 

species that share habitat with the pronghorn.

• Promote a collaboration agreement between the SEMARNAT and SAGARPA for the installation of 

pronghorn friendly fences.

• Build a financial strategy for the activities in this program, which involves the government, general 

society, and private industries through agreements, contracts, or donations for technical support, cash, or 

donated species.

• Promote the participation of the general society in activities included in this document, through 

volunteering, technical support, or financing.

XX. 2. Programming Component

• Create a calendar of activities and projects to be completed in the Programa de Acción, establishing 

long and short-term goals.

• Identify the action steps necessary to reach the goals and objectives of this program, as well as, the 

priority of the diverse activities within each phase.
255

• Identify opportunities for activities that could be done simultaneously, by efficiently utilizing 

resources or by using synergies between different conservation initiatives.

• Plan the development of the activities proposed in this program, for the short and long term.

XX. 2. 1. Activities

• Program the execution of the activities described in this program.

• Create a list of the activities and projects with timelines that need to be developed and assign the 

responsible parties.

• Plan the financial needs for the different projects, and decide how they will be met, considering the 

timeframe to obtain such financial support.

XX. 3. Evaluation and Follow-Up Component

• Guarantee the accomplishment of the objectives and goals of this program, through the evaluation 

and follow up of the milestones and strategy implemented. For such purpose, there has to be 

indicators and goals that can be measured, are specific, well-defined, achievable, and meaningful in 

the short and long term.

XX. 3. 1. Activities

• Identify the critical timeframes to conduct evaluations during the project’s execution.

• Establish regular meetings with the involved entities (nationals and internationals) for the evaluation 

and updating of the actions needed for the conservation of the species.

• Evaluate the success of the program and make the pertinent updates for the short and long term.

• Use indicators to qualify the development of the objectives and goals of the activities planned.

• Build diffusion mechanisms to communicate the partial and final results of the different projects, to 

help the working groups identify the progress and difficulties faced during the implementation of 

any programs, hence, to be able to make changes to the programs when deemed necessary.
256

XX. Success Indicators

Note: Short term 1-2 years, Medium term 3-4 years, Long term 5 or more years.

Conservation 

Strategy

No. Success Indicator Short term Medium 

term

Long term

Protection and 

surveillance

1 Reduce the number of illegal 

hunting claims.

x x

2 Increase the number of 

participating groups from the 

society (environmental 

surveillance committees, 

conservation networks, and 

environmental supporters 

within the community) 

focused on the conservation 

of the pronghorn.

x

3 Number of meetings, 

benchmarking, community 

workshops, with the social 

participation groups 

interested in the conservation 

of the species and its habitat.

x x x

Recovery 4 Increase the number of 

responsible parties and 

programs focused on the 

identification and restoration 

of the habitat.

x x

Management 5 Increase the size of the areas 

for the available habitat for 

the conservation of the 

pronghorn incorporated to 

the conservation programs 

(ANP, UMA, etc.)

x X x

6 Increase the abundance of 

the wild pronghorn 

populations.

x x

7 Increase the number of 

individuals through the 

breeding programs and by 

increasing the number of 

relocated individuals.

x x x

8 Increase the livestock 

production programs under 

technical assistance in the 

Áreas Prioritarias (Priority 

Areas).

x

Knowledge 9 Number of the scientific 

researches focused in the 

x x
257

biological and ecological 

monitoring of the species.

10 Increase the number of 

Áreas Prioritarias (Priority 

Areas) where programs for 

the conservation and 

research of the pronghorn 

will develop.

xx

Culture 11 Increase the awareness and 

distribution of available 

information with emphasis in 

the regions of natural 

distribution of the species, 

by using electronic or 

printed media.

xxX

12 Increase the number of 

events for environmental 

education, capacitation and 

information.

Xxx

13 Increase the participation in 

disclosure forums about the 

species and conservation 

efforts.

xxx

Management 

and 

Programming

14 Increase the number of 

agreements amongst 

institutions, focused on 

programs for the 

conservation of the habitat of 

the pronghorn.

x

15 Increase the financial and 

number of human resources 

needed for conservation 

programs of the species.

xx

16 Increase the number of 

communities participating in 

ecotourism.

xx

17 Increase the number of 

international agreements for 

the conservation of the 

species and its habitat.

xxx

18 Increase the number of 

parties involved in the 

conservation of the species 

and its habitat.

xx

Evaluation 

and Follow up

19 Number of goals reached 

with the development of the 

planned steps in PACE of 

the pronghorn.

xx

20 Number of evaluation xxx
258

meetings with the Grupo de 

Especialistas (Specialists 

Group).
259

XXI. Programmed Activities Chart

Activity Success 

indicator

Short 

term

Medium 

term

Long 

term

1.1 Habitat Protection Components

Promote the conservation and protection of the 

priority areas for the conservation of the 

pronghorn and its habitat. Such areas include 

Áreas Naturales Protegidas (Protected Natural 

Areas), Predios Certificados para la 

Conservación (Certified Properties for the 

Conservation), Reservas comunales y/o privadas 

(Common and/or private reserves), as well as, 

Unidades de Manejo para la Conservación de la 

Vida Silvestre (UMA).

5, 7, 10 x x X

Achieve the incorporation of properties where 

there currently exist activities related to the 

conservation of the pronghorn and its habitat, for 

the benefit of the Pago por Servicios 

Ambientales (PSA - Captura de carbono, 

Hidrológicos y para Conservación de 

Biodiversidad), Programas de Conservación para 

el Desarrollo Rural Sustentable (PROCODES) 

and all of those who help with the productive 

activities.

5, 7, 8 x x x

Promote the productive activities within the 

zones classified as priority.

5, 7, 8, 10, 

14

X

Promote through an institutional coordination, 

the Ordenamientos Territoriales Municipales 

(Municipal territory laws) in the areas with 

conservation priorities for the pronghorn.

5, 7, 8, 10, 

14

X

Establish a signaling program for the sites 

identified as critical for the conservation of the 

specie.

2, 5, 11, 18 x x

Consolidate, along with the authorities, the 

outline for the participation of different sectors to 

avoid the destruction of the pronghorn habitat, 

due to changes in the use of the land.

4, 5, 14 x x

1.2 Components of the protection plan for the pronghorn populations and its distribution areas

Categorize and prioritize the action needed to 

guarantee the protection of the pronghorn and its 

habitat.

6, 8, 9, 10, 

13, 14

x x x

Design and implement strategies for the 

protection of specific pronghorn populations and 

their habitats, based on their situation and 

specific problems.

2, 7,5, 6, 15, 

16

x X

1.3 Legal Components

Promote and spread the information amongst the 

institutions involved in the conservation, 

14, 15, 17, 

18

X x
260

protection, and management of the evaluation 

mechanisms and in some instances, the 

modification of the current laws.

Establish the general guidelines for the 

implementation of prevention and impact 

mitigation actions that may generate as projects 

to be developed are implemented in the 

distribution areas for the pronghorn.

14, 15, 18, 

20

x x x

Propose mechanisms to strengthen the 

compliance of the environmental rules and 

regulations in the national territories, including 

the close monitoring of the relationship with the 

countries involved in the existing International 

projects.

4, 5, 6, 7 x x

Promote evaluation mechanisms to evaluate 

management projects in the ANP where 

pronghorn are distributed.

5, 8, 10, 20 x x x

Provide technical information about the species, 

to help those local authorities, which request 

such information, to make the right decisions.

2, 3, 12, 13, 

20

x x x

1.4 Inspection and Surveillance Component

Create an efficient system for the uptake and 

processing of complaints to the pertinent 

authorities that will require an immediate set of 

actions with the objective of stopping and 

discouraging any illegal attempts that may be 

taking place in those areas designated for 

pronghorn.

1, 2, 3 x x x

Promote social participation strategies for the 

environmental surveillance, with different 

approaches that will target several sectors, for 

the conservation of areas designated for 

pronghorn.

1, 2, 3 x x

Promote, closely with the Procuraduría Federal 

de Protección al Ambiente (PROFEPA), the 

timely processing of any complaints that are 

related with affecting, directly or indirectly, the 

pronghorn and its habitat.

1, 2 x x

Generation of maps that will include the main 

risk factors that affect (directly or indirectly) the 

pronghorn populations, to be able to prioritize 

the required legal and preventive actions needed 

to preserve the species.

1, 4, 14 x x

Recognize and involve the legal hunting 

departments, to request their assistance in 

spreading the regulations and conservation 

efforts for the species, with the objective of 

reducing any pronghorn hunting by designing 

actions for each kind of identified hunting.

2, 8, 16 x x
261

Promote inspection and surveillance rounds in 

the areas where pronghorn are distributed, during 

the seasons when hunting is allowed for other 

species that share the habitat with the pronghorn.

2, 3, 14, 18 x x

Collaborate with the Procuraduría Federal de 

Protección al Ambiente (PROFEPA), in training 

federal inspectors and the community 

surveillance group, whose main objective is to 

help prevent and detect pronghorn illegal hunting 

and any activities related to the destruction and 

fragmentation of its habitat.

1, 2, 3, 4, 13, 

15

x x

Reinforce inspection and surveillance activities 

with state and municipal governments.

2, 4 x x x

Promote amongst the general society the 

detection and denunciation of illegal hunting of 

the pronghorn.

1, 2, 3, 4 x x x

Coordinate, across and within institutions, the 

participation of communities in rural areas in the 

conservation of the pronghorn and its habitat.

5, 8, 11, 12, 

13

x x

Design and spread programs that will stop and 

discourage any illegal activities related with 

hunting of the pronghorn. The development of 

such programs should include academic 

members and government representatives, and 

other institutions involved in the conservation of 

the pronghorn.

2, 15 x x x

2.1 Habitat and Ecosystem Restoration Component

Identification of “critical” (critical) zones within 

the current pronghorn distribution areas that are 

key for the continuation of the genetic flow of 

this species.

4, 9, 14 x x

Determine the possibility and mechanisms 

necessary for the recovery of the populations and 

the identification of critical areas.

5 x x x

Coordinate, across and within institutions, 

actions to implement the recovery of populations 

and improvement of disturbed areas identified as 

“critical”.

4, 14, 15 x x

Implement actions for the restoration of critical 

areas identified as distribution areas for the 

pronghorn along with the ANP.

4, 5, 14, 15 x x

3.1 Impact Mitigation and Prevention Components

Establish preventive and corrective actions, in 

coordination with the local authorities and 

property owners, to prevent the fencing needed 

for the cattle, thus allowing the free flow of 

pronghorn between different areas.

10 x x x

Monitor the effect that the main risk factors 10 x x x
262

identified may have in the pronghorn 

populations.

Periodically evaluate the impact of the main risk 

factors in the pronghorn populations.

10, 11 x x x

Establish mechanisms, within the institutions, 

that will guarantee the prevention of impacts in 

the pronghorn population and its habitat.

10 x x x

3.2 Habitat Management Component

Promote and manage payment programs for 

environmental services with the Comisión 

Nacional Forestal (CONAFOR) for the areas 

with pristine habitat for the pronghorn.

5, 8 x x

Promote the creation of new federal, state, or 

governmental natural areas, the certification of 

the properties for the conservation and 

establishment of the Unidades de Manejo para la 

Conservación de la Vida Silvestre, in distribution 

areas for the pronghorn, as a tool for the 

conservation and restoration of the habitat for the 

species.

5, 7, 8 x x

Accomplish the implementation of the properties 

where conservation efforts for the pronghorn and 

its habitat are taking place, with the benefits 

from the Pago por Servicios Ambientales (PSA), 

Programas de Empleo Temporal (PET), and 

Programas de Conservación para el Desarrollo 

Rural Sustentable (PROCODES), in priority 

areas that may be under any protection status or 

that may have been identified as important for 

this species, as well as, limit and/or regulate the 

productive activities and the infrastructure that 

can threaten such areas.

5, 6, 8, 9 x x x

Promote the review and follow up of 

management programs of the ANP and UMA 

located in the distribution areas with the 

objective of proposing adaptations and 

improvements, in an agreeable way with the 

property and landowners in these areas.

5, 16 x x x

Promote and follow up the Programas de 

Ordenamiento Territorial in the elected 

municipality and communities settled in regions 

with conservation priority for the pronghorn, 

with the objective of promoting the continuity of 

the habitat that will allow the genetic flow of the 

species.

5, 16 x x

Promote the productive diversification in areas 

located within the pronghorn distribution areas, 

with low impact activities that will benefit the 

conservation of the wildlife and their habitats.

8, 14, 18, 19 x x
263

Promote the recovery of the habitat throughout 

the implementation of sustainable tourism 

programs that will increase the interest of the 

pronghorn in the society (showing live 

individuals, guided tours, camping, nature 

tourism through the protected areas, etc).

8, 14, 18, 19 x x

3.3 Species Management Component

Elaborate a standard manual of procedures for 

the management of individuals, focused on 

reproduction, and of populations, focused on 

recovery and sustainable benefit.

11 x

Develop regional diagnosis with the objective of 

promoting intersectional meetings according to 

the priority to be addressed.

2, 3, 4, 9, 15 x x

Coordinate the Programa de Fomento Ganadero 

(PROGAN) de la SAGARPA, mainly in the 

natural areas located in the distribution areas for 

the pronghorn, with the objective of organizing 

the livestock activity.

1, 4, 7, 15 x

Subscribe the production organizations to the 

Sistema- Producto Ganadería Diversificada 

SAGARPA, with the objective of financing the 

recovery, repopulation, and reproduction projects 

for the pronghorn.

1, 4, 7, 15 x

Promote an agreement between SEMARNAT 

and SAGARPA, for the implementation of an 

improvement program for cattle management in 

the distribution areas for the pronghorn.

8, 14, 18, 19 x x

Promulgate a directory of specialists and 

working groups that will conduct studies or 

actions for the management, recovery, 

conservation, and protection of the pronghorn at 

the regional, national, and international level.

1, 4, 7, 9, 15 x x

4.1 Components in the Priority Areas

Identify the critical sites for the recovery of the 

pronghorn in Mexico, particularly the main 

populations and the dynamics between 

populations, through a monitoring and 

population density study at the national level.

9, 10 x x

Identify the priority areas (actual and potential) 

for the distribution, repopulation, and 

reproduction of the pronghorn.

9, 10, 15 x x

Estimate the populations of pronghorn in the 

priority areas.

9, 10, 15 x x x

Estimate the availability of the habitat for the 

pronghorn in the priority areas.

9, 10, 15 x x x

Promote, in a coordinated way, technical 

assessments in the livestock subject amongst 

communities within the influential areas.

8, 9, 15 x x x
264

Promote coordinated action for the territorial 

laws at the municipal and state level, focused on 

avoiding changes in the use of the land in the 

priority areas for the conservation of the 

pronghorn.

11 x x x

Promote the active social participation in the 

protection of the pronghorn and its habitat, 

beginning by acknowledging the cultural and 

environmental heterogeneity existing in each 

region.

2, 14, 18 x x

4.2 Scientific Research Component

Create a geographic information system with 

information regarding the:

1. Geographic location of the pronghorn’s 

habitats, the physical and biological 

characteristics of the area and the changes 

tendencies of the land.

2. Availability of areas in zones with habitat 

potential.

3. Availability of food source areas within the 

potential habitats.

4. Generation of maps that will include the main 

risk factors that affect the different pronghorn 

populations in Mexico.

9, 11, 15, 18 x x

Describe the demography and reproductive 

biology of the pronghorn in Mexico (with 

emphasis in the reproduction rate, the survival of 

the fawns, and more).

11 x x x

Determine the actual distribution of the 

pronghorn in Mexico, with emphasis on the 

identification of the priority areas for its 

conservation.

5, 11 x x x

Estimate the size of the pronghorn population in 

Mexico, with emphasis on the priority areas for 

its conservation.

9, 15, 18 x x

Describe the genetic structure of the pronghorn 

populations in Mexico.

9, 10, 11, 13 x x

Evaluate the real and potential effect that 

competition for food with the cattle has on the 

pronghorn populations.

9, 10, 11, 13 x x x

Identify the priority areas for the conservation of 

the habitat of the pronghorn.

9, 10, 11, 13 x x x

Define the best techniques for the controlled 

reproduction, population management, capture, 

translocations, and follow up of the populations.

9, 10, 11, 13 x x x

Manage the search for financial support for the 

identified projects, as a key strategy for the 

conservation of the species.

15, 19, 20 x x x

4. 3 Biological Monitoring Component
265

Systematically follow up the pronghorn 

populations

5, 9 x x

Systematically follow up the pronghorn 

reproductive activities.

5, 9 x x x

Conduct longitudinal demographic analysis in 

the different pronghorn populations.

4, 7, 9, 11 x x x

Monitor the quality of the habitat in the critical 

locations for the distribution of the pronghorn.

4, 7, 9, 11 x x x

Periodically recollect and analyze the 

information about demographic tendencies for 

the pronghorn populations, the availability of its 

habitat, and its relation with the identified risk 

factors.

4, 7, 8, 9, 11 x x X

Design, in coordination with the ANP and 

institutions involved, a protocol for the 

monitoring of the pronghorn, to unify the criteria 

for all the priority areas and initiate the creation 

of a database for the CONANP and the 

participating institutions.

9, 20 x x x

Systematically implement national census for the 

pronghorn every three years, with the objective 

of knowing the changes and pressures that the 

populations are been exposed to.

9, 20 x x X

Monitor the distribution, feeding, and influence 

areas in the critical locations for its distribution.

4, 7, 8, 9, 11 x x x

Periodically gather and analyze the information 

regarding the demographic tendencies of the 

pronghorn populations and their relation with the 

risk factors identified.

4, 11 x x x

Determine the dispersion of the pronghorn 

populations through the use of known 

techniques.

4, 7, 8, 9, 11 x x x

5.1 Environmental Education Component

Identify the sectors that directly influence the 

pronghorn populations and its habitat, in order 

apply the environmental education strategies.

11, 12, 13, 

16

x x

Define the priorities, focus, and diffusion 

methods necessary for the conservation of the 

pronghorn and its habitat, in the general 

population.

12, 13, 16 x x

Update the information regarding the pronghorn 

and its habitat, included in the basic school 

education programs in the country.

12, 13, 14, 

16

x x

Design a manual for the environmental educator 

about the pronghorn in Mexico, and distribute it 

amongst professors and environmental 

educators.

12, 13 x x

Provide training to professors and environmental 

educators about the biology of the pronghorn, its 

12, 13 x x
266

habitat, problematic, and potential use.

Promote the presence of individuals of the 

species in zoos, with the objective of educating 

the population about the pronghorn and the 

problems that are affecting them, hoping that 

people will become sensitive about it.

12, 13, 15 x

Build a data base including information about 

people, institutions, organizations, interest 

groups, and facilities, that can support and 

influence the environmental education, research, 

management, protection, conservation, recovery, 

and diffusion activities about the biology and 

problematic of the pronghorn and its habitat.

12, 14, 16 x x

5.2 Communication and Diffusion Component

Spread the scientific information about the 

pronghorn to the different areas of the society in 

an appropriate language for their comprehension, 

awareness, and higher participation.

9, 11, 12, 13 x x x

Design the definition of the contents and optimal 

communication media, with a regional emphasis.

11, 12, 13 x x

Promote and manage events for pronghorn 

conservation.

12, 14 x x x

Make available educational materials about the 

species, to institutions involved, and guarantee 

the availability of the materials.

3, 4, 11, 12, 

13, 14,15

x x

Spread the importance of the influence of the 

society in the protection, conservation, and 

recovery of the pronghorn and its habitat.

3, 4, 11, 12, 

13, 14

x x x

Establish technical and financial synergies 

amongst the different communication resources 

for the development and distribution of 

informational material.

3, 4, 11, 12 x x x

Develop a proposal to make a year, like “The 

Year of the Pronghorn”.

9, 14, 15, 17 x x x

Develop a program of activities about the species 

for the year designated as “The Year of the 

Pronghorn”.

14 x x x

Promote the integration, diffusion, and 

participation of all the responsible parties 

involved; in the activation of a web site for the 

consulting of general people and specialists, with 

the objective of developing the interest and 

participation in the conservation of the 

pronghorn at the national and international level.

12 x x

Promote and manage a communication strategy 

to sensitize the population at two levels:

1. In the rural sector, to promote the 

coexistence, convenience, and respect of 

the species, by using speeches, 

2, 3, 4, 12 x x
267

conferences, videos, radio, television, and 

brochures.

2. In the urban sector, utilize mass 

communication with explicit messages 

and accessible to the entire population.

5.3 Social Capacitation Component

Promote best practice exchanges amongst 

communities, with the objective of sensitizing 

and educating the locals about their importance 

in the cultural recovery of the pronghorn and its 

importance for the ecosystems, as well as, 

developing educational forums focused on:

o Promoting the productive 

activities that are compatible with 

the conservation of the pronghorn 

and its habitat.

o Environmental regulations.

o Biological monitoring of the 

species.

2, 3, 12, 13 x x x

Educate and sensitize the locals about the 

importance of the conservation of the habitat, as 

a resource with ecological value.

2, 3, 12, 13 x x x

Educate the people in local rural communities, 

who are culturally linked to the pronghorn, to 

obtain their assistance on the monitoring, 

surveillance, and environmental education.

2, 3, 12, 13 x x x

In coordination with the sectors involved, create 

a technical manual with the recommendations for 

the installation of pronghorn friendly fences and 

structures.

2, 3, 12, 13 x x x

Educate the people in local communities, who 

are culturally linked to the pronghorn, to obtain 

their assistance on the monitoring, surveillance, 

and environmental education.

2, 3, 12, 13 x x x

Educate personnel in the CONANP, and other 

federal, and state institutions, organizations, 

technicians, and property owners in the 

identification of the pronghorn habitat, in the 

monitoring procedures for the areas that the 

species visits, and the protection and surveillance 

strategies.

2, 3 x x x

6. 1 Components of the Responsible Parties Involved

Establish a schedule for regular meetings for the 

evaluation and follow up of PACE, with the 

participation of the Subcomité Técnico 

Consultivo para la Conservación, Manejo y 

Aprovechamiento Sustentable of the pronghorn 

and subject experts.

11, 12, 14, 

15, 20

x x

Establish a communication mechanism for the 2, 13, 15, 17, x x X
268

continuous communication between the 

members of the Subcomité Técnico Consultivo 

para la Conservación, Manejo y 

Aprovechamiento Sustentable of the pronghorn 

in addition to the web site.

20

Establish a collaboration program and meeting 

agenda for the working groups and committees 

of the species that share habitat with the 

pronghorn.

2, 3, 9, 13, 

15, 18

xxX

Promote a collaboration agreement between the 

SEMARNAT and SAGARPA for the installation 

of pronghorn friendly fences.

9, 14, 15xxx

Build a financial strategy for the activities in this 

program, which involves the government, 

general society, and private industries through 

agreements, contracts, or donations for technical 

support, cash, or donated species.

15, 18, 19xxx

Promote the participation of the general society 

in activities included in this document, through 

volunteering, technical support, or financing.

14, 15xxx

6.2 Programming Component

Create a calendar of activities and projects to be 

completed in the Programa de Acción, 

establishing long and short-term goals.

15, 19, 20xx

Identify the action steps necessary to reach the 

goals and objectives of this program, as well as, 

the priority of the diverse activities within each 

phase.

10, 14, 15xxx

Plan the financial needs for the different projects, 

and decide how they will be met, considering the 

timeframe to obtain such financial support and 

the resources needed.

2, 10, 11, 14, 

15

xx

6.3 Evaluation and Follow up Component

Identify the critical timeframes to conduct 

evaluations during the project’s execution.

19, 20x

Establish regular meetings with the involved 

entities (nationals and internationals) for the 

evaluation and updating of the actions needed for 

the conservation of the species.

11,12,13 20x

Evaluate the success of the program and make 

the pertinent updates for the short and long term.

18, 19xxx

Use indicators to qualify the development of the 

objectives and goals of the activities planned.

18, 19xxx

Build diffusion mechanisms to communicate the 

partial and final results of the different projects, 

to help the working groups identify the progress 

and difficulties faced during the implementation 

of any programs, hence, to be able to make 

changes to the programs when deemed 

12x
269

necessary.
270

XXII. Specific Activities

XXIII.1 Peninsular Pronghorn

Component Activity Goals 09-10 Goals 11-12

Protection of the 

habitat

Establish the UMA 2 UMA 2 UMA

Protection of the 

populations

Protection of the 

breeding sites

200 pronghorn 200 pronghorn

Repopulation and 

transfer

100 pronghorn 100 pronghorn

Sustainable use 1 functional UMA 2 functional UMA

Legal Area Evaluate the 

pronghorn 

management

programs with ANP

1 ANP 1 ANP

Establish the 

general guidelines 

for the 

implementation of 

prevention and 

impact mitigation 

actions

1 written document

Inspection and 

surveillance

Incorporate UMA in 

the continuous 

surveillance efforts

2 UMA 2 UMA

Incorporate the 

hunting departments 

in the surveillance 

efforts

Creation of a 

regional association

Creation of a 

regional association

Populations and 

habitat restoration

Identify critical 

zones within the 

Baja California 

peninsula

1 written document

Coordinate activities 

amongst institutions

1 program

Prevention and 

impact mitigation

Coordinate activities 

amongst institutions

1 program

Habitat management Incorporate the 

already established 

UMA to the benefits 

of the governmental 

programs developed

2 UMA 2 UMA

Promote the 

productive 

diversification

1 UMA to serve a 

role model for the 

region

Management of the 

species

Create a 

standardized 

handbook for the 

management of the 

1 handbook
271

species

Knowledge 

development

Conduct a census in 

the entire Baja 

California peninsula

1 census

Scientific 

investigation

Generation of maps 

that will include the 

main risk factors 

that affect the 

peninsular 

pronghorn

1 document

Determine the 

genetics of the 

subspecies

1 document

Biological 

monitoring

Continuous follow 

up of the wild 

population and its 

habitat in the 

REBIVI and APFF 

Valle de los Cirios

2 reports 2 reports

Environmental 

education

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 environmental 

education program

Increase the number 

of peninsular 

individuals in the 

local zoos.

1 zoo 2 zoos

Communication and 

spread

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 program

Social capacitation Educate the people 

in local 

communities in the 

rural areas, who are 

culturally linked to 

the pronghorn

10 workshops 10 workshops
272

Parties involved Establish meeting 

agendas and regular 

meetings for the 

evaluation and 

follow up of PACE

2 2
273

XXIII.2 Sonoran Pronghorn

Component Activity Goals 09-10 Goals 11-12

Protection of the 

populations

Protection of the 

breeding sites

50 pronghorn

Sustainable use 1 functional UMA

Legal Area Evaluate the 

pronghorn 

management

programs with ANP

1 ANP

Establish the 

general guidelines 

for the 

implementation of 

prevention and 

impact mitigation 

actions

1 written document

Inspection and 

surveillance

Incorporate UMA in 

the continuous 

surveillance efforts

3 UMA 3 UMA

Incorporate the 

hunting departments 

in the surveillance 

efforts

Creation of a 

regional association

Creation of a 

regional association

Populations and 

habitat restoration

Identify critical 

zones in Sonora

1 written document

Coordinate activities 

amongst institutions

1 program

Prevention and 

impact mitigation

Coordinate activities 

amongst institutions

1 program

Habitat management Incorporate the 

already established 

UMA to the benefits 

of the governmental 

programs developed

3 UMA 3 UMA

Promote the 

productive 

diversification

1 UMA to serve a 

role model for the 

region

Management of the 

species

Create a 

standardized 

handbook for the 

management of the 

species

1 handbook

Knowledge 

development

Conduct a census in 

the distribution 

areas

1 census

Scientific 

investigation

Generation of maps 

that will include the 

main risk factors 

that affect the 

1 document
274

Sonoran pronghorn

Determine the 

genetics of the 

subspecies

1 document

Biological 

monitoring

Continuous follow 

up of the wild 

population and its 

habitat in the 

REBIPI and 

surrounding areas

1 report

Environmental 

education

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 environmental 

education program

Communication and 

spread

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 program

Social capacitation Educate the people 

in local 

communities in the 

rural areas, who are 

culturally linked to 

the pronghorn

2 workshops

Parties involved Establish meeting 

agendas and regular 

meetings for the 

evaluation and 

follow up of PACE

2 2

XXIII.3 Mexican Pronghorn

Component Activity Goals 09-10 Goals 11-12

Protection of the 

habitat

Establish the UMA 4 UMA 2 UMA

Protection of the 

populations

Protection of the 

breeding sites

50 pronghorn

Repopulation and 300 pronghorn 100 pronghorn
275

transfer

Sustainable use 1 functional UMA 2 functional UMA

Legal Area Evaluate the 

pronghorn 

management

programs with ANP

1 ANP

Establish the 

general guidelines 

for the 

implementation of 

prevention and 

impact mitigation 

actions

1 written document

Inspection and 

surveillance

Incorporate UMA in 

the continuous 

surveillance efforts

4 UMA 2 UMA

Incorporate the 

hunting departments 

in the surveillance 

efforts

Creation of a 

regional association

Creation of a 

regional association

Populations and 

habitat restoration

Identify critical 

zones in Chihuahua

1 written document

Coordinate activities 

amongst institutions

1 program

Prevention and 

impact mitigation

Coordinate activities 

amongst institutions

1 program

Habitat management Incorporate the 

already established 

UMA to the benefits 

of the governmental 

programs developed

4 UMA 2 UMA

Promote the 

productive 

diversification

1 UMA to serve a 

role model for the 

region

Management of the 

species

Create a 

standardized 

handbook for the 

management of the 

species

1 handbook

Knowledge 

development

Conduct a census in 

the entire 

Chihuahua state

1 census

Scientific 

investigation

Generation of maps 

that will include the 

main risk factors 

that affect the 

peninsular 

pronghorn

1 document

Determine the 1 document
276

genetics of the 

subspecies

Biological 

monitoring

Continuous follow 

up of the wild 

population and its 

habitat in the 

Chihuahua, 

Coahuila, and 

Nuevo León states

2 reports 2 reports

Environmental 

education

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 environmental 

education program

Communication and 

spread

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 program

Social capacitation Educate the people 

in local 

communities in the 

rural areas, who are 

culturally linked to 

the pronghorn

10 workshops 10 workshops

Parties involved Establish meeting 

agendas and regular 

meetings for the 

evaluation and 

follow up of PACE

2 2
277

XXIII. Pronghorn in the Rest of the Mexican Plateau

XXIV.1 Zacatecas

Component Activity Goals 09-10 Goals 11-12

Protection of the 

habitat

Establish the UMA 2 UMA 2 UMA

Protection of the 

populations

Protection of the 

breeding sites

100 pronghorn 100 pronghorn

Repopulation and 

transfer

100 pronghorn 100 pronghorn

Sustainable use 1 functional UMA 2 functional UMA

Legal Area Legally establish a 

ANP with habitat 

for the pronghorn

1 ANP

Establish the 

general guidelines 

for the 

implementation of 

prevention and 

impact mitigation 

actions

1 written document

Inspection and 

surveillance

Incorporate UMA in 

the continuous 

surveillance efforts

2 UMA 2 UMA

Incorporate the 

hunting departments 

in the surveillance 

efforts

Creation of a 

regional association

Creation of a 

regional association

Populations and 

habitat restoration

Identify areas in 

critical conditions

1 written document

Coordinate activities 

amongst institutions

1 program

Prevention and 

impact mitigation

Coordinate activities 

amongst institutions

1 program

Habitat management Incorporate the 

already established 

UMA to the benefits 

of the governmental 

programs developed

2 UMA 2 UMA

Promote the 

productive 

diversification

1 UMA to serve a 

role model for the 

region

Management of the 

species

Create a 

standardized 

handbook for the 

management of the 

species

1 handbook

Knowledge 

development

Evaluate the 

techniques and 

1 document
278

procedures used for 

the pronghorn 

repopulation

Scientific 

investigation

Generation of maps 

that will include the 

main risk factors 

that affect the 

transferred 

pronghorn

1 document

Biological 

monitoring

Continuous follow 

up of the transferred 

populations

2 reports 2 reports

Environmental 

education

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 environmental 

education program

Communication and 

spread

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 program

Social capacitation Educate the people 

in local 

communities in the 

rural areas, who are 

culturally linked to 

the pronghorn

2 workshops 2 workshops

Parties involved Establish meeting 

agendas and regular 

meetings for the 

evaluation and 

follow up of PACE

2 2
279

XXIV.2 Durango

Component Activity Goals 09-10 Goals 11-12

Protection of the 

habitat

Establish the UMA 2 UMA 2 UMA

Protection of the 

populations

Protection of the 

breeding sites

50 pronghorn 100 pronghorn

Repopulation and 

transfer

100 pronghorn 100 pronghorn

Sustainable use 1 functional UMA 2 functional UMA

Legal Area Establish the 

general guidelines 

for the 

implementation of 

prevention and 

impact mitigation 

actions

1 written document

Inspection and 

surveillance

Incorporate UMA in 

the continuous 

surveillance efforts

2 UMA 2 UMA

Incorporate the 

hunting departments 

in the surveillance 

efforts

Creation of a 

regional association

Creation of a

regional association

Populations and 

habitat restoration

Identify areas in 

critical conditions in 

the Durango state

1 written document

Coordinate activities 

amongst institutions

1 program

Prevention and 

impact mitigation

Coordinate activities 

amongst institutions

1 program

Habitat management Incorporate the 

already established 

UMA to the benefits 

of the governmental 

programs developed

2 UMA 2 UMA

Promote the 

productive 

diversification

1 UMA to serve a 

role model for the 

region

Management of the 

species

Create a 

standardized 

handbook for the 

management of the 

species

1 handbook

Knowledge 

development

Evaluate the 

techniques and 

procedures used for 

the pronghorn 

repopulation

1 document

Scientific Generation of maps 1 document
280

investigation that will include the 

main risk factors 

that affect the 

transferred 

pronghorn

Biological 

monitoring

Continuous follow 

up of the transferred 

populations

2 reports 2 reports

Environmental 

education

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 environmental 

education program

Communication and 

spread

Define and 

prioritize the 

promotion and 

spread of 

information for the 

conservation, 

protection, and 

management of the 

pronghorn, in the 

local communities

1 program

Social capacitation Educate the people 

in local 

communities in the 

rural areas, who are 

culturally linked to 

the pronghorn

2 workshops 2 workshops

Parties involved Establish meeting 

agendas and regular 

meetings for the 

evaluation and 

follow up of PACE

2 2

Acronym Appendix

AGFD Arizona Game and Fish Department

AMAVISI Asociación de Manejadores de Vida Silvestre, A. C. (Wildlife 

Management Association)

ANP Áreas Naturales Protegidas (Protected Natural Areas)

BFA Base de la Fuerza Aérea Francis E. Warren (Air Force Base Francis E. 

Warren)
281

CEDES Comisión de Ecología y Desarrollo Sustentable del Estado de Sonora 

(Ecology and Sustainable Development Department of the Sonora State)

CES Centro Ecológico de Sonora (Ecological Center of Sonora)

CIBNOR Centro de Investigaciones Biológicas del Noreste (Biological Research 

Center of the Northeast)

CONAFOR Comisión Nacional Forestal (National Forest Department)

CONANP Comisión Nacional de Áreas Naturales Protegidas (National Department 

of the Protected Natural Areas)

DGFS Dirección General de Fauna Silvestre (Wild Fauna General Department)

DGVS Dirección General de Vida Silvestre (Wildlife General Department)

EAVS Estación de Aprovechamiento de Vida Silvestre (Wildlife Use Station)

FWS Servicio de Pesca y Vida Silvestre de Estados Unidos (Fish and Wildlife 

Service in the USA)

GEF Fondo Mundial para el Medio Ambiente (Global Environmental 

Facility)

IMADES Instituto del Medio Ambiente y el Desarrollo Sustentable del Estado de 

Sonora, (currently CEDES) (Environmental and Sustainable 

Development Institute in the Sonora State)

INE Instituto Nacional de Ecología (Ecology National Institute)

L. A. Zoo Zoológico de Los Ángeles (Los Angeles Zoo)

LGVS Ley General de Vida Silvestre (Wildlife Law)

NMDGF Departamento de Caza y Pesca de Nuevo México (New Mexico 

Department of Game and Fish)

ONG Organización No Gubernamental (Non-governmental Organization)

PACE Programa de Acción Para la Conservación de La Especie (Species 

Conservation Action Program)

PET Programas de Empleo Temporal (Temporary Employment Program)

PREP Proyectos para la Recuperación de Especies Prioritarias (Project for the 

Recovery of the Priority Species)

PREPBe Proyecto para la Conservación, Manejo y Aprovechamiento Sustentable 

del Berrendo en México (Project for the Conservation, Management, 

and Sustainable Benefit of the Pronghorn in Mexico)

PROCER Programa de Conservación de Especies en Riesgo (Program for the 

Conservation of the Endangered Species)

PROCODES Programas de Conservación para el Desarrollo Rural Sustentable

(Conservation Program for the Sustainable Rural Development)

PROFEPA Procuraduría Federal de Protección al Ambiente (Federal Department 

for the Environmental Protection)

PROGAN Programa de Fomento Ganadero (Livestock Development Program)

PSA Pago por Servicios Ambientales (Payment for Environmental Services)

ReBiPi Reserva de la Biosfera “El Pinacate y Gran Desierto de Altar” 

(Biosphere Reserve)

ReBiVi Reserva de la Biosfera “El Vizcaíno” (Biosphere Reserve)

SAGARPA Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y 

Alimentación (Agriculture, Livestock, Rural Development, Fish, and 

Feeding Department)

SEDENA Secretaría de la Defensa Nacional (National Defense Department)

SEMARNAP Secretaría de Medio Ambiente, Recursos Naturales y Pesca (currently 
282

SEMARNAT) (Environment, Natural Resources, and Fish Department)

SEMARNAT Secretaría de Medio Ambiente y Recursos Naturales (Environment and 

Natural Resources Department)

SUMA Sistema de Unidades para la Conservación de la Vida Silvestre (Units 

System for the Wildlife Conservation)

TNC The Nature Conservancy

UAZ Universidad Autónoma de Zacatecas

UICN Unión Internacional para la Conservación de la Naturaleza 

(International Committee for the Conservation of Nature)

UMA Unidad de Manejo para la Conservación de Vida Silvestre (Management 

Unit for the Wildlife Conservation)

UNAM Universidad Nacional Autónoma de México

UPC Unidos para la Conservación A.C. (United for the Conservation)

WGFD Wyoming Game and Fish Department
283

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291

Appendix D. Population Viability Assessment
292

REVISION

Population Viability Analysis for the Sonoran Pronghorn

(Antilocapra americana sonoriensis)

Report prepared by

Philip S. Miller, Ph.D.

Senior Program Officer

Conservation Breeding Specialist Group (SSC/IUCN)

In consultation with

U.S. Fish and Wildlife Service Sonoran Pronghorn Recovery Team

Prepared for 

U.S. Fish and Wildlife Service

Arizona Ecological Services - Tucson 

201 N. Bonita Avenue, Suite 141

Tucson, AZ 85745

29 January, 2014

REVISED 26 MARCH 2014
Miller –Sonoran Pronghorn PVA REVISION 26 March, 2014

293

Population Viability Analysis for the Sonoran Pronghorn 

(Antilocapra americana sonoriensis)

Philip S. Miller, Ph.D.

Senior Program Officer

Conservation Breeding Specialist Group (SSC/IUCN)

In consultation with

Technical Subgroup

U.S. Fish and Wildlife Service Sonoran Pronghorn Recovery Team

Introduction

Population viability analysis (PVA) can be an extremely useful tool for investigating current and future 

demographic dynamics of Sonoran pronghorn populations within the species’ range. The need for and 

consequences of alternative management strategies can be modeled to suggest which practices may be the 

most effective in managing Sonoran pronghorn populations. VORTEX, a simulation software package 

written for PVA, was used here as a vehicle to study the interaction of a number of Sonoran pronghorn

life history and population parameters, and to test the effects of selected management scenarios.

The VORTEX package is a simulation of the effects of a number of different natural and human-mediated 

forces – some, by definition, acting unpredictably from year to year – on the health and integrity of 

wildlife populations. VORTEX models population dynamics as discrete sequential events (e.g., births, 

deaths, sex ratios among offspring, catastrophes, etc.) that occur according to defined probabilities. The 

probabilities of events are modeled as constants or random variables that follow specified distributions. 

The package simulates a population by recreating the essential series of events that describe the typical 

life cycles of sexually reproducing organisms.

PVA methodologies such as the VORTEX system are not intended to give absolute and accurate “answers” 

for what the future will bring for a given wildlife species or population. This limitation arises simply from 

two fundamental facts about the natural world: it is inherently unpredictable in its detailed behavior; and 

we will never fully understand its precise mechanics. Consequently, many researchers have cautioned 

against the exclusive use of absolute results from a PVA in order to promote specific management actions 

for threatened populations (e.g., Ludwig 1999; Beissinger and McCullough 2002; Reed et al. 2002; Ellner 

et al. 2002; Lotts et al. 2004). Instead, the true value of an analysis of this type lies in the assembly and 

critical analysis of the available information on the species and its ecology, and in the ability to compare 

the quantitative metrics of population performance that emerge from a suite of simulations, with each 

simulation representing a specific scenario and its inherent assumptions about the available data and a 

proposed method of population and/or landscape management. Interpretation of this type of output 

depends strongly upon our knowledge of pronghorn biology, the environmental conditions affecting the 

species, and possible future changes in these conditions. 

The VORTEX system for conducting population viability analysis is a flexible and accessible tool that can 

be adapted to a wide variety of species types and life histories as the situation warrants. The program has 

been used around the world in both teaching and research applications and is a trusted method for 

assisting in the definition of practical wildlife management methodologies. For a more detailed 

explanation of VORTEX and its use in population viability analysis, refer to Lacy (2000) and Miller and 

Lacy (2005).
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Primary Questions for PVA Modeling

The Sonoran Pronghorn Recovery Team’s Technical Subgroup identified a set of primary questions for 

which PVA model construction and implementation could be useful in addressing:

1. What are the most sensitive demographic parameters that drive population growth in our 

simulation models?

2. Can we use the PVA to derive reasonable population abundance estimates to be used as recovery 

criteria?

3. Is there a genetic “founder effect” that may impact long-term viability of newly established 

populations like Kofa NWR?

4. What are the relative impacts of linking to a captive program?

5. How long do we need to maintain semi-captive breeding programs?

6. What are the relative impacts of other pronghorn population/habitat management actions?

7. What are the most effective management actions to undertake in Mexico?

8. What are the benefits of demographic linkage between U.S. and Mexico populations?

9. Is a captive program important to augment populations in Mexico?

This report addresses questions 1 and 2; other questions listed above may be addressed in future efforts.

Baseline Input Parameters for Population Viability Simulation Models

Much of the data used to derive input parameters for the population dynamics models discussed were 

gleaned from Bright and Hervert (2005, 2011), Hosack et al. (2002), and various internal reports 

compiled by the Arizona Game and Fish Department. When specific published or unpublished data were 

not available, expert judgment was used to derive appropriate parameter values.

Timestep for all simulations: Since pronghorn reproductive ecology is easily described on an annual 

basis, we have chosen the timestep for our simulations as one year. 

Metapopulation structure: A subset of pronghorn models constructed for this project – namely, those for 

the Cabeza Prieta and Kofa populations – include a type of “managed metapopulation” structure. 

Specifically, the existing wild population is linked to its corresponding pen population through managed 

translocation. More on the specifics of this translocation will be presented in later versions of this report.

Breeding system: Pronghorn are known to display a polygynous breeding system, where a single male 

may mate with multiple females during a give year. This is simulated in VORTEX by allowing adult males 

to be sampled multiple times as mates for available females.

Age of first offspring: VORTEX considers the age of first reproduction as the age at which the first fawn is 

born, not simply the onset of sexual maturity. Female pronghorn in the wild will successfully produce 

their first fawn at two years of age. In highly managed pen populations, a few adult females may produce 

their first fawn at just one year of age.

Maximum age of reproduction: In its simplest form, VORTEX assumes that animals can reproduce (at the 

normal rate) throughout their adult life. We assume here that pronghorn live no more than 13 years in the 

wild.

Reproductive events per year: We assume that an adult female will produce only once per year, and will 

produce no more than two fawns in any one reproductive event.
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295

Offspring sex ratio: Without data to the contrary, we assume a 50:50 sex ratio across all fawns produced 

in a given year.

% Adult females breeding: This describes the average proportion of females that reproduce in a year. We 

assume that nearly all (specifically, 95%) adult females produce fawns in a given year in the wild. In pen 

populations, we additionally assume that 5% of all one-year-old fawns will reproduce.

Density dependent reproduction: VORTEX can model density dependence with an equation that specifies 

the proportion of adult females that reproduce as a function of the total population size. In addition to 

including a more typical reduction in breeding in high-density populations, the user can also model an 

Allee effect: a decrease in the proportion of females that bread at low population density due, for 

example, to difficulty in finding mates that are widely dispersed across the landscape.

The equation that VORTEX uses to model density dependence is:

PP(NN) = �PP(0) − ��PP(0) − PP(KK)� �

NN

KK�

BB

�� NN

NN + AA

in which P(N) is the percent of females that breed when the population size is N, P(K) is the percent that 

breed when the population is at carrying capacity, and P(0) is the percent breeding when the population is 

close to zero (in the absence of any Allee effect). The exponent B can be any positive number and 

determines the shape of the curve relating the percent breeding to population size, as the population 

becomes large. If B = 1, the percent breeding changes linearly with population size. If B = 2, P(N) is a 

quadratic function of N. The parameter A defines the magnitude of the Allee effect.

There appears to be little evidence for strong density dependence in reproduction in wild pronghorn 

populations. In light of this information, we do not include this process in our models described here.

Environmental variation (EV) in % breeding: Annual environmental variation in female reproductive 

success is modeled in VORTEX by specifying a standard deviation (SD) for the proportion of adult females 

that successfully produce offspring in a given year. In the absence of specific data on this parameter, we 

assume that the variation is equal to 3%, thereby producing a full statistical distribution of female 

breeding rates between 89% - 100% (mean ± 2SD). Given the high rate of reproductive success seen in 

pronghorn populations, this relative low level of inter-annual variability is thought to be reasonable for 

this species.

Distribution of litter size: The table below gives the probability of a given breeding female producing a 

litter of the specified size. These values are based on a mean litter size observed across multiple years of 

1.8 fawns per doe (Bright and Hervert).

Number of offspring Probability (%)

1 20

2 80

Mate monopolization: In many species, some adult males may be socially restricted from breeding despite 

being physiologically capable. This can be modeled in VORTEX by specifying a portion of the total pool of 

adult males that may be considered “available” for breeding each year. We assume here that pronghorn 

exhibit this type of social stratification of breeding success, although quantitative data are lacking. In 

absence of specific data, we assume that only about 60% of adult Sonoran pronghorn are available for 

breeding in any given year. 
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Mortality rates: VORTEX defines mortality as the annual rate of age-specific death from year x to x + 1; in 

the language of life-table analysis, this is equivalent to q(x). We assume that our model, intended to 

reflect the current pronghorn populations in Arizona and Sonora, will include the effects of human 

disturbance among age-specific mortality rates.

Little data exist on accurate estimates of age-specific mortality rates in wild Sonoran pronghorn 

populations. In light of this, we rely on information from recent pen populations and expert judgment to 

derive rates that are consistent with general knowledge of pronghorn demography and observed trends in 

wild population abundance. We assume here that, in wild pronghorn populations, mean fawn mortality is 

70% among females and 65% among males. The mechanism explaining this slight increase in female 

mortality is not yet known. After the high first-year mortality, mean annual mortality declines to a stable 

rate of approximately 10 – 15%, with slightly higher rates of mortality among males as they endure 

additional stress from competing amongst each other for access to breeding females. 

Captive pen populations experience significantly lower mortality rates through intense active 

management. To simulate this difference, we assume that fawn mortality in the pens is just 10% for 

females (5% for males). Subadult and adult rates are set to 5% for both males and females.

We have adjusted simulated mortality rates in Mexico’s Quitovac Management Unit to at least partially 

account for the apparent decline in population abundance observed in this population since a maximum 

abundance observed in 2004. This assumes, of course, that (i) the observed decline in population 

abundance as measured by the recent aerial surveys is real, and (ii) increases in both fawn and adult 

mortality are major factors contributing to the observed decline in abundance. For our initial models here, 

we assume Quitovac fawn mortality is 80% for females and 70% for males. Female mortality for those 

individuals age 2+ years is 17%, while male mortality is 15% for subadults and 20% for adults.

Inbreeding depression: VORTEX includes the ability to model the detrimental effects of inbreeding, most 

directly through reduced survival of offspring through their first year. While specific data on inbreeding 

depression in either captive or wild pronghorn populations are not available for this analysis, the 

preponderance of evidence for the deleterious impacts of inbreeding in mammal populations suggests that 

it can be a real factor in small populations. We therefore elected to include this process in our models, 

with a genetic load of 3.14 lethal equivalents, and with approximately 50% of this load expressed as lethal 

genes. These values are in accordance with the median value of inbreeding depression severity calculated 

for captive mammal populations assessed by Ralls et al. (1988).

Catastrophes: Catastrophes are singular environmental events that are outside the bounds of normal 

environmental variation affecting reproduction and/or survival. Natural catastrophes can be tornadoes, 

floods, droughts, disease, or similar events. These events are modeled in VORTEX by assigning an annual 

probability of occurrence and a pair of severity factors describing their impact on mortality (across all 

age-sex classes) and the proportion of females successfully breeding in a given year. These factors range 

from 0.0 (maximum or absolute effect) to 1.0 (no effect), and in its most basic implementation in VORTEX, 

are imposed during the single year of the catastrophe, after which time the demographic rates rebound to 

their baseline values.

While pronghorn are surely well-adapted to desert environments, they must also suffer from periods of 

extremely low rainfall in any given year. The 2002 drought event in southern Arizona and the apparent 

toll it took on the Cabeza Prieta pronghorn population suggests that this is indeed a realistic addition to 

our population dynamics model. We have therefore elected to include severe single-year drought as a 

catastrophe in our models. Specifically, based on simple analysis of recent historic records we assume 

that a severe drought occurs in this area on average once in approximately ten years. Therefore we set our 

catastrophe frequency at 10% in all models. For wild populations, we also assume that survival across all 
Miller –Sonoran Pronghorn PVA REVISION 26 March, 2014

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pronghorn age classes would drop by approximately 15 – 20% during the year of the drought event. We 

therefore set our drought survival severity to 0.83; in other words, we expect survival in drought years to 

be reduced by approximately 17% across all age classes. Because of the intensive management of pen 

populations, we assume that survival during drought years would decline by only 5% (drought severity = 

0.95). 

Because of comparatively lower levels of active management of pronghorn populations and their habitat, 

we assume that the impact of a severe drought event in the two Mexico populations will be greater than in 

Arizona’s Cabeza Prieta and Kofa populations. Specifically, we assume that the drought survival severity 

factors are 0.75 and 0.65 for the Pinacate and Quitovac populations, respectively.

Initial population size: VORTEX operates on a pre-breeding census model; therefore, all models are 

initialized with animals at least one year of age, i.e., including those youngest individuals that were born 

the previous breeding cycle and have survived to just before one year of age. Initial abundance estimates 

for Cabeza Prieta, Pinacate and Quitovac wild populations are based on the latest estimates derived from 

aerial surveys. The Kofa wild initial abundance is based on the first group of animals translocated to this 

area in early 2013. Initial abundances for the two pen populations are based on the most recent (April 

2013) census data. Initial abundance estimates for each population included in this analysis are given in 

the table below.

Carrying capacity: How close is a given subpopulation to its maximum, long-term equilibrium abundance 

– is there an opportunity for the population to grow to a larger size? This is simulated through specifying 

a given habitat’s population carrying capacity, K. The carrying capacity for a given habitat defines an 

upper limit for the population size, above which additional mortality is imposed randomly across all age 

classes in order to return the population at the end of a specific timestep to the value set for K.

An estimate for the carrying capacity in the Cabeza Prieta habitat is based on a simple analysis of the size 

and general habitat quality/availability within the area. Given this simple estimate, carrying capacity 

estimates for the Kofa, Pinacate and Quitovac populations were scaled appropriately. We assume that the 

two pen populations are already at carrying capacity through the management of high reproductive output 

of the available females. Carrying capacity estimates for each population included in this analysis are 

given in the table below.

Population N0 K

Cabeza Prieta Wild 159 400

Cabeza Prieta Pen 57 57

Kofa Wild 9 700

Kofa Pen 22 25

Pinacate Wild 52 150

Quitovac Wild 189 700

A summary of the population-specific model input for each population is provided in Table 1.
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Cabeza Prieta population: Demographic linkage between captive and wild components: Beginning in 

2006, pronghorn raised in the Cabeza Prieta pens were used to supplement the wild population that had 

experienced a dramatic decline during the period 1996 – 2002, most likely due to severe drought 

impacting both reproductive success and adult survival. Data from AGFD Updates and other sources 

allow us to estimate that an average of 21 pronghorn were released into Cabeza Prieta each year, in a 

roughly 2:1 ratio of males to females. To simulate this linkage between the two populations in our PVA, 

we set up a “metapopulation” model structure with explicit connectivity between the Cabeza Prieta Wild 

and Pen populations. However, we do not want animals to move between the populations in a stochastic 

fashion that results from allowing dispersal to control individual movement. To gain more explicit control 

of animal movement, we used a special feature within Vortex that “harvests” a given number of 

individuals of a given age-sex cohort from the Wild population, and then uses these same animals to 

“supplement” the Pen population immediately thereafter. This allows us to more carefully control the 

specific number, demographic characteristics, and identity of the animals as they transition from penreared animals to wild animals occupying the Refuge site. 

To generate a simulated population trajectory that is similar to what we have observed in the wild over the 

period of supplementation, we set the model to remove (”harvest”) each year eight adult females and 

approximately 14 males (12 yearlings and 2 adults). We also assume a 10% risk of mortality for each 

individual being translocated from pen to wild; this translates into an average of (0.9)(22) = 20 animals 

supplemented to the wild each year.

We set the following rules which the software must follow in all translocation scenarios:

1. The total number of adult males and females in the pen must exceed 25 in order for removal to 

take place

2. There must be at least four adult males in order to trigger the removal of two individuals from this 

cohort

Iterations and years of projection: All population projections (scenarios) were simulated 1000 times, with 

each projection extending to 50 years. All simulations were conducted using VORTEX version 9.99b (May 

2010).
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Table 1. Summary of population-specific demographic parameters used as input to Vortex simulation models as part of the Sonoran pronghorn PVA.

Parameter Cabeza Wild Cabeza Pen Kofa Wild Kofa Pen Pinacate Wild Quitovac Wild

Breeding Age (♀/ ♂) 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2

Maximum Age 13 13 13 13 13 13

Broods per Year 1 1 1 1 1 1

Maximum Progeny per Brood 2 2 2 2 2 2

Sex Ratio at Birth (%♂) 50 50 50 50 50 50

Density Dependent Breeding? No No No No No No

% ♀♀ Breeding Annually Age 2+: 95 Age 1: 5

Age 2+: 95

Age 2+: 95 Age 1: 5

Age 2+: 95

Age 2+: 95 Age 2+: 95

EV (% ♀♀) 3 3 3 3 3 3

Offspring Distribution 1 Fawn: 20%

2 Fawns: 80%

1 Fawn: 20%

2 Fawns: 80%

1 Fawn: 20%

2 Fawns: 80%

1 Fawn: 20%

2 Fawns: 80%

1 Fawn: 20%

2 Fawns: 80%

1 Fawn: 20%

2 Fawns: 80%

Annual Mortality (%) (♀/ ♂)

Age 0 – 1 70 / 65 10 / 5 70 / 65 10 / 5 70 / 65 80 / 70

Age 1 – 2 12/10 5 / 5 12/10 5 / 5 12/10 17/15

Age 2 + 12 / 15 5 / 5 12 / 15 5 / 5 12 / 15 17 / 20

Drought Catastrophe

Frequency (%) (Alt 1 / Alt 2) 5/10 5/10 5/10 5/10 5/10 5/10

Severity (Survival) 0.83 0.95 0.83 0.95 0.75 0.65

% ♂♂ in Breeding Pool 60 60 60 60 60 60

Initial Population Size 159 57 9 22 52 189

Carrying Capacity 400 57 700 25 150 700

Inbreeding Depression? Yes Yes Yes Yes Yes Yes

Lethal Equivalents 3.14 3.14 3.14 3.14 3.14 3.14
300

Results from Simulation Models

Baseline Model Analysis

Separate models were developed for each of the four pronghorn populations (Cabeza Prieta, Kofa, 

Pinacate, and Quitovac) and, where appropriate, were evaluated initially in a simple manner for their 

ability to track existing wild population trends estimated from aerial survey data. [Note that the Kofa 

population is not included in this particular baseline model analysis as the wild population was initiated 

only in early 2012.] This preliminary analysis is presented in Table 2.

Table 2. Population growth rates inferred from aerial surveys for three Sonoran pronghorn populations currently in 

the wild, and growth rates calculated from VORTEX demographic models constructed using input described in this 

report. Time period in parentheses associated with observed growth rates indicates the period in which the rates 

were estimated. 

Population Observed Growth Rate 

(Dates)

Growth Rate (Model)

Cabeza Prieta (Linked Wild –

Pen)

1.09 (2006 – 2012) 1.10

Pinacate 1.10 (2002 – 2011) 1.03

Quitovac 0.89 (2004 – 2011) 0.92

Simulated growth rates for the Cabeza Prieta and Quitovac model populations are very similar to those 

estimated from data on population trends from aerial surveys. The simulated Pinacate population growth 

rate is considerably lower than the rate estimated from aerial survey data over the last decade, which will 

likely require some modification of model input parameters to align the model trajectory more closely to 

the observed abundance trajectory (assuming, of course, some degree of confidence in the trajectory 

inferred from the aerial survey data).

Despite some of these population-specific adjustments that may need to be made to simulated model 

input, it is clear that the model structure and the associated demographic input parameters developed in 

this project can lead to a reasonable depiction of Sonoran pronghorn population dynamics. It is therefore 

possible to use this model structure to evaluate comparative sensitivity of model performance to 

uncertainty in specific demographic input, and to provide preliminary guidance on identifying population 

abundance thresholds that may relate to long-term species recovery criteria.

Sensitivity Analysis

During the development of the baseline input dataset, it quickly became apparent that a number of 

demographic characteristics of Sonoran pronghorn populations in Arizona and especially Mexico are 

highly uncertain. This type of measurement uncertainty, which is distinctly different from the annual 

variability in demographic rates due to extrinsic environmental stochasticity and other factors, impairs our

ability to generate precise predictions of population dynamics with any degree of confidence. 

Nevertheless, an analysis of the sensitivity of our models to this measurement uncertainty can be an 

invaluable aid in identifying priorities for detailed research and/or management projects targeting specific 

elements of the species’ population biology and ecology.

A first step in a more broad sensitivity analysis focused on the relative impact of changes in survival of 

both male and female juveniles (one year old) and adults. A suite of models was constructed using a 

baseline input dataset similar to a Cabeza Prieta-type population that is not linked to a separate pen 

population. Numerous scenarios were then built in which individual age/sex-specific survival rates were 

incrementally changed by 10% or 20% above and below the baseline value of the specific parameter. This 
301

systematic perturbation allows for more direct comparison of model results. The output metric of choice 

for this analysis is the mean stochastic population growth rate calculated directly from the model results.

The results of this analysis are shown as a “spider plot” in Figure 1. 

The central data point in the plot is the population growth rate from the baseline model, with all input 

parameters at their consensus value. [Note that this growth rate of r = 0.05 is different from that rate 

reported for the other Cabeza Prieta model in Table 2. This is because we assume an isolated population 

in this analysis, while the other model assumed explicit connection to the associated pen population.] 

Other data points in this plot give the population growth rate for a scenario in which male or female 

juvenile or adult survival is adjusted to 10% or 20% higher or lower than the baseline value. 

Figure 1 shows that, on a per-unit basis, changes to adult female survival lead to larger changes in 

population growth rates than changes of the same magnitude in juvenile female survival. In other words, 

these results indicate that our models are highly sensitive to changes in adult female survival. In contrast, 

changes to male survival of either juveniles or adults lead to very small changes in population growth, 

suggesting considerably lower levels of model sensitivity in these parameters. This type of result is 

consistent with general principles of population biology, in which relatively long-lived species of 

mammals with relatively lower levels of reproductive output are characterized by greater importance of 

adult female survival. 

Note that this result is contrary to that reported by Hosack et al. (2002), where the authors identify fawn 

survival rates as the most sensitive model parameter. The analysis described here is a more rigorous 

approach to the issue of model sensitivity than that reported in the earlier paper, and the conclusions of 

Hosack et al. (2002) are not well-supported by the quantitative data presented therein. It is also important 

to note that those parameters to which a demographic model is most sensitive may not be the same 

parameters that are most directly affected by human activities and are therefore putting the population at 

risk (e.g., Mills et al. 1999). Successful conservation requires careful additional study to identify the 

specific risks the populations face and to develop appropriate remedial actions.

Risk Analysis: Derivation of Preliminary Recovery Criteria

In addition to the sensitivity analysis described above, this PVA project was designed to help provide 

some guidance on the derivation of recovery criteria for individual wild Sonoran pronghorn populations, 

Figure 1. “Spider plot” of stochastic 

growth rate among alternative 

demographic models of Sonoran 

pronghorn population dynamics. See 

accompanying text for additional 

information on model structure and 

interpretation of results.
302

i.e., those not receiving animals from intensively managed pen populations . Given a Recovery Team 

definition of “viability” as a probability of population extinction of no more than 10% in 50 years, the 

PVA model platform can be used to help focus on the long-term population abundance required, given a 

specific set of demographic characteristics, to maintain extinction risk below the specified threshold.

Specifically, we would like to know the population abundance that would be required to minimize the risk 

of population instability and, ultimately, extinction due to negative effects of stochastic fluctuations in 

population demographic processes. This process requires, of course, some specification of at least 

minimum demographic conditions that do not send the population into long-term deterministic decline. In 

other words, the population must have birth and death rates that confer at least a long-term stochastic 

growth rate of r = 0.0 (or, equivalently, λ = 1.0). 

To begin this analysis, we started with population-specific baseline models, and then constructed a suite 

of additional scenarios with different combinations of values for initial population size, drought frequency 

and for adult female mortality – the parameter identified as highly sensitive in our earlier analysis. All 

other model input parameters were held at their baseline values. The range of initial population size 

values was bounded roughly by the current size of a given population and a value of at least 50% of the 

estimated carrying capacity. We elected to evaluate alternative drought frequency estimates of 5% or 10% 

per year as there is some uncertainty in the true value of this parameter. We used these models to first 

identify the lowest levels of annual adult female mortality necessary to maintain positive long-term 

population growth. The results of this analysis are shown in Figure 2.

A comparison of mean stochastic growth rates as a function of drought frequency shows that, not 

surprisingly, growth rates decline when severe drought occurs more frequently. Moreover, the 

consequences of more frequent drought are more severe when adult female mortality increases, 

demonstrating a type of synergistic interaction between these two processes. We also see that, across all 

existing pronghorn populations, mean stochastic growth rate declines rather strongly as adult female 

mortality increases. Again this is not surprising, especially given the previously observed sensitivity of 

these models to small changes in this mortality parameter. 

If we adopt a conservative approach to our risk analysis by focusing on those models featuring the 

relatively higher 10% drought frequency (right column of Figure 2), we can identify a correspondingly 

conservative threshold value for adult female mortality that is associated at least implicitly with a high 

probability of long-term population persistence. Under the conditions assessed in these models, both the 

Cabeza Prieta and Kofa populations demonstrate long-term positive mean growth when the annual adult 

female mortality rate is no greater than 16%. [Remember that this analysis assumes no linkage between 

the Cabeza Prieta pen and wild population.] Note that the Kofa surface shows a higher sensitivity to 

higher levels of mortality than Cabeza Prieta. This is due to the fact that we included smaller initial 

population size values for the Kofa population – as low as 50 animals – since the current abundance there 

is considerably smaller than its counterpart at Cabeza Prieta. 

The two populations in Mexico show a more restricted range of mortality values that are associated with 

long-term positive population growth. At 10% drought frequency, positive growth in Pinacate occurs 

when adult female mortality does not exceed approximately 15%, while positive growth in Quitovac is 

possible only when annual adult female mortality does not exceed 14%. These more restrictive conditions 

stem for our assumption that both these population suffer more from a severe drought than those 

populations farther to the north.

Taken together, these results suggest that a common value of 15% annual adult female mortality is a 

reasonable threshold to use when assessing population abundance targets as recovery criteria. It is clear, 

however, that this threshold does not satisfy the conditions necessary for positive population growth in 

the Quitovac population – and arguably also fails to satisfy the required conditions in the Pinacate 
303

population. The applicability of this threshold mortality is highly dependent on the frequency of drought

used in the risk analysis – a parameter that is not known with confidence. All in all, it is recognized that 

for this threshold to apply to Sonoran pronghorn populations in Mexico, more intensive drought 

management may be required to reduce its demographic impacts.
304

Figure 2. Stochastic growth rate for the four wild populations of Sonoran pronghorn currently in the United 

States and Mexico. The surfaces show growth rate as a function of both initial population abundance and 

annual mean adult female mortality, under conditions of relatively lower (left column) or higher (right column) 

frequency of a drought catastrophe. Gray horizontal plane identifies the region where long-term mean 

stochastic growth rate is 0.0 A, Cabeza Prieta; B, Kofa; C, Pinacate; D, Quitovac. See text for more 

information on model structure.
305

With this information on growth rate thresholds in place, we can then evaluate the extinction risk 

displayed by our models across the ranges of both initial population sizes and adult female mortality 

presented previously. These data are presented in Figure 3. It is important to note in these analyses that 

the initial population size represents the abundance only at the beginning of the simulation, and that each 

of these populations can grow to their corresponding carrying capacity values as governed by the

underlying growth rate – itself a function of the model input parameters and, perhaps most importantly, 

the adult female mortality rate. Therefore, the initial abundance values are not to be taken as a long-term 

abundance value but only a starting point for the simulations. 

In general, we see that the risk of extinction for all four populations increases with greater drought 

frequency, higher adult female mortality, and with smaller initial population sizes. Looking at the model 

results in more detail, we see that the Cabeza Prieta models show extinction risks that fall below the 

identified 10% threshold for all combinations of initial abundance and adult female mortality. This means 

that, for example, if the population begins the simulation comprised of 150 individuals – much like the 

Cabeza Prieta population in 2012 – and if adult female mortality is approximately 15% annually, the 

population will be able to grow towards its ecological carrying capacity and be buffered against 

extinction, even when drought is thought to occur more frequently (right-hand column of Figure 3). As 

adult female mortality increases, the underlying population growth rate for the Cabeza Prieta population 

will decline and could even become negative which will lead to an associated increase the risk of 

extinction. However, because of the relatively large initial abundances used in this analysis, the 

population shows relatively lower extinction risk over the 50 years of the simulation.

The extinction risk surface for the Kofa population shows some important differences in the region of low 

initial population abundance. This is because we initiated some Kofa population simulations with just 50 

individuals since the actual current abundance is just 10-20 animals. This analysis shows us that, even if 

the carrying capacity for the Kofa habitat is large, a relatively small population in the early stages of 

establishment in the wild may still be relatively unstable demographically and therefore more prone to 

extinction – even at moderate levels of adult female mortality. At these moderate mortality rates, this risk 

drops dramatically to near 0.0 as the initial population size increases to 100 – 150 individuals.

In keeping with the results we saw for the stochastic growth rate analysis presented in Figure 2, the two 

populations in Mexico demonstrate considerably higher risks of extinction under a greater range of 

demographic characteristics. The Pinacate population shows consistently higher extinction risks across 

nearly the full range of conditions modeled in this analysis. An important factor in understanding these 

results is the relatively restricted carrying capacity of this habitat, which restricts the long-term population 

abundance. This is particularly important when also considering our assumption of relatively greater 

sensitivity of this population to the detrimental effects of severe drought in the absence of intensive 

population management to mitigate its effects. Under the range of conditions evaluated here, the Pinacate 

population shows acceptable levels of extinction risk with an initial population size of no less than 100 

individuals.

The extinction risk surface for the Quitovac population is qualitatively similar to that for the Cabeza 

Prieta population, but the actual risk values are considerably higher because of the drought sensitivity 

defining these models. While extinction probabilities approach 30% for the highest adult female mortality 

values, our threshold rate of 15% leads to extinction risks that fall below the 10% viability threshold for 

all initial population sizes – although the smallest initial abundance of 150 individuals confers a risk of 

nearly 5% over the timeframe of the simulation. Once again, the presumed severe impact of drought in 

these southern populations means comparatively larger estimates of long-term population abundance 

required to achieve the desired level of viability.
306

Figure 3. Extinction risk over the 50-year simulation timeframe for the four wild populations of Sonoran 

pronghorn currently in the United States and Mexico. The surfaces show extinction risk as a function of both 

initial population abundance and annual mean adult female mortality, under conditions of relatively lower (left 

column) or higher (right column) frequency of a drought catastrophe. Gray horizontal plane identifies the 10% 

risk threshold identified as minimal conditions for population viability. A, Cabeza Prieta; B, Kofa; C, Pinacate; 

D, Quitovac. See text for more information on model structure.
307

From this demographic analysis, and given the assumption that a management strategy is in place to 

maintain average adult female mortality at levels that would support population growth, it is possible to 

derive minimum pronghorn population abundance estimates that confer long-term demographic stability 

and can therefore be used as preliminary population recovery criteria, in accordance with the Recovery 

Team definition of population viability. Abundance estimates for the Mexico populations require 

additional comment. The Pinacate estimate may appear relatively low in comparison to other populations 

and thus may be interpreted as indicative of relatively greater population stability. This is not the case; the 

target abundance for this population will likely be constrained by the habitat carrying capacity. 

Consequently, the lower amount of habitat available to the Pinacate population may require more 

dedicated management activity to maintain high levels of long-term population stability. Similarly, a large 

abundance estimate for Quitovac would reflect that population’s comparatively higher levels of 

instability, based on the expert judgment of species experts participating in this analysis and the 

preliminary observations of strong declines in pronghorn abundance over the past decade. 

The model output used to create Figures 2 and 3 are presented in Appendix I.

Additional Notes on Model Structure

Two issues are of particular importance in our discussions of the results presented here. Firstly, it is 

important to remember that despite considerable effort directed at better understanding Sonoran 

pronghorn population abundance and demography, the models described here are based on knowledge 

that remains incomplete. This is especially true for the Pinacate and Quitovac populations in Mexico, for 

which few relevant population-level studies have been initiated. Consequently, it may be prudent to adopt 

a conservative and precautionary approach to assigning recovery criteria for these populations in the face 

of considerable uncertainty. This approach may take the form of adding a buffer to abundance targets, 

perhaps as a proportion of the minimum abundance estimates derived from the simulation modeling 

exercise.

Secondly, the issue of climate change may be of special importance when trying to understand the future 

dynamics of desert wildlife populations. For example, a recent study on sensitivity of various species in 

Arizona to climate change (Bagne and Finch 2012) concludes that Sonoran pronghorn may be among the 

most vulnerable species to the detrimental impact of climate change. Early efforts in this PVA project 

(not reported here) have attempted to explore the potential mechanisms by which climate change in the 

southwestern United States and northern Mexico may impact Sonoran pronghorn population demography. 

While speculative, the analyses provide a framework within which hypotheses can be formulated and 

tested, thereby possibly helping to guide species management within a critically important adaptive 

framework. Additionally, consideration of the future destabilizing impacts of large-scale ecological 

processes such as climate change may prompt the species Recovery Team to further buffer recovery 

criteria abundance estimates. Future work on this issue, in both research and management contexts, may 

be beneficial to developing more effective long-term Sonoran pronghorn conservation strategies.
308

References

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Beissinger, S. and D. McCullough (eds.). 2002. Population Viability Analysis. University of Chicago Press, 

Chicago.

Bright, J.L,, and J.J. Hervert. 2005. Adult and fawn mortality of Sonoran pronghorn. Wildlife Society Bulletin 33:43-

50.

Bright, J.L., and J.J. Hervert. 2011. Sonoran Pronghorn Aerial Survey Summary: 2006 – 2010. Nongame and 

Endangered Wildlife Program Technical Report 263. Arizona Game and Fish Department, Phoenix, Arizona.

Ellner, S.P., J. Fieberg, D. Ludwig, and C. Wilcox. 2002. Precision in population viability analysis. Conservation 

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Lacy, R.C. 2000. Structure of the VORTEX simulation model for population viability analysis. Ecological Bulletins

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Miller, P.S., and R.C. Lacy. 2005. VORTEX: A Stochastic Simulation of the Extinction Process. Version 9.50 User’s 

Manual. IUCN/SSC Conservation Breeding Specialist Group, Apple Valley, MN.

Mills, L.S., D.F. Doak, and M.J. Wisdom. 1999. Reliability of conservation actions based on elasticity analysis of 

matrix models. Conservation Biology 13:815-829.

Ralls, K., J.D. Ballou, and A. Templeton. 1988. Estimates of lethal equivalents and the cost of inbreeding in 

mammals. Conservation Biology 2:185-193.

Reed, J.M., L.S. Mills, J.B. Dunning Jr., E.S. Menges, K.S. McKelvey, R. Frye, S.R. Beissinger, M.-C. Anstett, and 

P.S. Miller. 2002. Emerging issues in population viability analysis. Conservation Biology 16:7-19.
309

Appendices

Appendix A. Additional Drought Simulation Model Analysis

After completing the original PVA report in February 2014, a request was made to further investigate the 

impact of drought on Sonoran pronghorn population dynamics. Specifically, the team wanted to look at 

the impact of drought that was more frequent than the events originally modeled. To satisfy this request, a 

third set of drought analysis models were created with the frequency of drought (defined here as 

probability of occurrence in a given year) increased from the original values of 5% and 10% per year to 

15% per year. This frequency is more in line with recent observations of drought in the region of existing 

Sonoran pronghorn habitat, where such severe rainfall deficit events have occurred about once every 6 – 7 

years since 1992. 

All new models were constructed in a manner identical to the original models described in this report, 

with the exception of changing the probability of drought to 15% per year for each of the four populations 

studied in this analysis. The impact of drought in each specific population was not altered.

As expected, an increase in the frequency of drought reduces mean stochastic growth rate (Figure A1; 

Tables A1 – A4) in all scenarios. Under the assumption of this higher drought frequency, the Cabeza 

Prieta population shows a positive mean population growth rate when mean annual adult female mortality 

is no greater than about 16%. Similarly, the Kofa population shows a positive growth rate when adult 

female mortality does not exceed 15-16%, with the greatest sensitivity to mortality seen at the lowest 

initial population sizes. In contrast to the US populations, the two Mexico populations show significantly 

lower growth rates at higher drought frequencies. The Pinacate population shows positive mean annual 

growth rates only at the lowest mortality rates tested here, at 12-13%, while the Quitovac population 

shows negative mean growth rates at all tested combinations of initial population size and mean annual 

adult female mortality. These results are driven in large part by the assumption of greater drought impact 

in these two populations.

In a manner similar to that seen for population growth, an increase in drought frequency also increases the 

risk of population extinction in all scenarios (Figure A2; Tables A5 – A8). The Pinacate and Quitovac 

populations in Mexico show the greatest increase in risk, again largely due to the assumption of a greater 

impact of drought in these areas that see relatively lower levels of active habitat and population 

management compared to their counterpart populations in the United States. 
310

Figure A1. Mean stochastic growth rate over the 50-year simulation timeframe for the four wild populations of 

Sonoran pronghorn currently in the United States and Mexico. The surfaces show growth rate as a function of 

both initial population abundance and annual mean adult female mortality, under alternative assumptions of 

drought frequency (probability of occurrence: 5% (left column), 10% (middle column) or 15% (right column). 

Gray horizontal plane identifies the region where long-term mean stochastic growth rate is 0.0. Top row (A), 

Cabeza Prieta; second row (B), Kofa; third row (C), Pinacate; bottom row (D), Quitovac. See text for more 

information on model structure.
311

Figure A2. Extinction risk over the 50-year simulation timeframe for the four wild populations of Sonoran 

pronghorn currently in the United States and Mexico. The surfaces show extinction risk as a function of both 

initial population abundance and annual mean adult female mortality, under alternative assumptions of drought 

frequency (probability of occurrence: 5% (left column), 10% (middle column) or 15% (right column). Gray 

horizontal plane identifies the region where long-term mean stochastic growth rate is 0.0. Top row (A), Cabeza 

Prieta; second row (B), Kofa; third row (C), Pinacate; bottom row (D), Quitovac. See text for more information 

on model structure.
312

Table A1a. Mean stochastic population growth rates for a simulated Cabeza Prieta Sonoran pronghorn 

population with the assumption of a 5% frequency of drought. Each growth rate corresponds to a scenario 

defined by a specific value for the initial population size (left-hand column) and the mean annual adult female 

mortality rate (column headings). See report text for additional information on model construction and input 

parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.055 0.048 0.040 0.032 0.025 0.016 0.008 0.000 -0.011

200 0.056 0.049 0.042 0.035 0.025 0.019 0.009 0.001 -0.008

250 0.057 0.049 0.042 0.035 0.026 0.019 0.011 0.002 -0.005

300 0.058 0.049 0.043 0.034 0.027 0.019 0.011 0.003 -0.004

350 0.056 0.049 0.043 0.034 0.027 0.019 0.013 0.003 -0.004

Table A1b. Mean stochastic population growth rates for a simulated Cabeza Prieta Sonoran pronghorn 

population with the assumption of a 10% frequency of drought. Each growth rate corresponds to a scenario 

defined by a specific value for the initial population size (left-hand column) and the mean annual adult female 

mortality rate (column headings). See report text for additional information on model construction and input 

parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.046 0.038 0.030 0.022 0.014 0.005 -0.004 -0.013 -0.021

200 0.047 0.039 0.031 0.025 0.016 0.008 -0.001 -0.008 -0.019

250 0.047 0.040 0.031 0.025 0.017 0.009 0.002 -0.007 -0.016

300 0.048 0.041 0.032 0.025 0.019 0.009 0.000 -0.007 -0.016

350 0.047 0.040 0.033 0.025 0.019 0.010 0.004 -0.007 -0.016

Table A1c. Mean stochastic population growth rates for a simulated Cabeza Prieta Sonoran pronghorn 

population with the assumption of a 15% frequency of drought. Each growth rate corresponds to a scenario 

defined by a specific value for the initial population size (left-hand column) and the mean annual adult female 

mortality rate (column headings). See report text for additional information on model construction and input 

parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.035 0.028 0.019 0.012 0.004 -0.007 -0.015 -0.024 -0.032

200 0.037 0.029 0.021 0.013 0.005 -0.004 -0.011 -0.020 -0.030

250 0.038 0.029 0.022 0.015 0.005 -0.002 -0.01 -0.018 -0.029

300 0.039 0.031 0.024 0.015 0.007 0.000 -0.007 -0.017 -0.026

350 0.038 0.031 0.024 0.016 0.008 0.000 -0.009 -0.016 -0.026
313

Table A2a. Mean stochastic population growth rates for a simulated Kofa Sonoran pronghorn population with the 

assumption of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.047 0.040 0.030 0.020 0.012 0.001 -0.008 -0.017 -0.025

100 0.053 0.046 0.038 0.031 0.021 0.013 0.003 -0.006 -0.016

150 0.057 0.048 0.042 0.031 0.025 0.017 0.007 -0.002 -0.011

200 0.057 0.050 0.042 0.034 0.027 0.018 0.011 0.002 -0.008

250 0.058 0.050 0.043 0.035 0.027 0.019 0.011 0.002 -0.005

300 0.059 0.050 0.043 0.037 0.028 0.020 0.011 0.005 -0.004

350 0.058 0.053 0.043 0.036 0.027 0.021 0.013 0.005 -0.003

Table A2b. Mean stochastic population growth rates for a simulated Kofa Sonoran pronghorn population with the 

assumption of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.036 0.028 0.018 0.010 -0.001 -0.010 -0.020 -0.028 -0.038

100 0.044 0.036 0.028 0.018 0.010 0.002 -0.008 -0.018 -0.026

150 0.046 0.038 0.031 0.022 0.013 0.005 -0.003 -0.011 -0.022

200 0.047 0.040 0.032 0.025 0.018 0.008 -0.001 -0.008 -0.018

250 0.049 0.041 0.033 0.026 0.016 0.010 0.001 -0.008 -0.017

300 0.048 0.041 0.034 0.026 0.019 0.010 0.001 -0.006 -0.015

350 0.050 0.041 0.034 0.027 0.019 0.011 0.002 -0.006 -0.014

Table A2c. Mean stochastic population growth rates for a simulated Kofa Sonoran pronghorn population with the 

assumption of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.026 0.016 0.006 -0.001 -0.013 -0.021 -0.032 -0.040 -0.047

100 0.034 0.024 0.016 0.008 -0.001 -0.009 -0.019 -0.029 -0.040

150 0.036 0.028 0.019 0.013 0.004 -0.005 -0.015 -0.025 -0.033

200 0.037 0.030 0.022 0.015 0.006 -0.002 -0.013 -0.021 -0.027

250 0.039 0.030 0.023 0.016 0.006 -0.002 -0.010 -0.018 -0.027

300 0.039 0.031 0.024 0.016 0.007 0.000 -0.008 -0.017 -0.024

350 0.039 0.031 0.024 0.017 0.009 0.002 -0.008 -0.016 -0.024
314

Table A3a. Mean stochastic population growth rates for a simulated Pinacate Sonoran pronghorn population 

with the assumption of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.040 0.032 0.023 0.013 0.004 -0.005 -0.016 -0.022 -0.034

100 0.045 0.037 0.030 0.022 0.011 0.003 -0.004 -0.015 -0.022

150 0.046 0.038 0.031 0.023 0.015 0.007 0.000 -0.008 -0.021

Table A3b. Mean stochastic population growth rates for a simulated Pinacate Sonoran pronghorn population 

with the assumption of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.025 0.016 0.005 -0.002 -0.014 -0.022 -0.032 -0.040 -0.020

100 0.030 0.022 0.013 0.005 -0.004 -0.012 -0.021 -0.032 -0.041

150 0.030 0.023 0.015 0.007 -0.003 -0.010 -0.020 -0.029 -0.037

Table A3c. Mean stochastic population growth rates for a simulated Pinacate Sonoran pronghorn population 

with the assumption of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.006 -0.003 -0.012 -0.022 -0.029 -0.3037 -0.047 -0.054 -0.060

100 0.014 0.005 -0.004 -0.013 -0.021 -0.031 -0.038 -0.047 -0.055

150 0.015 0.007 0.000 -0.010 -0.019 -0.028 -0.036 -0.046 -0.053
315

Table A4a. Mean stochastic population growth rates for a simulated Quitovac Sonoran pronghorn population 

with the assumption of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.043 0.035 0.027 0.020 0.010 0.001 -0.007 -0.016 -0.024

200 0.043 0.036 0.029 0.021 0.014 0.006 0.004 -0.013 -0.021

250 0.044 0.038 0.031 0.021 0.014 0.007 -0.003 -0.012 -0.021

300 0.046 0.039 0.031 0.022 0.015 0.006 -0.003 -0.010 -0.018

350 0.045 0.038 0.031 0.022 0.016 0.008 -0.002 -0.010 -0.018

Table A4b. Mean stochastic population growth rates for a simulated Quitovac Sonoran pronghorn population 

with the assumption of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.020 0.010 0.001 -0.006 -0.015 -0.023 -0.032 -0.040 -0.05

200 0.020 0.012 0.004 -0.005 -0.012 -0.019 -0.029 -0.038 -0.048

250 0.023 0.016 0.006 -0.001 -0.010 -0.019 -0.028 -0.035 -0.044

300 0.023 0.014 0.006 0.000 -0.009 -0.018 -0.027 -0.036 -0.044

350 0.023 0.016 0.007 -0.001 -0.008 -0.017 -0.025 -0.033 -0.024

Table A4c. Mean stochastic population growth rates for a simulated Quitovac Sonoran pronghorn population 

with the assumption of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a 

specific value for the initial population size (left-hand column) and the mean annual adult female mortality rate 

(column headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 -0.007 -0.015 -0.026 -0.030 -0.042 -0.046 -0.057 -0.066 -0.074

200 -0.003 -0.010 -0.019 -0.029 -0.035 -0.047 -0.0536 -0.062 -0.070

250 -0.002 -0.009 -0.018 -0.026 -0.037 -0.043 -0.052 -0.063 -0.069

300 0.000 -0.010 -0.016 -0.025 -0.034 -0.043 -0.050 -0.062 -0.069

350 -0.002 -0.009 -0.014 -0.024 -0.032 -0.043 -0.050 -0.060 -0.068
316

Table A5a. Extinction probabilities for a simulated Cabeza Prieta Sonoran pronghorn population with the 

assumption of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.000 0.000 0.000 0.000 0.000 0.000 0.004 0.009 0.024

200 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.007 0.012

250 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003 0.002

300 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002

350 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003

Table A5b. Extinction probabilities for a simulated Cabeza Prieta Sonoran pronghorn population with the 

assumption of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). See report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.000 0.000 0.000 0.001 0.008 0.013 0.014 0.032 0.083

200 0.000 0.000 0.000 0.000 0.000 0.003 0.003 0.013 0.038

250 0.000 0.000 0.000 0.000 0.000 0.000 0.003 0.009 0.021

300 0.000 0.000 0.000 0.000 0.000 0.000 0.006 0.002 0.008

350 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002 0.006

Table A5c. Extinction probabilities for a simulated Cabeza Prieta Sonoran pronghorn population with the 

assumption of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a specific 

value for the initial population size (left-hand column) and the mean annual adult female mortality rate (column 

headings). Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report 

text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.000 0.000 0.002 0.006 0.002 0.023 0.056 0.077 0.138

200 0.000 0.000 0.000 0.001 0.001 0.005 0.017 0.031 0.074

250 0.000 0.000 0.000 0.000 0.002 0.006 0.008 0.026 0.048

300 0.000 0.000 0.000 0.000 0.000 0.005 0.008 0.011 0.027

350 0.000 0.000 0.001 0.000 0.000 0.000 0.005 0.007 0.018
317

Table A6a. Extinction probabilities for a simulated Kofa Sonoran pronghorn population with the assumption of a 

5% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the initial 

population size (left-hand column) and the mean annual adult female mortality rate (column headings). Numbers 

in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for additional 

information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.005 0.004 0.013 0.034 0.061 0.093 0.148 0.260 0.279

100 0.000 0.002 0.000 0.001 0.004 0.007 0.024 0.053 0.091

150 0.000 0.000 0.000 0.000 0.000 0.002 0.009 0.012 0.025

200 0.000 0.000 0.000 0.000 0.000 0.001 0.004 0.002 0.011

250 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.002

300 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.005

350 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003

Table A6b. Extinction probabilities for a simulated Kofa Sonoran pronghorn population with the assumption of a 

10% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the initial 

population size (left-hand column) and the mean annual adult female mortality rate (column headings). Numbers 

in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for additional 

information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.016 0.021 0.050 0.070 0.117 0.159 0.250 0.335 0.428

100 0.000 0.001 0.004 0.009 0.022 0.024 0.062 0.099 0.131

150 0.000 0.000 0.000 0.000 0.009 0.008 0.013 0.033 0.070

200 0.000 0.000 0.001 0.000 0.002 0.001 0.009 0.014 0.029

250 0.000 0.000 0.000 0.000 0.002 0.001 0.004 0.006 0.008

300 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.016

350 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.001 0.005

Table A6c. Extinction probabilities for a simulated Kofa Sonoran pronghorn population with the assumption of a 

15% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the initial 

population size (left-hand column) and the mean annual adult female mortality rate (column headings). Numbers 

in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for additional 

information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.022 0.047 0.071 0.123 0.204 0.270 0.373 0.468 0.554

100 0.003 0.002 0.007 0.014 0.048 0.053 0.107 0.172 0.258

150 0.001 0.001 0.002 0.008 0.007 0.024 0.047 0.085 0.135

200 0.001 0.000 0.001 0.000 0.008 0.006 0.027 0.040 0.062

250 0.000 0.000 0.000 0.001 0.002 0.002 0.010 0.019 0.044

300 0.001 0.000 0.000 0.000 0.000 0.002 0.006 0.011 0.026

350 0.000 0.000 0.000 0.000 0.001 0.001 0.003 0.002 0.013
318

Table A7a. Extinction probabilities for a simulated Pinacate Sonoran pronghorn population with the assumption 

of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). 

Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for 

additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.008 0.019 0.031 0.051 0.093 0.131 0.218 0.275 0.389

100 0.001 0.003 0.003 0.005 0.005 0.026 0.043 0.091 0.117

150 0.000 0.000 0.000 0.003 0.003 0.020 0.021 0.033 0.084

Table A7b. Extinction probabilities for a simulated Pinacate Sonoran pronghorn population with the assumption 

of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). 

Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for 

additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.025 0.057 0.092 0.119 0.205 0.288 0.361 0.475 0.577

100 0.004 0.009 0.014 0.023 0.067 0.094 0.120 0.120 0.301

150 0.003 0.007 0.006 0.015 0.031 0.047 0.082 0.082 0.196

Table A7c. Extinction probabilities for a simulated Pinacate Sonoran pronghorn population with the assumption 

of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). 

Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for 

additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

50 0.109 0.137 0.191 0.273 0.350 0.446 0.556 0.637 0.707

100 0.016 0.037 0.064 0.100 0.143 0.224 0.271 0.361 0.474

150 0.004 0.021 0.031 0.061 0.092 0.148 0.199 0.300 0.373
319

Table A8a. Extinction probabilities for a simulated Quitovac Sonoran pronghorn population with the assumption 

of a 5% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). See 

report text for additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.001 0.000 0.001 0.004 0.010 0.024 0.034 0.063 0.089

200 0.001 0.000 0.002 0.001 0.008 0.010 0.011 0.047 0.058

250 0.000 0.000 0.000 0.000 0.001 0.003 0.016 0.023 0.051

300 0.000 0.001 0.000 0.000 0.001 0.003 0.005 0.010 0.021

350 0.000 0.000 0.001 0.002 0.002 0.003 0.007 0.009 0.022

Table A8b. Extinction probabilities for a simulated Quitovac Sonoran pronghorn population with the assumption 

of a 10% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). 

Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for 

additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.013 0.017 0.032 0.049 0.081 0.106 0.165 0.227 0.316

200 0.007 0.013 0.020 0.028 0.037 0.058 0.110 0.161 0.236

250 0.003 0.005 0.008 0.015 0.019 0.049 0.085 0.116 0.175

300 0.003 0.001 0.006 0.007 0.018 0.031 0.069 0.091 0.150

350 0.001 0.000 0.003 0.009 0.014 0.028 0.047 0.063 0.108

Table A8c. Extinction probabilities for a simulated Quitovac Sonoran pronghorn population with the assumption 

of a 15% frequency of drought. Each growth rate corresponds to a scenario defined by a specific value for the 

initial population size (left-hand column) and the mean annual adult female mortality rate (column headings). 

Numbers in red denote growth rates that exceed the identified extinction threshold of 0.10. See report text for 

additional information on model construction and input parameterization.

Adult Female Mortality Rate (%)

N0 12 13 14 15 16 17 18 19 20

150 0.071 0.092 0.145 0.168 0.274 0.291 0.414 0.506 0.597

200 0.034 0.061 0.078 0.124 0.169 0.236 0.298 0.385 0.474

250 0.017 0.029 0.066 0.092 0.150 0.177 0.254 0.364 0.389

300 0.019 0.030 0.038 0.059 0.091 0.136 0.197 0.304 0.352

350 0.010 0.019 0.031 0.045 0.080 0.135 0.161 0.251 0.324
320

Appendix E. Threats Indic ators For Delisting And Downlisting

The following list includes indicators of each threat to Sonoran pronghorn habitat quality 

referenced in Criteria #3. The list was developed by referencing the conceptual models 

(Appendix A) for threats and indirect threats. It does not include uncertain or minor threats (i.e. 

poaching and disease). It also does not include indices for threats which cannot be abated as part 

of Sonoran pronghorn recovery actions (threats caused by weather or climate change). The list 

also does not include indices for the threats of habitat loss or fragmentation (which are discussed 

separately in Criteria #2) or human disturbance (discussed separately in criteria #4). 

Threats Indicators:

1. Number or length of barriers to pronghorn, including fences, roads, railroads, and canals.

2. Number of annual canal-related incidences.

3. Distance between water sources.

4. Number of livestock, particularly in the Mexico Conservation Unit.

5. Area with livestock utilization rates that have negatively affected quality of Sonoran 

pronghorn forage.

6. Area with fire frequencies outside the natural range of variation.

7. Spread of invasive plants (area by species).

8. Extent (area) of native shrub invasions (e.g., Creosotebush).

9. Altered runoff patterns due to infrastructure such as roads and bridges (area or length).

10. Miles of new drag roads and undesignated vehicle routes.
321

Appendix F. Threats Tracking Table

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Listing Factor A: Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range 

Habitat loss All sources All 2 All of 2.1. Assess the quantity and quality of habitat.

All of 2.2. Protect and/or increase the amount of existing habitat rangewide.

All of 2.3. Prevent or minimize the loss of habitat to land use impacts.

All of 2.4. Implement environmental services, employment programs, rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

Mining Cabeza

Kofa

Sauceda

2 2.3.2.2. Work with authorities in the U.S. to prevent, minimize, and/or 

mitigate habitat loss or future detrimental land use changes.

Mining Quitovac 2 2.2.4.3. Work with La Herradura and Noche Buena mines to restore 

Sonoran pronghorn habitat.

2.3.1. Cooperate with La Herradura mine on their mining plan to prevent 

and minimize habitat loss.

2.3.2.1 Work with agencies and authorities (federal, state, municipal) to 

monitor, prevent, minimize, and/or mitigate habitat loss or future

detrimental land use changes in Mexico.

2.3.3. Monitor hectares (acres) of Sonoran pronghorn habitat lost and 

extent of habitat fragmentation caused by all land uses by land use type.
322

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Agriculture Pinacate 2 2.2.1.1. Expand Pinacate core area.

2.3.2.1. Work with agencies and authorities (federal, state, municipal) to 

monitor, prevent, minimize, and/or mitigate habitat loss or future land use 

changes in Mexico.

2.3.3. Monitor hectares (acres) of Sonoran pronghorn habitat lost and 

extent of habitat fragmentation caused by all land uses by land use type.

2.4. Implement environmental services, employment programs, and rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

Agriculture Quitovac 2 2.2.1.2. Create a protected reserve in the Quitovac Management Unit.

2.3.2.1. Work with agencies and authorities (federal, state, municipal) to 

monitor, prevent, minimize, and/or mitigate future land use changes in 

Mexico.

2.2.4.1. Identify and prioritize areas where restoration is needed. 

2.2.4.2. Restore and protect potential Sonoran pronghorn habitat that is 

highly degraded.

2.2.5. Promote the conservation and protection of ANPs and UMAs.

2.2.6. Ask existing UMAs to incorporate Sonoran pronghorn in their list of 

protected animals.

2.4. Implement environmental services, employment programs, and rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

Livestock grazing Pinacate 2 2.2.1.1. Expand Pinacate core area.

2.4. Implement environmental services, employment programs, and rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

Livestock grazing Quitovac 2 2.2.1.2. Create protected reserve(s) for Sonoran pronghorn in the Quitovac 

management unit.

2.2.1.3. Identify and designate priority conservation areas (Area Prioritaria 

para la Conservacion-CONANP/CONABIO) or State designation for the 

conservation of pronghorn.

2.4. Implement environmental services, employment programs, and rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

2.2.5. Promote the conservation and protection of ANPS and UMAS.
323

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

2.2.6. Ask existing UMAS to incorporate Sonoran pronghorn in their list 

of protected animals.

Renewable energy Kofa 2 2.2.2. Acquire more land for Sonoran pronghorn conservation in the U.S.

2.2.3. Protect, through appropriate laws, regulations, and policies, Sonoran 

pronghorn habitat in the U.S.

2.3.3. Monitor hectares (acres) of Sonoran pronghorn habitat lost and 

extent of Sonoran pronghorn habitat fragmentation caused by all land uses 

by land use type.

Habitat 

fragmentation

All sources All 2 All of 2.6. Protect and/or improve the connectivity of habitat.

2.3.3. Monitor hectares (acres) of Sonoran pronghorn habitat lost and 

extent of habitat fragmentation caused by all land uses by land use type.

2.4. Implement environmental services, employment programs, rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

Habitat conversion 

(caused by 

agriculture, mining, 

livestock grazing)

All 2 2.6.1.5. Protect corridors used for seasonal movements.

All of 2.6.3. Minimize current and avoid future Sonoran pronghorn habitat 

fragmentation. 

2.3.2. Work with agencies and authorities (federal, state, municipal) to 

monitor, prevent, minimize, and/or mitigate habitat loss or future 

detrimental land use changes.

Physical barriers 

(highways, fences, 

canals, railroads)

All 2 All of 2.6.1. Improve habitat connectivity where impeded by barriers. 

All of 2.6.2. Prevent creation and/or minimize impacts of new barriers. 

Human disturbance All 2,4 See actions associated with Human disturbance threat.

Reduced forage 

quality

All sources All 3 All of 2.7. Enhance forage quality and availability to support viable 

populations of Sonoran pronghorn range-wide.

2.4. Implement environmental services, employment programs, rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

2.5.8 Establish Best Management Practices (BMPs) for U.S. projects on 

BLM land, to minimize the impacts of projects on Sonoran pronghorn 

habitat quality.
324

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Invasive plant 

species

All 3 2.5.4. Avoid and minimize impacts on Sonoran pronghorn habitat quality 

from adjacent projects. 

2.5.3.2 Manage invasive non-native plant species.

Livestock grazing Quitovac

Pinacate

Kofa

Sauceda

3 All of 2.5.1. Limit livestock grazing where it impacts Sonoran pronghorn 

habitat.

All of 2.5.2. Reduce impacts of livestock grazing where it will occur.

2.5.3.1. Remove feral burros, goats, cattle, and horses.

Increased cover of 

creosote

All 3 No actions for this source.

Lack of pollination 

of forage species

All 3 No actions for this source.

Trails/routes 

(trampling/killing 

forage species)

Quitovac

Cabeza

2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran 

pronghorn habitat.

2.5.5. Minimize and mitigate impacts of border-related activity on Sonoran 

pronghorn habitat

Altered hydrology All 3 2.5.4. Avoid and minimize impacts on Sonoran pronghorn habitat quality 

from adjacent projects. 

2.5.5. Minimize and mitigate impacts of border-related activity on Sonoran 

pronghorn habitat.

2.5.6. Reduce the impacts of mines (e.g., La Herradura) on Sonoran 

pronghorn habitat quality.

2.5.7. Reduce the negative impacts of agriculture on Sonoran pronghorn 

habitat quality. 

2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran 

pronghorn habitat.

Erosion All 3 2.5.4. Avoid and minimize impacts on Sonoran pronghorn habitat quality 

from adjacent projects. 

2.5.5. Minimize and mitigate impacts of border-related activity on Sonoran 

pronghorn habitat.

2.5.6. Reduce the impacts of mines (e.g., La Herradura) on Sonoran 

pronghorn habitat quality.

2.5.7. Reduce the negative impacts of agriculture on Sonoan pronghorn 

habitat quality. 

2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran 

pronghorn habitat.
325

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Altered fire regimes All 3 No actions for this source. All of 2.7. Enhance forage quality and 

availability to support viable populations of Sonoran pronghorn rangewide addresses the stressor.

Extreme heat All 3 No actions for this source. All of 2.7. Enhance forage quality and 

availability to support viable populations of Sonoran pronghorn rangewide addresses the stressor.

Low annual rainfall All 3 No actions for this source. All of 2.7. Enhance forage quality and 

availability to support viable populations of Sonoran pronghorn rangewide addresses the stressor.

Increased frequency 

and severity of 

drought

All 3 No actions for this source. All of 2.7. Enhance forage quality and 

availability to support viable populations of Sonoran pronghorn rangewide addresses the stressor.

Altered habitat 

structure

All sources All 3 2.5. Maintain and improve the quality of existing habitat (including an 

appropriate mix of vegetation types) range-wide.

2.4. Implement environmental services, employment programs, rural 

development programs in priority conservation areas in Sonora, and limit 

and/or regulate activities and infrastructure that can threaten those areas.

2.3.2. Work with agencies and authorities (federal, state, municipal) to 

monitor, prevent, minimize, and/or mitigate future detrimental land use 

changes.

2.5.8 Establish Best Management Practices (BMPs) for U.S. projects on 

BLM land, to minimize the impacts of projects on Sonoran pronghorn 

habitat quality.

Altered fire regimes All 3 No actions for this source.

Renewable energy Kofa 3 No actions for this source.

Military operations Kofa

Sauceda

3 No actions for this source.
326

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Livestock grazing Quitovac

Pinacate

Kofa

Sauceda

3 All of 2.5.1. Limit livestock grazing where it impacts Sonoran pronghorn 

habitat.

All of 2.5.2. Reduce impacts of livestock grazing where it will occur.

2.5.3.1. Remove feral burros, goats, cattle, and horses.

Mining All 3 2.5.6 Reduce the impacts of mines (e.g., La Herradura) on Sonoran 

pronghorn habitat quality.

Off-highway 

vehicles

Quitovac 3 2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran 

pronghorn habitat.

All populations 3 No actions for this source

Illegal extraction Pinacate 3 No actions for this source.

Reduced access 

to water

Inadequate 

distribution

All 3 All of 2.8. Maintain and improve availability of and access to water (both 

natural and human-made) range-wide.

Physical barriers 

(highways, fences, 

canals, railroads)

All 3 All of 2.6.1. Improve habitat connectivity where impeded by barriers. 

All of 2.6.2. Prevent creation and/or minimize impacts of new barriers. 

Human disturbance 3, 4 See actions for human disturbance.

Reduced 

availability of 

water

All sources All 3 2.8. Maintain and improve availability of and access to water (both natural 

and human-made) range-wide.

Low annual rainfall All 3 2.8. Maintain and improve availability of and access to water (both natural 

and human-made) range-wide.

Increased frequency 

and severity of 

drought

All 3 2.8. Maintain and improve availability of and access to water (both natural 

and human-made) range-wide.

Altered runoff 

patterns

All 3 2.8. Maintain and improve availability of and access to water (both natural 

and human-made) range-wide.

2.5.1. Limit livestock grazing where it impacts Sonoran pronghorn habitat.

2.5.2. Reduce the impacts of livestock grazing where it will continue.

2.5.4. Avoid and minimize impacts on habitat quality from adjacent 

projects and activities.

2.5.5. Minimize and mitigate impacts of border-related activity on Sonoran 

pronghorn habitat.

2.5.9. Minimize impacts of off-road racing in Sonora on Sonoran 

pronghorn habitat.
327

Threat - stress Threat - source Population Recovery 

Criteria

Recovery Actions (from recovery action outline)

Historic drying of 

Gila and Sonoyta 

rivers

All 3 2.8. Maintain and improve availability of and access to water (both natural 

and human-made) range-wide.

Listing Factor B: Overutilization for Commercial, Recreational, Scientific, or Educational Purposes 

None

Listing Factor C: Disease or predation

Predation Forced use of 

densely vegetated 

areas due to 

increased 

drought/heat

All 3 No actions for this source.

All sources All 3 1.1.4. Reduce predation by native, feral, and domestic predators.
328

Disease All sources All 3 1.1.2.1. Vaccinate against Epizootic Hemorrhagic Disease and Blue 

Tongue.

1.1.2.2. Vaccinate against other diseases as vaccinations become available.

Livestock as 

carriers

Quitovac

Pinacate

Kofa

Sauceda

3 All of 2.5.1. Limit livestock grazing where it impacts Sonoran pronghorn 

habitat.

2.5.3.1. Remove feral burros, goats, cattle, and horses.

Lack of genetic 

diversity

Small population 

size; historic 

bottleneck

All 5 1.1.1. Maintain genetic diversity of Sonoran pronghorn.

Listing Factor D: Inadequacy of Existing Regulatory Mechanisms

None 6 NA

Listing Factor E: Other Natural or Manmade Factors Affecting Its Continued Existence

Human 

disturbance

Border activities All 4 All of 3.1. Minimize and mitigate the impact of border-related activities

Recreation All 4 All of 3.2. Minimize and mitigate the impact of recreational activities.

Military activities Cabeza

Sauceda

Kofa

4 All of 3.3. Minimize and mitigate the impact of military activities.

Land management 

activities

All 4 All of 3.4. Minimize and mitigate the impact of public land management 

activities.

Mining Quitovac

Kofa

4 All of 3.5. Minimize and mitigate the impact of mining activities.

Ranching Quitovac

Pinacate

Kofa

Sauceda

4 All of 3.6. Minimize and mitigate the impact of other activities.

Agriculture Quitovac 4 All of 3.6. Minimize and mitigate the impact of other activities.

High mortality 

rates

Drowning in canals Kofa

Cabeza

3 All of 1.1.5. Reduce mortality caused by canals.

Entanglement in 

fences

All 3 2.6.1.3. Remove or modify existing barriers and impediments to allow for 

Sonoran pronghorn passage (e.g., remove/modify fences, railroad tracks, 

roads, install overpasses). 
329

Vehicle collision All 3 2.6.1.3. Remove or modify existing barriers and impediments to allow for 

Sonoran pronghorn passage (e.g., remove/modify fences, railroad tracks, 

roads, install overpasses). 

Thermal stress All 3 No action for this source.

Poaching Quitovac 3 All of 1.1.3. Decrease poaching.

Capture -related 

mortality

All 3 1.2.1. Evaluate and modify as needed methods of captive breeding, 

handling, transport, and transplant.

Military activities Cabeza

Kofa

Sauceda

3 3.3.1. Continue to work with the military partners in the U.S. (BMGR

(MCAS Yuma and Luke Air Force Base), ARNG, YPG) to minimize the 

impact of military activities on Sonoran pronghorn.

Catastrophic or 

stochastic events

Lack of redundancy 

of populations

All 1 1.3. Establish new populations.

Small population 

sizes

All 1 1.2. Maintain current captive breeding program.

All Listing 

Factors

All All All 1 All of 4. Identify and address Sonoran pronghorn population monitoring 

needs.

1,2,3,4,5,6 All of 5. Identify and address priority research needs.

1,2,3,4,5,6 All of 6. Maintain existing and develop new partnerships.

1,2,3,4,5,6 All of 7. Secure adequate funding to implement recovery actions.

1,2,3,4,5,6 All of 8. Practice adaptive management.
330