U.S. Fish & Wildlife Service

Whooping Crane

(Grus americana)

Draft Revised

International Recovery Plan

January 2005
DRAFT Whooping Crane Recovery Plan 2005 

DISCLAIMER 

Recovery plans delineate reasonable actions believed necessary 

to recover and/or protect listed species. Plans are published 

by the Environment Canada in Canada and by the U.S. Fish and 

Wildlife Service in the United States, sometimes prepared with 

the assistance of recovery teams, contractors, State or 

Provincial Agencies, and others. Objectives will be attained 

and any necessary funds made available subject to budgetary 

constraints affecting the parties involved, as well as the need 

to address other priorities. Recovery plans do not necessarily 

represent the views nor the official position or approval of any 

individuals or agencies involved in the plan formulation, other 

than Environment Canada and United States Fish and Wildlife 

Service. They represent the official position of the agencies 

mentioned only after they have been signed as approved by 

appropriate personnel and posted on the public registry. 

Approved recovery plans are subject to modification as dictated 

by new findings, changes in species status, and the completion 

of recovery actions. 

LITERATURE CITATION 

The Literature Citation should read as follows: 

Canadian Wildlife Service and U.S. Fish and Wildlife Service. 

2005. Draft International recovery plan for the whooping crane. 

Ottawa: Recovery of Nationally Endangered Wildlife (RENEW), and 

U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 196pp. 

In the U.S., copies may be obtained on line: 

http://ecos.fws.gov/recovery_plan/pdf_files/ 

In Canada additional copies may be obtained from: 

Recovery Secretariat 

c/o Canadian Wildlife Service 

4th Floor PVM, 351 Joseph Blvd 

Hull, QC K1A 0H3 

Tel: 1-819-953-1410 

On Line: 

http://www.speciesatrisk.gc.ca/species/publications/plans/index_

e.cfm

 i
DRAFT Whooping Crane Recovery Plan 2005 

ACKNOWLEDGMENTS

The principal compilers of this document were Brian Johns and 

Tom Stehn, co-chairmen of the International Whooping Crane 

Recovery Team along with retired co-chairman Dr. James Lewis. 

Biologists who provided updated material and reviewed sections 

of the document include Dr. George Archibald, Doug Bergeson, Joe 

Duff, Dr. David Ellis, Marty Folk, Dr. George Gee, Wally Jobman, 

Ken Jones, Dwight Knapik, Claire Mirande, Steve Nesbitt, Debbie 

Nordstrom, Dr. Glenn Olsen, Dr. Mike Putnam, Scott Swengel, Dr. 

Richard Urbanek and Earl Wiltse. Stuart Leon and Wendy Brown 

provided initial agency review of the document for the United 

States Fish and Wildlife Service, and Mary Rothfels for Canadian 

Wildlife Service. The 5 Canadian and 5 U.S. members currently 

serving on the Recovery Team provided overall recovery 

objectives and strategies. Members in December, 2003 were Dr. 

George Archibald, Sandie Black DVM, Mark Bradley, Rick Espie, 

Dr. John French, Brian Johns, Deborah Johnson, Julie Langenberg 

VMD, Steve Nesbitt and Tom Stehn. 

 

 ii
DRAFT Whooping Crane Recovery Plan 2005 

TABLE OF CONTENTS

 Page 

DISCLAIMER/LITERATURE CITATION i 

ACKNOWLEDGMENTS ii 

TABLE OF CONTENTS iii 

LIST OF TABLES AND FIGURES vi 

GLOSSARY OF ACRONYMS viii 

PREFACE x 

EXECUTIVE SUMMARY xi 

 

I. BACKGROUND INFORMATION 1 

INTRODUCTION 1 

SPECIES INFORMATION 4 

Status 4 

Description 4 

Life Span 5 

Mortality – Documented Losses 5 

Breeding Ecology 6 

Migratory Behavior 8 

Winter Ecology 9 

Diet 9 

DISTRIBUTION 11 

Historical Distribution and Numbers 11 

Current Distribution and Abundance 18 

HABITAT REQUIREMENTS 21 

Breeding Habitat 21 

Migration Habitat 24 

 Wintering Habitat 25 

RATE OF POPULATION GROWTH 25 

THREATS AND REASONS FOR LISTING 27 

Human Settlement 27 

Freshwater Inflows 28 

Hunting 29 

Disturbance 30 

Disease/Parasites 30 

Predation 31 

Life History 32 

Food Availability/Sibling Aggression 32 

Severe Weather 33 

Loss of Genetic Diversity 33 

Climate Change 34 

Red Tide 34 

Chemical Spills 34 

Collisions with Power Lines and Fences 36 

Collisions with Aircraft 37 

Pesticides 37 

CONSERVATION MEASURES 38 

Critical Habitat 39 

RECOVERY TEAM 41 

 iii
DRAFT Whooping Crane Recovery Plan 2005 

INFORMATION NEEDS 41 

Survey Requirements 41 

Biological/Ecological Research Requirements 42 

Threat Clarification Research Requirements 42 

RECOMMENDED SCALE FOR RECOVERY ACTIONS 43 

ANTICIPATED CONFLICTS OR LOGISTICAL DIFFICULTIES 43 

POTENTIAL IMPACTS FOR OTHER SPECIES/ECOLOGICAL PROCESSES 43

II. RECOVERY 44 

STATUS REVIEW 44 

RECOVERY STRATEGY 44 

RECOVERY POTENTIAL AND RATIONALE 45 

RECOVERY GOAL 47 

DOWNLISTING RECOVERY OBJECTIVES AND CRITERIA 47 

Delisting Criteria 49 

2003 SARA RECOVERY OBJECTIVES 50 

SHORT TERM RECOVERY OBJECTIVES 50 

LONG TERM ACTIONS NEEDED 50 

NARRATIVE OUTLINE FOR RECOVERY ACTIONS TO ACHIEVE OBJECTIVES 52 

REDUCTION OR ALLEVIATION OF THREATS TO WHOOPING CRANES 

 THROUGH IMPLEMENTATION OF RECOVERY ACTIONS 66 

FUTURE CONSIDERATIONS 68

III. IMPLEMENTATION SCHEDULE 70 

LEAD ORGANIZATIONS RESPONSIBLE FOR SPECIES RECOVERY AND KEY 

CONTACTS 74 

CANADA/U.S. INTERNATIONAL RECOVERY TEAM MEMBERS 74 

 Contact Information 75 

OTHER CONTACTS 77 

PREPARED BY 78 

KEY LANDS ON WHICH SPECIES OCCURS AND ASSOCIATED CONTACTS 78 

DATE COMPLETED 78 

KEY REFERENCES 79 

APPENDICES 

APPENDIX A: MINIMUM VIABLE POPULATION AND GENETICS A-1 

Minimum Viable Population A-1 

Downlisting Based on MVP Criteria A-2 

Population Growth and Retention of Genetic Material A-2 

Loss of Genetic Diversity and Estimate of Relatedness A-3 

APPENDIX B: SOCIAL AND ECONOMIC CONSIDERATIONS B-1 

APPENDIX C: ACTIONS ALREADY COMPLETED OR UNDERWAY C-1 

Protection C-1 

Breeding Grounds Management and Research C-2 

Migration Monitoring C-9 

Migration Habitat Management and Research C-10 

Wintering Grounds Management and Research C-13 

Captive Propagation C-18 

Research and Propagation at PWRC C-19 

 iv
DRAFT Whooping Crane Recovery Plan 2005 

Propagation at ICF C-29 

Propagation at CZ C-35 

Cross-fostering, Translocation, and Guide-bird Studies C-37 

Reintroducing a Non-migratory Population in Florida C-44 

Research on Reintroducing Migratory Populations C-52 

Proposed Migratory Reintroductions C-53 

 v
DRAFT Whooping Crane Recovery Plan 2005 

LIST OF TABLES AND FIGURES 

Table 1. Whooping Crane peak winter numbers in North America, 

1938–2002. 16 

Table 2. Known number of nesting pairs, productivity, and 

distribution of eggs removed from Aransas Wood Buffalo 

Population, 1966-2002. C-4 

 

Table 3. Age of captive whooping cranes when they first produced 

eggs, Patuxent Wildlife Research Center, 1975-1993. 

 C-22 

Table 4. Size and productivity of the captive whooping crane 

flock at Patuxent Wildlife Research Center, 1975-2002. 

 C-24 

Table 5. Size and productivity of the captive whooping crane 

flock at International Crane Foundation, 1989-2002. 

 C-30 

Table 6. Hatching and fledging rates of AWBP eggs transferred to 

International Crane Foundation, 1990-1996. C-32 

Table 7. Size and productivity of the captive whooping crane 

flock at Calgary Zoo, 1992-2002. C-36 

Table 8. Eggs transplanted, hatched and chicks fledged at Grays 

Lake, 1975-1988. C-39 

Table 9. Number of birds released and surviving in the Florida 

nonmigratory population, 1993–2002. C-51 

Table 10. Number of birds released and surviving in the eastern 

population, 2001–2002. C-58 

Figure 1. Breeding and wintering areas, and migration pathway of 

the Aransas Wood Buffalo Population. 3 

Figure 2. The principal known breeding and wintering areas of 

the whooping crane (Grus americana) (adapted from Meine 

and Archibald 1996). 12 

Figure 3. Wintering area of the Aransas Wood Buffalo Population, 

Aransas National Wildlife Refuge and Critical Habitat 

boundary on the Gulf of Mexico coast of Texas. 19 

Figure 4. Breeding area of the Aransas Wood Buffalo Population, 

Wood Buffalo National Park. 22 

 vi
DRAFT Whooping Crane Recovery Plan 2005 

Figure 5. Whooping crane captive propagation, 1941-1979. C-20 

Figure 6. Summer and winter ranges and migration route of the 

reintroduced Rocky Mountain whooping crane population. 

 C-38 

Figure 7. The Florida peninsula, showing the primary range of 

the Florida non-migratory population. C-48 

Figure 8. Eastern United States whooping crane population 

summering and wintering areas and 2001 migration route. 

 C-55 

 vii
DRAFT Whooping Crane Recovery Plan 2005 

GLOSSARY OF ACRONYMS 

A Alberta 

ACRES Audubon Center for Research on Endangered Species 

AFLP Amplified Fragment Length Polymorphisms 

ANWR Aransas National Wildlife Refuge 

AWBP Aransas Wood Buffalo Population 

BR Bureau of Reclamation 

CCWHC Canadian Cooperative Wildlife Health Centre 

CG Coast Guard 

COSEWIC Committee on the Status of Endangered Wildlife in 

Canada 

CWS Canadian Wildlife Service 

CZ Calgary Zoo 

DVC Disseminated Visceral Coccidiosis

EEE Eastern Equine Encephalitis 

ES Ecological Services (USFWS) 

ESA United States Endangered Species Act 

FAA Federal Aviation Authority 

FCC Federal Communications Commission 

FERC Federal Energy Regulatory Commission 

FL Florida Fish and Wildlife Conservation Commission 

FP Florida Population 

GIS Geographical Information System 

GIWW Gulf Intracoastal Waterway 

ICF International Crane Foundation 

IFIM Instream Flow Incremental Methodology 

LE Law Enforcement (USFWS) 

M Manitoba 

MOU Memorandum of Understanding 

MVP Minimum Viable Population 

NAS National Audubon Society 

NEPA National Environmental Policy Act

NGO Non-Government Organization 

NWA National Wildlife Area 

NWHC National Wildlife Health Center (USGS) 

NWI National Wetland Inventory 

NWR National Wildlife Refuge 

OM Operation Migration 

PA Public Affairs (USFWS) 

PCA Parks Canada Agency 

PWRC Patuxent Wildlife Research Center (USGS) 

PRT Platte River Whooping Crane Habitat Maintenance Trust 

RMP Rocky Mountain Population 

RW Refuges and Wildlife (USFWS) 

S Saskatchewan 

SARA Canadian Species at Risk Act 

TC Transport Canada 

TNRCC Texas Natural Resources Conservation Commission 

 viii
DRAFT Whooping Crane Recovery Plan 2005 

TPWD Texas Parks and Wildlife Department 

USACE U. S. Army Corps of Engineers 

USFWS U. S. Fish and Wildlife Service 

USGS U. S. Geological Survey 

WBNP Wood Buffalo National Park 

WCCA Whooping Crane Conservation Association 

WCCMT Whooping Crane Captive Management Team 

WCEP Whooping Crane Eastern Partnership 

WCHAT Whooping Crane Health Advisory Team 

WCRT Whooping Crane Recovery Team 

WI Wisconsin Department of Natural Resources 

WNV West Nile Virus 

 ix
DRAFT Whooping Crane Recovery Plan 2005 

PREFACE 

The Whooping Crane Recovery Plan (Plan) was prepared under the 

authorities of the U.S. Endangered Species Act of 1973, as 

amended, the Canada Wildlife Act of 1974 and the Canadian 

Species at Risk Act of 2003. Decision-makers are provided with 

an orderly set of events that, if carried to successful 

completion, will change the status of this species from the 

Endangered to the Threatened level. The Plan describes 

management and research actions that are underway and proposes 

additional actions needed to assure the recovery of the whooping 

crane. Funding levels and time schedules are estimated, and 

priorities set for each management and research action. This 

revision of the Whooping Crane Recovery Plan describes recovery 

actions and costs required for the birds and habitat in both 

Canada and the United States. Part I covers basic biology of 

the species, historical and present distribution, habitat 

requirements, numbers and rate of growth, biological factors 

limiting the population, human threats, protective actions, and 

information needs. Part II states the recovery goals and a 

step-down outline of specific actions needed for recovery. Part 

III provides an implementation schedule for recovery and contact 

information. The appendices cover recovery actions already 

completed or currently underway. 

The recovery program for the whooping crane is an excellent 

example of international cooperation to save a species. 

Cooperative recovery actions of the 2 nations are outlined in a 

“Memorandum of Understanding On the Conservation of the Whooping 

Crane” approved in 1990 and updated at 5-year intervals. 

Development of this Recovery Plan by a joint Canada/U.S. 

Recovery Team is appropriate because conservation and management 

of the species in both countries is essential to the whooping 

crane’s recovery. 

Because it is an international document, the Plan has a unique 

format to satisfy the requirements of both Canada and the United 

States. This plan is lengthy because of the tremendous interest 

in the whooping crane, the large amount of knowledge already 

gained, and all the recovery actions that have already occurred 

and are needed. 

 x
DRAFT Whooping Crane Recovery Plan 2005 

EXECUTIVE SUMMARY 

Current Status and Distribution: In the United States, the 

whooping crane (Grus americana) was listed as Threatened with 

Extinction in 1967 and Endangered in 1970 – both listings were 

“grandfathered” into the Endangered Species Act of 1973. 

Critical Habitat was designated in 1978. In Canada, it was 

designated as Endangered in 1978; critical habitat is designated 

upon publication of the final recovery strategy on the SARA 

public registry. 

Whooping cranes occur only in North America. They currently 

exist in the wild at 3 locations and in captivity at 7 sites. 

The December, 2003 total wild population was estimated at 315. 

This includes: 194 individuals in the only self-sustaining 

Aransas-Wood Buffalo National Park Population (AWBP) that nests 

in Wood Buffalo National Park (WBNP) and adjacent areas in 

Canada and winters in coastal marshes in Texas; 85 captiveraised individuals released in an effort to establish a nonmigratory Florida Population (FP) in central Florida, and 36 

individuals introduced starting in 2001 in the eastern U.S. that 

migrate between Wisconsin and Florida. The last remaining bird 

in the reintroduced Rocky Mountain Population (RMP) died in the 

spring, 2002. The captive population contained 119 birds in 

December, 2003 with annual production from the Calgary Zoo (CZ), 

International Crane Foundation (ICF), Patuxent Wildlife Research 

Center (PWRC), and the San Antonio Zoo. The total population, 

wild and captive,in December, 2003 was 434. 

Habitat Requirements: The whooping crane breeds, migrates, 

winters and forages in a variety of habitats, including coastal 

marshes and estuaries, inland marshes, lakes, ponds, wet meadows 

and rivers, and agricultural fields. 

Reasons for Listing and Limiting Factors: Historic population 

declines resulted from habitat destruction, shooting, and 

displacement by activities of man. Current threats include 

limited genetics of the population, loss and degradation of 

migration stopover habitat, construction of additional power 

lines, degradation of coastal habitat and threat of chemical 

spills in Texas. 

Recovery Goal: The recovery goal is to establish multiple selfsustaining populations of whooping cranes in the wild in North 

America, allowing initially for reclassification to threatened 

status and, ultimately, removal from the List of Threatened and 

Endangered Species. Populations may be migratory or nonmigratory. 

 xi
DRAFT Whooping Crane Recovery Plan 2005 

Recovery Strategy: The wild whooping crane population is 

characterized by low numbers, slow reproductive potential, and 

limited genetic diversity. A stochastic, catastrophic event 

could eliminate the wild, self-sustaining Aransas-Wood Buffalo 

population. Therefore, the recovery strategy involves: 

protection and enhancement of the breeding, migration, and 

wintering habitat for the AWBP to allow the wild flock to grow 

and reach ecological and genetic stability; reintroduction and 

establishment of self-sustaining wild flocks geographically 

separate from the AWBP to ensure resilience to catastrophic 

events; and maintenance of a captive breeding flock to protect 

against extinction. Offspring from the captive breeding 

population will be released into the wild to establish these 

populations. Production by released birds and their offspring 

will ultimately result in self-sustaining wild populations. The 

continued growth of the Aransas-Wood Buffalo population, 

establishment of additional populations and maintenance of the 

captive flock will also address the loss of genetic diversity. 

RECOVERY OBJECTIVES AND CRITERIA: 

This plan sets forth 2 primary objectives and measurable 

criteria that will allow the species to be reclassified to 

threatened (downlisted). The numerical population criteria can 

only be achieved if threats to the species’ existence are 

sufficiently reduced or removed, i.e., the population criteria 

are a benchmark for threat reduction. 

Objective 1 – Establish and maintain wild self-sustaining 

populations of whooping cranes in the wild that are genetically 

stable and resilient to stochastic environmental events. 

Criterion 1 – Maintain and allow for a continued increase 

of the AWBP at a minimum of 40 productive pairs, and 

establish a minimum of 25 productive pairs in selfsustaining separate populations at each of 2 other discrete 

locations. A productive pair is defined as a pair that 

nests regularly and has fledged offspring. The two 

additional populations may be migratory or non-migratory. 

Population targets are 160 in the AWBP, and 100 each in the 

Florida non-migratory population and the eastern migratory 

population. All 3 populations must be self-sustaining for 

a decade at the designated levels before downlisting could 

occur. 

Alternative Criterion 1 - If a second and third wild 

population cannot become self-sustaining, then the AWBP 

must be self-sustaining and remain above 1,000 individuals 

 xii
DRAFT Whooping Crane Recovery Plan 2005 

(i.e. 250 productive pairs) for downlisting to occur. The 

Memorandum of Understanding on Conservation of Whooping 

Cranes, approved by Canadian and U.S. federal officials, 

recognizes a goal of 1,000 individuals in the AWBP 

population. These higher numbers are needed to ensure a 

better chance for survival because the AWBP currently has a 

very limited range and could be decimated by a catastrophic 

event. The target of 1,000 is reasonable for downlisting 

given the historical growth of the AWBP, its low 

probability of extinction (Mirande et al. 1993), and 

theoretical considerations of minimum population viability 

(Salwasser et al 1984).

Objective 2 – Maintain a genetically stable captive population 

to ensure against extinction of the species. 

Criterion 2 - Maintain 153 whooping cranes in captivity (21 

productive pairs). Genetic analysis suggests that that 

these numbers can maintain 90% of the genetic material of 

the species for 100 years (Jones and Lacy 2003). To 

achieve this, this Plan recommends having 50 captive 

breeder pairs of whooping cranes by 2010, including 15 

pairs at PWRC, 12 at ICF, 10 at CZ, 10 at ACRES, and 3 at 

the San Antonio Zoo. A breeder pair (as differentiated 

from a productive pair) is defined as a pair that breeds or 

is intended to breed in the future. Production from ICF, 

PWRC, and CZ will be the principal source of birds for 

release to the wild for reintroduced populations. However, 

sources of release birds should be based on the optimal 

genetic mix to ensure long-term population viability. 

Delisting Criteria 

Delisting criteria have not yet been established because the 

status and biology of the species dictate that considerable time 

is needed to reach downlisting goals. In addition, new threats 

are expected to rise and will have to be overcome before 

downlisting occurs. Additional information is also needed on 

the conservation biology of very small populations, including a 

determination of effective population size for whooping cranes 

to maintain genetic viability over the long-term, and on impacts 

of stochastic and catastrophic events on population survival.

Actions Needed: 

1. Continue to build the AWBP and protect and manage its habitat 

to minimize the probability that a catastrophic event will 

eradicate this population. 

 

 xiii
DRAFT Whooping Crane Recovery Plan 2005 

2. Attain breeder pair and productivity goals at 4 captive 

facilities in the United States and 1 in Canada to produce 

the birds required for reintroductions. Continue research to 

improve production of captive flocks. 

3. Establish 2 additional self-sustaining wild populations. 

Continue research to identify appropriate reintroduction 

sites and improve reintroduction techniques. Protect and 

manage habitat of reintroduced populations. 

4. Continue to use genetic information to determine Ne and revise 

criteria as warranted. 

5. Maintain an information/education program. 

Date of Recovery: The estimated time to achieve downlisting is 

the year 2035. At current rates of reintroduction it takes over 

10 years to build a population of more than 100 individuals. 

These individuals must then reach breeding age (3-5 years) and 

produce enough young to become self-sustaining for a decade to 

meet criteria for downlisting. This is expected to take a 

minimum of 32 years. New information gathered through recovery 

actions will be incorporated into additional population 

viability analysis as the population approaches its downlisting 

goals. Delisting criteria will be established at that time, and 

the overall recovery strategy and actions will be revised as 

appropriate. 

Total Estimated Cost of Recovery ($000’s):

The current budget expenditures needed annually for recovery 

approach $4 million (US). The cost through 2010 is estimated at 

$31,817,000 (US) and nearly $125 million (US) through 2035. 

 xiv
DRAFT Whooping Crane Recovery Plan 2005 

Total Estimated Cost of Recovery ($000’s):

 Year Action l Action 2 Action 3 Action 4 Action 5 Total 

2003 882 1705 1630 - 15 4232

2004 924 1585 1630 30 15 4184

2005 916 1585 1630 - 15 4146

2006 885 1215 1755 - 15 3870

2007 885 1205 1755 - 15 3860

2008 885 1205 1755 - 15 3860

2009 885 1175 1755 5 15 3835

2010 885 1175 1755 - 15 3830

2011 885 1150 1755 - 15 3805

2012 885 1150 1755 - 15 3805

2013 885 1120 1755 - 15 3775

2014 885 1120 1755 5 15 3780

2015 885 1095 1755 - 15 3750

2016 885 1095 1755 - 15 3750

2017 885 1070 1750 - 15 3720

2018 885 1070 1750 - 15 3720

2019 885 1045 1750 5 15 3700

2020 885 1045 1750 - 15 3695

2021 885 1045 1750 - 15 3695

2022 885 1045 1750 - 15 3695

2023 885 1045 1750 - 15 3695

2024 885 1045 1750 5 15 3700

2025 885 1045 1750 - 15 3695

2026 885 1045 1750 - 15 3695

2027 885 1045 1750 - 15 3695

2028 885 1045 1750 - 15 3695

2029 885 1045 1750 5 15 3700

2030 885 1045 1750 - 15 3695

2031 885 1045 1750 - 15 3695

2032 885 1045 1750 - 15 3695

2033 885 1045 1750 - 15 3695

2034 885 1045 1750 5 15 3700

2035 885 1045 1750 - 15 3695

Cost until 2010: $31,817,000 (US) 

Cost until 2020: $69,317,000 (US) 

Cost until 2035: $124,757,000 (US) 

 xv
DRAFT Whooping Crane Recovery Plan 2005 

PART I. BACKGROUND INFORMATION 

 

INTRODUCTION

The whooping crane is a flagship species for the North American 

wildlife conservation movement and symbolizes the struggle for 

survival that characterizes many endangered species worldwide. 

It is a large, distinctive, and photogenic bird, popular with 

the public and the media, and it is often used to illustrate 

endangered species literature. 

Canadian Wildlife Service (CWS), Parks Canada Agency (PCA), U.S. 

Fish and Wildlife Service (USFWS), U.S. Geological Survey 

(USGS)-Biological Resources Division, Provincial Wildlife 

Agencies, and State Wildlife Agencies implement recovery with 

the support of many non-profit groups and private individuals 

(Lewis 1991). The Audubon Center for Research on Endangered 

Species (ACRES), Calgary Zoo (CZ), International Crane 

Foundation (ICF), National Audubon Society (NAS), National Fish 

and Wildlife Foundation, Operation Migration Ltd., San Antonio 

Zoo, World Wildlife Fund, and the Whooping Crane Conservation 

Association (WCCA) are among the groups that have been or 

currently are more active in aiding recovery. 

Historically, population declines were caused by shooting and 

destruction of nesting habitat in the prairies from agricultural 

development. The species was listed because of low population 

numbers, slow reproductive potential due to delayed sexual 

maturity with pairs averaging less than 1 chick annually, cyclic 

nesting and wintering habitat suitability, a hazardous 4,000 km 

migration route that is traversed twice annually, and many human 

pressures on the wintering grounds. Current threats to the wild 

cranes include collisions with manmade objects such as power 

lines and fences, shooting, predators, disease, habitat 

destruction, severe weather, and a loss of two thirds of the 

original genetic material. Threats to the captive cranes 

include disease, accidents and limited genetic material. 

The whooping cranes in Canada nest in WBNP and vicinity and 

migrate through Alberta, Saskatchewan, and, occasionally, 

Manitoba, in spring and fall, staging in fall in southern 

Saskatchewan (Fig. 1). Spring and fall migration occurs in the 

central Great Plains of the U.S. The cranes winter on the 

central Gulf Coast of Texas at Aransas National Wildlife Refuge 

(ANWR) and vicinity. No individuals remain from reintroduction 

attempts in the Rocky Mountains that took place from 1975 to 

1989, and in 1997. In 1993, introduction of a non-migratory 

1
DRAFT Whooping Crane Recovery Plan 2005 

flock was initiated in the Kissimmee Prairie and surrounding 

area in central Florida south of Orlando. An attempt to 

establish a migratory flock between central Wisconsin and the 

central Gulf Coast of Florida began in 2001. Captive whooping 

cranes are maintained at PWRC, Laurel, Maryland; ICF, Baraboo, 

Wisconsin; the CZ in Calgary, Alberta, ACRES, Belle Chasse, 

Louisiana; San Antonio Zoo, San Antonio, Texas; the New Orleans 

Zoo, New Orleans, Louisiana, and the Lowry Park Zoo, Tampa, 

Florida. 

 

2
DRAFT Whooping Crane Recovery Plan 2005 

Figure 1. Breeding and wintering areas and migration pathway of 

the AWBP. 

3
DRAFT Whooping Crane Recovery Plan 2005 

SPECIES INFORMATION 

Status 

The whooping crane was listed as Endangered in 1970 in the 

United States by USFWS, and in 1978 in Canada by the Committee 

on the Status of Endangered Wildlife (COSEWIC). 

Description

The whooping crane is in the Family Gruidae, Order Gruiformes 

(Krajewski 1989, Meine and Archibald 1996). The closest 

taxonomic relatives in continental North America are 5 races of 

sandhill crane (G. canadensis): the lesser (G. c. canadensis); 

Canadian (G. c. rowani); greater (G. c. tabida); Florida (G. c. 

pratensis); and Mississippi (G. c. pulla) (the last also listed 

as endangered by USFWS)(Meine and Archibald 1996). The common 

name "whooping crane" probably originated from the loud, singlenote vocalization given repeatedly by the birds when they are 

alarmed. 

As the tallest North American bird, males approach 1.5 m (5 ft) 

when standing erect, and exceed the greater sandhill crane in 

height by 12 to 20 cm (5 to 8 in). Males are generally larger 

than females. Captive males average 7.3 kg (16 lbs), and 

females average 6.4 kg (14 lbs). Seasonal weight variation is 

considerable, with a maximum in December and January and a 

minimum in July and August. Whooping cranes are sexually 

monomorphic (Walkinshaw 1973). However, the guard call 

vocalization is sexually distinct (98.8% accurate, Carlson 1991) 

and the vocalization and visual components of the unison call 

are sexually distinct (Archibald 1975). 

Adult plumage is snowy white except for black primaries, black 

or grayish alulae, sparse black bristly feathers on the carmine 

crown and malar region, and a dark gray-black wedge-shaped patch 

on the nape. The size of the post-occipital patch varies 

considerably between individuals. The black primaries and 

alulae are not visible when the wings are folded back, and the 

plumed, decurved tertials ordinarily conceal the short tail. 

The strong bill is a dark olive-gray which becomes lighter 

during the breeding season. The area at the base of the bill is 

pink or rosaceous. The iris of the eye is blue at hatching, 

gradually turns gray in chicks, and by one year of age is yellow 

(Jane Nicolich, pers. comm.). The legs and feet are gray-black. 

The juvenile plumage is a reddish cinnamon color. At age 80-100 

4
DRAFT Whooping Crane Recovery Plan 2005 

days, the chick is capable of sustained flight. At age 120 

days, white feathers begin to appear on the neck and back. 

Juvenile plumage is replaced through the winter months. The 

plumage is predominantly white by the following spring and the 

dark red crown, lores, and malar areas are apparent. Rusty 

juvenile plumage remains only on the head, the upper neck, 

secondary wing coverts, and scapulars (Stephenson 1971). 

Yearlings achieve typically adult plumage late in their second 

summer.

Life span 

Whooping cranes are a long-lived species. Wild whooping cranes 

were not individually marked until 1975 (Drewien and Bizeau 

1978, Kuyt 1978a, 1979a); consequently, some aspects of their 

life history and population biology remain uncertain. Current 

estimates suggest a maximum longevity in the wild of at least 30 

years (Mirande et al. 1993). Binkley and Miller (1983) 

suggested a maximum life span of 22-24 years of age, however at 

present, 1 wild female is 25 years old and 2 males are 24 years 

old (Brian Johns, pers. comm.). Captive individuals live 35-40 

years (Moody 1931, McNulty 1966). A 38-year-old male was still 

reproductively active in the captive flock at PWRC in 2002; he 

died in January 2003. 

Mortality – documented losses 

Probable cause of death has been identified for 8 whooping 

cranes, including 2 radio-tagged birds, which died on the 

wintering grounds between 1950-1987. Losses were due to 

shooting (2 known and a third suspected), avian tuberculosis 

(1), shooting injuires that were likely sustained during fall 

migration (birds arrived injured at Aransas NWR and later died) 

2), avian predation (1), and non-shooting trauma injury 

following fall migration (1) (Lewis et al. 1992a). Between 1950 

and 1986, 26 whooping cranes have been lost on the wintering 

grounds. This represents 1.4% of 1,893 wintering cranes. About 

15% of the annual losses occurred during the 5 to 6 months the 

cranes spent on the wintering grounds (Lewis et al. 1992a). Two 

losses occurred among cranes summering on ANWR. During these 

same years, birds that started migration in the spring and 

failed to return in the fall (e.g., April to November mortality) 

numbered 131, or 83.4% of the total losses (157). Mortality 

during April through November was 5 times greater than mortality 

on the wintering grounds. As previously noted, the principal 

known cause of loss during migration is collision with utility 

lines. Aerial surveys in summer in WBNP indicate that summer 

5
DRAFT Whooping Crane Recovery Plan 2005 

losses are infrequent. 

Breeding ecology 

Whooping cranes may start nesting as early as 3 years of age. 

To date, 3-year-old whooping cranes have been documented nesting 

10 times (5 males and 5 females), including one instance where 

both members of the pair were 3 years old (Kuyt and Goossen 

1987, Brian Johns, pers. comm.). 

Pair formation can occur rapidly or be a lengthy process. 

Bishop (1984) observed pair bonds that developed over 1 to 3 

winters from associations in subadult flocks on the wintering 

grounds. Stehn (1997) observed that 27.7% of pair bonds formed 

during spring migration or on the breeding grounds without any 

prior association at Aransas. Bishop and Blankinship (1982) 

documented several instances in which 2- and 3-year-old colorbanded birds paired with unmarked birds. Whooping cranes are 

monogamous, but will re-pair, sometimes within only a few days, 

following the death of their mate (Blankinship 1976, Stehn 

1992c, 1997). 

Experienced pairs arrive at WBNP in late April and begin nest 

construction. They show considerable fidelity to their breeding 

territories, and normally nest in the same general vicinity each 

year. Several pairs have nested in the same areas for 19 

consecutive years. These nesting territories, termed "composite 

nesting areas", vary considerably in size, and range from about 

1.3 to 47.1 km2

 (0.8 to 29 mi2) but average 4.1 km2 (2.5 mi2) 

(Kuyt 1976a, 1976b, 1981a, 1993a). Adjoining pairs usually nest 

at least 1 km (1 mi) apart, however, nests have been recorded as 

close as 400 m (435 yds) from each other (Brian Johns, pers. 

comm.). From the initiation of egg laying until chicks are a 

few months of age, the activities of pairs and family groups are 

restricted to the breeding territory. 

The average age of first egg production is 5 years (Kuyt and 

Goossen 1987). Eggs are normally laid in late April to mid-May, 

and hatching occurs about 1 month later. The incubation period 

is from 29 to 31 days (Kuyt 1982). Kuyt (1995) reported that 

"Among 514 clutches observed between 1966 and 1991, 454 (90.8%) 

contained 2 eggs, 43 (8.6%) only 1 egg, and 3 (0.6%) 3 eggs." 

Eggs are light brown or olive-buff overlaid with dark, purplishbrown blotches concentrated primarily at the blunt end. Eggs 

average 100 mm in length and 63 mm in width (Bent 1926, Allen 

1952, Stephenson and Smart 1972, Kuyt 1995). Whooping cranes 

may re-nest if their first clutch is destroyed or lost before 

6
DRAFT Whooping Crane Recovery Plan 2005 

mid-incubation (Erickson and Derrickson 1981, Kuyt 1981b, 

Derrickson and Carpenter 1982). However, egg predation is 

uncommon, and re-nesting by whooping cranes has only been 

documented a few times (Kuyt 1981b). Whooping cranes generally 

nest annually, but may skip a season when nesting habitat 

conditions are unsuitable, if they are nutritionally stressed 

(Chavez-Ramirez et al. 1997, Johns 1998b) or for other (not 

apparent) reasons. 

Whooping cranes usually produce clutches of 2 eggs laid 48-60 

hours apart. Incubation begins with the first egg laid, 

resulting in asynchronous hatching of the eggs. This asynchrony 

may follow the insurance hypothesis, as discussed by Forbes and 

Mock (2000), where parents add marginal offspring to their 

clutch/brood as a hedge against early failure of core brood 

members. Hatching asynchrony may be an adaptation to the 

availability of food resources or a means of ensuring that the 

adults do not expend an inordinate amount of time attending to 2 

young if they are in marginal habitat. In whooping cranes, eggs 

laid after incubation has begun usually only produce fledged 

young if the earlier laid egg fails to hatch or the chick dies 

soon after hatching. Not attempting to breed in a particular 

year may be a time and energy saving adaptation to prepare for a 

future breeding season (Stenning 1996). 

Erickson (1975) noted that although whooping cranes lay 2 eggs, 

only about 10% of families arriving on the winter range have 2 

chicks. About 90% of nests therefore contain 1 egg that is 

unlikely to result in a fledged chick. However, the second egg 

plays an unknown role in providing insurance that at least one 

chick survives. Boyce et al., (in prep) suggest that removal of 

the second egg could actually increase the likelihood that one 

chick fledges. In nests with 2 eggs, the first hatched has the 

greater chance of survival in the wild. Habitat conditions, 

including food availability and predator abundance, affect 

survival. In years with suitable habitat conditions crane pairs 

may raise 2 young (Johns 1998a). For example, during the 1958-

59 winter, 8 of the 9 young that arrived at Aransas were from 

twin pairs. In 1997 and 1998, at least 9% of second hatched 

whooping crane young survived (Bergeson et al. 2001a). 

During the years from 1938-l964, prior to egg-removal at WBNP, 

101 single chicks and 15 pairs of "twin" siblings arrived at 

Aransas NWR from 230 nests or 213 2-egg clutches (Kuyt 1987). 

"Twins" arrived in 9 of the 29 years. No pairs brought 2 

juveniles during the egg-pickup years 1965-1996 even though a 

few nests were left with 2 eggs in most years. Between 1997-

7
DRAFT Whooping Crane Recovery Plan 2005 

2003, with no egg pickup, 3 pairs successfully raised twin 

chicks and migrated from WBNP (Brian Johns, pers. comm.), 

however only 2 pairs brought twin chicks to Aransas NWR(Tom 

Stehn, pers. comm.). 

Whooping crane parents share incubation and brood-rearing 

duties. Except for brief intervals, 1 member of the pair 

remains on the nest at all times. Females tend to incubate at 

night (Allen 1952, Walkinshaw 1965, 1973) and take the primary 

role in feeding and caring for the young (Blankinship 1976). 

Chicks are capable of swimming shortly after hatching; however, 

parents and young return to the nest each night during the first 

3-4 days after hatching. Later, parents brood their young 

wherever they are at night or during foul weather. During the 

first 20 days after hatching, families generally remain within 

1.8 km of the nest site (Ernie Kuyt, pers. comm.) with daily 

movements averaging 340 m (Doug Bergeson, pers. comm.). 

Information on marked individuals suggests that most juveniles 

and subadults spend the summer near their natal area (Kuyt 

1979b, 1981a). Sexually immature birds (up to 4-year-olds) 

spend the summer as pairs or in small "bachelor" groups of 3 to 

5 birds, rarely as singles. These birds usually occur on the 

peripheries of territories of nesting pairs. 

Migratory Behavior 

As spring approaches, “dancing” behaviour (running, leaping and 

bowing, unison calling and flying) increases in frequency, and 

are especially indicative of pre-migratory restlessness (Allen 

1952, Blankinship 1976, Stehn 1992b). Family groups and pairs 

are usually among the first to depart wintering grounds, often 

assisted by seasonal strong southeast winds. First departure 

dates are normally between March 25 and April 15, with the last 

birds usually leaving by May 1. Occasional stragglers may 

linger into mid-May, and in 19 years between 1938-2002, 1 to 4 

birds (33 birds total) have remained at ANWR throughout the 

summer. Some of these birds were ill or crippled or mates of 

birds that were crippled. The spring migration is usually 

completed in 2-4 weeks, more rapidly than the reverse trip in 

the fall, as there is no known spring staging area. 

Parents separate from their young of the previous year upon 

departure from ANWR in northward migration, while in route to 

the breeding grounds or soon after arrival on the breeding 

grounds (Allen 1952, Stehn 1992a, Brian Johns, pers. comm.). 

8
DRAFT Whooping Crane Recovery Plan 2005 

Autumn migration normally begins in mid-September, with most 

birds arriving on the wintering grounds between late October and 

mid-November. Occasionally, stragglers may not arrive until 

late December. Whooping cranes migrate south as pairs, in 

family groups, or as small flocks of 3 to 5 birds (Johns 1992). 

They are diurnal migrants and make regular stops to feed and 

rest. Pairs with young are among the last to leave the breeding 

range (Allen 1952, Archibald et al. 1976, Stephen 1979). The 

migration corridor (Fig. 1) was determined by mapping confirmed 

sightings reported by individuals (Stephen 1979, Johnson and 

Temple 1980, Austin and Richert 2001) and radio-tracking 

whooping cranes during the period 1981-1984 (Kuyt 1992). Their 

first stop often occurs in northeast Alberta or northwest 

Saskatchewan, about 500 km southeast of their departure area in 

WBNP. Local weather conditions influence distance and direction 

of travel, but whooping cranes generally are capable of reaching 

the autumn staging grounds in the north-central portion of the 

Saskatchewan agricultural area on the second day of migration. 

Most of the cranes remain for 2 to 4 weeks in the large triangle 

between Regina, Swift Current, and Meadow Lake, where they feed 

on waste grain in barley and wheat stubble fields and roost in 

the many wetlands (Johns 1992). The remainder of the migration 

from Saskatchewan to the wintering grounds is usually rapid, 

probably weather-induced, and may be completed in a week (Kuyt 

1992). 

Winter Ecology 

For almost half of the year, whooping cranes occupy winter areas 

on and adjacent to ANWR. Although close association with other 

whooping cranes is tolerated at times on the wintering grounds, 

pairs and family groups typically occupy and defend relatively 

discrete territories. Studies indicate a declining territory 

size as the population increases with territories averaging 117 

ha (Stehn and Johnson 1987). Limited expansion of the wintering 

area has occurred (Tom Stehn, pers. comm.). Subadult and 

unpaired adult whooping cranes form small flocks and use areas 

outside occupied territories (Blankinship 1976, Bishop and 

Blankinship 1982). Subadults tend to winter near the 

territories where they spent their first year (Bishop 1984). 

Paired cranes will often locate their first winter territory 

near the winter territory of one of their parents (Bishop 1984, 

Stehn and Johnson 1987). 

Diet 

Whooping cranes are omnivorous (Walkinshaw 1973), probing the 

9
DRAFT Whooping Crane Recovery Plan 2005 

soil subsurface with their bills and taking foods from the soil 

surface or vegetation. Young chicks are fed by their parents. 

They gradually become more independent in their feeding until 

they separate from the parents preceding the next breeding 

season. Summer foods include large nymphal or larval forms of 

insects, frogs, rodents, small birds, minnows, and berries 

(Allen 1956, Novakowski 1966, Bergeson et al. 2001b). Foods 

utilized during migration are poorly documented but include 

frogs, fish, plant tubers, crayfish, insects, and agricultural 

grains. The largest amount of time is spent feeding in 

harvested grain fields (Johns et al. 1997). The winter diet 

consists predominately of animal foods, especially blue crabs 

(Callinectes sapidus), clams (Tagelus plebius, Ensis minor, 

Rangia cuneata, Cyrtopleura costada, Phacoides pectinata, Macoma 

constricta), and the plant wolfberry (Lycium carolinianum)(Allen 

1952, Uhler and Locke 1970, Blankinship 1976 and 1987, Hunt and 

Slack 1987, Chavez-Ramirez 1996). Most foraging occurs in the 

brackish bays, marshes, and salt flats lying between the 

mainland and barrier islands. Occasionally, they fly to upland 

sites when attracted by fresh water to drink or by foods such as 

acorns, snails, crayfish and insects, and then return to the 

marshes to roost (Hunt 1987, Chavez-Ramirez et al. 1995). 

Uplands are particularly attractive when partially flooded by 

rainfall, burned to reduce plant cover or when food is less 

available in the salt flats and marshes (Bishop and Blankinship 

1982). Some whooping cranes use upland sites frequently in most 

years, but agricultural croplands adjacent to ANWR are rarely 

visited. 

High fall tides and heavy rains sometimes flood tidal flats. In 

these circumstances, the birds forage almost exclusively on blue 

crabs and wolfberry in flooded areas. In December and January, 

tidal flats typically drain as a result of lower tides, and the 

birds move into shallow bays and channels to forage primarily on 

clams, although blue crabs are occasionally captured while 

probing the bottom. Clams are a significant dietary item when 

water depths are low, temperatures cold, and following drought 

when the blue crab population is low. Most clams and small blue 

crabs (5 cm or less in width) are swallowed whole. Larger crabs 

are pecked into pieces before being swallowed (Blankinship 

1976).

The AWBP whooping cranes spend their summers and winters in 

restricted locations. Therefore, their pressure on local 

invertebrate food species may cause depletions, especially of 

blue crabs at Aransas. However, the total whooping crane 

population is so small that it is unlikely to exert any 

10
DRAFT Whooping Crane Recovery Plan 2005 

ecological effects except in small areas. 

DISTRIBUTION 

Historical Distribution and Numbers 

Fossilized remains from the Upper Pliocene in Idaho (Miller 

1944, Feduccia 1967), and from the Pleistocene in California, 

Kansas, and Florida (Wetmore 1931, 1956) appear inseparable from 

the present form. Current evidence indicates that the 

historical range extended from the Arctic coast south to central 

Mexico, and from Utah east to New Jersey, South Carolina, 

Georgia, and Florida (Allen 1952, Nesbitt 1982). Distribution 

of these fossil remains suggests a wider distribution during the 

Pleistocene. 

The major nesting area during the 19th and 20th centuries 

extended from central Illinois, northwestern Iowa, northwestern 

Minnesota, and northeastern North Dakota northwesterly through 

southwestern Manitoba, southern Saskatchewan and into east 

central Alberta (Allen 1952)(Fig. 2). Some nesting apparently 

occurred at other sites such as Wyoming in the 1900's, but 

documentation is limited (Kemsies 1930, Allen 1952). Allen 

(1952) believed the whooping cranes principal wintering range 

was the tall grass prairies, in southwestern Louisiana, along 

the Gulf Coast of Texas, and in northeastern Mexico near the Rio 

Grande Delta. Other significant wintering areas were the 

interior tablelands in western Texas and the high plateaus of 

central Mexico, where whooping cranes occurred among thousands 

of sandhill cranes. 

11
DRAFT Whooping Crane Recovery Plan 2005 

Figure 2. The principal known breeding and wintering areas of 

the whooping crane (Grus americana) (adapted from Meine 

and Archibald 1996).

 

12
DRAFT Whooping Crane Recovery Plan 2005 

In the 19th century, there were several migration routes. The 

two most important ones (Allen 1952:103) were “... those between 

Louisiana and the nesting grounds in Illinois, Iowa, Minnesota, 

North Dakota, Manitoba, and the other from Texas and the Rio 

Grande Delta region of Mexico to nesting grounds in North 

Dakota, the Canadian Provinces, and Northwest Territories.”. A 

route through west Texas into Mexico apparently followed the 

route still used by sandhill cranes, and it is believed the 

whooping cranes regularly traveled with them to wintering areas 

in the central interior highlands region (Allen 1952). 

Another migration route crossed the Appalachians to the Atlantic 

Coast. These birds apparently nested in the Hudson Bay area of 

Canada. Coastal areas of New Jersey, South Carolina, and more 

southerly river deltas were the wintering grounds. The specimen 

record or sighting reports for some eastern and mid-western 

locations are Alabama 1899; Arkansas 1889; Florida 1927 or 1928; 

Georgia 1885; Illinois 1891; Indiana 1881; Kentucky 1886; 

Michigan 1882; Minnesota 1917; Mississippi 1902; Missouri 1884; 

New Jersey 1857; Ohio 1902; Ontario 1895; South Carolina 1850; 

and Wisconsin 1878 (Burleigh 1944, Sprunt and Chamberlain 1949, 

Allen 1952, Hallman 1965). 

Atlantic Coast locations used by whooping cranes include the 

Cape May area and Beesley’s Point at Great Egg Bay in New 

Jersey; the Waccamaw River in South Carolina; the deltas of the 

Savannah and Altamaha Rivers, and St. Simon's Island in Georgia; 

and the St. Augustine area of Florida. Gulf Coast locations 

include Mobile Bay, Alabama; Bay St. Louis in Mississippi; and 

numerous records from southwestern Louisiana where the last bird 

was captured in 1950. Coastal Louisiana contained both a nonmigratory flock and wintering migrants (Allen 1952). 

Nesbitt (1982) summarized the following evidence that whooping 

cranes occurred in Florida, perhaps well into the 20th century. 

0. E. Baynard, a respected field naturalist, said the last flock 

of whooping cranes (14 birds) he saw in Florida was in 1911 near 

Micanopy, southern Alachua County. Two whooping cranes were 

reported east of the Kissimmee River on January 19, 1936, and a 

whooping crane was shot and photographed north of St. Augustine, 

St. Johns County, 1927 or 1928. 

Records from interior areas of the southeast include the 

Montgomery, Alabama, area; in Arkansas at Crocketts Bluff on the 

White River, and near Corning; in Missouri in Jackson County 

near Kansas City, near Corning, in Lawrence County southwest of 

Springfield, in Audrain County, and near St. Louis; and in 

13
DRAFT Whooping Crane Recovery Plan 2005 

Kentucky near Louisville and Hickman. It is unknown whether 

these records represent wintering locations, remnants of a nonmigratory population, or wandering birds. 

Although whooping cranes may never have formed large flocks and 

were thus reported infrequently, they ranged widely and utilized 

the vast wetland acreages available prior to influx of white 

settlers. The growth of the AWBP at the end of the 20th century 

may provide insight for densities that could have occurred prior 

to colonial times. At WBNP, Kuyt (1993a) reported 13 nesting 

pairs had a mean home range size of 4.1 km sq (414 ha), Doug 

Bergeson (pers. comm.) reported the mean home range size for 14 

pairs as 3.8 km sq (384 ha). At ANWR, Stehn and Johnson (1987) 

found 86 whooping cranes distributed over 8,175 ha with an 

average territory size of 117 ha on the refuge where the density 

was highest. If these densities are expanded to the known 

historical distribution of the species, it is reasonable to 

assume that more than 10,000 whooping cranes once roamed across 

North America (Tom Stehn, pers. comm.). This analysis differs 

from previously published information that did not have the 

insight of current crane densities. Within the wintering area 

at ANWR and the nesting area in WBNP, the cranes are found 

within a relatively small area. Expanded throughout the known 

historical nesting and wintering range, the species may have 

been more numerous than reported and by 1870 may have already 

been greatly reduced in number. It is erroneous to think that 

the whooping crane is not well adapted to its environment, was 

never numerous, and was about to become extinct even before 

human actions threatened the species (Tom Stehn, pers. comm). 

Allen (1952:83) estimated that the whooping crane population in 

"... 1860, or possibly 1870, totaled between 1300 and 1400 

individuals." Banks (1978), using 2 independent techniques, 

derived estimates of 500 to 700 whooping cranes present in 1870. 

The whooping crane disappeared from the heart of its breeding 

range in the north-central United States by the 1890s. The last 

documented nesting in the aspen parklands of Canada occurred at 

Eagle Lake (now called Kiyiu Lake), Saskatchewan, in 1922 

(Hjertaas 1994). By 1944 only 21 birds remained in 2 small 

breeding populations, a non-migratory population that inhabited 

the area around White Lake in southwestern Louisiana, and the 

migratory AWBP that wintered on ANWR in coastal Texas and nested 

in an unknown location (Table 1). The last reported 

reproduction in the non-migratory Louisiana population occurred 

in 1939 (Lynch 1956, Gomez 1992, Drewien et al. 2001). In March 

1950 the Louisiana population ceased to exist as the last 

individual was taken into captivity. The nesting area of AWBP 

14
DRAFT Whooping Crane Recovery Plan 2005 

was discovered in 1954 in WBNP, Northwest Territories, Canada 

(Fig. 2). 

15
DRAFT Whooping Crane Recovery Plan 2005 

Table 1. Whooping crane peak winter numbers in North America 

1938-2003.

 AWBP Louisiana 

Winter Adulta Younga Total

1938-39 14 4 11 29

1939-40 15 7 13 35

1940-41 21 5 6 32

1941-42 14(13) 2 6 22 

1942-43 15 4 5 24

1943-44 16 5 4 25

1944-45 15 3 3 21

1945-46 18(14) 4(3) 2 24

1946-47 22 3 2 27

1947-48 25 6 1 32

1948-49 27 3 1 31

1949-50 30 4 1 35

1950-51 26 5 0 31

1951-52 20 5 25

1952-53 19 2 21

1953-54 21 3 24

1954-55 21 0 21

1955-56 20 8 28

1956-57 22 2 24

1957-58 22 4 26

1958-59 23 9 32

1959-60 31 2 33

1960-61 30 6 36

1961-62 34 5 39

1962-63 32 0 32

1963-64 26(28) 7 33

1964-65 32 10 42

1965-66 36 8 44

1966-67 38 5 43

1967-68 39 9 48

1968-69 44 6 50

1969-70 48 8 56

1970-71 51 6 57

1971-72 54 5 59

1972-73 46 5 51

1973-74 47 2 Rocky Mountain 49

1974-75 47 2 Adult Young 49

1975-76 49 8 4 61

1976-77 57 12 3 3 75

1977-78 62 10 6 2 80

1978-79 68 7 6 3 84

1979-80 70 6 8 7 91

16
DRAFT Whooping Crane Recovery Plan 2005 

1980-81 72 6 15 5 98

1981-82 71 2 13 0 86

1982-83 67 6 10 4 87

1983-84 68 7 13 17 105

1984-85 71 15 21 12 119

1985-86 81 16 27 4 128

1986-87 89 21 20 1 131

1987-88 109 25 16 0 150

1988-89 119 19 14 0 152

1989-90 126 20 13 0 159

1990-91 133 13 13 0 159

1991-92 124 8 12 0 Floridab 144

1992-93 121 15 9 0 Adult Young 145

1993-94 127 16 8 1 8 152

1994-95 125 8 4 0 16 153

1995-96 130 28 3 0 25 186

1996-97 144 16 3 0 56 219

1997-98 152 30 3 3 60 248

1998-99 165 18 4 0 57 244

1999-00 171 17 2 0 65 Eastern 255

2000-01 171 9 2 0 74 Migratory 256

2001-02 161 15 1 0 87 6 270

2002-03 169 16 0 0 85 1 21 292

2003-04 169 25 0 0 85 2 36 317

a

 Where two numbers occur in a column, the one in parenthesis is 

the original count and the second is the adjusted number as 

explained in Boyce (1987). The 1945 count at ANWR and vicinity 

was 14 and 3, but 22 adult-plumaged birds returned to the 

refuge in the winter of 1946. Consequently, it is evident that 

some birds were not counted in 1945. 

b

 Number of birds present on December 31. 

 

_________ 

17
DRAFT Whooping Crane Recovery Plan 2005 

Current Distribution and Abundance 

Whooping cranes occur only in North America within Canada and 

the United States. Approximately 96% of the wild nesting sites 

occur in Canada and the balance in Florida. Fifty-eight percent 

of the December, 2003 wild population (185 of 317 individuals) 

had summered in Canada, with 87 in Florida and 36 in the 

Wisconsin – Florida population. Seventeen percent of the 

captive individuals (19) remain in Canada and the balance (95 

cranes) is housed in the United States. 

The AWBP contains 194 individuals in December, 2003 and is the 

only self-sustaining wild population. This population nests in 

the Northwest Territories and adjacent areas of Alberta, Canada, 

primarily within the boundary of WBNP (Johns 1998b). In 2003, 

61 of the 64 known adult pairs nested (Brian Johns, pers. 

comm.). These cranes migrate southeasterly through Alberta, 

Saskatchewan and eastern Manitoba, stopping in southern 

Saskatchewan for several weeks in fall migration before 

continuing migration into the United States (Fig. 1). They 

migrate through the Great Plains states of eastern Montana, 

North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and 

Texas. Their spring migration is more rapid and they simply 

reverse the route followed in fall. They winter along the Gulf 

of Mexico coast at ANWR and adjacent areas (Fig. 3). The winter 

habitat extends 48-56 km along the coast from San Jose Island 

and Lamar Peninsula on the south to Welder Point and Matagorda 

Island on the north, and consists of estuarine marshes, shallow 

bays, and tidal flats (Allen 1952, Blankinship 1976). Some 

individuals occur occasionally on nearby privately owned pasture 

or croplands. 

18
DRAFT Whooping Crane Recovery Plan 2005 

Figure 3. Wintering area of the Aransas Wood Buffalo Population, 

Aransas National Wildlife Refuge and Critical Habitat 

boundary on the Gulf of Mexico coast of Texas. 

 

19
DRAFT Whooping Crane Recovery Plan 2005 

The second population of wild whooping cranes is nonmigratory 

(Nesbitt et al. 1997) and occurs in central Florida. This 

population, known as the Florida Population (FP), has been 

designated experimental nonessential in the United States by 

USFWS. First reintroduced in 1993, approximately 87 birds 

survived at the end of 2003 from 268 captive-reared whooping 

cranes released over a 11-year period. Egg production in this 

population was first recorded in 1999. Eleven pairs have laid 

eggs through 2003, and 3 chicks have fledged. Two pairs first 

produced eggs in 1999, 3 additional pairs produced eggs in 2000 

and hatched one chick that did not fledge, 2 pairs produced 2 

eggs in 2001, and 4 pairs laid eggs in 2002 and 1 chick fledged. 

In 2003 7 pairs laid eggs and 2 chicks fledged. The FP is found 

primarily on the Kissimmee Prairie and surrounding areas. The 

Kissimmee Prairie is south of Orlando and consists of 500,000 ha 

of freshwater marsh and open grasslands in Osceola and Polk 

Counties associated with the flood plain of the Kissimmee River. 

Most grasslands are improved pasture used for livestock grazing 

and are heavily used by the cranes for foraging. 

A third, population of wild whooping cranes is migratory and was 

reintroduced starting in 2001. Captive-reared whooping cranes 

from PWRC are brought to the Wisconsin summering area, trained 

to fly behind ultralight aircraft, and led to Florida. This 

population migrates from the Necedah NWR in central Wisconsin to 

Chassahowitzka NWR, a 12,500 ha expanse of salt marsh on the 

Gulf Coast of Florida. Of the 5 whooping cranes led south in 

2001 that survived the winter, all five returned to summer in 

central Wisconsin on their own and returned to western Florida 

in the subsequent winter. As of December 2003 this population 

numbers 36 birds. Plans call for continued releases for at 

least 10 more years to try to establish a migratory flock of a 

minimum of 100 individuals, including 25 nesting pairs. 

No whooping cranes remain in the Rocky Mountains. The last bird 

from the cross-fostering experiment disappeared during migration 

from the winter grounds in 2002 at the age of 19. These birds 

had summered in Idaho and Montana and wintered in New Mexico, 

staging in spring and fall near the Monte Vista NWR, Colorado. 

In 1989, because of the lack of breeding attempts and high 

mortality (Garton et al.1989), the Recovery Team decided to 

discontinue the reintroduction attempt. Additional guide bird 

and ultralight experiments were carried out through 1997, but 

not with an expectation of establishing a population in the 

Rocky Mountains. 

Whooping cranes occur in captivity at 7 North American locations 

20
DRAFT Whooping Crane Recovery Plan 2005 

and totaled 114 in December, 2003. The U.S. Geological Survey 

(USGS) maintains 51 adults at PWRC in Laurel, Maryland. The 

USFWS funds, cooperatively with ICF, 32 cranes at the Foundation 

facility in Baraboo, Wisconsin. Eighteen birds are kept at the 

Devonian Wildlife Conservation Center operated by the CZ. The 

captive flocks at Laurel, Maryland; Baraboo, Wisconsin; and 

Calgary, Alberta are the primary sources for captive-reared 

cranes used in the second and third wild flocks. Since 1993, 14 

to 48 young have been released annually into the wild in 

Florida. Between 2001 and 2003, a total of 40 young started the 

fall migration in Wisconsin behind ultralight aircraft. Three 

pairs also reside at the San Antonio Zoological Gardens, San 

Antonio, Texas that produce chicks for the Florida 

reintroduction. Ten whooping cranes are present at ACRES, Belle 

Chasse, Louisiana and are expected to start breeding in the near 

future (the first egg was produced in 2003). Four birds are 

present at Lowery Park Zoo, Tampa, Florida, including two from 

the FP undergoing rehabilitation. Two subadult cranes are at 

the Audubon Zoo in New Orleans, Louisiana for future display 

purposes. Only at the CZ, ICF, Lowry Park and San Antonio Zoos 

are whooping cranes on exhibit for public viewing. 

 

HABITAT REQUIREMENTS 

Breeding Habitat 

Whooping Cranes formerly bred in isolated marshes on the 

prairies and in aspen parkland. The current nesting area within 

WBNP lies between the headwaters of the Nyarling, Sass, Klewi, 

and Little Buffalo rivers (Fig. 4). The area is poorly drained 

and interspersed with numerous potholes. Wetlands vary 

considerably in size, shape and depth, and most possess soft 

marl bottoms (Timoney et al. 1997). Wetlands are separated by 

narrow ridges which support an over story of white spruce (Picea 

alauca), black spruce (P. mariana), tamarack (Larix laricina), 

willows (Salix spp.), and an understory of dwarf birch (Betula 

glandulosa), Labrador tea (Ledum groenlandicum), bearberry 

(Arctosta phylos uva-ursi) and several species of lichen, 

underlain by sphagnum moss (Novakowski 1966). Bulrush (Scirpus 

validus) is the dominant emergent in the potholes used for 

nesting, although cattail (Typha sp.), sedge (Carex aquatilis), 

musk-grass (Chara sp.), and other aquatic plants are common 

(Allen 1956, Novakowski 1965, 1966, Kuyt 1976a, 1976b, 1981a). 

Nest sites are primarily located in shallow diatom ponds that 

contain bulrush (Timoney 1997). 

21
DRAFT Whooping Crane Recovery Plan 2005 

Figure 4. Breeding area of the Aransas Wood Buffalo Population, 

Wood Buffalo National Park. 

22
DRAFT Whooping Crane Recovery Plan 2005 

Wildfires, caused primarily by lightning, are generally thought 

to have beneficial effects on crane habitat by recycling 

nutrients, removing and thinning vegetation on the forested 

ridges between nesting ponds, making the area more accessible to 

cranes. Fires have burned large portions of the nesting area 

during drought (e.g., 1981)however, wildfires do not appear to 

have influenced whooping cranes choice of nest sites (Timoney 

1999). Although molting adults or flightless young are 

vulnerable to fire, losses of eggs, chicks, or adults have not 

been confirmed. Due to the potential negative effects of a 

major fire control operation in the nesting area, it was advised 

that the area be classified as a modified response area where 

fire suppression activities are limited (Timoney 1997). 

There is little competition by other species for nesting 

territories in WBNP (Kuyt 1989). Sandhill cranes are present on 

the nesting grounds, however, it is unlikely they would outcompete the larger whooping cranes for preferred nest sites and 

territories. Most territory overlap would probably occur on the 

dryer sedge nest areas. 

Although the quality of nesting habitat can be debated, there is 

no evidence that growth of the AWBP is limited by availability 

of summer habitat. Hatching success is high in most years (Kuyt 

1976c, 198la, 1981b) and the area is remote from human 

activities. Thousands of hectares of unoccupied, apparently 

similar habitat are available in the area. Some new pairs have 

pioneered unoccupied nesting habitat adjacent to occupied range 

as the population increases (Kuyt 1978b, Johns 1998a, Johns et 

al. in press). Wetlands suitable for breeding may also still 

exist in the historical range on the Canadian prairies, although 

dry conditions in recent years and agricultural practices have 

greatly decreased the number and extent of these wetlands. A 

project of the Canadian Wildlife Service and Parks Canada is 

underway to identify suitable unoccupied nesting habitat within 

WBNP and adjacent areas. 

In 2003, 3 pairs nested just outside of WBNP. Additional 

expansion of the flock out of WBNP into adjacent areas of 

Alberta and the Northwest Territories would be into habitat with 

no formal protection. Land uses such as forestry, agriculture 

and activities such as hunting could cause disturbance or change 

the quality of habitat available for cranes. 

23
DRAFT Whooping Crane Recovery Plan 2005 

Migration Habitat 

Whooping cranes use a variety of habitats during migration (Howe 

1987, 1989, Lingle 1987, Lingle et al. 1991, Johns et al. 1997). 

Nine radio-tagged whooping cranes monitored for one or more 

seasons and others that associated with them fed primarily in a 

variety of croplands and roosted in palustrine (marshy) wetlands 

(Howe 1987, 1989). A majority of the roosting wetlands were 

less than 4 ha (75%) and within 1 km of a suitable feeding site. 

More than 40% of the roosting wetlands were smaller than 0.5 ha. 

Johns et al. (1997) found that on average wetlands were larger 

than those of Howe (1987, 1989), with spring sites averaging 36 

ha. and fall sites averaging 508 ha. in size. The majority 

(94.9% spring; 72.9% fall) of these roost sites were also within 

1 km of a suitable feeding site. Heavily vegetated wetlands 

were generally not used, but family groups appeared to select 

more heavily vegetated areas than non-families (Howe 1987, 

1989). Cropland accounted for 70% of the feeding sites of nonfamilies, but wetlands accounted for 67% of the feeding sites of 

families. 

Known staging areas and potential breeding wetlands on the 

prairies could be negatively impacted by drought, drainage, 

cattle grazing, contaminated runoff, or other disturbances 

associated with agricultural activities. Since fall staging 

habitat in Saskatchewan is primarily on private lands, 

conservation activities should include stewardship actions 

(Johns et al. 1997). Clusters of migratory observations 

suggested relationships with large-scale spatial patterns in 

land cover (Richert et al. 1999, Richert and Church 2001). 

Areas characterized by wetland mosaics appear to provide the 

most suitable stopover habitat (Johns et al. 1997, Richert et 

al. in press). In states and provinces excluding Nebraska, 

whooping cranes primarily used shallow, seasonally and 

semipermanently flooded palustrine wetlands for roosting, and 

various cropland and emergent wetlands for feeding (Austin and 

Richert 2001, Johns et al. 1997). Large palustrine wetlands 

included in this category (and the number of confirmed sightings 

through spring 2000) are those at Quivira NWR in Kansas (124), 

Salt Plains NWR in Oklahoma (84), Cheyenne Bottoms State 

Wildlife Area in Kansas (56), Last Mountain Lake NWA in 

Saskatchewan (46) and large reservoir margins in the Dakotas 

(Wally Jobman, USFWS files, Brian Johns, CWS files). 

During migration, whooping cranes are often recorded in riverine 

habitats, especially in Nebraska. Frequently used riverine 

habitats (and the number of confirmed sightings through spring 

24
DRAFT Whooping Crane Recovery Plan 2005 

2000) are the South Saskatchewan River in Saskatchewan 

(29)(Brian Johns, CWS files), Platte River (64), North and 

Middle Loup Rivers (18), and Niobrara River (13) in Nebraska; 

Missouri River in North Dakota (8), and the Red River (3) in 

Texas (Wally Jobman, USFWS files). Cranes roost on submerged 

sandbars in wide unobstructed channels that are isolated from 

human disturbance (Armbruster 1990). 

Wintering Habitat 

About 9,000 ha of salt flats on ANWR and adjacent islands 

comprise the principal wintering grounds (Fig. 3). Marshes are 

dominated by salt grass (Distichlis spicata), saltwort (Batis 

maritima), smooth cordgrass (Spartina alterniflora), glasswort 

(Salicornia sp.),and sea ox-eye (Borrichia frutescens). Inland 

margins of the flats are dominated by Gulf cordgrass (Spartina 

spartinae). Interior portions of the refuge are gently rolling 

and sandy and are characterized by oak brush, grassland, swales, 

and ponds. Typical plants include live oak (Quercus 

virginiana), redbay (Persea borbonia), and bluestem (Andropogon

spp.)(Stevenson and Griffith 1946, Allen 1952, Labuda and Butts 

1979). In the last 30 years, many upland sites have been 

grazed, mowed, or burned under controlled conditions (Labuda and 

Butts 1979) to maintain oak savannah habitat. The refuge 

maintains as many as 3,300 ha of grassland for cranes, 

waterfowl, and other wildlife. Human visitation is carefully 

controlled, and other potentially conflicting uses of the 

refuge, such as activities associated with oil and gas 

exploration, are reduced when whooping cranes are present. 

RATE OF POPULATION GROWTH 

The whooping crane has a long-term recruitment rate of 13.9%, 

the highest of any North American crane population (Drewien et 

al. 1995). The AWBP is increasing at an annual rate of more 

than 4%. Population studies indicate a 10-year cycle of unknown 

cause in survivorship (Boyce and Miller 1985, Boyce 1987, 

Nedelman et al. 1987). M. Boyce (pers. comm.) has correlated 

the crane cycle with that of boreal forest predator cycles. 

From 1983 to 1989, the population increased from 75 to a high of 

146 birds, chiefly because of suitable nesting habitat 

conditions during that period, then dropped to the anticipated 

10-year low of 132 by the 1991-92 winter (Table 1). The AWBP 

then increased to a record high of 188 in the 1999-00 winter. 

Again, with the expected 10-year cycle, the population declined 

to 180 in 2000-01 and 176 in 2001-02, then rebounded to 185 in 

2002-03. 

25
DRAFT Whooping Crane Recovery Plan 2005 

The growth of the AWBP up to the year 2000 seems to have 

resulted primarily from a decline in the mortality rate rather 

than an increase in recruitment. Between 1938-2000, 341 

whooping cranes disappeared from the wild population. Annual 

mortality averages 9.8% (12.1% prior to 1970 and 7.6% since that 

time). In addition, recruitment has also declined from the pre1970 average of 15.9% to 10.8%. If recruitment can be increased 

and if losses of white-plumaged birds can be reduced, population 

growth will accelerate. The factors causing the decline in 

recruitment are unknown, but identifying these sources and 

implementing remedial actions where feasible should be a high 

priority. 

A Population Viability Assessment Workshop held in 1991 for the 

whooping crane was funded by USFWS as a cooperative endeavor 

with CWS, U. S. Whooping Crane Recovery Team, Canadian Whooping 

Crane Recovery Team, ICF, The Captive Breeding Specialist Group, 

and Species Survival Commission of the International Union for 

Conservation of Nature. The final report included priorities 

for research and management of the wild and captive populations 

as a meta-population to maximize retention of genetic 

heterozygosity and minimize the risk of extinction (Mirande et 

al. 1993). 

Several population viability analysis packages have been tested 

using whooping crane data from the AWBP (Mirande et al. 1997a, 

Brook et al. 1999). Annual growth of the population during the 

past 65 years has averaged 4.5% per year. If this rate 

continues, starting with a peak population of 185 birds in 2002, 

the population will reach 500 birds about 2025 and 1,000 birds 

about 2041 (John Cannon, pers. comm.). However, the standard 

deviation of the annual growth rates over the past 65 

years has been 12.9%, almost triple the average annual growth 

rate. For example, the growth rate was as high as 33% in 1954-

55 and as low as -38% in 1940-41. In the last 15 years, with 

total population >100 birds, the annual growth rate has varied 

from a high of 19% in 1994-95 to a low of -10% in 1990-91. This 

variation makes it difficult to predict the future population 

size for any given year. However, it is likely that the AWBP 

will continue to grow with a low probability (<1.0%) of 

extinction over the next 100 years (Mirande et al. 1997a). 

Mirande et al. (1993) modeled the captive population from its 

establishment to 1991 and found a growth rate of 1.1% (SD+-

0.114)(Mirande et al. 1993). At that rate the population would 

be 127 birds retaining only 89% of the initial heterozygosity at 

26
DRAFT Whooping Crane Recovery Plan 2005 

the end of 100 years. However, much of the production from the 

captive flock went to support the cross-fostering experiment in 

the Rocky Mountains between 1975 and 1989. Expansion and major 

improvements in production have occurred in the 1990s and 

demonstrated the capacity to support the non-migratory 

reintroduction program in Florida. Mirande et al. (1993) also 

noted that improvements were achievable over the next 1 to 5 

years. In fact, major improvements in production occurred in 

1992 and 1993, indicating that the captive flocks would be able 

to sustain a reintroduction program. The captive flocks have 

contributed 262 young to the Florida introduction between 1993-

2003, with 237 from captive-produced eggs, and 39 from WBNP eggs 

hatched in captivity. 

THREATS AND REASONS FOR LISTING 

The 1967 Federal document that first listed the whooping crane 

as in danger of extinction did not address the five factor 

threats analysis later required by Section 4 of the 1973 ESA. 

However, we address these factors in the summary below to 

organize threats to the species in a manner consistent with 

current listing and recovery analyses under the ESA. The five 

factor analysis is also utilized in a later section that 

addresses how threats are minimized by proposed recovery 

actions. 

Listing Factor A: The present or threatened destruction, 

modification, or curtailment of habitat or range.

Human Settlement: The growth of the human population in North 

America has resulted in significant whooping crane habitat 

alteration and destruction. Historically, whooping cranes 

declined or disappeared as agriculture claimed the northern 

Great Plains of the U.S. and Canada (Allen 1952). By the mid1900s, only one small population survived. Ironically, the 

steadfast use of a traditional summer area that appears to have 

saved the whooping crane as a small relict breeding population 

in WBNP, prevents its voluntary return to what was once its 

principal nesting range. Re-colonization of these historic 

breeding areas remains unlikely unless humans assist with 

reintroductions. 

Conversion of pothole and prairie to hay and grain production 

made much of the historic nesting habitat unsuitable for 

whooping cranes. Disruptive practices included draining, 

fencing, sowing, and the human activity associated with these 

actions. Settlement of the mid-continent and coastal prairies 

27
DRAFT Whooping Crane Recovery Plan 2005 

and associated disturbance, in addition to alteration of 

habitat, may have interfered with continued use of prairie and 

wetlands by breeding whooping cranes. The extensive drainage of 

wetlands in the prairie pothole region of Canada and the United 

States also resulted in a tremendous loss of migration habitat 

available to whooping cranes. 

Freshwater Inflows: Currently, expanding human populations 

throughout the range of the whooping cranes continue to threaten 

survival and recovery of the birds. Impacts are particularly 

severe on the winter grounds. Freshwater inflows starting 

hundreds of kilometers inland primarily from the Guadalupe and 

San Antonio rivers that flow into whooping crane critical 

habitat at Aransas are needed to maintain the proper salinity 

gradients, nutrient loadings, and sediments that produce an 

ecologically healthy estuary (TPWD 1998). Inflows are essential 

to maintain the productivity of coastal waters and produce foods 

used by the whooping cranes. Coastal water with low saline 

levels, which whooping cranes can drink rather than fly inland 

for freshwater, are maintained by these in-stream flows. 

Upstream reservoir construction and water diversions for 

agriculture and human use reduce these inflows. 

TPWD has made recommendations for target inflows needed to 

maintain the unique biological communities of the Guadalupe 

Estuary (TPWD 1998) that flows into whooping crane critical 

habitat. A simple inverse relationship exists between blue crab 

catch rates and mean salinity within an estuary (Longley 1994). 

By 2040, due to constructed diversions, a decrease of freshwater 

inflows into the crane’s winter range is projected in an average 

year to cause an 8% decline in blue crab populations, the 

primary food of the whooping crane (Texas Department of Water 

Resources 1980). Inflows are already insufficient and reduced 

over historic levels. With projected losses, freshwater inflows 

would be insufficient to sustain the ecosystem in an average 

rainfall year. Long before the ecosystem collapsed for lack of 

inflows, significant adverse impacts to the primary winter food 

supply of the whooping crane would occur (Kretzschmar 1990). 

Texas Water Development Board data indicate natural droughts 

already threaten the Guadalupe ecosystem. Withdrawals of 

surface and groundwater for municipal and industrial growth will 

leave insufficient inflows to sustain the ecosystem in less than 

50 years. The state water plan proposes a diversion at the 

mouth of the Guadalupe River, pumping at least 94,500 acre-feet 

annually back to San Antonio for municipal use. 

28
DRAFT Whooping Crane Recovery Plan 2005 

Listing Factor B: Overutilization for commercial, recreational, 

scientific, or educational purposes. 

Hunting: Hunting was clearly one of the primary reasons for the 

whooping crane’s historical decline. Allen (1952:75) recorded 

389 whooping cranes known to have died from gunshot or other 

causes from colonial times to 1948. The majority of documented 

losses occurred between 1870 and 1930, with 274 mortalities 

reported. Most losses (about 66%) occurred during migration, 

especially between the 1880s and 1920s (Allen 1952). Allen 

(1956) reported that nearly 200 taxidermy mounts, study skins, 

and skeletons, and an undetermined number of eggs were in 

museums in the United States and Canada. Hahn (1963) indicated 

that 309 mounts and 9 skeletons existed in museums throughout 

the world. The lack of records associated with most of these 

specimens suggests few were collected by museum employees. 

Considering the low reproductive potential of the species, and 

the small percentage of shootings actually documented, the 

shooting mortality possibly exceeded annual reproduction by the 

early 1900's. 

 

A decline in human-caused mortality followed enactment of 

protective legislation. Although hunting whooping cranes is no 

longer legal, shootings occasionally occur (Lewis et al. 1992a). 

Four documented shootings of AWBP whooping cranes occurred 

during migration or on the wintering grounds between 1968-1991. 

A vandal shot an adult in Saskatchewan in April 1990. Another 

vandal shot an adult female in April 1991 as she migrated 

through Texas. An adult female was shot by a snow goose hunter 

in 1968 just north of the ANWR boundary. Another adult female 

was shot reportedly mistaken for a snow goose (Anser

caerulescens) along the bay edge of San Jose Island in January 

1989. The most recently documented loss associated with hunting 

was an adult female shot in migration near Ennis, Texas in 

November, 2003. Other unexplained losses may be due to 

shooting. Although examinations of retrieved carcasses have 

rarely revealed the presence of shotgun pellets, 3 lead pellets 

were found during the post-mortem examination of a male from the 

Rocky Mountain population in January 1984 (Snyder et al. 1992). 

Vandals have shot 3 whooping cranes in Florida in 1999 and 2000. 

Whooping cranes of the AWBP occasionally associate with sandhill 

cranes during migration and RMP birds frequently associated with 

sandhill cranes. Substantial hunting of sandhill cranes and 

snow geese occurs in and adjacent to areas used by migrating and 

wintering AWBP whooping cranes. Hunters may misidentify and 

shoot whooping cranes as these species. Sandhill crane hunting 

29
DRAFT Whooping Crane Recovery Plan 2005 

seasons in Canada and the United States in the migration 

corridor were originally seasonally timed or geographically 

limited to protect whooping cranes (Buller 1967, Archibald et 

al. 1976, Thompson and George 1987). Recent expansions of 

sandhill crane hunting seasons offer an increased potential for 

overlap with whooping crane migration periods that may have 

increased the risks to whooping cranes (Konrad 1987, Brian 

Johns, pers. comm.). In some instances, larger land units have 

been closed to sandhill crane or waterfowl hunting due to the 

presence of a flock or flocks of whooping cranes. Quivira NWR 

in Kansas is closed during most fall migrations when whooping 

cranes stopover (David Hilley, pers. comm.). Tundra swan hunts 

recently initiated in the northern Great Plains (Montana, 1983; 

North Dakota, 1988; South Dakota, 1990), also present 

opportunities for misidentification of whooping cranes and 

accidental shooting. 

Disturbance: The whooping crane is sensitive to disturbance on 

the breeding grounds and will not remain near human activity. 

However the egg transfer and banding programs have demonstrated 

that cranes will tolerate human intrusion for short intervals. 

Some disturbances cause the birds to leave an area; the effects 

of others may be subtle. The public has no access to most of 

the whooping crane nesting habitat, but does have significant 

access to whooping crane winter habitat, as these water areas 

are public domain. Cranes are somewhat tolerant of people in 

carefully operated boats and land vehicles (Mabie et al. 1989), 

this is evidenced by the lack of concern cranes show for barges 

that travel along the GIWW. Airboats, low-altitude aircraft, 

and especially helicopters are more disturbing, and cranes are 

particularly sensitive to humans on foot (Lewis and Slack 1992). 

Crane displacement results in short-term or long-term loss of 

habitat and social disruption of the flock.

Listing Factor C: Disease or Predation.

Disease/Parasites: Little is known about the importance of 

diseases or parasites as mortality factors for wild whooping 

cranes. Loss of wetlands has concentrated birds using aquatic 

habitat, thereby increasing the risk of disease. For example, 

avian cholera epizootics occur fairly regularly in several areas 

used by cranes and this disease has been confirmed in one 

whooping crane. Additionally, human impacts on the environment 

and movements around the globe are resulting in emerging disease 

problems of possible significance to whooping cranes. For 

example, West Nile Virus appeared for the first time in North 

America in 1999, and is now spreading rapidly. Coccidia have 

30
DRAFT Whooping Crane Recovery Plan 2005 

been found in a whooping crane with an injured wing captured in 

WBNP, in whooping crane droppings collected on the Texas 

wintering grounds (Forrester et al. 1978), are common in cranes 

in the Florida release population (Spalding et al. 1996), and 

have caused deaths of several whooping crane chicks at PWRC 

(Carpenter et al. 1980). The defense of large territories and 

small brood size ensure low density use of the WBNP natal area, 

and thereby reduce the likelihood of coccidia oocysts being 

ingested in quantity sufficient to cause significant disease. 

However, the disseminated form of coccidiosis (DVC) is believed 

to have contributed to mortality of 2 released whooping cranes 

in Florida (Marilyn Spalding, pers. comm.) A variety of other 

parasites have been documented in released whooping cranes in 

Florida, but none have been shown likely to cause significant 

disease (Spalding et al. 1996). 

Although wild whooping cranes are presumably susceptible to a 

variety of infectious and toxicological diseases, evidence of 

disease-related mortality is only infrequently documented. From 

1976 to 1989, the USFWS necropsied or examined 25 whooping crane 

carcasses found dead in the field or removed from the wild 

because of sickness or debility. Of these, nine were diseased. 

Seven had avian tuberculosis (Snyder et al. 1997), a subadult 

crane captured in New Mexico was suffering from avian cholera 

(Snyder et al. 1987), and an adult died from acute lead 

poisoning (Brand et al. 1992, Snyder et al. 1992). The high 

incidence of avian tuberculosis indicates that whooping cranes 

may be particularly susceptible to this disease. 

Predation: Adult whooping cranes are generally not susceptible 

to predation unless they are weakened by disease or injury, or 

are flightless during feather molt. However, eggs and chicks 

are predated (Bergeson et al. 2001a). Potential predators in 

the WBNP nesting ground include the black bear (Ursus 

americanus), wolverine (Gulo luscus), gray wolf (Canis lupus), 

red fox (Vulpes fulva), mink (Mustela vison), lynx (Lynx 

canadensis), and raven (Corvus corax). Black bears and other 

mammals destroy eggs, and wolves, foxes, and ravens kill chicks 

(Kuyt 198la, 198lb, Bergeson et al. 2001a). The overall impact 

of predation on AWBP recruitment remains uncertain but may be a 

factor in the 10 year population cycle (Boyce et al. in prep). 

Predator control is not considered an appropriate management 

technique within Canadian National Parks. Whooping cranes are 

also exposed to predators during migration (Lewis et al. 1992a). 

On numerous occasions, golden eagles disrupted human-led 

sandhill crane migrations behind trucks and ultralights. In the 

west, two attacks on subadult whooping cranes were documented 

31
DRAFT Whooping Crane Recovery Plan 2005 

during migration. In 2002, a bald eagle killed a whooping crane 

hatchling in Florida. Bobcats (Lynx rufus) and alligators 

(Alligator mississippiensis) are significant predators on 

reintroduced whooping cranes in Florida. Bobcat predation 

appears most severe on individuals that do not show proper 

roosting behaviors or use habitat with heavy cover. Bobcats and 

coyotes also take cranes that are sick or injured at ANWR. 

Predation rates are significant in Florida, but appear to be 

very low in wild birds in Texas where cranes spend more time in 

coastal wetlands. 

Listing Factor D: the inadequacy of existing regulatory 

mechanisms. 

The whooping crane became endangered primarily from shooting and 

habitat loss prior to the enactment of major conservation 

legislation. The current legal framework (ESA, Migratory Bird 

Treaty Act, SARA, and NEPA) should provide for adequate 

protection and conservation of the whooping crane and its 

habitat. 

Listing Factor E: other natural or anthropogenic factors 

affecting its continued existence.

Multiple factors limit the growth of the AWBP. Some are part of 

the basic biological environment of the whooping crane, others 

are human-related. 

Life History: Delayed sexual maturity, small clutch size, and 

low recruitment rate preclude rapid population recovery. 

Nesting can occur as early as age 3 (Brian Johns, pers. comm.), 

with the average age of first egg production at age 5 and the 

first fertile eggs as 5.4 years (Kuyt and Goossen, 1978). The 

current northern breeding grounds may be another handicap to 

productivity because the ice-free season is only 4 months. 

During that time, pairs must incubate their eggs for 29-31 days, 

and rear their chicks to flight age in 3 months. Consequently, 

unless nest loss occurs early in incubation, there is rarely 

time to lay a second clutch and fledge young if the first clutch 

fails. 

Food Availablility/Sibling Aggession: About 734 crane chicks 

were observed to hatch at WBNP during 1976-2001, and 381 (59% 

survival) arrived at Aransas the following winter (Brian Johns, 

pers. comm). Factors limiting chick survival are only partially 

known. Most mortality occurs soon after hatching, and chicks 

that fledge have a high probability of successfully completing 

32
DRAFT Whooping Crane Recovery Plan 2005 

their first migration (Kuyt 1976a). Most immediate posthatching mortality may be related to sibling aggression and 

short-term food shortage because eggs hatch asynchronously and 

the precocial young are extremely aggressive toward each other. 

The dominant chick apparently obtains principal access to food 

made available by the parents; consequently brood-size is 

rapidly reduced during periods of food shortage (Drewien 1973, 

Miller 1973, Bergeson et al. 2001b). Prolonged food shortage, 

possibly related to drought, and drought-increased predation 

(Kuyt 1981b) may account for additional mortality. 

Severe Weather: Cold weather and precipitation soon after 

hatching may lead to loss of chicks; in particular, pairs with 

two young often lose one during these periods of adverse weather 

(Brian Johns, pers. comm.). While flooding of nests is thought 

to be rare, drought is a far greater hazard because the 

attractiveness of traditional nest sites is reduced, food 

supplies are diminished, and newly-hatched chicks are forced to 

travel long distances between wetlands. Drought conditions 

increase exposure of eggs and chicks to terrestrial predators. 

Whooping cranes are exposed to various natural obstacles and 

threats during migration. Snow and hailstorms, low 

temperatures, and drought can present navigational handicaps or 

reduce food and habitat availability. Hurricanes and drought 

can create problems on the wintering grounds. A late-season 

hurricane could place cranes at risk due to high wind velocities 

and flooding. Fortunately, the hurricane season ends (November 

30) just after most whooping cranes arrive. Drought at Aransas 

influences availability and abundance of the natural food supply 

by altering salinity of tidal basins and estuaries (Blankinship 

1976). 

Loss of Genetic Diversity: As a consequence of the 1941 

population bottleneck, the current population is derived from an 

estimated 6 to 8 founders, with a loss of 66% of all genetic 

material (Mirande et al. 1993, Glenn et al. 1999). 

Subsequently, the captive population, which is derived from the 

AWBP and one female from the Louisiana population, has received 

this legacy of genetic loss. This high level of diversity loss 

has serious implications for this population. 

Genetic theories suggest that small populations can continue to 

lose genetic diversity with each generation, and that continued 

loss of genetic material leads to inbreeding depression and 

declining productivity (Jimenez et al. 1994, Frankham 1995, Lacy 

1997, Brook et al. 2002, Woodworth et al. 2002). There is 

concern that the limited genetic material of the whooping crane 

33
DRAFT Whooping Crane Recovery Plan 2005 

may lead to reduced productivity in WBNP, and may contribute to 

increasing difficulty in captive propagation. 

Limited genetic diversity is a detriment to a population 

currently threatened with unprecedented global habitat change as 

well as introduced diseases. The AWBP is challenged to grow to a 

level where the creation of new alleles through mutation will 

offset its past, current, and future losses in genetic 

diversity. 

[A detailed discussion on genetic issues is presented in 

Appendix A.] 

Climate Change: The threat of global climate change may 

adversely affect the water regime of WBNP, with potentially 

severe impacts on whooping crane reproduction. Permanently 

lowered water tables, for example, would shrink wetlands, reduce 

the availability of quality nesting sites, reduce invertebrate 

food availability, and allow predators to access nests and 

young. On the winter area, a reduction in rainfall would reduce 

inflows and reduce the blue crab population that the cranes rely 

on. Global warming and associated sea level rise, combined with 

land subsidence, is projected to be about 17 inches on the Texas 

coast over the next 100 years (Twilley et al. 2001). This would 

reduce suitability of salt marsh and open water areas, making 

much of the present acreage too deep for use by whooping cranes 

(Tom Stehn, pers. comm.). 

Red Tide: Red tide (Gymnodinum breve) is a bloom of 

phytoplankton, a microscopic algae that historically occurred 

infrequently on the Texas Coast. In recent years, it has 

occurred nearly annually during late summer and fall, lasting 

for several months. It is not known what factors are causing 

the increased number of outbreaks of red tide. A toxin produced 

by the algae can concentrate in filter-feeding molluscs, 

including clams. It has been known to cause bird die-offs and 

could pose a significant threat to whooping cranes that in midwinter feed heavily on clams. Although red tide has been 

documented in Critical Habitat in recent years, no really severe 

outbreaks have occurred. 

 

Chemical Spills: The only self-sustaining wild population 

remains vulnerable to destruction through a contaminant spill, 

due primarily to its limited wintering distribution along the 

Gulf Intracoastal Waterway (GIWW) on the Texas coast. Numerous 

oil and gas wells and connecting pipelines are located in bay 

and upland sites near the cranes winter habitat. Many barges 

34
DRAFT Whooping Crane Recovery Plan 2005 

carrying dangerous, toxic chemicals travel the GIWW daily 

through the heart of whooping crane winter habitat. A spill or 

leak of these substances could contaminate or kill the cranes' 

food supply, or poison the cranes (Robertson et al. 1993). 

Spills that occur in summer, when whooping cranes are absent, 

could adversely affect survival by reducing productivity of the 

environment or leaving a toxic residue. 

Gulf Engineers and Consultants, Inc. (1992) assessed threats to 

the whooping crane and its habitat from spills of vessel fuels 

and cargoes. They concluded that the hazard of spill exists, 

but the probability of occurrence is low. Catastrophic events 

such as a large spill are infrequent, and therefore, difficult 

to predict. Ratification of the 1993 North American Free Trade 

Agreement and industrial growth in South Texas makes increased 

traffic likely on the GIWW, with a greater potential for 

accidents. Thus, the probabilities of occurrence of the most 

likely spill (1 per 1,075 years) and worst spill (1 per 7,982 

years)predicted by Gulf Engineers and Consultants, Inc. (1992) 

are likely conservative and may increase over time. The worst 

spill estimated by the Environmental Protection Agency (1992) 

would involve approximately 33,000 barrels of liquids. 

During summer, 1974, 25 to 50 barrels of crude petroleum leaked 

from a barge. The high viscosity of the oil, and the prompt 

action by clean-up crews, limited the spill to an area averaging 

about 1.6 m wide and extending 16 km along the canal. 

The U.S. Coast Guard (CG) has the lead responsibility for spill 

response and containment. The USFWS has response plans for the 

Gulf of Mexico (USFWS 1979) and specifically for Aransas NWR 

(Robertson et al. 1993). It is impossible to provide full 

protection for the cranes as long as chemicals are transported 

on the GIWW through the heart of winter range. Spills of 

hazardous chemicals may limit human approach to only those 

personnel wearing special protective suits and breathing 

apparatus. Spill of gaseous materials could directly kill all 

cranes downwind. The emphasis in the Aransas oil spill plan is 

for rapid response time to limit the amount of habitat impacted. 

Minimum response time by refuge staff is 1-2 hours, and 3-4 

hours for spill control specialists. An event occurring at 

night or in bad weather (the most probable times) would further 

slow response. High winds greatly reduce the effectiveness of 

containment booms for products floating on the surface. 

If crane habitat becomes contaminated, the Aransas oil spill 

plan calls for hazing cranes away from the spill area and 

35
DRAFT Whooping Crane Recovery Plan 2005 

capturing individuals that become seriously contaminated. 

The response of whooping cranes to spilled materials, and to 

humans trying to haze the cranes away, is currently unknown. 

Since adult cranes are territorial, it is likely not possible to 

haze them from their large territories. Food supplies such as 

grain or milo could be placed on the edges of crane territories, 

but the cranes would still return to salt marsh ponds at night 

for required safe roosting habitat. Oiled cranes would be 

captured when possible and cleaned, although wild cranes are 

very difficult to capture and susceptible to death from capture 

myopathy, especially when young. There is no magic fix and no 

satisfactory plan if a serious spill occurs (Tom Stehn, pers. 

comm.). 

Whooping cranes on the winter range are also exposed to 

contaminants associated with runoff from agricultural and 

industrial activities and subjected to risks associated with 

offshore and onshore gas and oil operations. Nearby Lavaca Bay 

was closed for multiple years to the harvesting of fish and 

crabs because of industrial pollution including high levels of 

mercury (Lewis et al. 1992b). 

Collisions with Power Lines and Fences: Human settlement in the 

prairies also brought rural electrification and the fencing of 

open lands. Collisions with power lines are a substantial cause 

of whooping crane mortality in migration (Brown et al. 1987, 

Lewis et al. 1992a). Collisions with power lines are known to 

have accounted for the death or serious injury of at least 30 

whooping cranes since 1956. In the 1980s, 2 of 9 radio-marked 

whooping cranes from AWBP died within the first 18 months of 

life as a result of power line collisions (Kuyt 1992). Of 27 

documented mortalities in the RMP, almost 2/3 were from 

collisions with power lines (40.1%) and wire fences (22.2%). 

Six individuals within the Florida populations and one 

individual in the migratory Wisconsin population have also died 

in collisions with power lines. 

Additional power line construction, throughout the principal 

migration corridor, will increase the potential for collision 

mortalities. Tests of line marking devices, using sandhill 

cranes as surrogate research species, have identified techniques 

effective in reducing collisions by up to 61% (Morkill 1990, 

Morkill and Anderson 1991, 1993, Brown and Drewien 1995). 

Techniques currently recommended include marking lines in areas 

frequently used by cranes and avoiding placement of new line 

corridors around wetlands or other crane use areas. 

36
DRAFT Whooping Crane Recovery Plan 2005 

Guy wires associated with telecommunication towers (radio, 

television, cellular, and microwave) present another collision 

obstacle to cranes. Such towers have been increasing at an 

estimated 6 to 8% annually. The USFWS Office at Grand Island, 

Nebraska, reviewed 260 tower site actions for Nebraska in fiscal 

year 2000. The Federal Communication Commission’s (FCC) 1999 

Antenna Structure Registry (November 1, 1999) listed 48,000 

lighted towers over 60.7 m above ground level and over 68,000 

towers total in the United States. They estimated 24 to 38% of 

the towers were not properly registered with FCC. By 2003, all 

television stations must be digitized, adding potentially 1,000 

new towers exceeding 305 m height. 

Collisions with Aircraft: One whooping crane was killed in June 

1982 during a KC-135 tanker takeoff from Minot Air Force Base, 

North Dakota (Harrison 1983). Feather remains were identified by 

the Smithsonian Institute. Whooping crane collisions with 

aircraft are anticipated to be rare because of the small number 

of whooping cranes. 

Pesticides: There is no evidence that pesticide contamination is 

a significant threat to whooping cranes. Whooping crane egg and 

tissue specimens examined for pesticide residues at PWRC have 

shown concentrations well below those encountered in most other 

migratory birds (Robinson et al. 1965, Lamont and Reichel 1970, 

Anderson and Kreitzer 1971, Lewis et al. 1992b). Eggshell 

thickness, a measure of contaminant exposure, has been measured 

from the 1970s to date in eggs taken from the wild and those in 

captivity. No evidence of shell thinning has been detected.

 

37
DRAFT Whooping Crane Recovery Plan 2005 

CONSERVATION MEASURES 

Before the mid-1950s, a few significant events helped protect 

whooping cranes. The most important pieces of early protective 

legislation for whooping cranes were the Migratory Bird Treaty 

Act in the United States and the Migratory Birds Convention Act 

in Canada. These acts were ratified by the U.S. Congress on 

December 8, 1916 and by the Canadian Parliament on August 29, 

1917. The Acts assured legal protection for migratory bird 

species in Canada and the United States and provided a basis for 

preventing the hunting of species requiring complete protection. 

The significance of the establishment of WBNP in the Northwest 

Territories in December 1922 was not realized until three 

decades later when the whooping crane nesting grounds were 

discovered there (Allen 1956). WBNP is a vast boreal forest and 

muskeg area (4,288,542 ha) designated by the Canadian government 

(Raup 1933) as a preserve and management area for the wood bison 

(Bison bison athabascae). The portion of the Park occupied by 

nesting whooping cranes is primarily located northwest of the 

intersection of the boundaries of Saskatchewan, Alberta, and the 

Northwest Territories (Kuyt 1978b). The location of the crane 

summering grounds allows them to be protected by provincial and 

territorial wildlife acts as well as the National Parks Act. 

The breeding grounds are also designated as a Wetland of 

International Importance by the RAMSAR Convention and an 

Important Bird Area in Canada. Some of the Canadian prairie 

wetlands used regularly by migrating whooping cranes have 

received protection as Migratory Bird Sanctuaries, National 

Wildlife Areas (NWA), or under the Saskatchewan Wildlife Habitat 

Protection Act. Also, several stopover areas are designated as 

Important Bird Areas in Canada. 

ANWR, purchased for $463,500 for the Bureau of Biological 

Survey’s refuge program, was established in 1937 to protect the 

whooping crane and other wildlife of coastal Texas (Stevenson 

and Griffith 1946, Howard 1954). Leroy Denman (San Antonio Loan 

and Trust) retained mineral rights. These rights included a 

clause that used oil and gas royalties to refund to the 

government the entire purchase price of the refuge. The Refuge 

includes 22,148 ha of Blackjack Peninsula and adjacent 

properties, and provides essential wintering habitat for 

whooping cranes. Matagorda Island (44,606 ha of State and 

Federal ownership) is managed in conjunction with Aransas. 

Adjoining bay waters (5,236 ha) surrounding the Blackjack 

Peninsula, known as the Proclamation Boundary, were closed to 

hunting of migratory birds by Presidential Proclamation in 1938 

38
DRAFT Whooping Crane Recovery Plan 2005 

for additional protection. 

In the U.S., the whooping crane was listed as Threatened with 

extinction in 1967 (Fed. Reg. Vol. 32, Number 48, March 11), and 

as Endangered in 1970 (Fed. Reg. Vol. 35, Number 199, October 

13). Both of these listings were “grandfathered” into the 

Endangered Species Act of 1973 (U.S.C., 1531-1 543; 87 Stat. 

884), which resulted in establishing the U.S. Whooping Crane 

Recovery Team and facilitated further conservation actions on 

behalf of the species. 

In 1974, the Canada Wildlife Act authorized the federal 

government to conduct research on endangered species. In 1976 

the Committee on the Status of Endangered Wildlife was 

established and the whooping crane was designated as Endangered 

in 1978 (Edwards et al. 1994). The Species at Risk Act was 

passed by the Canadian Parliament in 2002, which further 

protects the whooping crane. 

Critical Habitat 

Critical habitat is defined in the U.S. Endangered Species Act 

as habitat that contains those physical or biological features, 

essential to the conservation of the species, which may require 

special management considerations or protection. Critical 

habitat was designated in 1978 (Fed. Reg. Vol. 43, Number 94, 

May 15, U.S. Fish and Wildlife Service 1994). Critical habitat 

is in effect for 5 sites in 4 states. 

Wintering grounds: ANWR and vicinity, Texas (Fig. 3) has been 

designated as critical to the conservation of the species. At 

ANWR, the listing of critical habitat has been extremely 

important in protecting habitat along the GIWW. 

Migration – United States: Cheyenne Bottoms State Waterfowl 

Management Area and Quivira NWR, Kansas; the Platte River 

bottoms between Lexington and Denman, Nebraska; and Salt Plains 

NWR, Oklahoma have been designated as critical to the 

conservation of the species. 

Critical habitat is defined in the Canadian Species at Risk Act 

as habitat that is necessary for the survival or recovery of a 

listed wildlife species and that is identified as the species’ 

critical habitat in the recovery strategy or in an action plan 

for the species. Critical habitat is in effect for 3 sites in 2 

provinces and a territory. 

39
DRAFT Whooping Crane Recovery Plan 2005 

Breeding grounds: Critical habitat for survival is that portion 

of the northeast corner of WBNP that is bounded by the Little 

Buffalo River to the east and south, the north boundary of the 

park from the Little Buffalo River to Territorial Highway #5 and 

south along Highway #5 to 1140

 West Latitude, south at 1140 West 

Latitude to 600

 North Longitude then southeast to the Little 

Buffalo River closest to Conibear Lake. Critical habitat for 

recovery includes the marshes adjacent to the northeast corner 

of Wood Buffalo National Park bounded by the Buffalo River to 

the west, Highway 6 to the north and the Canadian Shield to the 

east. 

Additional habitat for recovery include wetlands available for 

re-introductions in other jurisdictions. There are ongoing 

studies to identify additional critical habitat that may be 

necessary for the recovery of the Whooping Crane. 

Migration – Saskatchewan Staging Area: During fall migration 

whooping cranes typically stop in south central Saskatchewan for 

several days or weeks. This area of Saskatchewan, which forms a 

diamond between Meadow Lake, Swift Current, Estevan and the 

Quill Lakes can be described as a staging area for whooping 

cranes. The cranes spend their evenings roosting in shallow 

wetlands, while their days are occupied with feeding in 

harvested agricultural fields, chiefly wheat and barley (Johns 

et al. 1997). Fall staging wetlands are primarily on private 

lands (85%)(Johns et al. 1997). Few wetlands are used repeatedly 

from one year to the next since most staging wetlands are 

ephemeral and their availability to cranes fluctuates annually 

due to variations in precipitation. Preferred staging wetlands 

have the following characteristics: permanently (32%) or 

semipermanently (53%) flooded; soft mud bottoms (83%); almost 

any size from less than 1⁄2 ha to several thousand hectares; water 

depths at roost sites average 13 cm (SD 7.5); roost sites are 

generally within 2 km of suitable feeding areas (agricultural 

fields) and are usually over 1 km from human habitation (Johns 

et al. 1997). 

Large wetlands with a secure water supply are extremely 

important as staging sites since they provide refuge when 

ephemeral wetlands are dry. The Last Mountain Lake and Stalwart 

National Wildlife Areas and the Last Mountain Lake Migratory 

Bird Sanctuary are used repeatedly by cranes and are deemed 

critical to the survival and recovery of the species. The South 

Saskatchewan River and its sandbars between Outlook and 

Saskatoon is also deemed critical to the survival and recovery 

of the species. 

40
DRAFT Whooping Crane Recovery Plan 2005 

Due to the ephemeral nature of most prairie wetlands and their 

use by whooping cranes, no further specific critical habitat 

designations can be made at this time. However, several 

additional areas do exhibit repeated use by whooping cranes and 

may be considered critical at some time in the future. These 

specific wetlands and adjacent smaller wetlands in their 

vicinity are: Midnight Lake, Witchekan Lake, Blaine Lakes, 

Radisson Lake, Buffer Lake, Muskiki Lake, Quill Lakes, Kutawagan 

Lake, Luck Lake, Creelman Marsh and wetlands near Tribune and 

Bromhead. 

In addition, the uplands on provincial crown land associated 

with known roosting sites for whooping cranes have been 

protected under the Saskatchewan Wildlife Habitat Protection 

Act.

RECOVERY TEAM

 

The Canada/United States Whooping Crane Recovery Team consists 

of 5 representatives from Canada and 5 from the U.S. appointed 

by CWS and USFWS, respectively. The team, co-chaired by the 

whooping crane coordinators of the two countries, is responsible 

for making recommendations on actions needed to recover the 

species. After approval is received from the wildlife agencies 

of the two countries, then recovery actions are implemented 

whenever possible. 

Whooping crane recovery teams were initially formed in 1975 in 

the U.S. and 1985 in Canada, though ad hoc committees were in 

existence before that. Whooping crane coordinators were 

appointed in 1981 in Canada and 1984 in the U.S. In 1995, the 

separate recovery teams from both countries were joined as an 

international team. A Memorandum of Understanding (MOU) on the 

conservation of the whooping crane signed in 1985 and renewed 

periodically governs recovery actions that are outlined in a 

recovery plan written by the team. 

INFORMATION NEEDS 

Survey Requirements 

Aerial population surveys are a continuing need on nesting and 

winter areas. There remains a need to identify unoccupied but 

potential nesting and winter habitat to identify any limitations 

on population growth. Some of these habitats may require 

protection by purchase, lease, or legal action. Water level 

41
DRAFT Whooping Crane Recovery Plan 2005 

surveys are a necessity in WBNP to fully understand ecological 

changes and their impact on population trends. Surveys of 

coastal water salinity levels, freshwater inflows, and crane 

food resources will continue to be necessary on the winter area 

at Aransas to identify ecological trends. Migration activities 

must be monitored to ensure safety of the cranes and evaluate 

changes in conditions faced on the long biannual journey. 

Biological/Ecological Research Requirements 

Causes of mortality in wild and captive cranes should continue 

to be identified and addressed. Frequent monitoring of the 

birds will be required to detect losses. Such monitoring will 

require radio tracking or satellite tracking of wild birds in 

some instances. Further understanding of migration stopover 

habitat is needed to refine the effectiveness of habitat 

augmentation and management on the Platte River and elsewhere. 

Additional research is necessary to refine methods of creating 

marsh habitat with dredged sediments to ensure long-term 

benefits to whooping cranes. For captive populations, research 

needs include refining means of disease prevention, pairing and 

promoting early breeding, genetic management, nutrition of 

captive birds, and behavioral training to promote wildness in 

birds destined for release in the wild. Research is continuing 

to refine reintroduction techniques for establishing a second 

migratory population to promote appropriate migratory behavior 

and survival. In 2001 the Whooping Crane Health Advisory Team 

(WCHAT) identified the high priority research needs in captivity 

as: (1) the effect of West Nile virus on cranes and development 

of a vaccine, (2) developing a more effective TB test for 

screening whooping cranes, and (3) developing a fecal 

corticosterone test to compare levels of stress associated with 

various management techniques in captivity.

Threat Clarification Research Requirements 

Research already identified is needed to further define 

potential threats. For example, the impact that anticipated 

reduced freshwater inflows at Aransas will have on salinity, 

winter food resources, and population survival needs to be 

quantified. Continued research on mortality in reintroduced 

populations is another example. Such losses threaten the 

success of the reintroductions. Research is also needed to 

derive techniques to separate family lines so management of the 

captive flock can be improved, to preserve and increase the 

genetic diversity of the flock. 

42
DRAFT Whooping Crane Recovery Plan 2005 

RECOMMENDED SCALE FOR RECOVERY ACTIONS 

Recovery plans are usually produced for individual species. 

However, their habitat management recommendations often benefit 

numerous wildlife species. Therefore, the recommendations in 

this plan vary from specific objectives for crane management to 

larger scale habitat objectives. For example, habitat 

restoration in the Platte River Valley of Nebraska benefits 

other endangered species as well as other wildlife. 

Consequently, recovery activities described within this plan are 

integrated with larger-scale recovery efforts wherever possible.

ANTICIPATED CONFLICTS OR LOGISTICAL DIFFICULTIES 

There are no unique conflicts or logistical difficulties that 

can be identified at the present time. There will continue to 

be challenges of the type that impede new research and untested 

recovery techniques. Budgetary constraints are always potential 

difficulties in fulfilling recovery goals. 

POTENTIAL IMPACTS FOR OTHER SPECIES/ECOLOGICAL PROCESSES 

Management impacts are generally beneficial for other species. 

Preservation and management of crane habitats will benefit those 

species that already inhabit such sites. For example, 

protecting freshwater inflow into coastal areas will benefit all 

native coastal species. A possible exception is predators 

(e.g., alligator, bobcat, wolf, fox, raven, and coyote) if 

predator control becomes necessary in nesting or winter habitats 

in the initial stages of reintroduction. A few bobcats and 

alligators have been removed from reintroduction sites in 

Florida. Hunting seasons for whooping crane look-alike species 

may be affected by the presence of whooping cranes. These issues 

are discussed in THREATS AND REASONS FOR LISTING – Hunting. 

43
DRAFT Whooping Crane Recovery Plan 2005 

PART II. RECOVERY 

The following section presents a strategy for recovery of the 

species, including objective and measurable recovery criteria 

and site-specific management actions to monitor and reduce or 

remove threats to the whooping crane, as required under section 

4 of the Endangered Species Act (ESA) and under section 41 of 

the Species at Risk Act (SARA). The Recovery Plan also has 

addressed the five statutory listing/recovery factors (section 

4(a)(1) of the ESA) and the short and long term goals of the 

SARA (section 41(1)(d)) to the current extent practicable, to 

demonstrate how the recovery criteria and actions will lead to 

removal of the whooping crane from the List of Threatened and 

Endangered Species. 

STATUS REVIEW 

In the U.S., under Section 4(a)(2) of the ESA, the USFWS is 

charged with periodically reviewing the status of listed species 

to determine whether any species warrants reclassification. The 

Committee on the Status of Endangered Wildlife in Canada 

(COSEWIC) reviewed the status of the Whooping Crane in 1978 and 

again in 2000. The whooping crane was listed as an endangered 

species in Canada under the Species at Risk Act in 2003. 

COSEWIC must review the classification at least once every ten 

years. In both countries, the whooping crane remains endangered 

because of its low population size and the limited range of the 

single self-sustaining wild population. 

RECOVERY STRATEGY 

The recovery strategy involves: protection and enhancement of 

the breeding, migration, and wintering habitat for the AWBP to 

allow the wild flock to grow and reach ecological and genetic 

stability; reintroduction and establishment of self-sustaining 

wild flocks geographically separate from the AWBP to ensure 

resilience to catastrophic events; and maintenance of a captive 

breeding flock to protect against extinction. 

Work will continue to reduce existing threats (habitat loss and 

degradation, disease, mortality from power lines, loss of 

genetic diversity), as well as new threats that may arise. 

Because of the limited range of the AWBP in both summer and 

winter (i.e., pioneering new habitat is limited to areas 

adjacent to existing use areas), efforts have been initiated to 

reintroduce a second population in Florida and a third 

population in the eastern U.S. These additional populations 

44
DRAFT Whooping Crane Recovery Plan 2005 

provide protection against extinction of the species in the 

wild, in the event that a catastrophic event impacts the AWBP, 

or if that flock slowly begins to decline in size. These 

reintroduced populations must be geographically isolated from 

the AWBP so that potential negative influences of the captiveraised birds do not impact the AWBP. Negative factors could 

include disease transmission and behavioral differences, 

including vocalizations. Further, reintroduced populations 

listed as experimental nonessential under Section 10(j) of the 

ESA are required to be geographically distinct from existing 

wild populations. 

In order to be genetically viable over the long-term, the 

whooping crane population must be large enough so that creation 

of new alleles through genetic drift will offset the loss of 

genetic material in a small population. Growth of the AWBP and 

the two reintroduced populations are expected to ultimately 

increase numbers to a level at which the population should not 

lose any more genetic material. 

RECOVERY POTENTIAL AND RATIONALE 

With its low reproductive rate and the many threats to breeding, 

migration, and wintering habitat, it is unlikely the whooping 

crane will ever become abundant. Conservation of this species 

will require vigilant management and the interest and concern of 

an informed public. 

However, based upon overall habitat availability, a positive 

growth rate, and success in captive breeding, the potential for 

continued survival of the species and ultimate recovery is good. 

Average annual population growth in the AWBP was 4% from 1938-

1991. Based on this growth rate, Mirande et al. (1993) 

projected the AWBP population to reach 500 individuals within 17 

years, with no measurable probability of extinction over 100 

years. 

The inherent capacity of whooping cranes to rebound 

demographically is low due to delayed sexual maturity (age 3-4 

years) and a low reproductive rate (2 eggs in the annual nesting 

attempt with only 1 chick typically fledging). Nevertheless, if 

breeding pairs are protected from excessive mortality, a 

breeding pair’s breeding experience and longevity can compensate 

for low reproductive rate. As nesting pairs gain experience, 

they become more successful in rearing chicks. At the same 

time, cranes can reproduce over a relatively long lifetime: 3 to 

45
DRAFT Whooping Crane Recovery Plan 2005 

5% are predicted to live and remain productive beyond age 30 

years (Mirande et al. 1993). 

 

The present nesting habitat at WBNP may not be as productive as 

the major historical nesting wetlands in the prairie grasslands. 

(Brian Johns, pers. comm.). However, WBNP provides suitable 

protected nesting habitats that have supported population 

recovery from 3 or 4 nesting pairs in 1941 to 61 pairs in 2003. 

Sufficient migratory stopover habitat is available to support 

the present population and numbers likely to be attained in the 

near future. Winter habitats at Aransas are presently 

sufficient to support at least 500 individuals (Tom Stehn, pers. 

comm.). However, uncertainty remains about possible long-term 

declines in suitable habitat as a consequence of expanding human 

populations and their demands for fresh water, housing, 

recreation, agricultural production, and industrial products. 

Some of the prime historical grassland nesting habitat could be 

restored in southern Canada and the northern United States. 

However, such actions would be costly, require purchase of large 

land blocks, and restoration of wetlands. 

Threats to whooping cranes have been alleviated to a degree 

sufficient to allow an average annual growth of 4.5% for a half 

century in the AWBP. The Cooperative Protection Plans 

implemented by provincial, state and federal agencies are 

believed to reduce losses to shooting and disease (Lewis 1992). 

Some power lines are being marked to make them more visible, a 

technique shown to reduce sandhill crane collisions with power 

lines (Morkill 1990, Morkill and Anderson 1991, Brown and 

Drewien 1995), that would also help reduce whooping crane 

mortality. Erosion losses of critical winter habitat along the 

Gulf Intracoastal Water Way have been reduced significantly 

through the use of concrete matting (Zang et al. 1993, Evans and 

Stehn 1997). Dredged material has been used to create winter 

habitat (Evans and Stehn 1997). 

 

Four captive flocks, those at Calgary, ICF, PWRC, and San 

Antonio Zoological Gardens, are producing offspring. Captive 

production has been sufficient to provide over 268 birds for the 

non-migratory reintroduction experiment in Florida since 1993. 

Another reintroduction using captive-produced young was started 

in 2001 in the eastern U.S with Wisconsin as the proposed 

nesting area and western Florida the wintering site. 

 

46
DRAFT Whooping Crane Recovery Plan 2005 

RECOVERY GOAL: 

The goal of this plan is to protect the whooping crane and its 

habitat, and allow the overall population to reach a level of 

ecological and genetic stability so that it can be reclassified 

to threatened status (downlisted). The ultimate goal is to 

recover the whooping crane and remove it from the List of 

Threatened and Endangered Species (delist). However, because of 

the length of time expected to reach downlisting goals, and 

because of current information gaps in our knowledge of the 

species, it is not feasible to establish delisting objectives 

and criteria at this time. 

DOWNLISTING RECOVERY OBJECTIVES AND CRITERIA: 

This plan sets forth 2 primary objectives and measurable 

criteria that will allow the species to be reclassified to 

threatened (downlisted). These numerical population criteria 

can only be achieved if threats to the species’ existence are 

sufficiently reduced or removed, i.e., the population criteria 

are a benchmark for threat reduction. Specific actions to 

reduce these threats are addressed in the narrative outline 

(page 52) and are cross-referenced with the listing factors 

(page 66). 

Objective 1 – Establish and maintain self-sustaining populations 

of whooping cranes in the wild that are genetically stable and 

resilient to stochastic environmental events. 

Criterion 1 – Maintain and allow for a continued increase 

of the AWBP at a minimum of 40 productive pairs, and 

establish a minimum of 25 productive pairs in selfsustaining separate populations at each of 2 other discrete 

locations. 

A productive pair is defined as a pair that nests regularly 

and has fledged offspring. The two additional populations 

may be migratory or non-migratory. Multiple populations 

provide protection against stochastic, catastrophic events 

in nature. A single wild population remains vulnerable to 

extinction during one, or a series, of adverse events, 

regardless of its size. 

Population targets are 160 in the AWBP, and 100 each in the 

Florida non-migratory population and the eastern migratory 

population. These numerical objectives are based partly on 

a population viability assessment of what is needed to 

47
DRAFT Whooping Crane Recovery Plan 2005 

maintain genetic material for the population (see Appendix 

A). All 3 populations must be self-sustaining for a decade 

at the designated levels before downlisting could occur. A 

self-sustaining population is defined as a stable or 

growing population without any additional reintroductions 

from captivity. Although the 61 nesting pairs that the 

AWBP reached in 2003 exceeded the minimum number 

established in the downlisting criterion, two additional 

self-sustaining populations have not yet been established. 

 

Alternative Criterion 1 - If a second and third wild 

population cannot become self-sustaining, then the AWBP 

must be self-sustaining and remain above 1,000 individuals 

(i.e. 250 productive pairs) for downlisting to occur. The 

Memorandum of Understanding on Conservation of Whooping 

Cranes, approved by Canadian and U.S. federal officials, 

recognizes a goal of 1,000 individuals in the AWBP 

population. These higher numbers are needed to ensure a 

better chance for survival because the AWBP currently has a 

very limited range and could be decimated by a catastrophic 

event. The target of 1,000 is reasonable for downlisting 

given the historical growth of the AWBP, its low 

probability of extinction (Mirande et al. 1993), and 

theoretical considerations of minimum population viability 

(Salwasser et al 1984). To ensure sufficient genetic 

variability, the AWBP must increase to the level where the 

creation of new alleles through genetic drift will offset 

the loss of genetic diversity. After reaching the goal of 

250 pairs, the population should gain genetic variation 

faster than the population loses genetic material. 

Objective 2 – Maintain a genetically stable captive population 

to ensure against extinction of the species. 

Criterion 2 - Maintain 153 whooping cranes in captivity (21 

productive pairs). Genetic analysis suggests that these 

numbers can maintain 90% of the genetic material of the 

species for 100 years (Jones and Lacy 2003). To achieve 

this, this Plan recommends having 50 captive breeder pairs 

of whooping cranes by 2010, including 15 pairs at PWRC, 12 

at ICF, 10 at CZ, 10 at ACRES, and 3 at the San Antonio 

Zoo. A breeder pair (as differentiated from a productive 

pair) is defined as a pair that breeds or is intended to 

breed in the future. Production from ACRES, CZ, ICF and 

PWRC will be the principal source of birds for release to 

the wild for reintroduced populations. However, sources of 

48
DRAFT Whooping Crane Recovery Plan 2005 

release birds should be based on the optimal genetic mix to 

ensure long-term population viability. 

Delisting Criteria 

It is not feasible to establish well-defined objectives and 

criteria for delisting at this time. The extremely endangered 

status and the slow reproductive rate of the species dictate 

that considerable time will be needed to reach downlisting 

goals. Considering the historic slow growth of the AWBP and the 

challenges of reintroducing populations, downlisting is unlikely 

to be reached before year 2035. It is unrealistic to predict 

the environment and threats to the species that will prevail at 

that time. New threats are expected to manifest and will have 

to be overcome before downlisting occurs. Additional 

information is also needed regarding the conservation biology of 

very small populations, including impacts of stochastic and 

catastrophic events on survival. For whooping cranes, the 

effective population size (Ne) required to maintain genetic 

viability over the long-term needs to be calculated. Appendix A 

provides detailed information on genetic issues and conservation 

of small populations. 

De-listing criteria will require a population target established 

with a high level of confidence. Without knowledge of a minimum 

size of the population needed to ensure species survival, it 

would be unreasonable to provide delisting criteria. Current 

estimates of the population needed to ensure survival range 

widely between 1,000 and 7,000 and would provide little 

confidence if a specific numerical target for delisting were set 

at this time. With additional knowledge regarding the dynamics 

and long-term survival of very small populations, numerical 

population targets can be set to remove the whooping crane from 

the List of Threatened and Endangered Species. 

New information gathered through recovery actions will be 

incorporated into additional population viability analysis as 

the population approaches its downlisting goals. Delisting 

criteria will be established at that time, and the overall 

recovery strategy and actions will be revised as appropriate. 

Future revisions of this recovery plan are anticipated, and a 

delisting goal for the species will be set prior to downlisting 

anticipated in 2035. 

49
DRAFT Whooping Crane Recovery Plan 2005 

2003 SARA RECOVERY OBJECTIVES 

In Canada, the 1978 COSEWIC designation of the whooping crane as 

endangered did not include a formal list of recovery objectives 

and actions later required under section 41(1)(d) of the 2003 

SARA. The section below describes the recovery objectives and 

actions proposed and/or underway. 

SHORT-TERM RECOVERY OBJECTIVES 

Objective 1: The short-term recovery objective of 40 productive 

pairs in the AWBP for 10 consecutive years has been 

met. To reach the long-term recovery goal of 1000 

birds in North America by the year 2035 the AWBP 

needs to increase to 240 individuals and 70 

productive pairs by 2010. 

Objective 2: Increase the captive populations to 45 breeding 

pairs by 2010. 

Objective 3: Increase FP to 100 individuals and 10 productive 

pairs by 2010. Establish a third population 

containing 80 adults by 2010. 

Objective 4: Analyse banding data and determine the Ne/N ratio 

for the AWBP. 

Objective 5: Promote education on whooping crane recovery 

through innovative media technologies. 

 

LONG-TERM ACTIONS NEEDED 

1. Continue to build the AWBP and protect and manage its habitat 

to minimize the probability that a catastrophic event will 

eradicate this population. 

2. Attain breeder pair and productivity goals at 4 captive 

facilities in the United States and 1 in Canada to produce 

the birds required for reintroductions. Continue research to 

improve production of captive flocks. 

3. Establish 2 additional self-sustaining wild populations 

separate from the AWBP. Continue research to identify 

appropriate reintroduction sites and improve reintroduction 

techniques. Protect and manage habitat of reintroduced 

populations. 

50
DRAFT Whooping Crane Recovery Plan 2005 

4. Continue to use genetic information and advances in 

conservation biology to determine Ne and revise criteria as 

warranted. 

5. Maintain an information/education program. 

51
DRAFT Whooping Crane Recovery Plan 2005 

NARRATIVE OUTLINE FOR RECOVERY ACTIONS TO ACHIEVE OBJECTIVES 

1. Increase the AWBP 

Reduce mortality and remove habitat constraints that might 

limit population recovery. The nesting and winter habitats 

appear to have potential to support substantially more than the 

61 nesting pairs and the associated subadults and young-of-theyear present in 2003 (Johns 1998a, Brian Johns, pers. comm., Tom 

Stehn, pers. comm.). 

 

For those birds still identifiable by color marking, 

determine longevity and record movements in response to habitat 

changes. Identify pairs on summer and winter territories to 

determine adult survivorship and productivity by recording 

unison calls and analyzing sonograms as developed by Dr. Bernard 

Wessling. Measure chick survival in WBNP in relation to food 

supply, water levels, predation and weather conditions. Analyze 

data to estimate population size, amount of habitat, and 

recruitment needed to achieve recovery goals. Develop 

management options by comparing mean annual population growth 

rates with and without egg manipulation practices. Periodically 

update the Population Viability Assessment as new data and 

improved models become available. 

1.1. Monitor population numbers, including annual recruitment 

and mortality. 

 

Conduct aerial population censuses on nesting and wintering 

areas to determine status and distribution. Nesting ground 

surveys will include: numbers of nests, location of 

territories, and clutch size (May); habitat conditions, nesting 

success, and chick survival (June); and habitat conditions and 

fledging (August). Weekly winter surveys will determine 

population size and number of juveniles, delineate territories, 

and detect mortality. Annual surveys of nesting and wintering 

areas should provide a record of each pair’s annual 

productivity. 

1.1.1. Conduct aerial surveys in WBNP to determine 

distribution, productivity, recruitment and 

mortality. 

 

52
DRAFT Whooping Crane Recovery Plan 2005 

1.1.1.1. Analyze data on egg management and develop a 

strategy to maximize size of the AWBP. Develop 

management options regarding egg manipulation. 

1.1.1.2. Monitor habitat in WBNP, including water levels 

and crane foods. Expand the surface-water 

monitoring network to measure water level 

fluctuations and their effect on nesting success. 

Define specific factors that impact cranes in 

relation to water levels in WBNP. 

1.1.2. Conduct aerial surveys at ANWR to determine total 

population numbers, movements, territories, and 

mortality. 

1.1.2.1. Monitor food resources and salinities and relate 

to energy budgets of the cranes and winter 

mortality. Hire a technician to carry out this 

task. 

 

1.2. Monitor movements in migration. 

Continue spring and fall migration monitoring to identify 

and map migration stopover habitat, and provide opportunities 

to protect birds from disease outbreaks, shooting, collisions 

with power lines, and to protect traditional migration stopover 

sites. Continue the whooping crane reporting network to 

document sightings. 

1.3. Reduce mortality. 

Whooping cranes disappear from unknown causes during most 

years. Spring migration, summer, and fall migration are the 

periods that should receive emphasis to further diminish 

mortality of fledged birds (Lewis et al. 1992a). However, 

management actions need to be taken wherever they can 

effectively reduce mortality, regardless of relative rates of 

losses. Determine mortality factors, measure impacts, and 

carry out strategies to reduce losses. Aerial surveys on the 

nesting and wintering areas help detect losses and their 

causes. Determine mortality factors in WBNP and ANWR on adults 

and chicks and develop strategies to increase survival. 

Utilize satellite telemetry to determine causes of most 

mortality occurring during migration. Develop methods to 

address mortality factors not considered in subtasks below. 

1.3.1. Prevent shooting. 

53
DRAFT Whooping Crane Recovery Plan 2005 

Federal, provincial and state wildlife agencies should 

continue to follow and update contingency plans for 

protection of whooping cranes that appear in hunt areas or 

other hazardous situations. Continue to work with provincial 

and state agencies to minimize conflicts between sport 

hunting and whooping cranes. Continue education programs, 

including identification brochures for hunters, to increase 

competency of the public to identify whooping cranes and 

their protected status. Create a web site that offers an 

identification guide for whooping cranes and look-alike 

species. Continue public outreach programs to prevent 

shootings and inform the public of the need to report 

sightings. 

1.3.2. Diminish losses to disease. 

Develop methods of disease prevention, detection, and 

treatment for avian tuberculosis, West Nile Virus (WNV), 

Eastern Equine Encephalitis (EEE), and parasites. When 

possible, prevent whooping crane use of areas where waterfowl 

disease outbreaks are underway or have recently occurred. 

The Contingency Plan for Cooperative Protection of Whooping 

Cranes covers response to disease incidents. Response will 

be directed by the Canadian Cooperative Wildlife Health 

Centre (CCWHC) in Canada and the National Wildlife Health 

Center (NWHC) in the United States. Disease research will 

determine where prevention and control methods should be 

directed, and whether control will involve site modification, 

inter-specific separation, individual prophylaxis, or a 

combination of responses. WCHAT will continue to provide 

advice and recommendations to the Recovery Team on all health 

issues. 

1.3.3. Reduce collisions/mortality. 

Collisions with power lines and fences are a frequent 

cause of death or injury. Use telemetry to locate areas 

receiving high crane use and locations where power lines are 

a significant problem. Monitor the placement and design of 

all new power lines in areas of known crane use. When 

possible, bury new power lines or route around areas 

frequently used by whooping cranes making low-level flights. 

Mark existing problem lines or modify fences to reduce 

collisions. Remove unnecessary fences and power lines from 

traditional stopover sites, Critical Habitat, National 

Wildlife Areas, National Wildlife Refuges and National 

54
DRAFT Whooping Crane Recovery Plan 2005 

Wetland Areas used by cranes. Barbed wire fences should be 

of no more than 3-strand design. Visibility should be 

maximized on any existing structures or those, which of 

necessity, must be constructed in whooping crane use areas or 

flight routes by following USFWS and/or CWS guidelines to 

reduce bird strikes. USFWS has issued interim guidelines for 

recommendations on communication tower siting, construction, 

operation and decommissioning. If communication equipment 

cannot be co-located on existing towers and a new tall tower 

is built requiring guy wires, the wires should have visual 

markers in place to reduce bird strikes. If possible, towers 

should be kept less than 61 m in height with a larger tower 

base and no guy wires. Tower lights for aviation safety 

should have flashing white strobe lights rather than 

continuous lighting. If guy wires are unavoidable, the wires 

should be marked. The Recovery Team should stay in contact 

with the Avian Power Line Interaction Committee to stay 

appraised of new developments in collision reduction. 

1.4. Restrict detrimental human activities. 

Cranes need to be protected from disturbance, especially in 

migration and on wintering areas. Disturbance can result from 

activities such as petroleum exploration, mining, hunting, 

fishing, bird watching, and boat and airplane traffic. The 

cumulative effect on cranes should be evaluated. Sources and 

intensity of disturbance are expected to increase in the 

future. Human activities should be monitored, regulated and/or 

prohibited wherever they cause problems for the cranes. 

1.4.1. Restrict construction periods. 

Conduct seismic exploration, drilling, pipeline activity, 

dredging, and other development or construction activities 

within or near migration and wintering habitat only when 

cranes are absent. Accomplish scheduling through federal, 

provincial, and state permitting procedures and by agreement 

with the company or agency involved. 

1.4.2. Restrict aircraft altitude. 

An altitude restriction of 610 m minimum, required by 

Canadian and U.S. regulations over nesting and winter 

habitat, is particularly important in regulating helicopter 

flights. Biological survey flights, research, and emergency 

situations, including unusual weather conditions, should be 

the only exceptions to these restrictions. 

55
DRAFT Whooping Crane Recovery Plan 2005 

1.5. Identify, protect, manage, and create habitat. 

 

Determine availability of suitable habitat for breeding, 

staging, migrating, and wintering, including spatial needs and 

territories of an expanding population. 

1.5.1. Identify essential habitat. 

Suitable breeding habitat that is currently unoccupied by 

whooping cranes should be identified. Complete the mapping 

of these habitats using available satellite imagery. 

Evaluate the potential of Northwest Territories and Alberta 

summer habitats to support a population of 1,000 birds. 

Additional study is needed to delineate areas that are 

important to migrating whooping cranes. Utilize satellite 

telemetry to identify additional stopover sites. Describe 

the unique characteristics of such habitat. Solicit reports 

and record sightings of whooping cranes by qualified 

observers. 

Identify food and water requirements of an expanding 

crane population in nesting, migration and winter habitats. 

Investigate spatial needs of nesting and wintering adult 

pairs, family groups, and subadult groups to understand 

territorial defense behaviors that influence habitat 

requirements. 

1.5.1.1. Measure food resources. 

The food base for cranes on sites utilized by cranes 

and areas not utilized should be sampled. Describe the 

food complex that seems attractive and supports crane 

needs. Relate this information to the evaluation of the 

ability of summer and winter habitats to support 1,000 

whooping cranes. Obtain more information on blue crab 

populations in the crane marshes at Aransas. The food 

needs and energetics of whooping cranes during migration 

should be studied. 

 

1.5.2. Protect habitat. 

In 2003 there were 3 pairs of whooping cranes nesting 

outside the boundaries of WBNP. As the population grows, 

more birds will begin to nest outside the park. Identify, 

56
DRAFT Whooping Crane Recovery Plan 2005 

map, and protect additional breeding habitat adjacent to 

WBNP. 

Ensure long-term protection of migration stopovers sites, 

including staging areas in southern Saskatchewan and 

traditional stopovers along the Platte River, Nebraska. 

Ninety-five percent of the stopover sites in Canada are in 

private ownership (Johns et al. 1997). Work with landowners 

to ensure that habitat remains suitable for cranes. Several 

traditional stopover areas along the migration route in the 

United States have been designated as critical habitat. 

Identify, map, and protect additional important migration 

stopover areas. Conservation of stopover habitat should 

primarily focus on providing wetland mosaics (Richert et al. 

in press). Complete analysis of whooping crane habitat 

availability in Kansas and Texas. 

Protection is also needed for winter habitat required to 

accommodate an expanding crane population that uses lands in 

public and private ownership. The threat of increasing human 

population growth, activities and development, which would be 

detrimental to the cranes and their habitat, makes it highly 

desirable to protect these areas. In most instances, 

protection would not significantly alter current uses. Where 

non-refuge lands are involved, work with owners/managers to 

ensure that habitat remains suitable for cranes. When 

necessary, lease or purchase critical sites. Purchase fee 

title or conservation easements for all essential marshes 

used by whooping cranes during winter. Study range expansion 

at Aransas and provide protection, including conservation 

easements, on areas that a larger whooping crane population 

will occupy. Complete protection for 100 hectares of salt 

marsh and adjacent uplands on the Johnson Ranch located on 

Lamar Peninsula. The area used historically for wintering 

along the Texas coast, including ANWR and Matagorda Island, 

has been declared critical habitat under the ESA. With the 

population wintering in a larger area, 8 crane territories 

were located outside critical habitat in the 2001-02 winter. 

Evaluate the need to expand critical habitat boundaries at 

Aransas and in the migration corridor to ensure protection of 

all important U.S. whooping crane habitats. 

1.5.2.1. Prevent contamination of habitat. 

Preventive measures range from efforts to minimize 

existing damage to the long-range efforts to reduce the 

potential for contamination of habitat. Work with resource 

57
DRAFT Whooping Crane Recovery Plan 2005 

agencies in Texas to ensure that pollution is minimized 

during the rapid population and industrial growth that is 

occurring. Work with the Coast Guard and marine 

transportation industry to reduce the risk of chemical 

spills. Whooping crane protection should be specified 

explicitly in contaminant spill contingency plans which 

involve state, federal, and provincial agencies along with 

local oil spill control groups in efforts to contain and 

clean up leaks and spills which could impact whooping crane 

habitat. Ensure that response personnel are sufficiently 

trained and equipped. 

 

The USFWS should coordinate with the appropriate regulatory 

agencies all aspects of the oil and gas industry within 

whooping crane habitat. Encourage responsible agencies to 

inspect facilities to see that they conform to regulations 

and, if needed, to modify regulations to provide protection 

for cranes. For example, Quivira NWR is an important 

stopover site for migrating whooping cranes. The refuge 

contains numerous oil and gas wells where spills could 

occur. However, each production site is surrounded by a 

containment levee to ensure site protection if an accident 

occurs. 

1.5.2.2. Prevent erosion of winter habitat at Aransas. 

Erosion structures need to be monitored and maintained 

to remain effective. Other winter crane use areas need to 

be monitored for erosion. 

1.5.2.3. Better manage deposition of dredge material. 

Permit applications for dredging projects should be 

reviewed carefully and modified if they are incompatible 

with whooping crane management objectives. Solutions 

include re-use of existing disposal sites by removal of 

dredged material after it dries, and barging or pumping of 

dredged material to sites away from the marsh. Continue 

experiments to create new crane marsh habitat with dredged 

materials. Implement the USACE 50-year Dredge Material 

Plan, which calls for creation of 654 ha of marsh at 11 

sites. Continue research as part of the plan and modify as 

needed to maximize benefits to whooping cranes. 

1.5.2.4. Maintain freshwater inflows. 

58
DRAFT Whooping Crane Recovery Plan 2005 

Human withdrawal of water from the Guadalupe and San 

Antonio Rivers threatens productivity of marshes and bays 

at Aransas. Through consultation and management, agencies 

must ensure that stream flows are maintained to continue 

productivity of the Texas bay systems used by whooping 

cranes. Inflows on the Mission/Aransas watershed also 

potentially affect critical habitat. Future expansion of 

the flock northwards could make inflows critical on the 

Lavaca/Navidad Rivers. 

1.5.2.5. Maintain appropriate in-stream flow. 

Maintain suitable stopover habitat on the Platte River, 

Nebraska, and the South Saskatchewan River, Saskatchewan, 

and on other rivers used by migrating cranes, by ensuring 

adequate flows that provide quality roosting riverine and 

wet meadow habitats. These flows are necessary for 

scouring invading cottonwoods and willow from the riverbed. 

Purchase or lease of lands bordering key roosts may be 

necessary to protect the sites from human disturbance and 

to provide wet meadow habitat that is an important source 

of protein for whooping cranes. 

 

1.5.2.6. Monitor global warming 

The expected sea level rise along with climate change 

caused by global warming will have a major negative impact 

on whooping crane wintering habitat. Continued research 

and management will be needed to protect this habitat. 

1.5.3. Manage habitat. 

First priority should be given to habitats designated as 

critical or essential. Essential habitat is that used by and 

important to an endangered species, but not given any special 

protection or designation by law. Evaluate and improve 

management practices on NWR, NWA, Waterfowl Production Area, 

federal, and provincial and state wildlife areas important to 

whooping cranes to develop and maintain habitat. Acquire or 

develop cooperative agreements on private lands. Review 

management practices systematically to determine benefit or 

detriment to whooping cranes. 

1.5.3.1. Fire management 

The effect of fire on nesting and wintering habitat is 

thought to be beneficial. Parks Canada Agency should 

59
DRAFT Whooping Crane Recovery Plan 2005 

continue to review fire management in WBNP and carefully 

manage fire suppression activities that would be 

detrimental to the crane summering area (Timoney 1999). 

Better define the role of fire in maintaining suitable 

nesting habitat. Maintain upland prairie savannah habitat 

used by the cranes at ANWR using prescribed fire as well as 

attract cranes to the uplands by making additional foods 

available. 

 

1.5.3.2. Maintain upland water sources. 

Maintain freshwater ponds and/or create new ponds on 

the wintering grounds to ensure a supply of freshwater for 

the cranes and to optimize distribution of upland use by 

cranes. Human activities on upland areas need to be 

controlled to minimize disturbance to cranes at freshwater 

sources. 

1.5.3.3. Manage vegetation. 

Manage vegetation in essential or critical roosting 

habitat on the migration route. This may require 

mechanical or chemical removal of established trees or 

other vegetation that may be discouraging use by cranes 

(i.e., the degraded Platte River, Nebraska). Cranes make 

significant use of uplands in winter when relatively open 

feeding conditions are maintained. Mowing, roller 

chopping, and prescribed burning can provide such areas. 

Control the exotic Chinese tallow tree (Sapium sebiferum) 

that invades wetland swales at ANWR with an aggressive 

herbicide application program. Continue to develop other 

habitat management practices that increase the habitat base 

available in wintering areas. These techniques should 

emphasize use in areas that are most protected from human 

encroachment. 

1.5.4. Create wetland habitat. 

On the migration route, wetland restoration may be needed 

in areas where there has been extensive loss of crane 

habitat. On and near the ANWR wintering grounds, enhance the 

whooping crane wintering habitat to provide for an expanding 

crane population. Increase management activities to provide, 

better use of existing protected areas. Create new habitat 

to help compensate for habitat losses and increase the 

carrying capacity of the wintering area. Saltwater marsh can 

be created in open water areas using dredged material. 

60
DRAFT Whooping Crane Recovery Plan 2005 

Lowering of some areas mechanically, to allow flooding by 

high tides and collection of runoff, should promote 

development of salt or brackish marsh areas. 

2. Develop and maintain captive populations. 

Maintain 45 breeder pairs of whooping cranes at PWRC (15), 

ICF (12), CZ (10), ACRES (5), and San Antonio Zoo (3). Birds 

unable to reproduce can be used for parent-rearing, role models, 

or education programs. 

2.1. Develop more sensitive measures of genetic diversity. 

Develop a thorough pedigree history for each producing pair 

in the captive flocks, outlining production histories, 

difficulties encountered, and analyze for genetic inheritance 

of deficiencies. Identify ways to separate family lines by 

exploring the use of anonymous fragment length polymorphisms 

(AFLP) or other techniques. Convene a genetics workshop to 

write specific genetic plans for the Florida nonmigratory and 

eastern migratory populations. 

Based on the above actions: (1) obtain genetic 

representatives of as many wild pairs as possible; (2) retain 

in captivity those birds that are especially valuable because 

of their genetic background; and (3) give careful attention to 

genetic and demographic considerations to ensure health of the 

captive population. The managers of the captive population 

should make annual analyses of the genetics and demographics of 

captive populations. Results of these analyses could be used 

to guide selection of eggs for transfer from the wild, 

selection of individuals for pairing, and maintenance of 

appropriate population demography. Frozen semen banks should 

be maintained to prevent loss of founder lines. 

2.2. Increase captive breeders. 

The small captive population of the past placed constraints 

on productivity, and reduced the potential to form socially and 

genetically compatible pairs. As more pairs begin egg 

production, there will be an increase in offspring available 

for reintroduction efforts, and to enhance the behavioral, 

demographic, and genetic management of the captive population. 

2.3. Refine aviculture methods and productivity. 

61
DRAFT Whooping Crane Recovery Plan 2005 

Captive breeding centers should optimize the production of 

whooping cranes in captivity through the application of proven 

aviculture techniques described in the Crane Propagation Manual 

(Ellis et al. 1996). Research is needed in the fields of 

reproductive physiology, genetics, behavior, and veterinary 

science. 

2.3.1. Refine breeding pair management. 

Develop and/or refine various procedures used in captive 

propagation of whooping cranes, particularly behavioral and 

physiological management, to maximize productivity of captive 

populations. Use research surrogates to accomplish 

biological research and develop techniques. Determine 

optimum techniques for handling, pairing, and inducing crane 

reproduction at captive breeding centers. One major need is 

to bring whooping cranes into production at an earlier age 

comparable to that of wild cranes. 

2.3.2. Refine incubation procedures. 

Whooping crane eggs have greater hatchability rates when 

incubated naturally for at least two weeks. Examine factors 

involved in incubating crane eggs, both artificially and 

naturally, to determine the environment required and to 

enhance overall egg hatchability and flock productivity. 

Sandhill cranes and other cranes are available and desirable 

for natural incubation. Improve mechanical incubation to 

allow reduction in the numbers of captive cranes used for 

incubation and a savings in costs and pen space. 

2.3.3. Refine rearing procedures for reintroductions. 

Direct captive rearing techniques and procedures at 

conditioning the birds for release into the wild. Birds 

destined for release into the wild should either be parentreared by whooping cranes or isolation-reared using live 

whooping cranes as models. Whooping cranes should not be 

reared by other species. Birds reared for captive breeding 

would initially be parent-reared or exposed to proper imprint 

cues to assure reproduction. When possible, expose captivereared birds to conditions and situations in captivity that 

they would be facing after release. 

2.3.4. Refine veterinary procedures. 

62
DRAFT Whooping Crane Recovery Plan 2005 

Long-term survival and productivity of the captive 

populations will require healthy flocks. Proposed protocols 

are described in the report entitled "Whooping Crane Health 

Management Workshop" (Anonymous 1992). Conduct research at 

the captive centers, the NWHC and other partner centers on 

the diagnosis, treatment, and prophylaxis of ailments in 

whooping cranes and other cranes in order to ensure flock 

health and minimize mortality. Monitor routine health 

practices at all times, and modify as necessary. Included 

under this task are the recording of health and postmortem 

findings, and the long-term storage of preserved tissues in a 

centralized facility. Captive health research needs include 

orthopedic problems, chick developmental problems, parasite 

control, drug and vaccine use, emerging infectious diseases 

such as WNV, and salmonella pathogenicity. 

2.3.5. Exchange aviculture information. 

Staff of captive centers should exchange information 

including annual progress reports on propagation activities. 

Propagation and veterinary personnel should meet periodically 

to exchange information and jointly address similar problems, 

and develop implementation plans and protocols. Cooperation 

and exchange between captive centers is needed to train new 

staff. 

2.4. Maintain captive facilities. 

All aspects of Task 2 require adequate facilities for the 

captive whooping crane populations and surrogate species. All 

facilities should be maintained in conditions suitable for the 

cranes’ health, safety, and productivity so that recovery and 

research objectives can be achieved. Captive sites will 

conform to national animal care guidelines. Once established 

at a site, captive pairs should not be moved to another captive 

facility since moves can cause mortality, disrupt and/or 

permanently hinder production. 

3. Establish two additional wild populations. 

The USFWS and CWS should coordinate their research and 

management efforts to establish at least two discrete, selfsustaining populations, each consisting of a minimum of 25 

nesting pairs by year 2035. As long as they meet recovery 

criteria, these new populations can be either migratory or nonmigratory. Plans call for all releases to be in the eastern 

U.S., at least through 2010. 

63
DRAFT Whooping Crane Recovery Plan 2005 

3.1. Develop release techniques. 

Test techniques for establishing migratory and nonmigratory populations. Research and establish protocols for 

age of released birds, rearing methods, time of year, prerelease conditioning procedures, methods for teaching suitable 

migration behavior, and predator avoidance training. The 

number of released birds and post-release monitoring should be 

adequate to ensure proper evaluation. 

3.2. Evaluate and select release sites. 

Evaluate proposed potential release sites based on the 

biological needs of the whooping crane, the likelihood of 

establishing discrete, self-sustaining populations, and the 

impact of such an introduction on other resources and programs. 

Select proposed sites and rank them according to their 

biological suitability. Examine proposed release sites and 

other habitats to be used by released cranes to determine 

potential conflicting management problems, e.g., land and water 

resource development, habitat degradation, impact on other 

wildlife species, distribution of power lines, cellular phone 

towers and fences, disease, predators, and hunting of lookalike species. Conduct research studies on the suitability of 

release sites at Marsh Island and White Lake, Louisiana. 

3.3. Establish a non-migratory population. 

Continue to test the soft release of whooping cranes, 

isolation-reared or parent-reared in captivity, as a means of 

establishing a non-migratory population in Florida or 

elsewhere. Supplement the Florida population until it attains 

25 nesting pairs. Monitor the released birds to gather data on 

habitat use, movements, mortality factors, nesting success, and 

other data crucial to success of a reintroduction. Conduct an 

ongoing evaluation of release success. Implement management 

techniques throughout the range of the new wild population to 

increase project success. Management should be designed to 

minimize unnecessary conflict with other land and resource 

uses. 

3.4. Establish a migratory population. 

Continue to test various means of teaching captive-produced 

birds to migrate and survive in the wild. Supplement this 

population until 25 nesting pairs are reached. Monitor the 

64
DRAFT Whooping Crane Recovery Plan 2005 

released birds to gather data on habitat use, movements, 

mortality factors, nesting success, and other data crucial to 

success of the reintroduction. Conduct an ongoing evaluation 

of release success. Techniques worth investigating include 

leading birds behind an ultralight or model aircraft, stage-bystage migration by truck, or allowing released cranes to follow 

wild cranes in migration. Implement management techniques 

throughout the range of the new wild population to increase 

project success. Management should be designed to minimize 

unnecessary conflict with other land and resource uses. 

4. Determine Ne for species survival. 

Determine a minimum population size needed to ensure survival 

of the whooping crane through stochastic and catastrophic events 

while maintaining genetic diversity. Use knowledge from 

advances in the conservation biology of small populations, 

population viability theory, experience with long-term survival 

of endangered populations and genetic information to determine Ne

and revise recovery criteria as warranted. 

4.1. Analyse banding data to determine the Ne/N ratio for 

the AWBP. 

An analysis of banding data collected from the AWBP from 1977 – 

1988 would provide an estimate of productive pairs vs total 

population size. 

5. Maintain and expand information/education programs. 

Implement information and education programs to further 

recovery of the whooping crane. Issue press releases for 

December population counts at ANWR; spring departure from ANWR, 

arrival in Saskatchewan and requests for reports of migration 

sightings; number of nesting pairs in WBNP; number of chicks 

surviving to autumn in and near WBNP; and autumn arrival in 

Saskatchewan and other provinces, and similar significant events 

for the FP and eastern migratory population. Provide outreach 

opportunistically at meetings and festivals. 

5.1. Develop media products. 

Develop and distribute printed and audio-visual media 

regarding recovery efforts. Target important segments of the 

public and specific needs of the recovery program. Encourage 

collaboration between the various agencies and organizations 

65
DRAFT Whooping Crane Recovery Plan 2005 

that have specific responsibilities or interests in whooping 

crane recovery. 

5.2. Provide viewing opportunities. 

Provide opportunities for the public to view whooping 

cranes near major use areas wherever such viewing does not 

interfere with recovery of the cranes. Provide live whooping 

cranes when available for educational displays at zoos. 

Provide specimen mounts for museums and educational 

institutions to further public education and research. 

REDUCTION OR ALLEVIATION OF THREATS TO WHOOPING CRANES THROUGH 

IMPLEMENTATION OF RECOVERY ACTIONS

The following section describes recovery actions proposed and/or 

underway for recovery of the whooping cranes and identifies the 

tasks in the Recovery Outline that specifically address threats 

to the whooping crane as they relate to the 5 listing factors. 

Listing Factor A: The present or threatened destruction, 

modification, or curtailment of a species habitat or range. 

Habitat destruction and curtailment of the species range are 

addressed in Tasks 1.1 – 1.54 through: population and habitat 

monitoring on the breeding, migration, and winter grounds; 

reduction of collision and disease mortality; public education 

to prevent accidental shooting; habitat protection and 

management; and monitoring and regulation of specific threat and 

impacts such as chemical spill, coastal erosion, dredging, 

changing salinity from water withdrawal, and changes in instream flows. Establishment of two additional wild populations 

(Tasks 3 – 3.4) also address this threat through augmentation of 

the current population and expansion of whooping crane range in 

historical habitats. Development and maintenance of a captive 

population (Tasks 2 –2.4) provide protection against extinction 

in the wild and produce birds for reintroduction to the wild. 

Listing factor B: Overutilization for commercial, recreational, 

scientific, or educational purposes. 

Task 1.3.1 addresses prevention of accidental shooting of 

whooping cranes. Tasks 1.4 – 1.4.2 address protection from 

disturbance. Tasks 5.1-5.2 address public education regarding 

whooping cranes. 

66
DRAFT Whooping Crane Recovery Plan 2005 

Listing Factor C: Disease and predation. 

Disease and predation are important factors in population 

dynamics of whooping cranes. Diseases such as avian 

tuberculosis have been documented in the AWBP, and the 

introduced West Nile Virus is a new threat of unknown proportion 

to both captive and wild populations. Scientists must learn 

more about diseases in whooping cranes (Tasks 1.3.2, 2.3.4) and 

take measures to reduce this risk. 

Predation is a significant source of mortality on flightless 

chicks in WBNP and on reintroduced populations in Florida. 

Efforts must be taken to reduce predation where practical, 

especially in the reintroduced populations (Tasks 1.3, 3.1). 

Listing Factor D: The inadequacy of existing regulatory 

mechanisms. 

The CWS and USFWS believe that the current legal framework (ESA, 

Migratory Bird Treaty Act, SARA, and NEPA) provides for adequate 

protection and conservation of the whooping crane and its 

habitat. However, as the human population continues to grow and 

development potentially impinges on whooping crane habitat, 

governments must be willing to take decisive action to fully 

protect whooping cranes throughout their 2,400-mile range (Tasks 

1.4 – 1.4.2). 

Listing/Recovery Factor E: Other Natural or Human-Caused Factors 

Affecting Its Continued Existence. 

The primary source of mortality for fledged AWBP whooping cranes 

is collision with power lines. This threat needs to be analyzed 

and actions developed to minimize losses (Task 1.3.3). 

Collisions with fences and other man-made objects such as towers 

also need to be reduced (Task 1.3.3). 

Although accidental shootings are believed to cause a very low 

percentage of whooping crane mortality, Federal and State 

agencies need to continue to educate hunters to minimize and/or 

eliminate all such take (Tasks 1.3.1, 5, 5.1). A “Take” in the 

form of harassment is a threat primarily in winter as human uses 

of salt marsh increases (fishing, hunting, birdwatching, nature 

photography) as the human population continues to grow (Tasks 

1.4, 14.1, 1.4.2). Current restriction of aircraft flights over 

summer and winter habitat is successfully reducing disturbance 

(Task 14.2). 

67
DRAFT Whooping Crane Recovery Plan 2005 

The loss of genetic diversity can only be overcome as population 

numbers increase to the level where the creation of new alleles 

through mutation will offset its past, current, and future 

losses in genetic diversity. 

FUTURE CONSIDERATIONS 

Additional methodologies for re-establishing a migratory 

population need to be developed. Although the ultralight method 

appears to work well, it is labor intensive, expensive, and not 

practical for releasing hundreds of cranes. Also, it is 

unknown if cranes trained to follow an ultralight will have 

subsequent normal breeding behavior. Techniques for releasing 

juvenile captive-bred whooping cranes into migratory flocks of 

whooping or sandhill cranes should be explored. 

The suitability of habitat in Florida is an area of concern. 

High mortality continues to hinder the reintroduction of 

nonmigratory whooping cranes in Florida. Two of the 7 

ultralight whooping cranes that followed an ultralight during 

migration were later killed by bobcats at Chassahowitzka NWR in 

Florida in the 2001-02 winter. In 2002, the remaining 5 

completed a successful migration in both the spring and fall and 

summered in the core release area of central Wisconsin. The 5 

cranes returned to Florida but most did not remain in salt marsh 

habitat. It is unknown if the ultralight-trained whooping 

cranes will prefer non salt marsh habitat in Florida and 

possibly associate with the non-migratory whooping cranes in 

central Florida. 

Current plans call for all whooping crane releases to take place 

in the eastern U.S., at least through 2010. If either of the 

two eastern populations are not successful, and/or if the 

habitat in Florida is not suitable for whooping cranes, then the 

Recovery Team recommends consideration of reintroduction sites 

in Louisiana. In 2001, a committee was formed in Louisiana to 

investigate the potential for reintroducing whooping cranes to 

that state. At least two possible sites have been identified. 

Studies done by Cannon (1998) found winter habitat at Marsh 

Island, Louisiana, to be highly rated for whooping cranes. 

There is also interest in restoring nonmigratory whooping cranes 

to the vicinity of White Lake, Louisiana, where until 1950, a 

nonmigratory flock existed. In July, 2002, BP Amoco donated the 

71,130-acre White Lake Preserve to the State of Louisiana. A 

non-profit committee has been set up to oversee the property, 

and returning whooping cranes to this site has been discussed. 

68
DRAFT Whooping Crane Recovery Plan 2005 

Based on their historical presence in the state, Louisiana seems 

to be a good site for whooping crane reintroduction. 

Although the Recovery Team is interested in the idea of 

establishing a Louisiana population, there are currently not 

enough whooping cranes produced annually in captivity to support 

a reintroduction effort in that state. Additionally, much 

planning and coordination with state and local agencies and 

other interested parties in Louisiana is required to further 

these preliminary discussions. 

69
DRAFT Whooping Crane Recovery Plan 2005 

PART III. IMPLEMENTATION SCHEDULE

 

The implementation schedule outlines and prioritizes recovery 

tasks over the recovery period. It will be used in the ongoing 

monitoring of all recovery tasks and will provide the basis for 

funding of recovery actions. Tasks are identified under general 

categories, and all headings are derived from Part II's 

Narrative Outline for Recovery Actions to Achieve Objectives. 

The schedule ranks objectives and tasks, identifies respective 

responsible agencies, defines schedules, and estimates costs in 

terms of financial resources and person-years for the recovery 

period. Tasks must be continually revised as plans move from 

implementation to completion as a result of monitoring results 

and updating information. Each revision will identify 

additional actions and studies that will be needed during the 

recovery period. 

Recovery priorities are defined as follows: 

Priority 1: An action that must be taken to prevent extinction 

or 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 or habitat 

quality or some other significant negative impact 

short of extinction. 

Priority 3: All other actions necessary to provide for full 

recovery (or reclassification) of the species. 

 

70
DRAFT Whooping Crane Recovery Plan 2005 

IMPLEMENTATION SCHEDULE 

71 

Action Task # Priority Responsible Program Cooperator Duration Year1 Yea

Increase AWBP 1 1 CWS, USFWS 

USFWS-2

CWS, ES 

RW

USACE, BR, 

FERC, WBNP

Continuous See 11 

to

Monitor Population Numbers 11 2 CWS, 

USFWS-2 

CWS, RW Continuous See 11

to 

Conduct Aerial Surveys in WBNP 

111 2 CWS, WBNP CWS WBNP Continuous 25 2

Analyze Data on Egg Management 

1111 3 CWS CWS WCRT Continuous 5 - 

Monitor Habitat in WBNP 1112 2 WBNP WBNP CWS Continuous 10 1Conduct Aerial Surveys at ANWR 

112 1 USFWS-2 ES, RW - Continuous 20 21 

Monitor Foods and Salinities at ANWR 

1121 2 USFWS-2 RW, ES - Continuous 20 2

Monitor Movements in Migration 

12 2 CWS, USFWS-2,6 CWS, ES RW, A, M, S Continuous 5 5 

Reduce Mortality 13 2 CWS, USFWS-2,6 CWS, ES A, M, S Continuous - - Prevent Shooting 131 2 CWS, USFWS CWS, USFWS2,3,4,6 ES, RW, A, M, S Continuous 5 5 Diminish Disease Losses 132 2 CWS, USFWS NWHC WCRT, PWRC, 

CCWHC 

Continuous 20 20 

Diminish Collisions 133 1 CWS, USFWS CWS, ES FCC Continuous 2 2 Restrict Detrimental Human Activities 

14 2 CWS, PCA,

USFWS 

CWS, RW ES, WBNP Continuous 20 20 

Restrict Construction Periods 141 2 CWS, USFWS-2 ES A, M, S, RW, 

WBNP 

Continuous 5 5 

Restrict Aircraft Altitude 142 2 CWS, PCA, 

USFWS-2 

WBNP, RW FAA, TC Continuous - - 

Identify, Protect, Manage, and Create Habitat 

15 2 CWS, USFWS CWS, USFWS-2,6 WCRT 1 year 

study 

- 20 

Identify Essential Habitat 151 2 CWS, PCA CWS, USFWS-2,6 WBNP Continuous 30 50 

 Cost ($ x 
DRAFT Whooping Crane Recovery Plan 2005 

72 

Measure Food Resources in Summer and Winter 

1511 2 CWS, PCA,

USFWS 

CWS, USFWS-2,6 WBNP 4-year 

study 

40 40 

Protect Habitat 152 2 CWS, USFWS USFWS-2,6 3-year 

study 

10 10 

Prevent Contamination 1521 2 CWS, USFWS-2 ES, CG TNRCC,USACE Continuous 1 1 Prevent Erosion of Habitat 1522 2 USFWS-2 USACE RW, ES Continuous 1 1 Manage Dredge Material 1523 2 USFWS-2 USACE ES, RW Continuous 1 1 Maintain Freshwater Inflows 1524 1 USFWS-2,6 ES, RW TNRCC,TPWD, 

USACE 

Continuous 40 45 

Maintain Instream Flows 1525 2 USFWS-6 ES, PRT NAS Continuous 100 10Monitor Global Warming 1526 2 CWS, PCA, 

USFWS-2, 

RW, ES CWS, WBNP,ES Continuous - - 

Manage Habitat 153 2 CWS, PCA, 

USFWS-2,3,4,6 

RW, ES PRT, NAS, 

WBNP 

Continuous - - 

Fire Management 1531 2 PCA, USFWS RW, ES PRT, NAS 

WBNP 

Continuous 20 20 

Maintain Upland Water Sources 1532 2 USFWS-2 RW Continuous 2 2 Manage Vegetation 1533 2 USFWS-2,6 RW PRT, NAS Continuous 300 30Create Wetland Habitat 154 2 USFWS-2,6 ES, USACE RW Continuous 200 20Develop and Maintain Captive Populations 

2 1 CWS, CZ, USGS,

USFWS-2,9 

- all captive

centers 

Continuous See 21 

to 

Develop More Sensitive Measures of Genetic Diversity 

21 2 USGS - ICF, PWRC,

NGO, NWHL 

Continuous 60 60 

Increase Captive Breeders 22 1 CWS, USGS, 

USFWS-2,9 

ES all captive

centers 

Continuous 1400 140

Refine Avicultural Methods and Productivity 

23 2 USGS - all captive

centers 

Continuous See 23

to 
DRAFT Whooping Crane Recovery Plan 2005 

73 

Refine Breeding Pair Management 

231 2 USGS, all

captive centers 

- all captive

centers 

Continuous 50 50 

Refine Incubation Procedures 232 3 ICF, PWRC - all captive 

centers 

5 years 10 10 

Refine Rearing Procedures for Reintroductions 

233 2 PWRC, ICF, OM - all captive 

centers 

10 years 10 10 

Refine Veterinary Procedures 234 3 all captive 

centers, NWHC 

- - Continuous 20 20 

Exchange Avicultural Information 

235 3 WCCMT - all captive

centers 

Continuous 5 5 

Maintain Captive Facilities 24 3 USGS, USFWS-9 - all captive 

centers 

Continuous 150 30 

Establish Two Additional Wild Populations 

3 2 CWS,

USFWS-2,3,4,9 

ES,LE,RW OM, STATES, 

USGS 

20 years See 31 

to 

Develop Release Techniques 31 2 PWRC, ICF, 

USFWS-3,4 

- FL, OM, WCRT 10 years 750 75

Select Release Sites 32 2 CWS, USFWS2,3,4 - WCRT Do when needed - - Establish a Non-Migratory Population 

33 2 USFWS-4,9, FL - - 10 years 280 28

Establish Migratory Population 

34 2 USFWS-3,4, WI,

PWRC,ICF, OM 

- States 20 years 600 60

Determine Ne for Species Survival 

4 3 CWS, USFWS,

PWRC 

- - Continuous - 20 

Analyse banding data 41 3 CWS, USFWS, 

PWRC 

- - 1 year

study 

- 10 

Maintain I&E Program 5 3 CWS, 

USFWS2,3,4,6,9, ICF

PA States, Continuous

Provinces, 

WCCA 

5 5 

Develop Media Products 51 3 CWS, USFWS2,3,4,6,9 PA ICF,PRT PWRC, WCCA Continuous 5 5 Provide Viewing Opportunities 52 3 CWS, FL, WI 

USFWS-2,3,4,6 

ES, RW OM Continuous 5 5 
DRAFT Whooping Crane Recovery Plan 2005 

74 

LEAD ORGANIZATIONS RESPONSIBLE FOR SPECIES RECOVERY AND KEY 

CONTACTS 

 

Brian Johns – Whooping Crane Coordinator 

Canadian Wildlife Service 

Prairie and Northern Region 

115 Perimeter Road 

Saskatoon, Saskatchewan 

Canada S7N OX4 

(306) 975-4109 

Brian.Johns@ec.gc.ca 

Tom Stehn – Whooping Crane Coordinator 

U.S. Fish and Wildlife Service 

Aransas National Wildlife Refuge 

P. O. Box 100 

Austwell, Texas 

USA 77950 

(361) 286-3559 Ext. 221 

Tom_Stehn@fws.gov 

CANADA/U.S. INTERNATIONAL WHOOPING CRANE RECOVERY TEAM MEMBERS 

Brian Johns Canadian Wildlife Service CO-CHAIR 

Tom Stehn United States Fish and Wildlife Service CO-CHAIR 

 Canadian Representatives 

Mark Bradley - Wood Buffalo National Park 

Deborah Johnson - Northwest Territories Resources, Wildlife and 

Economic Development 

Brian Johns - Canadian Wildlife Service 

Sandie Black, DVM - Calgary Zoo 

Rick Espie - Saskatchewan Environment 

 United States Representatives 

Dr. George Archibald - International Crane Foundation 

Dr. John French - USGS, Biological Resources Division 

Julie Langenberg, VMD – Wisconsin Department of Natural Resources 

Steve Nesbitt - Florida Fish and Wildlife Conservation Commission 

Tom Stehn - U.S. Fish and Wildlife Service 
DRAFT Whooping Crane Recovery Plan 2005 

75 

Contact Information

Dr. George Archibald 

International Crane Foundation 

E-11376 Shady Lane Road 

Baraboo, WI 53913-447 

Phone (608) 356-9462 

FAX (608) 356-9465 

Email: george@savingcranes.org 

Sandie Black, DVM 

Head of Veterinary Services 

Calgary Zoo Animal Health Centre 

1625 Centre Ave E, 

Calgary AB, T2E 8K2 

CANADA 

Phone (403) 232-9309 

FAX (403) 237-8318 

Email: sandieb@calgaryzoo.ab.ca 

Mark Bradley 

Wood Buffalo National Park 

Parks Canada Agency 

Box 750 

Fort Smith, Northwest Territories

Canada X0E 0P0 

Phone (403) 872-7900 

FAX (403) 872-3910 

Email: Mark_Bradley@pch.gc.ca 

Deborah Johnson 

Regional Biologist 

Wildlife and Fisheries Division 

Department of Resources, 

Wildlife and Economic Development 

Government of the Northwest Territories 

Fort Smith, Northwest Territories 

Canada X0E 0P0 

Phone (867) 872-6449 

FAX (867) 872-4250 

Email: DEBORAH_JOHNSON@gov.nt.ca

Rick Espie 

Biodiversity Specialist 

Saskatchewan Environment 
DRAFT Whooping Crane Recovery Plan 2005 

76 

3211 Albert Street 

Regina, Saskatchewan 

Canada S4S 5W6 

Phone (306) 787-2461 

Fax (306) 787-9544 

Email: REspie@serm.gov.sk.ca 

Dr. John French 

U.S. Geological Survey 

Patuxent Wildlife Research Center 

12011 Beech Forest Road 

Laurel, Maryland 20708-4041 

Phone (301) 497-5702 

FAX (301) 497-5505 

Email: John_B_French@usgs.gov 

Brian Johns 

Canadian Whooping Crane Coordinator 

Canadian Wildlife Service 

Environmental Conservation Branch 

Prairie and Northern Wildlife Research Centre 

115 Perimeter Road 

Saskatoon, Saskatchewan 

Canada S7N 0X4 

Phone (306) 975-4109 

FAX (306) 975-4089 

Email: Brian.Johns@ec.gc.ca 

Julie Langenberg, VMD 

Department of Natural Resources 

101 S Webster St. Box 7921 

Madison, WI 53707-7921 

Phone (608) 266-3143 

FAX (608) 267-7857 

Email: Langej@dnr.state.wi.us 

Steve Nesbitt 

Florida Fish and Wildlife Conservation Commission 

Wildlife Research Laboratory 

4005 South Main Street 

Gainesville, FL 32601-9099 

Phone (352) 955-2230 

FAX (352) 376-5359 

Email: Nesbits@fwc.state.fl.us 
DRAFT Whooping Crane Recovery Plan 2005 

77 

Tom Stehn 

U.S. Whooping Crane Coordinator 

U.S. Fish and Wildlife Service 

Aransas National Wildlife Refuge 

P.O. Box 100 

Austwell, Texas 77950 

Phone (361) 286-3559, ext. 221 

FAX (361) 286-3722 

Email: Tom_Stehn@fws.gov 

OTHER CONTACTS 

Bill Gummer 

Regional Director, Prairie and Northern Region 

CWS 

4999 98th Avenue 

Edmonton, AB T6X 2X3 

(780) 951-8853 

Dave Duncan 

Head, Wildlife Management Section 

CWS 

4999 98th Avenue 

Edmonton, AB T6X 2X3 

(780) 951-8675 

Dale Hall 

Director, Region 2 

USFWS 

P.O. Box 1306 

Albuquerque, NM 87103 

(505) 248-6282 

Stuart Leon 

Acting Chief, Endangered species 

Region 2 – USFWS 

P.O. Box 1306 

Albuquerque, NM 87103 

(505) 248-6776 
DRAFT Whooping Crane Recovery Plan 2005 

78 

PREPARED BY 

Brian Johns 

Canadian Wildlife Service 

 

James C. Lewis, Ph.D. 

Adjunct Professor 

University of New Mexico 

7712 Midge NE 

Albuquerque, New Mexico 

USA 87109 

(505) 821-3823 

jclewis@unm.edu 

Tom Stehn 

U.S. Fish and Wildlife Service 

KEY LANDS ON WHICH SPECIES OCCURS AND ASSOCIATED CONTACTS 

Canadian breeding grounds, contact Josie Weninger Superintendent, 

Wood Buffalo National Park, Box 750, Fort Smith, Northwest 

Territory, Canada XOE OPO 

Canadian migration staging/stopover areas, contact Brian Johns, 

Canadian Wildlife Service, address listed above. 

U.S. migration staging/stopover areas, USFWS, Grand Island Field 

Office, Federal Building, 2nd Floor, 203 West Second Street, Grand 

Island, Nebraska USA 68801 

AWBP wintering area along the Texas Gulf Coast, contact Tom 

Stehn, Aransas NWR, address listed above. 

 

Florida non-migratory population, contact Steve Nesbitt, address 

listed above. 

Eastern migratory experimental reintroduction, contact Beth 

Goodman, WI DNR, PO Box 7921, Madison, WI 53707. 

beth.goodman@dnr.state.wi.us 

DATE COMPLETED: September 15, 2004 
DRAFT Whooping Crane Recovery Plan 2005 

79 

KEY REFERENCES 

Allen, R. P. 1952. The whooping crane. Natl. Audubon Soc. 

Resource Rept. 3. 246 pp. 

_________. 1956. A report on the whooping cranes' northern 

breeding grounds. Natl. Audubon Soc. Supplemental Resource 

Rept. 3. 60 pp. 

Anderson, D. W., and J. F. Kreitzer. 1971. Thickness of 1967-69 

whooping crane eggshells compared to that of pre-1910 

specimens. Auk 88:433-434. 

Anonymous. 1992. Whooping crane health management workshop. 

USFWS, Madison, Wisconsin. 47 pp. 

Archibald, G. W. 1975. The evolutionary and taxonomic 

relationships of cranes as revealed by their unison calls. 

Ph.D. Dissertation, Cornell Univ., Ithaca, New York. 151 pp. 

_________. 1976. Crane taxonomy as revealed by the Unison Call. 

Pages 225-251 in J. C. Lewis, ed. Proc. International Crane 

Workshop. Oklahoma State Univ. Press, Stillwater, Oklahoma. 

Archibald, G.W., J. Baldwin, and P. Konrad. 1976. Is sandhill 

hunting a threat to the whooping crane? Pages 207-221 in J. 

C. Lewis, ed. Proc. International Crane Workshop. Oklahoma 

State Univ. Press, Stillwater, Oklahoma. 

Archibald, K., and G. W. Archibald. 1992. Releasing puppet-reared 

sandhill cranes in the wild: A progress Report. Pages 251-254 

in D. A. Wood, ed. Proc. 1988 N. Am. Crane Workshop. State of 

Florida Game and Fresh Water Fish Commission, Tallahassee, 

Florida. 

Armbruster, M. J. 1990. Characterization of habitat used by 

whooping cranes during migration. Biological Rept. 90(4):1-

16. 

Asherin, D., and R. Drewien. 1987. Computerized management and 

display of whooping crane observation data. Pages 276-282, in 

J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane 

Workshop. Platte River Whooping Crane Habitat Maintenance 

Trust and USFWS, Grand Island, Nebraska. 
DRAFT Whooping Crane Recovery Plan 2005 

80 

Asherin, D. A., D. B. Hamilton, W. M. Brown, and R. C. Drewien. 

1992. A microcomputer data base for managing whooping crane 

observation records. Pages 270-273 in D. Wood, ed. Proc. 

1988 Crane Workshop. Florida Game and Freshwater Fish 

Commission, Nongame Tech. Rep. # 12. 

Austin, J. E., and A. L. Richert. 2001. A comprehensive review of 

the observational and site evaluation data of migrant 

whooping cranes in the United States, 1943-99. U.S. 

Geological Survey, Northern Prairie Wildlife Research Center, 

Jamestown, North Dakota, and State Museum, University of 

Nebraska, Lincoln, Nebraska. 157 pp. 

Bakst, M. R. 1988. Turkey hen fertility and egg production by 

artificial insemination and multiple eversion during the prelay period. J. Reproduction and Fertility 83:1-5 

Ballou, J. D., M. Gilpin, and T. J. Foose. 1995. Population 

management for survival and recovery. In M. C. Pearl, ed. 

Methods and cases in conservation science. Columbia Univ. 

Press, New York. 375 pp. 

Banks, R. 1978. The size of the early whooping crane populations/ 

Unpubl. Rept. USFWS files. 10 pp. 

Bennett, A. J., and L. A. Bennett. 1987. Evaluation of the 

Okefenokee Swamp as a site for developing a nonmigratory 

flock of whooping cranes. Final Rept., Georgia Cooperative 

Fish and Wildl. Research Unit, Athens. 112 pp. 

Bent, A. C. 1926. Life histories of North American marsh birds. 

U.S. Natl. Museum Bull. 135:219-231. 

Bergeson, D. G., B. W. Johns, and G. Holroyd. 2001a. Mortality 

of whooping crane colts at Wood Buffalo National Park, 

Canada. Proc. N. Am. Crane Workshop 8:6-10. 

_________, M. Bradley, and G. Holroyd. 2001b. Food items and 

feeding rates for wild whooping crane colts in Wood Buffalo 

National Park. Proc. N. Am. Crane Workshop 8:36-39. 

Binkley, C. S., and R. S. Miller. 1983. Population 

characteristics of the whooping crane, Grus Americana. Can J. 

Zool. 61:2768-2776. 
DRAFT Whooping Crane Recovery Plan 2005 

81 

Bird, D. M., W. Burnham, and R. W. Fyfe. 1985. A review of crossfostering in birds of prey. ICBP Tech. Publ. 5:433-438. 

Bishop, M. A. 1984. The dynamics of subadult flocks of whooping 

cranes wintering in Texas 1978-l979 through 1982-1983. MS 

Thesis, Texas A & M Univ., College Station. 128 pp. 

_________. 1988. An evaluation of three areas in central Florida 

as potential reintroduction areas for a nonmigratory flock of 

whooping cranes. Univ. Florida, Gainesville. 63 pp. 

_________, and D. R. Blankinship. 1982. Dynamics of subadult 

flocks of whooping cranes at Aransas National Wildlife 

Refuge, Texas, 1978-1981. Pages 180-189, in J. C. Lewis, ed. 

Proc. 1981 International Crane Workshop. Natl. Audubon Soc., 

Tavernier, Florida. 

Bizeau, E., T. Schumacher, R. Drewien, and W. Brown. 1987. An 

experimental release of captive-reared greater sandhill 

cranes. Pages 78-89 in J. C. Lewis and J. W. Ziewitz, eds. 

Proc. 1985 Crane Workshop. Platte River Whooping Crane 

Habitat Maintenance Trust and USFWS, Grand Island, Nebraska. 

Blankinship, D. R. 1976. Studies of whooping cranes on the 

wintering grounds. Pages 197-206 in J. C. Lewis, ed. Proc. 

International Crane Workshop, Oklahoma State Univ. Press, 

Stillwater. 

_________. 1987. Research and management programs for wintering 

whooping cranes. Pages 381-386 in G. W. Archibald and R. F. 

Pasquier, eds. Proc. 1983 Crane Workshop, International Crane 

Foundation, Baraboo, Wisconsin. 

Bonds, C. J. 2000. Characterization of banded whooping crane 

territories from 1992-93 to 1996-97 using GIS and remote 

sensing. Ph.D. thesis. Texas A and M Univ.-College Station. 

106 pp. 

Bowman, M. R., J. Waldoch, J. M. Pittman and B. K. Hartup. 2002. 

Enrofloxacin plasma concentrations in sandhill cranes (Grus 

Canadensis) after administration in drinking water: A 

preliminary study. Proc. Am. Assoc. of Zoo Veterinarians Ann. 

Conf., Milwaukee, Wisconsin. Pages 389-390. 

Boyce, M. S. 1987. Time-series analysis and forecasting of the 
DRAFT Whooping Crane Recovery Plan 2005 

82 

Aransas-Wood Buffalo whooping crane population. Pages 1-9, in 

J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane 

Workshop. Platte River Whooping Crane Habitat Maintenance 

Trust and USFWS, Grand Island, Nebraska. 

_________, and R. S. Miller. 1985. Ten year periodicity in 

whooping crane census. Auk 102(3):658-660. 

_________, S. Lele and B. W. Johns. In prep. Whooping crane colt 

recruitment enhanced by egg removal. 

Brand, C. J., J. Langenberg, and J.W. Carpenter. 1992. Summary of 

diseases and disease recommendations in whooping cranes. In 

Mirande, R. Lacy, and U. Seal (compilers), Grus americana

Whooping Crane Conservation Viability Assessment Workshop 

Rept., Fossil Rim Wildl. Center, 6-8 August 1991. Captive 

Breeding Specialist Group (CBSG/SSC/IUCN). 

Brook, B. W., J. R. Cannon, R. C. Lacy, C. Mirande, and R. 

Frankham. 1999. A comparison of the population viability 

analysis packages GAPPS, INMAT, RAMAS, and VORTEX for the 

whooping crane Grus americana. Animal Conservation 2(1):23-

31. 

Brook, B. W., D. W. Tonkyn, J. J. Q'Grady, and R. Frankham. 2002. 

Contribution of inbreeding to extinction risk in threatened 

species. Conservation Ecology 6(1):art. no.-16. 

Brown, W. M., R. C. Drewien, and E. G. Bizeau. 1987. Mortality of 

cranes and waterfowl from powerline collisions in the San 

Luis Valley-Colorado. Pages 128-136, in J. C. Lewis and J. W. 

Ziewitz, eds. Proc. 1985 Crane Workshop. Platte River 

Whooping Crane Habitat Maintenance Trust and USFWS, Grand 

Island, Nebraska. 

_________, and R. C. Drewien. 1995. Evaluation of two powerline 

markers to reduce crane and waterfowl collision mortality. 

Wildl. Soc. Bull. 23(2):217-227. 

Buller, R. J. 1967. Sandhill crane study in the Central Flyway. 

USFWS Special Scientific Rept. Wildl. 113, Washington, D.C. 

17 pp. 

Burke, A. M. 1996. Habitat use and breeding biology of sandhill 

cranes in the Yorkton Region, Saskatchewan, Canada. 
DRAFT Whooping Crane Recovery Plan 2005 

83 

Unpublished Rept. College of Natural Resources. Univ. 

Wisconsin-Stevens Point. 

Burleigh, T. D. 1944. The bird life of the Gulf Coast Region of 

Mississippi. Louisiana State Univ., Occas. Pap. Mus. Zoology 

20:329-490. 

Cannon, J. R. 1998. Whooping crane wintering sites study: Final 

Rept. to Canadian-United States Whooping Crane Recovery Team, 

Calgary, Alberta, Canada. 19pp + appendices. 

_________. 1999. Wisconsin whooping crane breeding site 

assessment. Final Rept. to Canadian-United States Whooping 

Crane Recovery Team. 38 pp. 

_________, B. W. Johns, and T. V. Stehn. 2001. Egg collection 

and recruitment of young of the year in the Aransas/Wood 

Buffalo population of whooping cranes. Proc. N. Am. Crane 

Workshop 8:11-16. 

Carlson, G. 1991. The feasibility of individual identification 

and sex determination of whooping cranes (Grus americana) by 

analysis of vocalizations. M.S. Thesis, Idaho State Univ., 

Pocatello, Idaho. 60 pp. 

Carpenter, J. W., and S. R. Derrickson. 1982. Whooping crane 

mortality at the Patuxent Wildlife Research Center, 1966-

1981. Pages 175-179 in J. C. Lewis, ed. Proc. 1981 

International Crane Workshop. Natl. Audubon Soc., Tavernier, 

Florida. 

_________,T. R. Spraker, and M. N. Novilla. 1980. Disseminated 

visceral coccidiosis in whooping cranes. J. Am. Veterinary 

Medical Association 177:845-848. 

_________, F. Dien, and G. Clark. 1987. An outbreak of eastern 

equine encephalitis virus in captive whooping cranes. Pages 

123-127, in J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 

Crane Workshop. Platte River Whooping Crane Habitat 

Maintenance Trust and USFWS, Grand Island, Nebraska. 

Chavez-Ramirez, F. 1996. Food availability, foraging ecology, and 

energetics of whooping cranes wintering in Texas. Ph.D. 

dissertation, Texas A and M Univ. 103 pp. 

 
DRAFT Whooping Crane Recovery Plan 2005 

84 

_________, F., H. E. Hunt, R. D. Slack, and T. V. Stehn. 1995. 

Ecological correlates of whooping crane use of fire-treated 

upland habitats. Cons. Biol. 10(1):217-223. 

_________, F., J. T. Nelson, and R. D. Slack. 1997. Food and 

energy intake rates of wintering whooping cranes foraging on 

two selected food items. Proc. N. Am. Crane Workshop 7:259. 

Clegg, K. R., J. C. Lewis, and D. H. Ellis. 1997. Use of 

ultralight aircraft for introducing migratory crane 

populations. Proc. N. Am. Crane Workshop 7:105-113. 

_________ and J. C. Lewis. 2001. Continuing studies of 

ultralight aircraft applications for introducing migratory 

populations of endangered species. Proc. N. Am. Crane 

Workshop 8:96-108. 

Cooch, F.G. (ed.), W. Dolan, J.P. Goossen, G. L. Holroyd, B.W. 

Johns, E. Kuyt, and G. H. Townsend. 1988. Canadian Whooping 

Crane Recovery Plan. Canadian Wildl. Service, Ottawa. 56pp. 

Currier, P. J. 1997. Woody vegetation expansion and continuing 

declines in open channel habitat on the Platte River in 

Nebraska. Proc. N. Am. Crane Workshop 7:141-152. 

__________, G. R. Lingle, and J. G. Van Derwalker. 1985. 

Migratory bird habitat on the Platte and North Platte Rivers 

in Nebraska. The Platte River Whooping Crane Habitat 

Maintenance Trust, Grand Island, Nebraska. 177 pp. 

Darnell, T. M., E. H. Smith, J. W. Tunnell, Jr., K. Withers, and 

E. R. Jones. 1997. The influence of landscape features on 

bird use of marsh habitat created for whooping cranes through 

beneficial use of dredged material: Final report. Center for 

Coastal Studies, Texas A and M Univ.-Corpus Christi. 93 pp. 

Derby, C. and D. Strickland. 2001. Platte River Cooperative 

Agreement and proposed program: Efforts to protect, restore, 

and manage habitat for whooping crane, least terns, and 

piping plovers. Proc. N. Am. Crane Workshop 8: 

Derby, C., E. Lack, and D. Strickland. 2000. Habitat management 

methods for least terns, piping plovers, and whooping cranes. 

Western Ecosystem Technology, Inc., Cheyenne, Wyoming. 92pp. 
DRAFT Whooping Crane Recovery Plan 2005 

85 

Derrickson, S. R., and J. W. Carpenter. 1982. Whooping crane 

production at the Patuxent Wildlife Research Center, 1967-

1981. Pages 190-198 in J. C. Lewis, eds. Proc. 1981 

International Crane Workshop. Natl. Audubon Soc., Tavernier, 

Florida. 

DeSobrino, C. 1998. Evaluation of the Interlake region of 

Manitoba as a reintroduction site for whooping cranes: Food 

item evaluation. Unpublished Rept. of the Delta Waterfowl 

and Wetlands Research Station, Portage la Prairie, Manitoba. 

Dessauer, H.C and G. F. Gee. 1986. Esterase-D and 6-

phosphogluconate dehydrogenase polymorphisms in whooping 

cranes. Isozyme Bulletin 19:41 

_________, _________, and J. S. Rogers. 1992. Allozyme evidence 

for crane systematics and polymorphisms within populations of 

sandhill, sarus, siberian and whooping cranes. Molecular 

Phylogenetics and Evolution 1:279-288. 

Doughty, R. W. 1989. Return of the whooping crane. Univ. Texas 

Press, Austin. 182 pp. 

Drewien, R. C. 1973. Ecology of Rocky Mountain greater sandhill 

cranes. Ph.D. Dissertation, Univ. Idaho, Moscow, Idaho. 152 

pp. 

_________, and E. G. Bizeau. 1974. Status and distribution of 

greater sandhill cranes in the Rocky Mountains. J. Wildl. 

Management 38:720-742. 

_________, and_________. 1978. Cross-fostering whooping cranes to 

sandhill crane foster parents. Pages 201-222, in S. A. 

Temple, ed. Endangered Birds - Management Techniques for 

Preserving Threatened Species. Univ. Wisconsin, Madison, 

Wisconsin. 

_________, and__________. 1981. Use of radiotelemetry to study 

the movements of juvenile whooping cranes. Pages 130-134, in 

J. C. Lewis and H. Masatomi, eds. Crane Research Around the 

World. International Crane Foundation, Baraboo, Wisconsin. 

_________, and K. R. Clegg. 1992. Capturing whooping cranes and 

sandhill cranes by night-lighting. Proc. N. Am. Crane 

Workshop 6:43-49. 
DRAFT Whooping Crane Recovery Plan 2005 

86 

_________, and E. Kuyt. 1979. Teamwork helps the whooping crane. 

Natl. Geographic 155:680-693. 

_________, S. R. Derrickson, and E. G. Bizeau. 1981. Experimental 

release of captive parent-reared greater sandhill cranes at 

Grays Lake Refuge, Idaho. Pages 99-111, in J. C. Lewis, ed. 

Proc. 1981 International Crane Workshop. Natl. Audubon Soc., 

Tavernier, Florida. 

_________, S. H. Bouffard, D. D. Call, and R. A. Wonacott. 1985. 

The whooping crane cross-fostering experiment: The role of 

animal damage control. Pages 7-13, in P. T. Bromley, ed. 

Proc. Second Eastern Wildl. Damage Control Conf. N. Carolina 

State Univ., Raleigh. 

_________, W. Brown, and E. Bizeau. 1989. Whooping crane crossfostering experiment. Unpubl. Rept. to U.S. Whooping Crane 

Recovery Team. 10 pp. 

_________, W. M. Brown, and W. L. Kendall. 1995. Recruitment in 

Rocky Mountain greater sandhill cranes and comparison with 

other N. Am. crane populations. J. Wildl. Management 

59(2):339-356. 

_________, W. L. Munroe, K. R. Clegg, and W. M. Brown. 1997. Use 

of cross-fostered whooping cranes as guide birds. Proc. N. 

Am. Crane Workshop 7:86-95. 

_________, J. Tautin, M. L. Courville, and G. M. Gomez. 

2001. Whooping cranes breeding at White Lake, Louisiana, 

1939: observations by John J. Lynch, U.S. Bureau of 

Biological Survey. Proc. N. Am. Crane Workshop 8:24-30. 

Duff, J. W, W. A. Lishman, D. W. Clark, D. H. Ellis, G. F. Gee, 

and D. T. Sprague. 2001. Promoting wildness in sandhill 

cranes conditioned to follow an ultralight aircraft. Proc. N. 

Am. Crane Workshop 8:115-121. 

Edwards, R., S. Brechtel, R. Bromley, D. Hjertaas, B. Johns, E. 

Kuyt, J. C. Lewis, N. Manners, R. Stardom, and G. Tarry. 

1994. National recovery plan for the whooping crane. Rept. 

6, Ottawa: Recovery of Nationally Endangered Wildl. Comm., 

Canadian Wildl. Fed., Ontario. 39 pp. 

 

Ellis, D. H., and F. J. Dein. 1991. Flight restraint techniques 
DRAFT Whooping Crane Recovery Plan 2005 

87 

for captive cranes. Pages 447-452 in J. Harris, ed. Proc. 

1987 International Crane Workshop. International Crane 

Foundation, Baraboo, Wisconsin. 

_________, and G. F. Gee. 2001. Whooping crane egg 

management: Options and consequences. Proc. N. American 

Crane Workshop 8:17-23. 

_________, G. W. Archibald, S. R. Swengel, and C. B. Kepler. 

1991. Compendium of crane behavior. Part 1: Individual 

(nonsocial) behavior. Pages 225-234 in J. Harris, ed. Proc. 

1987 International Crane Workshop. International Crane 

Found., Baraboo, Wisconsin. 

_________, G. H. Olsen, G. F. Gee, J. M. Nicolich, K. E. 

O'Malley, M. Nagendran, S.G. Hereford, P. Range, W. T. 

Harper, R. P. Ingram, and D. G. Smith. 1992a. Techniques for 

rearing and releasing nonmigratory cranes: Lessons from the 

Mississippi sandhill crane program. Proc. N. Am. Crane 

Workshop 6:135-141. 

_________, J. C. Lewis, G. F. Gee, and D. G. Smith. 1992b. 

Population recovery of the whooping crane with emphasis on 

reintroduction efforts: Past and future. Proc. N. Am. Crane 

Workshop 6:142-150. 

_________, G. F. Gee, and C. M. Mirande, eds. 1996. Cranes: 

their biology, husbandry, and conservation. Natl. Biological 

Service and International Crane Foundation, Washington, D.C., 

307 pp. 

_________, B. Claus, T. Watanabe, R. C. Mykut, M. Kinloch, and C. 

H. Ellis. 1997. Results of an experiment to lead cranes on 

migration behind motorized ground vehicles. Proc. N. Am. 

Crane Workshop 7:114-122. 

_________, K. R. Clegg, J. C. Lewis, and E. Spalding. 1999. 

Golden eagle predation on experimental sandhill and whooping 

cranes. Condor 101(3):664-667. 

_________, and G. F. Gee. 2001. Whooping crane egg management: 

options and consequences. Proc. N. Am. Crane Workshop 8:17-

23. 

_________, C. Mellon, M. Kinloch, T. Dolbeare, and D. Ossi. 
DRAFT Whooping Crane Recovery Plan 2005 

88 

2001a. Results of the Utah-Arizona stage-by-stage migrations. 

Proc. N. Am. Crane Workshop 8:132-138 

_________, G. F. Gee, K. R. Clegg, J. W. Duff, W. A. Lishman, and 

W. J. L. Sladen. 2001b. Lessons from the motorized 

migrations. Proc. N. Am. Crane Workshop 8:139-144. 

_________, D. P. Mummert, M. Kinloch, C. Mellon, T. Dolbeare, and 

D. Ossi. 2001c. The one-by-one method for releasing cranes. 

Abstract in Proc. N. Am. Crane Workshop 8:225. 

Environmental Protection Agency. 1992. Supplemental assessment, 

section 7 consultation, Formosa Point Comfort Expansion, 

Letter of October 28, 1992. Dallas, Texas. 

Erickson, R. C. 1961. Production and survival of whooping cranes. 

USFWS, Unpubl. Administrative Rept. 29 pp. 

_________. 1968. A federal research program for endangered 

Wildlife. Trans. N. Am. Wildl. Conf. 33:418-433. 

_________. 1975. Captive breeding of whooping cranes at the 

Patuxent Wildlife Research Center. Pages 99-114, in R. D. 

Martin, ed. Breeding Endangered Species in Captivity. 

Academic Press, New York. 

_________. 1976. Whooping crane studies at the Patuxent Wildlife 

Research Center. Pages 166-176, in J. C. Lewis, ed. Proc. 

International Crane Workshop, Oklahoma State Univ. Press, 

Stillwater. 

_________ and S. R. Derrickson. 1981. Whooping crane (Grus 

americana). Pages 104-118, in J. C. Lewis and H. Masatomi, 

eds. Crane Research Around the World. International Crane 

Foundation, Baraboo, Wisconsin 

 

Evans, D. E., and T. V. Stehn. 1997. Use of dredged material to 

construct winter whooping crane habitat. Proc. N. Am. Crane 

Workshop 7:67-71. 

Feduccia, J. A. 1967. Ciconia maltha and Grus americana from the 

Upper Pliocene of Idaho. Wilson Bull. 79:316-318. 

Folk, M. J., S. A. Nesbitt, and M. G. Spalding. 2001. 

Interactions of sandhill cranes and whooping cranes with 
DRAFT Whooping Crane Recovery Plan 2005 

89 

foreign objects in Florida. Proc. N. Am. Crane Workshop 

8:195-197. 

Forrester, D. J., J. W. Carpenter, and D. R. Blankinship. 1978. 

Coccidia of whooping cranes. J. Wildl. Diseases 14:24-27. 

Foose, T.J. 1992. Interactive management of small wild and 

captive populations. In C. Mirande, R. Lacy, and U. Seal, 

compilers. Grus americana Whooping Crane Conservation 

Viability Assessment Workshop Report. Fossil Rim Wildl. 

Center, August 6-8, 1991. Captive Breeding Specialist Group 

(CBSG/SSC/IUCN). 

Forbes, S. and D. Mock. 2000. A tale of two strategies: lifehistory aspects of family strife. Condor 102:23-24. 

Frankel, O. H., and M. E. Soule. 1981. Design criteria for nature 

reserves. 5.2, Pages 98-122 in Conservation and Evolution. 

Cambridge Univ. Press, Cambridge, London. 327 pp. 

Frankham, R. 1995. Conservation genetics. Annual Review of 

Genetics 29:305-327. 

Franklin, I. R. 1980. Evolutionary change in small population. 

Pages 135-149 in M. E. Soule and B. A. Wilcox, eds. 

Conservation biology: an evolutionary – ecological 

perspective. Sinauer Associates Inc., Sunderland, 

Massachusetts. 

Garton, E. 0., R. C. Drewien, W. M. Brown, E. G. Bizeau, and P. 

H. Hayward. 1989. Survival rates and population prospects of 

whooping cranes at Grays Lake NWR. Final Rept. Fish and 

Wildl. Department, Univ. Idaho. in files Aransas Natl. Wildl. 

Refuge, Austwell, Texas. 47 pp. 

Gee, G. F., and S. A. Temple. 1978. Artificial insemination for 

breeding non-domestic birds. Symposium Zoological Soc. London 

43:51-72. 

_________, and C. M. Mirande. 1996. Special techniques, Part A: 

Crane artificial insemination. Pages 205-217 in D. H. Ellis, 

G. F. Gee, and C. M. Mirande, eds. Cranes: Their biology, 

husbandry, and conservation. Natl. Biological Service, 

Washington, D.C., and International Crane Foundation, 

Baraboo, Wisconsin, and USFWS, Washington, D.C. 308 pp. 
DRAFT Whooping Crane Recovery Plan 2005 

90 

_________, H. C. Dessauer, J. Longmire, W. E. Briles, and R. C. 

Simon. 1992. The study of relatedness and genetic diversity 

in cranes. Pages 225-230 in D. A. Wood, ed. Proc. 1988 N. Am. 

Crane Workshop. Florida Game and Fresh Water Fish Commission, 

Tallahassee, Florida. 

_________, J. Nicolich, S. A. Nesbitt, J. Hatfield, D. H. Ellis, 

and G. H. Olsen. 2001. Water conditioning and whooping crane 

survival after release in Florida. Proc. N. Am. Crane 

Workshop 8:160-165. 

Gerencser, J. 1997. Evaluation of pair-bond strength in cranes at 

the International Crane Foundation. Avicultural Magazine 

103(3):107-111. 

_________. 1998. Managing crane pair formation at the 

International Crane Foundation. AFA Watchbird 25(3):56-61. 

Glenn, T. C., W. Stephan, and M. J. Braun. 1999. Effects of a 

population bottleneck on mitochondrial DNA variation in 

whooping cranes. Conservation Biology 13(5):1097-1107. 

Gomez, G. M. 1992. Whooping cranes in southwest Louisiana: 

History and human attitudes. Proc. N. Am. Crane Workshop 

6:19-23. 

Gulf Engineers and Consultants, Inc. 1992. Spill contingency and 

prevention plan for the Gulf Intracoastal Waterway at the 

Aransas National Wildlife Refuge. Rept. to USACE, Contract 

No. DACW 64-91-D-0002, Baton Rouge, Louisiana, 93 pp. 

Hahn, P. 1963. Where is that vanished bird? Royal Ontario Museum, 

Univ. Toronto, Toronto, Canada. 

Hallman, R. C. 1965. Whooping crane shot in St. Johns County, 

Florida. Fla. Nat. 38:22. 

Harrison, M. 1983. Letter from Office of Airport Standards to 

R. Thorsell of Edison Electric Institute. USFWS file at 

Aransas NWR, Austwell, TX. 2 pp. 

Hartup, B. K., K. A. Linn and J. A. Langenberg. 2001a. Patellar 

ligament rupture and tibiotarsal crest fractures in whooping 

crane (Grus Americana) chicks: Potential risk factors and 
DRAFT Whooping Crane Recovery Plan 2005 

91 

treatment constraints. Proc. Am. Assoc. of Zoo Veterinarians 

Ann. Conf., Orlando, Florida. Pages 371-373. 

_________, N. M. Czekala, G. H. Olsen and J. A. Langenberg. 

2001b. Levels of fecal corticosterone in released sandhill 

cranes: An indicator of potential stress for reintroduced 

whooping cranes. Proc. Am. Assoc. of Zoo Veterinarians Ann. 

Conf., Orlando, Florida. Pages 222-223. 

Henszey, R. J., and T. A. Wesche. 1993. Hydrologic components 

influencing the condition of wet meadows along the central 

Platte River, Nebraska. Rept. to Nebraska Game and Parks 

Commission, Lincoln, Nebraska. HabiTech, Inc. Laramie, 

Wyoming. 84 pp. 

Hjertaas, D. 1994. Summer and breeding records of the whooping 

crane in Saskatchewan. Blue Jay 52:99-115. 

_________, B. W. Johns, and W. J. Lyon. 1997. Identification of 

potential reintroduction sites for whooping cranes in the 

prairie provinces of Canada. Proc. N. Am. Crane Workshop 

7:256-257. 

Horwich, R. H. 1986. Reintroduction of cranes to the wild. ICF 

Bugle 12(4):1-5. 

_________. 1989. Use of surrogate parental models and age periods 

in a successful release of hand-reared sandhill cranes. Zoo. 

Biol. 8:379-390. 

_________, J. Wood, and R. Anderson. 1992. Release of sandhill 

crane chicks hand-reared with artificial stimuli. Pages 255-

262 in D. A. Wood, ed. Proc. 1988 N. Am. Crane Workshop. 

Florida Game and Fresh Water Fish Commission. 

Howard, J. A. 1954. Aransas, a National Wildlife Refuge. U.S. 

Department of the Interior, USFWS. 12 pp. 

Howe, M. A. 1987. Habitat use by migrating whooping cranes in the 

Aransas-Wood Buffalo corridor. Pages 303-311, in J. C. Lewis 

and J. W. Ziewitz, eds. Proc. 1985 Crane Workshop. Platte 

River Whooping Crane Habitat Maintenance Trust and USFWS, 

Grand Island, Nebraska. 

_________. 1989. Migration of radio-marked whooping cranes from 
DRAFT Whooping Crane Recovery Plan 2005 

92 

the Aransas-Wood Buffalo population: Patterns of habitat use, 

behavior, and survival. USFWS, Fish Wildl. Tech. Rept 21. 

33pp. 

Hunt, H. E. 1987. The effects of burning and grazing on habitat 

use by whooping cranes and sandhill cranes on the Aransas 

Natl. Wildl. Refuge. Ph.D. Dissertation, Texas A & M Univ., 

College Station. 172 pp. 

_________, and R. Slack. 1987. Winter foods of the whooping crane 

based on stomach content analyses. Pages 217-218, in J. C. 

Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane Workshop. 

Platte River Whooping Crane Habitat Maintenance Trust and 

USFWS, Grand Island, Nebraska. 

Hurr, R. T. 1983. Ground-water hydrology of the Mormon Island 

Crane Meadows Wildl. area near Grand Island, Hall County, 

Nebraska. Pages H1-H12, in Hydrologic and Geomorphical 

studies of the Platte River Basin, U.S. Geological Survey 

Professional Paper 1277. 

Hyde, D. 0. 1968. Sandy, the sandhill crane. Dial Press, New 

York. 241 pp. 

Immelmann, K. 1972. Sexual and other long-term aspects of 

imprinting in birds and other species. Pages 147-174 in D. S. 

Lehrman et al., eds. Advances in the study of behavior. 

Vol.4, Academic Press, New York. 

Irby, H. D. 1990. Whooping crane/human interaction study. 

Welder Flats Coastal Preserves Baseline Studies Rept. Section 

III. Texas Parks and Wildl. Dept., Austin. 52 pp. 

 

Jarvi, S. I., G. F. Gee, W. E. Briles, and M. M. Miller. 1992. 

Identification of segregating hapolotypes of the major 

histocompatibility complex in cranes. Proc. N. Am. Crane 

Workshop 6:171. 

 

_________, ________ , M. M. Miller, and W. E. Briles. 1995. A 

complex alloantigen system in Florida sandhill cranes, Grus

canadensis pratensis: Evidence for the Major 

Histocompatibility (B) System. J. Heredity 86:348-353. 

Jimenez, J. A., K. A. Hughes, G. Alaks, L. Graham, and R. C. 
DRAFT Whooping Crane Recovery Plan 2005 

93 

Lacy. 1994. An Experimental-Study of Inbreeding Depression 

in a Natural Habitat. Science 266(5183):271-273. 

Johns, B. W. 1987. Whooping crane sightings in the prairie 

provinces 1979-1985. Canadian Wildl. Service Progress Note 

169. 6 pp. 

_________. 1992. Preliminary identification of whooping crane 

staging areas in prairie Canada. Pages 61-66 in D. A. Wood, 

ed. Proc. 1988 N. Am. Crane Workshop. Florida Game and Fresh 

Water Fish Commission, Tallahassee. 

_________. 1998a. Whooping cranes nesting in Alberta. Blue Jay 

56:31-33. 

_________. 1998b. 1997-Year of the crane. Alberta Naturalist 

28:3-4. 

_________, E. J. Woodsworth, and E. A. Driver. 1997. Habitat use 

by migrant whooping cranes in Saskatchewan. Proc. N. Am. 

Crane Workshop 7:123-131. 

_________, P. Goossen, E. Kuyt and L. Craig-Moore. In press. 

Philopatry and dispersal in whooping cranes (Grus americana). 

Proc. 2003 N. Am. Crane Workshop 9:0-00. 

Johnson, E. F. 1976. Aransas whooping cranes. Blue Jay 34:220-

228. 

Johnson, K. A. and S. A. Temple. 1980. The migration ecology of 

the whooping crane. Unpublished report prepared under 

contract 14-16-0009-78-034 to USFWS. U. of Wisconsin, 

Madison, Wisconsin. 87pp. 

Jones, K. L. 2003. Genetic variation and structure in cranes: a 

comparison among species. Ph.D. dissertation. University of 

Illinois - Chicago, Illinois. 

Jones, K. L. and B. Lacy. 2003. Whooping crane master plan for 

2003. Final report from workshop held at ICF in September, 

2002. 119 pp. 

_________, and C. Mirande. 2001. Genealogy of the whooping crane. 

International Crane Foundation, Baraboo, Wisconsin. 120 pp. 
DRAFT Whooping Crane Recovery Plan 2005 

94 

_________, T. C. Glenn, R. C. Lacy, J. R. Pierce, N. Unruh, C. M. 

Mirande, and F. Chavez-Ramirez. 2002. Refining the whooping 

crane studbook by incorporating microsatellite DNA and legbanding analyses. Conservation Biology 16(3):789-799. 

_________, G. Krapu, D. Brandt, and M. V. Ashley. In prep-a. 

Definition of subpopulations within mid-continent sandhill 

cranes: a nuclear approach. 

_________, and J. M. Nicolich. 2001. Artificial insemination in 

captive whooping cranes: results from genetic analyses. Zoo 

Biology 20(4):331-342. 

_________, J. M. Nicolich, and G. Gee. In prep-b. Investigation 

of fertility and artificial insemination timing in Florida 

sandhill cranes. 

Kemsies, E. 1930. Birds of the Yellowstone National Park, with 

some recent additions. Wilson Bull. 42:198-210. 

Kepler, C. B. 1976. Dominance and dominance-related behavior in 

the whooping crane. Pages 177-196, in J. C. Lewis, eds. Proc. 

International Crane Workshop. Oklahoma State Univ. Press, 

Stillwater, Oklahoma. 

_________. 1978. Captive propagation of whooping cranes: A 

behavioral approach. Pages 231-241, in S. A. Temple, ed. 

Endangered Birds - Management Techniques for Preserving 

Threatened Species. Univ. Wisconsin, Madison, Wisconsin. 

Konrad, P. M. 1987. Expanded sandhill crane hunting in the 

Dakotas and Oklahoma threatens endangered whooping cranes. 

Pages 69-77 in Proc. 1985 Crane Workshop. Platte River 

Whooping Crane Habitat Maintenance Trust and USFWS, Grand 

Island, Nebraska. 

Krajewski, C. 1989. Phylogenetic relationships among cranes 

(Gruiformes: Gruidae) based on DNA hybridization. Auk 

106:603-618. 

Kreger, M., J. Hatfield, G. Gee, D. Clugston, and I. Estevez. 

2001. Behavioral profiles of the captive whooping crane as 

an indicator of reintroduction survival. Abstract presented 

to Society for Conservation Biology, August, 2001. 
DRAFT Whooping Crane Recovery Plan 2005 

95 

Kretzschmar, G. E. 1990. Executive administrator, Texas Water 

Development Board. Letter to T. Grahl, USFWS-Ecological 

Services, Corpus Christi, Texas. December 5, 1990. 

Kuyt, E. 1976a. Whooping cranes: The long road back. Nature 

Canada 5:2-9. 

_________. 1976b. The continuing story of the whooping crane. 

Pages 109-111, in T. Mosquin and C. Suchal, eds. Proc. 

Symposium on Canada's Threatened Species and Habitats. Canada 

Natl. Federal Special Publ. 6, Ottawa, Canada. 

_________. 1976c. Recent clutch-size data for whooping cranes, 

including a three-egg clutch. Blue Jay 34:82-83. 

_________. 1978a. Whooping crane color-marking. N. Am. Bird 

Bander 3:162. 

_________. 1978b. A modern nesting record for whooping cranes in 

Alberta. Blue Jay 36:147-148. 

_________. 1979a. Banding of juvenile whooping cranes on the 

breeding range in the Northwest Territories, Canada. N. Am. 

Bird Bander 4:24-25. 

_________. 1979b. Banding of juvenile whooping cranes and 

discovery of the summer habitat use by non-breeders. Pages 

109-111 in J. C. Lewis, eds. Proc. 1978 International Crane 

Workshop. Colorado State Univ. Printing Service, Fort 

Collins, Colorado. 

_________. 1981a. Population status, nest site fidelity, and 

breeding habitat of whooping cranes. Pages 119-125, in J. C. 

Lewis and H. Masatomi, eds. Crane Research Around the World. 

Proc. International Crane Symposium, Sapporo, Japan, 

International Crane Foundation, Baraboo, Wisconsin. 

_________. 1981b. Clutch size, hatching success, and survival of 

whooping crane chicks, Wood Buffalo National Park, Canada. 

Pages 126-129, in J. C. Lewis and H. Masatomi, eds. Crane 

Research Around the World. Proc. International Crane 

Symposium, Sapporo, Japan, International Crane Foundation, 

Baraboo, Wisconsin. 
DRAFT Whooping Crane Recovery Plan 2005 

96 

_________. 1982. Whooping crane. Hinterland Who’s Who, Canadian 

Wildl. Service, Ottawa. 6pp. 

_________. 1987. Management and research of whooping cranes, 

1965-1982. Pages 365-369 in G. W. Archibald and R. F. 

Pasquier, eds. Proc. 1983 International Crane Workshop. 

International Crane Foundation, Baraboo, Wisconsin. 

_________. 1989. Use of a whooping crane nest by a sandhill 

crane. Blue Jay 47(1):33-38. 

_________. 1992. Aerial radio-tracking of whooping cranes 

migrating between Wood Buffalo National Park and Aransas 

National Wildlife Refuge, 1981-84. Occas. Pap. 74, Canadian 

Wildl. Service, 53 pp. 

_________. 1993a. Whooping crane, Grus americana, home range and 

breeding range expansion in Wood Buffalo Natl. Park, 1970-

1991. Can. Field-Nat. 107:1-12. 

_________. 1993b. Case study - whooping cranes. In A. W. Diamond 

and B. D. Bell, eds. The management of populations of 

endangered bird species. Chap. 4. Reproductive manipulation. 

International Council for Bird Preservation. 

_________. 1995. The nest and eggs of the whooping crane, Grus

americana. Canadian Field Naturalist 109:1-5. 

_________. 1996. Reproductive manipulation in the whooping crane 

Grus americana. Bird Conservation International 6:3-10. 

_________, and J. P. Goossen. 1987. Survival, age composition, 

sex ratio, and age at first breeding of whooping cranes in 

Wood Buffalo National Park, Canada. Pages 230-244, in J.C. 

Lewis and J.W. Ziewitz, eds. Proc. 1985 Crane Workshop, 

Platte River Whooping Crane Habitat Maintenance Trust and 

USFWS, Grand Island, Nebraska. 

_________, B. E. Johnson, and R. C. Drewien. 1981. A wolf kills a 

juvenile whooping crane. Blue Jay 39(2):116-119. 

Labuda, S. E., and K. 0. Butts. 1979. Habitat use by wintering 

whooping cranes on the Aransas National Wildlife Refuge. 

Pages 152-157, in J. C. Lewis, ed. Proc. 1978 International 

Crane Workshop, Colorado State Univ., Printing Service, Fort 
DRAFT Whooping Crane Recovery Plan 2005 

97 

Collins, Colorado. 

Lacy, R. C. 1997. Importance of genetic variation to the 

viability of mammalian populations. Journal of Mammalogy 

78(2):320-335. 

Lamont, T., and W. Reichel. 1970. Organochlorine pesticide 

residues in whooping cranes and Everglade kites. Auk 87:158-

159. 

Lande, R. 1995. Breeding plans for small populations based on the 

dynamics of quantitative genetic variance. Pages 318-340 In 

J. D. Ballou, M. Gilpin and T. J. Foose, eds. Population 

Management for survival and recovery. Analytical methods and 

strategies in small population conservation. Columbia Univ. 

Press, New York. 

Langenberg, J. A., and S. Donoghue. 1997. Clinical nutrition in a 

crane captive propagation program. Pages 52-61 In M. Gies, 

ed., Proc. 9th Dr. Scholl Conf. on Nutrition of Captive Wild 

Animals. Lincoln Park Zoological Soc., Chicago, Illinois. 

_________, K. Maguire, and N. Businga. 1998. New techniques in 

incubation management: egg radiography and egg sex 

identification. 1998 Proc. Assoc. Avian Veterinarians. 

Lamont, T., and W. Reichel. 1970. Organochlorine pesticide 

residues in whooping cranes and everglade kites. Auk 87:158-

159. 

Leach, B. 1987. The sandhill crane recovery project in the Lower 

Fraser Valley, British Columbia. Pages 415-423 in G. W. 

Archibald and R. F. Pasquier, eds. Proc. 1983 International 

Crane Workshop. International Crane Foundation, Baraboo, 

Wisconsin. 

Lewis, J. C. 1991. International cooperation in recovery of 

whooping cranes: A model for other nations. Pages 389-394 in. 

Proc. 1987 International Crane Workshop. International Crane 

Foundation, Baraboo, Wisconsin. 

_________. 1992. The contingency plan for federal-state 

cooperative protection of whooping cranes. Pages 293-300 in 

D. A. Wood, ed. Proc. 1988 N. Am. Crane Workshop. Florida 

Game and Fresh Water Fish Commission, Tallahassee. 
DRAFT Whooping Crane Recovery Plan 2005 

98 

_________. 1999. Population recovery techniques in North America 

using captive-reared cranes. Pages 2522-2532 in J. J. Adams 

and R. H. Slotow, eds. Proc. 22nd International Ornithological 

Congress, Durban, South Africa. 

_________, and F.G. Cooch. 1992. Introduction of whooping cranes 

in eastern North America. Pages 301-305 in D. A. Wood, ed. 

Proc. 1988 N. Am. Crane Workshop. Florida Game and Fresh 

Water Fish Commission, Tallahassee. 

_________, and L. Finger. 1993. Endangered and threatened 

wildlife and plants; Establishment of an experimental 

nonessential population of whooping cranes in Florida. 

Federal Register 58(13):5647-5658. 

_________, E. Kuyt, K. E. Schwindt, and T. V. Stehn. 1992a. 

Mortality in fledged cranes of the Aransas-Wood Buffalo 

population. Pages 145-148 in D. A. Wood, ed. Proc. 1988 N. 

Am. Crane Workshop. Florida Game and Fresh Water Fish 

Commission, Tallahassee. 

_________, R.C. Drewien, E. Kuyt, and C. S. Sanchez, Jr. 1992b. 

Contaminants in habitat, tissues, and eggs of whooping 

cranes. Proc. N. Am. Crane Workshop 6:159-165. 

Lewis, T. E., and R. D. Slack. 1992. Whooping crane response to 

disturbances at the Aransas National Wildlife Refuge. Proc. 

N. Am. Crane Workshop 6:176. 

 

Lingle, G. R. 1987. Status of whooping crane migration habitat 

within the Great Plains of North America. Pages 331-340 in J. 

C. Lewis and J. Zewitz, eds. Proc. 1985. Crane Workshop. 

Platte River Whooping Crane Habitat Maintenance Trust and 

USFWS, Grand Island, Nebraska. 

_________. 1992. History and economic impact of crane-watching in 

central Nebraska. Proc. N. Am. Crane Workshop 6:33-37. 

_________, G. A. Wingfield, and J. W. Ziewitz. 1991. The 

migration ecology of whooping cranes in Nebraska, U.S.A. 

Pages 395-401 in J. Harris, ed. Proc. 1987 International 

Crane Workshop, International Crane Foundation, Baraboo, 

Wisconsin. 
DRAFT Whooping Crane Recovery Plan 2005 

99 

Lishman, W. J., T. L. Teets, J. W. Duff, W. J. Sladen, G. G. 

Shire, K. M. Goolsby, W. A. Bezner-Kerr, and R. P. Urbanek. 

1997. A reintroduction technique for migratory birds: leading 

Canada geese and isolation-reared sandhill cranes with 

ultralight aircraft. Proc. N. Am. Crane Workshop 7:96-104. 

Longley, W. H. 1970. Sandhill cranes at the Carlos Avery Wildl. 

Area. The Loon 4:124-128. 

Longley, W. L., ed. 1994. Freshwater inflows to Texas bays and 

estuaries: ecological relationships and methods for 

determination of needs. Texas Water Development Board and 

Texas Parks and Wildl. Dept., Austin, Texas. 386 pp. 

Longmire, J. L., G. F. Gee, C. L. Hardeknopf, and G. A. Mark. 

1992. Establishing paternity in whooping cranes (Grus 

americana) by DNA analysis. Auk 109(3):522-529. 

Love, J., and P. Deininger. 1992. Characterization and 

phylogenetic significance of a repetitive DNA sequence from 

whooping crane (Grus americana). Auk 109:73-79. 

 

Lynch, J. 1956. The great white bird. Proc. Federal-Prov. Wildl. 

Conf. 20:287-301. 

Lyon, W.J., D. Hjertaas, and B.W. Johns. 1995a. Development of 

screening criteria and identification of potential 

reintroduction sites for whooping cranes in prairie Canada. 

The Canadian Plains Research Center, Univ. Regina. 

_________,_________,and _________. 1995b. Evaluation of three 

potential reintroduction sites for whooping cranes in Canada. 

The Canadian Plains Research Center, Univ. Regina, Regina, 

Saskatchewan, Canada. 

Mabie, D. W., L. A. Johnson, B. C. Thompson, J. C. Barron, and R. 

B. Taylor. 1989. Responses of wintering whooping cranes to 

airboat and hunting activities on the Texas Coast. Wildl. 

Soc. Bull. 17(3):249-253. 

Mahan, T. A., and B. S. Simmers. 1992. Social preference of four 

cross-foster reared sandhill cranes. Proc. N. Am. Crane 

Workshop 6:114-119. 

Maroldo, G. K. 1980. Crip: The constant dancer. Blue Jay 38:147-
DRAFT Whooping Crane Recovery Plan 2005 

100 

161. 

May, P. L. 1992. The feasibility of establishing a breeding 

whooping crane (Grus americana) flock on the Canadian 

Prairies. MS Thesis, Univ. Calgary. 

McIlhenny, E. A. 1943. Major changes in the bird life of southern 

Louisiana during sixty years. Auk 60:541-547. 

McMillen, J. L. 1987. Evaluation of the Seney National Wildl. 

Refuge as a reintroduction site for whooping cranes. Final 

Rept. Ohio Cooperative Fish and Wildl. Research Unit, 

Columbus, Ohio. 195 pp. 

McNulty, F. 1966. The whooping crane. E. P. Dutton & Co., New 

York, New York. 88 pp. 

Meine C. D., and G. W. Archibald. Compilers. 1996. The cranes: 

status survey and conservation action plan. IUCN/SSC Crane 

Specialist Group, IUCN the World Conservation Union, Gland, 

Switzerland. 282 pp. 

Melvin, S. M., and S. A. Temple. 1980. Migration ecology and 

wintering grounds of sandhill cranes from the Interlake of 

Manitoba. Unpubl. USFWS Rept., Washington. 

_________, W.J.D. Stephen, and S. Temple. 1990. Population 

estimates, nesting biology, and habitat preferences of 

Interlake, Manitoba, sandhill cranes, Grus canadensis. 

Canadian Field Naturalist 104:354-361. 

Miller, L. 1944. Some Pliocene birds from Oregon and Idaho. 

Condor 46:25-32. 

Miller, R. S. 1973. The brood sizes of cranes. Wilson Bull. 

85:436-440. 

Mirande, C., R. Lacy, and U. Seal. 1993. Whooping crane (Grus 

americana) conservation viability assessment workshop report. 

Captive Breeding Specialist Group, IUCN, Apple Valley, 

Minnesota. 115 pp. 

_________, G. F. Gee, A. Burke, and P. Whitlock. 1996. Egg and 

semen production. Pages 45-57 in D. H. Ellis, G. F. Gee, and 

C. M. Mirande, eds. Cranes: Their biology, husbandry, and 
DRAFT Whooping Crane Recovery Plan 2005 

101 

conservation. Natl. Biological Service, Washington, D.C., 

and International Crane Foundation, Baraboo, Wisconsin, and 

USFWS, Washington, D.C. 308 pp. 

_________, J. R. Cannon, K. Agzigian, R. E. Bogart, S. 

Christiansen, J. Dubow, A. K. Fernandez, D. K. Howarth, C. 

Jones, K. G. Munson, S. I. Pandya, G. Sedaghatkish, K. L. 

Skeri, S. A. Stenquist, and J. Wheeler. 1997a. Computer 

simulations of possible futures for two flocks of whooping 

cranes. Proc. N. Am. Crane Workshop 7:181-200. 

_________, J. W. Carpenter, and A. M. Burke. 1997b. The effect 

of disturbance on the reproduction and management of captive 

cranes. Proc. N. Am. Crane Workshop 7:56-61. 

Moody, A. F. 1931. Death of an American whooping crane. 

Aviculture Magazine 9:8-11. 

Morkill, A. E. 1990. Effectiveness of markers in reducing 

sandhill crane collisions with powerlines. Univ. Wyoming MS 

Thesis, Laramie. 

_________, and S. H. Anderson. 1991. Effectiveness of marking 

powerlines to reduce sandhill crane collisions. Wildl. Soc. 

Bull 19:442-449. 

_________, and _________. 1993. Effectiveness of yellow aviation 

balls in reducing sandhill cranes collisions with power 

lines. Pages 21-1 to 21-l7 in Proc. International Workshop On 

Avian Interactions With Utility Structures. Elect. Power Res. 

Institute, Pleasant Hill, California. 

Mummert, D. P., D. H. Ellis, and C. L. Chambers. 2001. Fate of 

the survivors of the 1995 and 1996 trucking migrations of 

costume-reared sandhill cranes in Arizona. Proc. N. Am. Crane 

Workshop 8:127-131. 

Nagendran, M. 1992. Winter release of isolation-reared greater 

sandhill cranes in south Texas. Proc. N. Am. Crane Workshop 

6:131-134. 

_________, R. P. Urbanek, and D. H. Ellis. 1996. Special 

techniques, Part D: Reintroduction techniques. Pages 231-240 

in D. H. Ellis, G. F. Gee, and C. M. Mirande, eds. Cranes: 

their biology, husbandry, and conservation. Natl. Biological 
DRAFT Whooping Crane Recovery Plan 2005 

102 

Service, Washington, D.C. and International Crane Foundation, 

Baraboo, Wisconsin. 

Nedelman, J., J. A. Thompson, and R. J. Taylor. 1987. The 

statistical demography of whooping cranes. Ecology 

68(5):1401-1411. 

Nelson, J. T. 1995. Nutritional quality and digestibility of 

foods eaten by whooping cranes on their Texas wintering 

ground. MS Thesis, Texas A and M Univ. 95pp. 

Nesbitt, S. A. 1979. Notes on the suitability of captive-reared 

sandhill cranes for release into the wild. Pages 85-88, in J. 

C. Lewis, ed. Proc. 1978 International Crane Workshop, 

Colorado State Univ., Printing Service, Fort Collins, 

Colorado. 

_________. 1982. The past, present, and future of the whooping 

crane in Florida. Pages 151-154 in J. C. Lewis, ed. Proc. 

1981 International Crane Workshop. Natl. Audubon Soc., 

Tavernier, Florida. 

_________. 1988. An evaluation of the Florida sandhill crane 

population of peninsular Florida and its potential to support 

a population of nonmigratory whooping cranes. Florida Game 

and Fresh Water Fish Commission, Tallahassee, Florida. 70 pp. 

_________, and K. S. Williams. 1990. Home range and habitat use 

of Florida sandhill cranes. J. Wildl. Manage. 54:92-96. 

_________, and J. W. Carpenter. 1993. Survival and movements of 

greater sandhill cranes experimentally released in Florida. 

J. Wildl. Management 57:673-679. 

_________, M. J. Folk, M. G. Spalding, J. A. Schmidt, S. T. 

Schwikert, J. M. Nicolich, M. Wellington, J. C. Lewis, and T. 

H. Logan. 1997. An experimental release of whooping cranes in 

Florida – the first three years. Proc. N. Am. Crane Workshop 

7:79-85. 

_________, M. J. Folk, K. A. Sullivan, S. T. Schwikert, and M. G. 

Spalding. 2001. An update of the Florida whooping crane 

release project through June 2000. Proc. N. Am. Crane 

Workshop 8:62-72. 
DRAFT Whooping Crane Recovery Plan 2005 

103 

Nicolich, J. M., G. F. Gee, and S. G. Hereford. 2001. Natural 

fertility in whooping cranes and Mississippi sandhill cranes 

at Patuxent Wildlife Research Center. Proc. N. Am. Crane 

Workshop 8:170-177. 

Novakowski, N. 5. 1965. The day we rescued a whooping crane. 

Audubon Mag. 67:230-233. 

_________. 1966. Whooping crane population dynamics on the 

nesting grounds, Wood Buffalo National Park, Northwest 

Territories, Canada. Canadian Wildl. Service, Res. Rept. Ser. 

1, 20 pp. 

Olsen, G. H., and M. Wise. 2001. Ingested metal in whooping 

cranes: An endoscopic technique for removal and implications 

for the release program. Proc. N. Am. Crane Workshop 8:198-

202. 

_________, J. A. Taylor, and G. F. Gee. 1997. Whooping crane 

mortality at Patuxent Wildlife Research Center, 1982-1995. 

Proc. N. Am. Crane Workshop 7:243-248. 

_________, M. M. Hendricks, and L. E. Dressler. 2001. 

Hematological and serum chemistry norms for sandhill and 

whooping cranes. Proc. N. Am. Crane Workshop 8:178-184. 

Platte River Management Joint Study. 1990. Biology workgroup 

final report. USFWS and Bureau of Reclamation, Denver, 

Colorado. 131 pp. 

Platte River Management Joint Study. 1993. Methods for 

calculating and displaying habitat target flows by species. 

Management Alternatives Work Group, Task 5a working document. 

USFWS, Grand Island, Nebraska. 34 pp. 

Primack, R. B. 1993. Essentials of conservation biology. Sinauer 

Associates Inc., Sunderland, Massachusetts. 564 pp. 

Randall, A., and J. R. Stoll. 1983. Existence value in a total 

valuation framework. In R. Rowe and L. Chestnut, eds. 

Managing Air Quality and Scenic Resources at National Parks. 

Westview Press, Boulder, Colorado. 

Raup, H. M. 1933. Range conditions in the Wood Buffalo Natl. 

Park of western Canada with notes on the history of the wood 
DRAFT Whooping Crane Recovery Plan 2005 

104 

bison. Am. Comm. International Wildl. Protection, Special 

Publ. 1:2-16. 

Reed, D. H., J. J. O’Grady, B. W. Brook, J. D. Ballou and R. 

Frankham. 2003. Estimates of minimum population sizes for 

vertebrates and factors influencing those estimates. Biol. 

Cons. 113:23-34. 

Richert, A. D. 1999. Multiple scale analyses of whooping crane 

habitat in Nebraska. Ph.D. Dissertation, Univ. NebraskaLincoln. 175 pp. 

_________, K. E. Church, and S. E. Richert. 1999. Methods for 

multiple-scale analysis of crane habitat. Pages 2544-2551 in 

J.J. Adams and R. H. Slotow, eds. Proc. 22nd International 

Ornithological Congress, Durban, South Africa. 

_________, and K. Church. 2001. Multiple spatial scale analysis 

of whooping crane habitat in Nebraska. Abstract in Proc. N. 

Am. Crane Workshop 8:217. 

_________, J. S. Taylor, and S. E. Richert. In press. Stopover 

habitat selection by whooping cranes in Nebraska. Proc. 

Midwest Fish and Wildl. Conf. 2000. 

 

Robertson, S., T. Stehn, and J. Magera. 1993. Oil spill 

contingency plan for Aransas National Wildlife Refuge, Texas. 

USFWS, Region 2. 25 pp. 

Robinson, W. H., M. G. Sheldon, and R. A. Wilson. 1965. Whooping 

crane studies. Pages 35-36 in The effects of pesticides on 

fish and Wildlife. USFWS Circulation 226. 

Salwasser, H., S. P. Mealy, and K. Johnson. 1984. Wildlife 

population viability: a question of risk. Trans. N. Am. 

Wildl. Nat. Resour. Conf. 49:421-439. 

Shaffer, M. l. 1981. Minimum population sizes for species 

conservation. BioScience 31:131-134. 

Sherrod, H. L., and R. Medina. 1992. Whooping crane habitat 

alteration analysis at Aransas National Wildlife Refuge, 

Texas. Pages 87-99 in D. A. Wood, ed. Proc. 1988 N. Am. Crane 

Workshop. Florida Game and Fresh Water Fish Commission, 

Tallahassee. 
DRAFT Whooping Crane Recovery Plan 2005 

105 

Shields, R. H., and E. L. Benham. 1969. Farm crops as food 

supplements for whooping cranes. J. Wildl. Management 33:811-

817. 

Snyder, S. B., M. Richard, R. Drewien, and J. C. Lewis. 1987. 

Pasteurella multocida infection in a whooping crane 

associated with an avian cholera outbreak. Pages 149-155 in 

J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane 

Workshop. Platte River Habitat Maintenance Trust and USFWS, 

Grand Island, Nebraska. 

_________, M. J. Richard, J. P. Thilsted, R. C. Drewien, and J. 

C. Lewis. 1992. Lead poisoning in a whooping crane. Pages 

207-210 in D. A. Wood, ed. Proc. 1988 N. Am. Crane Workshop. 

State of Florida Game and Fresh Water Fish Commission, 

Tallahassee, Florida. 

_________, M. J. Richard, and C. U. Meteyer. 1997. Avian 

tuberculosis in a whooping crane: treatment and outcome. 

Proc. N. Am. Crane Workshop 7:253-255. 

Sommerfeld, W. J., and J. Scarth. 1998. An evaluation of the 

Interlake region of Manitoba as a release site for the 

potential reintroduction of whooping cranes. Delta Waterfowl 

and Wetlands Research Station, Portage la Prairie, Manitoba. 

44 pp. 

Spalding, M. G., J. M. Kinsella, S. A. Nesbitt, M. J. Folk, and 

G. W. Foster. 1996. Helminth and arthropod parasites of 

experimentally introduced Whooping Cranes in Florida. J. 

Wildl. Dis. 32: 44-50. 

_________, S. A. Nesbitt, M. J. Folk, L. R. McDowell, and M. S. 

Sepulveda. 1997. Metal consumption by whooping cranes and 

possible zinc toxicosis. Proc. N. Am. Crane Workshop 7:237-

242. 

Sprunt, A., Jr., and E. B. Chamberlain. 1949. South Carolina bird 

life. Univ. South Carolina Press, Columbia. 585 pp. 

Stahlecker, D. A. 1988. An inventory of potential stopover 

roosting habitat for whooping cranes in the Wood BuffaloAransas migration corridor: A pilot study in the Clinton NE 

(1/100,000), Oklahoma map area. Eagle Ecological Services, 

Santa Fe, New Mexico 17 pp. 
DRAFT Whooping Crane Recovery Plan 2005 

106 

_________. 1992. Using National wetlands inventory maps to 

quantify whooping crane stopover habitat in Oklahoma. Proc. 

N. Am. Crane Workshop 6:62-68. 

_________. 1997a. Predicting availability of stopover roosting 

habitat for migrant whooping cranes in the Northern Great 

Plains. Rept. by Eagle Ecological Services for USFWS. 21 pp. 

_________. 1997b. Availability of stopover habitat for migrant 

whooping cranes in Nebraska. Proc. N. Am. Crane Workshop 

7:132-140. 

Stehn, T. V. 1987. Impacts of the Gulf Intracoastal Waterway on 

the endangered whooping crane. Unpubl. Rept. USFWS, Aransas 

NWR, Austwell, Texas. 13 pp. 

_________. 1992a. Unusual movements and behaviors of color-banded 

whooping cranes during winter. Proc. N. Am. Crane Workshop 

6:95-101. 

_________. 1992b. Behavior of whooping cranes during initiation 

of migration. Proc. N. Am. Crane Workshop 6:102-105. 

_________. 1992c. Re-pairing of whooping cranes at Aransas 

National Wildlife Refuge. Proc. N. Am. Crane Workshop 6:185-

187. 

_________. 1997. Pair formation by color-marked whooping cranes 

on the wintering grounds. Proc. N. Am. Crane Workshop 7:24-

28. 

_________. 2002. Whooping cranes during the 2001-2002 winter. 

Unpubl. file Rept., Aransas NWR, Austwell, Texas. 

_________, and E. F. Johnson. 1987. The distribution of winter 

territories of the whooping crane on the Texas coast. Pages 

180-195 in J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 

Crane Workshop. Platte River Whooping Crane Habitat 

Maintenance Trust and USFWS, Grand Island, Nebraska. 

Stenning, M. 1996. Hatching asynchrony, brood reduction and other 

rapidly reproducing hypothesis. Trends in Ecology & 

Evolution. Elsevier Trends Journals, Cambridge. 
DRAFT Whooping Crane Recovery Plan 2005 

107 

Stephen, W. J. D. 1979. Whooping crane sightings in prairie 

provinces 1977 and 1978. Blue Jay 37:163-168. 

Stephenson, J. D. 1971. Plumage development and growth of young 

whooping cranes. MS Thesis, Oregon State Univ., Corvalis. 56 

pp. 

_________, and G. Smart. 1972. Egg measurements for three 

endangered species. Auk 89:191-192. 

Stevenson, J. 0., and R. E. Griffith. 1946. Winter life of the 

whooping crane. Condor 48:160-178. 

Stoll, J. R. 1983. Recreational activities and nonmarket 

valuation: the conceptualization issue. South J. Agric. Econ. 

15(2):119-125. 

_________, and L. A. Johnson. 1984. Concepts of value, nonmarket 

valuation, and the case of the whooping crane. Trans. N. Am. 

Wildl. Natural Resources Conf. 49:382-393. 

Strom, K. J. 1987. Lillian Annette Rowe - Managing migratory 

crane habitation the Platte River, Nebraska. Pages 326-330, 

in J. C. Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane 

Workshop. Platte River Whooping Crane Habitat Maintenance 

Trust and USFWS, Grand Island, Nebraska. 

Stroud, R. K., C. 0. Thoen, and R. M. Duncan. 1986. Avian 

tuberculosis and salmonellosis in a whooping crane (Grus

Americana). J. Wildl. Diseases 22(1):106-110. 

Sutton, G. M. 1967. Oklahoma birds. Univ. Oklahoma Press, Norman. 

674 pp. 

Texas Department of Water Resources. 1980. Guadalupe Estuary: A 

study of the influence of freshwater inflows. August 1980, 

Austin, Texas. 386 pp. 

Texas Parks and Wildlife Department. 1998. Freshwater inflow 

recommendation for the Guadalupe Estuary of Texas. Coastal 

Studies Technical Report No. 98-1. Austin, Texas. 61 pp + 

Figures 

Thompson, B. C., and R. R. George. 1987. Minimizing conflicts 

between migratory game bird hunters and whooping cranes in 
DRAFT Whooping Crane Recovery Plan 2005 

108 

Texas. Pages 56-68, in J. C. Lewis and J. W. Ziewitz, eds. 

Proc. 1985 Crane Workshop. Platte River Whooping Crane 

Habitat Maintenance Trust and USFWS, Grand Island, Nebraska. 

Timoney, K. P. 1997. The summer breeding habitat of whooping 

cranes in Wood Buffalo National Park, Canada. Parks Canada. 

WBNP, Ft. Smith, NT. 

_________. 1999. The habitat of nesting whooping cranes. 

Biological Conservation 89:189-197. 

_________, S. C. Zoltai, and L. Goldsborough. 1997. Boreal diatom 

ponds: a rare wetland associated with nesting whooping 

cranes. Wetlands 17(4):539-551. 

Twilley, R. R., E. J. Barron, H. L. Gholz, M. A. Harwell, R. L. 

Miller, D. J. Reed, J. B. Rose, E. H. Siemann, R. G. Wetzel 

and R. J. Zimmerman. 2001. Confronting climate change in 

the Gulf Coast region: prospects for sustaining our 

ecological heritage. Union of Concerned Scientists, 

Cambridge, Massachusetts, and Ecological Society of America, 

Washington, D.C. 2001. Published report. 

Uhler, F. M., and L. M. Locke. 1970. A note on the stomach 

contents of two whooping cranes. Condor 72:246. 

Urbanek, R. P., and T. A. Bookhout. 1992. Development of an 

isolation-rearing/gentle release procedure for reintroducing 

migratory cranes. Proc. N. Am. Crane Workshop 6:120-130. 

_________, and _________. 1994. Performance of captive-reared 

cranes released into a migration route in eastern North 

America. Pages 1221-1329 in H. Higuchi and J. Minton, eds. 

The future of cranes and wetlands. Wild Bird Soc. Japan, 

Tokyo. 

U.S. Army Corps of Engineers. 1988. Study of erosion along GIWW 

in the Aransas National Wildlife Refuge. USACE. 45 pp. 

U.S. Fish and Wildlife Service. 1979. Contingency plan for the 

protection of whooping cranes during a major oil spill in the 

Gulf of Mexico. 23 pp. 

_________.1981. The Platte River ecology study. Spec. Res. Rept., 

Northern Prairie Res. Cent., Jamestown, North Dakota. 187 pp. 
DRAFT Whooping Crane Recovery Plan 2005 

109 

_________. 1994. Whooping crane recovery plan. USFWS, 

Albuquerque, New Mexico. 92 pp. 

_________. 2001. Endangered and threatened wildlife and plants: 

establishment of an nonessential experimental population of 

whooping cranes in the Eastern United States. Final Rule. 

Federal Register 66:33903-33917, June 26, 2001. 

Valente, K. F. 1992. The effects of T2 toxin on Northern 

bobwhite, MS Thesis, Univ. Maryland, College Park. 89 pp. 

Walkinshaw, L. H. 1965. Attentiveness of cranes at their nests. 

Auk 82:465-476. 

_________. 1973. Cranes of the world. Winchester Press, New York. 

370 pp. 

Ward, J., and S. Anderson. 1987. Roost site use versus preference 

by two migratory whooping cranes. Pages 283-288 in J. C. 

Lewis and J. W. Ziewitz, eds. Proc. 1985 Crane Workshop. 

Platte River Whooping Crane Habitat Maintenance Trust and 

USFWS, Grand Island, Nebraska. 

Wesche, T. A., Q. D. Skinner, and R. J. Henszey. 1990. Platte 

River wetland hydrology study; draft report for the first 18 

months. Wyoming Water Research Center, Univ. Wyoming, 

Laramie. 43 pp. 

Wessling, B. 2000. Crane voice prints. The ICF Bugle 26(3):1-2. 

Wetmore, A. 1931. The avifauna of the Pleistocene of Florida. 

Smithsonian Miscellaneous Collection 85:35-36. 

_________. 1956. A check-list of the fossil and pre-historic 

birds of N. America and the West Indies. Smithsonian Misc. 

Collection 131. Washington, D.C. 105 pp. 

Windingstad, R. M., H. E. Stiles, and R. C. Drewien. 1981. 

Whooping crane preyed upon by golden eagle. Auk 98:393-394. 

Woodworth, L. M., Montgomery, M. E., Briscoe, D. A., and R. 

Frankham. 2002. Rapid genetic deterioration in captive 

populations: Causes and conservation implications. 

Conservation Genetics 3(3):277-288. 
DRAFT Whooping Crane Recovery Plan 2005 

110 

Zang, J., F. Ting, D. Hershberger, H. Yu, and C. A. Spell. 1993. 

Bank erosion of the Gulf Intracoastal Waterway at the Aransas 

National Wildlife Refuge. USACE Rept. 332, Vicksburg, 

Mississippi. 

Ziewitz, J. W. 1992. Whooping crane riverine roosting habitat 

suitability model. Pages 71- 81 in D. A. Wood, ed. Proc. 1988 

N. Am. Crane Workshop. Florida Game and Fresh Water Fish 

Commission, Tallahassee. 

Zwank, P.J., and S. R. Derrickson. 1981. Gentle release of 

captive, parent-reared sandhill cranes into the wild. Pages 

112-116 in J. C. Lewis, ed. Proc. 1981 Crane Workshop. Natl. 

Audubon Soc., Tavernier, Florida. 

_________, and C. D. Wilson. 1987. Survival of captive, parentreared Mississippi sandhill cranes released on a refuge. 

Conservation Biology 1:165-168. 
DRAFT Whooping Crane Recovery Plan 2005 

APPENDIX A: MINIMUM VIABLE POPULATION AND GENETICS 

Minimum Viable Population 

 

Extinction in small populations has led to the theory of minimum 

viable population size, defined as the smallest number of 

individuals necessary to give a population a high probability of 

surviving over a specified time (Primack 1993). Small 

populations are subject to rapid decline due to 3 main causes: 

(1) genetic fluctuations (e.g., genetic drift, inbreeding); (2) 

demographic fluctuations (e.g., variations in birth and death 

rates); (3) environmental fluctuations in predation, disease, 

competition, food supply, and natural catastrophes. As the 

population increases, the threat of extinction due to stocastic 

events diminishes, and loss of genetic diversity slows, thereby 

increasing species security. 

Shaffer (1981) tried to provide a specific technique for 

determining the minimum viable population (MVP). "A minimum 

viable population for any given species in any given habitat is 

the smallest isolated population having a 99% chance of remaining 

extant for 1000 years despite the foreseeable effects of 

demographic, environmental, and genetic stochasticity, and 

natural catastrophes." e.g., the smallest population size that 

can be predicted to have a very high chance of persisting for the 

next 1000 years. In this case, the probability for remaining 

extant could be set at 95% or 99%, and the time frame could be 

adjusted to 100 or 500 years. The theory of MVP is simply a 

guide to aid in the preservation of a species. 

 

As for the population sizes necessary to achieve a minimum viable 

population, opinions vary widely. One rule of thumb is to 

protect 1,000 individuals of a vertebrate species, because this 

number seems adequate to preserve genetic diversity (Shaffer 

1981, Salwasser et al. 1984). Others suggest that an effective 

population size of 5,000 individuals is needed to retain 

evolutionary potential (Lande 1995). More recently, Reed et al. 

(2003) used population viability analysis to estimate MVP for a 

variety of vertebrate species. Their definition of MVP is a 

population that has a 99% probability of persistence for 40 

generations. Their results indicate that the lack of long-term 

studies for endangered species may lead to an underestimation in 

the extinction rates for the species. They recommend that 

recovery/conservation programs should be designed to support a 

population of up to 7,000 adults to ensure long-term survival. 

A-1 
DRAFT Whooping Crane Recovery Plan 2005 

Downlisting Based on MVP Criteria 

Population sizes sufficient to be referred to as a minimum viable 

population depend highly on the effective population size (Ne). 

As not all breeding adults pass on their genetic material equally 

and randomly, there is a difference between the number of 

breeders and effective population size. When defining the 

population size sufficient for downlisting, criterion must 

account for the difference between the total population and the 

breeding population size (i.e., the Ne/N ratio). For the wild 

whooping crane population, breeders comprise approximately 50% of 

the population. However, as the effective population will always 

be less than the number of breeders, proper estimates for Ne will 

need to be obtained before the minimum viable population for 

Whooping Cranes can be determined. 

Given the data to date, this plan recognizes growth of the AWBP 

to 1,000 individuals and 250 productive pairs as a criteria for 

downlisting. The Memorandum of Understanding on Conservation of 

Whooping Cranes, approved by Canadian and U.S. federal officials, 

recognizes a goal of 1,000 individuals in the AWBP population. 

If two additional self-sustaining populations can be established 

in the wild, each with 25 nesting pairs, and with the AWBP 

projected to reach 125 nesting pairs by the year 2020, a figure 

approaching a population of 1,000 whooping cranes may be obtained 

from these three populations. However due to the uncertainty 

surrounding the exact figure required, with suggested values 

ranging between 1,000 and 7,000, this Plan does not set a 

delisting goal for the whooping crane. If additional research 

into the exact calculation of an Ne/N ratio for the wild whooping 

crane population and additional research with other conservation 

programs can provide more assurances of the Ne required, a 

delisting goal will be set prior to the anticipated downlisting 

in 2035. 

Population Growth and Retention of Genetic Material 

A Conservation Viability Assessment (CVA) workshop held in 1991 

for the Whooping Crane was funded by USFWS as a cooperative 

endeavor with CWS, U. S. Whooping Crane Recovery Team, Canadian 

Whooping Crane Recovery Team, ICF, The Captive Breeding 

Specialist Group, and Species Survival Commission of the 

International Union for Conservation of Nature. The final report 

includes priorities for research and management of the wild and 

captive populations as a meta-population to maximize retention of 

genetic heterozygosity and minimize the risk of extinction 

(Mirande et al. 1993). The CVA developed stochastic simulation 

A-2 
DRAFT Whooping Crane Recovery Plan 2005 

models to estimate rates of genetic loss for the wild and captive 

whooping crane populations. As a consequence of the 1941 

population bottleneck, the current population is derived from an 

estimated 6 or 8 founders (Mirande et al. 1993, Glenn et al. 

1999), with an estimated genetic loss of 66% (Glenn et al. 1999). 

Mirande et al. (1993) showed that a loss of 6% to 8% of gene 

diversity would have resulted in the first generation following 

the bottleneck, where generation time is 12 years. It was 

estimated that about 87% of the gene diversity that survived the 

bottleneck has persisted from 1938 to 1990. In contrast, the 

captive-hatched descendants have retained about 96% of the gene 

diversity present in the post-bottleneck wild flock. As 

continued loss of genetic material could lead to inbreeding and 

declining productivity, the AWBP population must increase to the 

level where creation of new alleles will offset the loss of 

genetic diversity. 

Several other population viability analysis packages have been 

tested using whooping crane data (Mirande et al. 1997a, Brook et 

al. 1999). Modeling of the AWBP showed the population large 

enough to sustain a fairly steady annual growth rate of 0.046 

(SD=0.081) over the last 50 years (Mirande et al. 1997a). The 

standard deviation is about double the mean growth rate so in 

many years the population will decline temporarily even though 

long-term growth may be good. If this rate continues, the 

population will reach 500 birds in 17 years (about 2020) and 

1,000 in 33 years (2035). The population is projected to have a 

very low probability of extinction over the next 100 years (less 

than 1%). 

Given the current genetic analyses based on captive pedigrees, an 

estimated 153 whooping cranes (21 productive pairs) are needed in 

captivity to retain 90% of genetic material for 100 years (Jones 

and Lacy 2003). This Plan recommends having 50 captive breeder 

pairs of whooping cranes by 2010, including 15 pairs at PWRC, 12 

at ICF, 10 at CZ, 10 at ACRES, and 3 at the San Antonio Zoo. 

Production from ICF, PWRC, and CZ will be the principal source of 

birds for release to the wild. However, sources of release birds 

should be based on the optimal genetic mix to ensure long-term 

population viability. 

Loss of Genetic Diversity and Estimates of Relatedness 

For most of the 1940's, the AWBP teetered on the brink of 

extinction. Mitochondrial DNA from museum specimens collected 

before and after 1941, when the AWBP declined to 15 birds, showed 

a 66 percent reduction in haplotypes post-bottleneck, with the 

A-3 
DRAFT Whooping Crane Recovery Plan 2005 

rarest haplotype before 1940 now the most common (Glenn et al. 

1999). Although we lack pre-bottleneck diversity estimates for 

nuclear DNA, we realize that similar declines for this genome 

must have also occurred (Jones et al. 2002). This is evident 

from AWBP’s lack of genetic diversity as compared to other 

cranes. Compared with a subset of other cranes, an 

electrophoretic study of blood proteins showed that whooping 

crane diversity was less than that known from out-bred 

populations of Sandhill Cranes, and greater than that of the 

Mississippi Sandhill which was known to have undergone a similar 

genetic bottleneck (Dessauer et al. 1992). When diversity was 

compared across other markers, the Whooping Cranes were shown to 

be below average in band sharing of DNA fingerprints (Longmire et 

al. 1992); average in polymorphism of the major 

histocompatibility complex (Jarvi et al. 1992), and less than 

average in microsatellite DNA diversity (Jones et al. 2002, Jones 

2003). From these studies, it is evident that the extant 

whooping cranes show an overall reduction in genetic diversity 

compared to their pre-bottleneck ancestors and to that of outbred cranes. This known diversity reduction, along with the fact 

that generations of captivity increase inbreeding and decrease 

genetic diversity (Woodworth et al. 2002), indicates that genetic 

changes within the population threaten to reduce vitality before 

the population is large enough for mutation to offset losses in 

diversity from genetic drift (Frankel and Soule 1981, Ballou et 

al. 1995). 

In addition to the knowledge of genetic diversity, understanding 

individual-to-individual relatedness within the captive whooping 

crane populations is important to adequately manage the captive 

population and to establish viable wild populations (Jones et al. 

2002). In addition to pedigree management, there have been 

various molecular genetic techniques used in relatedness 

estimation. These studies have resolved unknown paternities 

(Longmire et al. 1992; Jones and Nicolich 2001), developed a 

species-specific probe for the whooping crane (Love and Deininger 

1992), and identified inter-relatednesses within the captive 

founder lines (Jones et al. 2002). A recently developed 

technique that could provide additional insights into the 

whooping crane population is Amplified Fragment Length 

Polymorphisms (AFLP). Because of the relative paucity of 

information in birds in general, and cranes in particular, the 

usefulness of this technique in cranes is currently unknown. An 

AFLP study, recently initiated at Patuxent Wildlife Research 

Center, will include samples from other crane populations with 

robust populations and those of reduced diversity. This 

comparison across crane species should provide additional 

A-4 
DRAFT Whooping Crane Recovery Plan 2005 

understanding of crane diversity in general and the relative 

state of genetic diversity of the whooping crane. 

A-5 
DRAFT Whooping Crane Recovery Plan 2005 

APPENDIX B: SOCIAL AND ECONOMIC CONSIDERATIONS

Numerous books, magazine articles, television programs, and 

nature documentary films have been produced about this 

magnificent bird. Corporations have funded whooping crane 

research and recovery efforts and also have used whooping cranes 

in promoting their environmental concern. The WCCA, a nonprofit 

group, was formed in 1961 to promote conservation of whooping 

cranes and to educate the public. Other organizations, such as 

the NAS, have participated in whooping crane research, 

conservation, and education. The Platte River Whooping Crane 

Habitat Maintenance Trust (PRT) was established in 1978 as a 

nonprofit conservation organization to protect and enhance 

habitat for migratory birds in Nebraska along the Platte and 

North Platte rivers, especially to protect and maintain whooping 

crane habitat. 

Appreciation of whooping cranes can also be expressed in monetary 

terms. Each year 70,000 to 80,000 people visit ANWR, most during 

the winter, spending significant amounts locally on lodging, 

gasoline, and supplies (Ellen Michaels, pers. comm.). Starting 

in 1964, 1 tour boat named the “Whooping Crane” offered weekend 

day-trips from Rockport, Texas to view the cranes along the Gulf 

Intracoastal Waterway that runs through ANWR. By 1990, 5 boats 

offered this opportunity, spanning every day of the week. During 

1990-1991, approximately 17,000 people took these tours, paying 

an average of $20 per ticket, for total seasonal expenditures of 

$340,000 (Ellen Michaels, pers. comm.). The Rockport Chamber of 

Commerce estimates that wildlife-related activities result in 

annual gross economic benefits of $6 million to the local 

economy. Some of these benefits result from the nearby presence 

of whooping cranes. Port Aransas, Texas, holds an annual event 

in February entitled “Festival of Whooping Cranes and Other 

Birds”. In 2001, an annual fall crane festival was started in 

Tennessee. 

In several areas where large numbers of sandhill cranes are 

viewed by tourists, an additional attraction for observers is the 

possibility of sighting whooping cranes. Approximately 80,000 

people visit the Platte River area of Nebraska each year during 

the peak of spring crane migrations, expending approximately $15 

million (Lingle 1992). In Baraboo, Wisconsin in 2000, 27,900 

people paid an entry fee of $7.00 for adults and $6.00 for 

seniors to visit ICF where a whooping crane breeding pair in a 

wetland exhibit are among the crane species on display. 

B-1
DRAFT Whooping Crane Recovery Plan 2005 

Although whooping cranes no longer occur in the Rocky Mountains, 

interest in crane festivals that the whooping cranes played a 

role in starting remains high. Approximately 75,000 people 

annually visit Bosque del Apache NWR, New Mexico, mostly in 

winter when the sandhill cranes are present (Peggy Mitchusson, 

pers. comm., 1993). The refuge and Socorro Chamber of Commerce 

also sponsor a fall "Festival of the Cranes" to promote tourism. 

The presence of whooping cranes in the past heightened interest 

in the crane migration at Alamosa/Monte Vista NWR in Colorado. 

Approximately 10,000 people visit the refuge during the peak 

migration periods, many of these during the spring Monte Vista 

Crane Festival. This 4-day festival is estimated to generate 

about $10,000 per day in revenue to the local economies (Ann 

Morekill, pers. comm., 1993). 

The total value for most endangered species is intangible and 

difficult to quantify; however, in recent years economists have 

developed methods to approximate the value of nonmarket resources 

such as endangered species. These methods measure: (1) the value 

people place on seeing an endangered species (use value); (2) the 

value they place on continued existence of the species for 

potential future observation value (option value); and (3) the 

value of simply knowing the species exists (existence value) 

(Randall and Stoll 1983). One method of estimating these values, 

the contingent valuation method, asks individuals to express 

their willingness to pay for nonmarket goods (Stoll 1983). 

Individuals are asked to estimate their willingness to pay for 

observing (use value) or preserving (option and existence value) 

the species. 

Contingent valuation methodologies have been used to estimate the 

value of whooping cranes. In written surveys distributed in 

1982-83 at ANWR, refuge visitors indicated willingness to pay an 

average of $4.47 for an annual permit to visit the refuge and an 

average of $16.33 per year to support a private foundation that 

would be responsible for conservation of whooping cranes. A mail 

survey to 4 metropolitan areas outside of Texas indicated that 

respondents were willing to contribute an average of $7.13 per 

year to the same hypothetical foundation. Allowing for sampling 

error and non-response bias, the total value of the whooping 

crane to United States' residents appears to range between 0.5 

billion to 1.5 billion dollars per year (Stoll and Johnson 1984). 

Three conclusions can be drawn from this evidence of the economic 

value of whooping cranes. First, local economies can realize 

significant economic benefit from the presence of an endangered 

species; these localities need assistance in identifying and 

B-2
DRAFT Whooping Crane Recovery Plan 2005 

capturing these economic benefits. Second, values for endangered 

species appear to be directly associated with the public's 

knowledge and awareness of the species. Value for the whooping 

crane derives not only from its aesthetic qualities and rarity, 

but probably more directly from its identity as a symbol of the 

effort to save species from extinction. This value would not 

have been realized without extensive education efforts. Finally, 

increasing interest in this endangered species, which brings 

economic benefits, has raised concerns about the effects of these 

appreciative uses upon the well being of the species. The issue 

of disturbance management is discussed elsewhere in this Plan. 

B-3
DRAFT Whooping Crane Recovery Plan 2005 

APPENDIX C: ACTIONS ALREADY COMPLETED OR UNDERWAY 

Protection 

In April, 1985, Bert Tetreault, Director General of the CWS and 

Robert A. Jantzen, Director of the USFWS signed an MOU entitled 

“Conservation of the Whooping Crane Relating to Coordinated 

Management Activities” (Lewis 1991). The MOU provides a more 

formal structure to the cooperative working relationships that 

have characterized these 2 nations' joint efforts in management 

and research of whooping cranes. Under the new agreement, each 

Service appointed an employee to be responsible for inter- and 

intra-nation coordination of whooping crane management and 

research. The MOU discusses disposition of birds and eggs, 

postmortem analysis, population restoration and objectives, new 

population sites, international management, recovery team, 

recovery plans, and consultation and coordination. The MOU was 

renewed in April 1990, again in October 1995 and August, 2001. 

The current MOU was signed by the USFWS, USGS, CWS, and Parks 

Canada. 

A plan for Federal-State Cooperative Protection of Whooping 

Cranes was approved in 1985 and is updated periodically by the 

USFWS and 13 States where whooping cranes occurred (Lewis 1992). 

The CWS and 3 Canadian provinces approved the Federal-Provincial 

Cooperative Protection of Whooping Cranes in 1987 (Cooch et al. 

1988). The plan describes response options when whooping cranes 

are observed in hazardous situations due to avian disease 

outbreaks, environmental contaminants, or hunting activities, or 

when these cranes are found injured, sick, or dead. Plan 

objectives are to provide added protection to whooping cranes, 

especially during migration, and to increase the opportunities to 

recover and rehabilitate birds found injured or sick. 

A whooping crane health management workshop was organized in 1992 

by the NWHC and ICF. Participants included the veterinary and 

wildlife disease specialists working with whooping cranes. 

Uniform health management protocols were established for disease 

monitoring of captive and wild flocks, and for pre-release and 

pre-transfer disease screening. Unpublished information was 

collated on disease research. Research needs were identified and 

prioritized including avian tuberculosis, EEE, and crane herpes. 

A centralized, computerized database on whooping crane mortality 

was initiated. WCHAT was established with clinical and research 

veterinarians identified to coordinate input and serve as 

official advisors to the recovery team. This Team continues to 

meet periodically to evaluate progress and address needs. It has 

C-1
DRAFT Whooping Crane Recovery Plan 2005 

regularly updated the health management protocols, developed 

plans for a centralized serum/tissue bank, and provided advice to 

the recovery team on issues such as new release site disease 

assessments, monitoring and control of emerging disease including 

EEE and West Nile virus, and selection of new captive facilities. 

Breeding Grounds Management and Research 

Management of WBNP and the crane breeding grounds is not nearly 

as complex an operation as management of the increasingly active 

wintering grounds in ANWR in regards to whooping crane issues. 

The breeding range of the AWBP flock is secure from human-induced 

changes such as forestry or conversion to agricultural land, 

because 96% of the nesting occurs within WBNP. To afford the 

highest level of protection, the breeding habitat is designated 

as a Zone 1 Special Preservation area. The Special Preservation 

designation establishes that within that area, there are to be no 

manmade facilities (except Hwy 5), and human access is prohibited 

from April 15 through October, except for park staff and 

scientists involved in whooping crane research. Under normal 

circumstances, habitat manipulation is not permitted in a 

Canadian national park. Policy would allow for manipulation of 

natural processes only if feasible, beneficial, and urgent to 

achieve recovery goals. Issues such as global warming, which may 

dry out the marshes, and acid rain, are external concerns that 

may affect the population and require habitat intervention. 

Erickson (1961) analyzed the Aransas winter population counts 

from 1938-1960. This analysis revealed 3 important 

characteristics of the wild population that were later confirmed 

by Novakowski (1966): (1) principal production was apparently 

derived from a fairly stable cohort of long-lived adults, (2) 

among birds returning to Canada, mortality was highest in the 

subadult cohort, and (3) because subadult mortality was 

apparently limiting recruitment into the breeding population, the 

population would remain insecure until this mortality was 

reduced. Based on these findings, Erickson proposed to bolster 

the wild population through captive propagation and the release 

of captive-produced stock. However, he cautioned that before 

stock was obtained from the wild, safe and effective procedures 

should be developed using sandhill cranes as research surrogates. 

Egg-taking experiments with sandhill cranes indicated that nest 

desertion was negligible and population productivity was 

relatively unaffected when single eggs were removed from 2-egg 

clutches. Others noted that cranes normally lay 2 eggs but 

rarely fledge 2 chicks. Observations on the breeding grounds by 

C-2
DRAFT Whooping Crane Recovery Plan 2005 

Novakowski (1966) confirmed that whooping cranes generally follow 

this pattern. It appeared that a single egg could be removed 

from each 2-egg clutch with the same favorable results 

experienced with sandhill cranes. 

The whooping crane population has been artificially augmented 

through translocation and captive rearing of wild eggs. The 

total number of cranes was increased by taking 1 egg from a 

clutch of 2 and rearing it in captivity (Erickson 1975). Between 

1967 and 1996, eggs were taken from WBNP to the captive sites 

with the initial transfer of 6 eggs to PWRC (Table 2)(Kuyt 1993b, 

1996). Subsequent egg transfers helped to build the captive 

flocks to the current population of 113 birds in spring 2002. 

The results of egg collection on the growth rate and overall 

fitness of the wild population are unknown. 

C-3
DRAFT Whooping Crane Recovery Plan 2005 

Table 2. Known number of nesting pairs, productivity, and 

distribution of eggs removed from Aransas Wood Buffalo 

Population, 1966-2003.

Year No. of known 

nesting 

pairsa

No. of 

juvenilesb

Max. no. of 

nonbreedersc

(including 

juveniles) 

Destination of eggs 

removed from WBNP 

PWRCd Grays 

Lake 

ICFe CZf

1966 5g 5 -h 0 0 0 0

1967 9g 9 -h 6 0 0 0

1968 10 6 30 10 0 0 0

1969 12 8 32 10(3)i 0 0 0

1970 15 6 27 0 0 0 0

1971 13 5 33 11(2) 0 0 0

1972 16 5 19 0 0 0 0

1973 14 2 21 0 0 0 0

1974 15 2 19 13 0 0 0

1975 16 8 25 0 14(3) 0 0

1976 16 12 37 0 15 0 0

1977 17 10 38 0 16 0 0

1978 15 7 45 0 13(2) 0 0

1979 19 6 38 0 19(3) 0 0

1980 19 6 40 0 12(2) 0 0

1981 17 2 39 0 12(2) 0 0

1982 17 6 39 2 14(1) 0 0

1983 24 7 27 2 16 0 0

1984 29 15 28 3(2) 22 0 0

1985 28 16 41 4(3) 23(3) 0 0

1986 29 21 52 12(10) 15(2) 0 0

1987 32 25 70 12(5) 12 0 0

1988 31 19 76 14j

(6) 12 0 0

1989 31 20 84 15(9) 0 0 0

1990 32 13 82 0 0 12(1) 0

1991 33 8 66 16(10) 0 0 0

1992 41 15 56 10(1) 0 11(1) 0

1993 45 16 57 16(1) 0 10(2) 0

1994 28 8 77 0 0 9 4

1995 49 28 60 14(2) 0 10 0

1996 45 16 70 8(1) 0 6 0

1997 51 30 84 0 0 0 0

1998 50 18 83 0 0 0 2

1999 48 17 92 0 0 0 0

2000 50 9 80 0 0 0 0

2001 52 15 72 0 0 0 0

2002 50 16 73 0 0 0 0

2003 61 25 72 0 0 0 0

C-4
DRAFT Whooping Crane Recovery Plan 2005 

 a Nesting pairs. (Canadian Wildlife Service, Brian Johns, pers. 

comm.) 

 b Fall arrivals, ANWR and area (U.S. Fish & Wildlife Service 

1994; Refuge Manager, ANWR, pers. comm.). c Calculated as following winter's peak population minus number 

of breeding adults. 

 d Patuxent Wildlife Research Center, Laurel, Maryland. e International Crane Foundation, Baraboo, Wisconsin. 

 f Calgary Zoo 

 g Data incomplete. h Cannot be calculated, as data on number of known nesting pairs 

are incomplete. 

i

 Numbers in parenthesis indicate nonviable eggs or eggs that 

failed as a result of embryonic death (1975-1988 data from 

R.C. Drewien). 

j

 Excluding one sandhill crane egg. 

__________ 

C-5
DRAFT Whooping Crane Recovery Plan 2005 

Viability testing of eggs during collection was initiated in 1985 

with the objective of leaving at least 1 viable egg in each nest 

visited. In nests with 2 viable eggs, 1 egg was removed and 

placed in nests that contained nonviable eggs or transported to 

the captive facilities. As a result of this procedure, the 

hatching success of tested known live eggs left in nests was 

11.7-15.5% over those of undisturbed nests from 1985-1988 (Kuyt 

1993b). However, some of the lower hatching success among 

undisturbed eggs/nests probably existed because they were 

primarily those of younger, less experienced pairs. The transfer 

of eggs between nests ended with the final pickup of eggs in 

1996. Chicks raised from these eggs currently form the nucleus 

of the breeding flocks being maintained at PWRC, ICF, and CZ. 

Egg collections and subsequent propagation efforts have been 

described elsewhere (Ellis et al. 1996, Kepler 1976, Kuyt l976a). 

CWS and USFWS obtained eggs from nests in WBNP in 1967 to 1971, 

and 1974 to further augment the PWRC population, and in 1975 

through 1988 to provide eggs for the Grays Lake cross-fostering 

experiment (Table 2). Egg transfers to PWRC were resumed in 

1982-1989 and 1991-1996. Egg transfers to ICF began in 1990 and 

resumed in 1992-1996. Eggs were shipped to Calgary in 1994 and 

1999 and a chick was transferred from WBNP in 1999. The 

transfers in the 1990s were designed to increase the size and 

genetic diversity of the captive flock. 

Erickson (1976) and Kuyt (1976a, 198la, 198lb) noted that egg 

removals have not adversely affected the productivity of the wild 

population. Between 1967 and 1996, the era of egg pickups, the 

AWBP increased from 48 to 160, and the number of nesting pairs 

increased from 5 to 45. Cannon et al. (2001) agree that although 

total numbers of whooping cranes, both captive and wild, can be 

increased by egg pickup, total numbers of chicks reaching Aransas 

are less when eggs are picked up compared to when no eggs are 

removed. Ellis and Gee (2001) further noted the potential 

benefits of removing the second fertile egg from nests. Lewis 

(2001) reviewed the paper of Cannon et al. and that of Ellis and 

Gee and came to the conclusion that the data as presented did not 

support the views of Cannon et al. and determined that a 

reanalysis of the existing egg collection data was warranted. 

Because of these differing opinions, B. Johns reviewed the data 

pair by pair and extracted as much information as possible from 

original reports and solicited the expertise of Dr. Mark Boyce, 

University of Alberta for the analysis. Mark Bradley (pers. 

com.) advises that the data set used has biases; specifically the 

non-random nest selection, lack of a control group, not testing 

C-6
DRAFT Whooping Crane Recovery Plan 2005 

eggs for viability in the early years of collection, limited 

samples in certain years, and potential inaccuracies in chick 

surveys. 

Boyce et al. (In prep) analysed colt recruitment in WBNP in 

relation to egg removal activities between 1987-1996. The egg 

collection was never intended to be established with an 

experimental design suitable for testing its effect on the 

population. As such there are inherent biases associated with 

the data set; including a bias towards experienced, productive 

pairs. The results of the analysis indicated that recruitment of 

young into the population was higher when eggs were removed than 

when eggs were not removed. Theta=0.498+0.0012 with removal, 

theta=0.355+0.0013 without removal, showing a 25% reduction in 

survival of chicks without removal. This advantage of increased 

recruitment from 1-egg nests is counterbalanced by occasional 

survival of both chicks from 2-egg nests. 

Boyce and Miller (1985) found a 10 year cycle in whooping crane 

counts, which held true through 2002 (Boyce et al. In prep). 

This trend parallels counts of predators (based on lynx fur 

returns) in the area (Boyce et al. In prep). There was a strong 

negative effect between egg collection and lynx populations, such 

that collection of eggs during a crashing lynx population may not 

be detrimental to the AWBP. This would provide additional 

offspring for recovery efforts elsewhere. During years that egg 

removal did not occur, 10% of recruits were from sets of twins. 

One interpretation is that periodically there are very good years 

and the whooping cranes can actually raise twins. The analysis 

revealed that there were no negative consequences from egg 

removal, even with the twinning effect. 

Boyce et al. (In prep) also evaluated the effects of egg 

substitution and found that it did not improve nest success over 

nests that had no substitutions. This could be due to the nest 

being situated in a poor habitat or because the pair was 

inexperienced. 

The recovery team recognizes that collection of eggs has 

benefited the whooping crane recovery program by providing stock 

to establish the captive flocks and providing offspring for 

release, thus increasing the total number of whooping cranes and 

helping to preserve the genetics of the species. The recovery 

team believes that data analyses to date do not indicate that egg 

collection would increase recruitment in the AWBP over the long 

term, but could increase recruitment in selected years. The 

recovery team would like to document the rate of twinning until 

C-7
DRAFT Whooping Crane Recovery Plan 2005 

2006 without any egg collection in order to observe the 

population dynamics through a full 10-year cycle (1997-2006) 

without any egg pickup. 

The genetic master plan indicates that the genetic diversity of 

the AWBP is well represented in the captive flocks, hence there 

would be little to be gained genetically in the captive flocks by 

removing additional eggs from Wood Buffalo at this time. There 

may be demographic benefits to egg collections (i.e. more chicks 

available for reintroductions), but the recovery team believes 

that production from the captive flocks is sufficient to support 

reintroductions at the present time. The current captive 

facilities are at peak manpower and pen capacity for raising 

existing chicks and would be strained to handle additional eggs 

at present. The issue of egg collection should be reevaluated in 

2006 at the completion of 10 years with no collection. 

Flightless young whooping cranes were captured and marked with 

colored plastic leg bands in WBNP from 1977 through 1988(Kuyt 

1978a, 1979a, Drewien and Kuyt 1979). Banding whooping cranes in 

WBNP was halted after 1988, since much information had already 

been obtained and the objectives of the original banding program 

had been met. Also, capturing the chicks can cause some 

mortality. Over the 12 years of the banding program, 134 birds 

were captured and 2 chicks died (1.5%). As of 2002-2003 winter, 

26 of the 185 birds (i.e. 14%) in the AWBP were still 

individually identifiable by their bands (Tom Stehn, pers. 

comm.). 

This marking program provided a wealth of information on whooping 

crane biology, including the summering locations of subadults, 

the dynamics and habitat use of wintering subadult flocks, age 

specific survivorship, the age of initial pairing and breeding, 

juvenile and adult philopatry and the identification of stopover 

sites, and wintering and breeding territories used by specific 

pairs (Kuyt 1979b, 1981a, 1981b, Bishop and Blankinship 1982, 

Bishop 1984, Stehn and Johnson 1987, Johns et al. In press). 

Other information gained from the banding studies included the 

ability to develop a studbook on a fairly large segment of the 

wild population, tracing the reproductive histories of many of 

the birds including mate switches and probable deaths. These 

data provide valuable insight into the relatedness and genetic 

diversity of the wild flock and may be of assistance in 

evaluating potential inbreeding effects in the future. 

C-8
DRAFT Whooping Crane Recovery Plan 2005 

Migration Monitoring 

Whooping cranes spend approximately 3 months annually in 

migration. Although a number of migration sightings have been 

reported and compiled over the years (Allen 1952, Sutton 1967, 

Walkinshaw 1973, Archibald et al. 1976, Stephen 1979, Asherin and 

Drewien 1987, Johns 1987, Asherin et al. 1992), few were 

confirmed. In order to protect migrating whooping cranes from 

disease outbreaks and other potential hazards, and to compile 

information on the characteristics and locations of stopover 

sites, the USFWS initiated the Cooperative Whooping Crane 

Tracking Project in 1975. The CWS started a similar program in 

1977. This program alerts key personnel about sightings so that 

reports can be verified stopover sites described, and the birds 

kept under protective surveillance by State, Provincial, and 

Federal personnel. This monitoring program is coordinated with 

reporting networks of wildlife agencies along the migration 

corridor. Whooping crane sightings compiled within the U.S. 

portion of the migration corridor by the USFWS (1,352 confirmed 

sightings, 1943-99) were summarized by Austin and Richert (2001). 

Whooping crane sightings compiled within the Canadian portion of 

the migration corridor were summarized by Johns 1992 and Johns et 

al. 1997) The presence of marked birds from the banding program 

conducted in WBNP provided more precise information on migration 

chronology, and yielded information on several events that would 

have otherwise gone undetected (Stehn 1992a,c). 

Radiotelemetry techniques were first tested on cross-fostered 

whooping cranes in the RMP (Drewien and Bizeau 1981). Beginning 

in 1979, flightless young were captured and marked with plastic 

leg bands to which miniature radio transmitters (45-60 g) were 

attached. Local movements of the radio-tagged birds were 

monitored on summering and wintering areas, and several 

individuals were followed during their fall migration between 

Grays Lake NWR in southeastern Idaho and Monte Vista NWR in 

south-central Colorado. No adverse effects were noted from 

capturing, banding, and radio-tagging young whooping cranes 

(Drewien and Bizeau 1981). 

On the basis of these preliminary studies, a cooperative USFWSCWS-NAS radio tracking program was initiated for birds in the 

AWBP to determine various aspects of migration ecology, including 

habitat characteristics, behavior, and sources of mortality. 

During each summer 1981-1983, small solar-powered transmitters 

were placed on several prefledged whooping cranes captured during 

the color-banding operation in WBNP (Kuyt 1979a, 1979b, 1992). 

Data were obtained on 3 southbound and 2 northbound migrations. 

C-9
DRAFT Whooping Crane Recovery Plan 2005 

Most information involved the individuals or family groups 

actually being followed, but data were also accumulated on other 

migrating whooping cranes encountered during the project. 

This successful tracking project resulted in important 

information concerning migration routes, migration timing, flight 

methods and speed, stopover locations and staging areas, habitat 

use, social behavior, activity budgets, predator/disturbance 

reactions, and sources of mortality (Howe 1989, Kuyt 1992). 

Perhaps the most important result obtained from this tracking 

project has been documenting mortalities on the breeding grounds 

(wolf predation) (Kuyt et al. 1981), during migration (power line 

collisions), and on the wintering grounds (predation and 

disease). Similar valuable information has been acquired on 

migration and behavior of whooping cranes in the RMP (Drewien and 

Bizeau 1981, Asherin and Drewien 1987, Drewien et al. 1989). 

Migration Habitat Management and Research 

Suitable stopover habitat is necessary for the birds to complete 

their migration in good condition. There has been considerable 

alteration and destruction of natural wetlands, rivers, and 

streams, some of which had served as potential roosting and 

feeding sites for migrating cranes. There may be additional 

areas along the migration route that need to be delineated and 

protected. 

South central Saskatchewan has been referred to as a traditional 

fall staging area for whooping cranes (Johns 1992). Habitats used 

by cranes, in the staging area, were characterized by Johns et 

al. (1997). Choice of wetland types for roosting was influenced 

by a variety of landscape features both natural and manmade. 

Roosting wetlands varied in size and type, depending on the 

season, in areas of higher than average wetland density. The 

staging area is in a highly modified environment with the 

majority of crane roosts (96% spring, 85% fall) being on private 

land. Foraging area use exhibited a similar trend (Johns 1997). 

Once the cranes leave the fall staging area the remainder of 

their migration is rapid and stopovers are of shorter duration 

(Kuyt 1992). There is no equivalent spring staging area. 

USFWS has funded studies of availability of suitable migration 

stopover habitat within the AWBP migration pathway in the United 

States, (Stahlecker 1988, 1992, 1997a, 1997b). National Wetland 

Inventory (NWI) maps, used in conjunction with aerial photo maps 

and suitability criteria (Armbruster 1990), were poor predictors 

(33% correct) of suitable roosts in Oklahoma but good predictors 

C-10
DRAFT Whooping Crane Recovery Plan 2005 

(97% correct) of unsuitability (Stahlecker 1992). NWI map review 

in Nebraska was a good predictor of both suitability (63% 

correct) and unsuitability (73% correct). Wetlands suitable for 

overnight roost sites for migrating whooping cranes were 

available throughout the migration corridor in the Dakotas and 

Nebraska (Stahlecker 1997a, 1997b), but may be limited in 

Oklahoma (Stahlecker 1992). Similar sampling to evaluate roost 

availability in Kansas and Texas should be conducted. 

Richert (1999) used Geographic Information Systems (GIS) and 

remote sensing technologies to evaluate whooping crane stopover 

habitat in Nebraska. Confirmed whooping crane sightings, when 

compared with habitat selection, suggest that whooping cranes 

select roost habitat by recognizing local and larger-scale land 

cover composition. Habitat selection was influenced by social 

group, season, and landscape pattern (Richert 1999). 

Based upon recommendations from the Recovery Team, the USFWS 

initiated a project in 1977 to conduct site evaluations at sites 

in the U.S. used by whooping cranes during migration. The site 

evaluation data base, containing 1,060 evaluations completed 

between 1977 and 2000, was summarized by Austin and Richert 

(2001). Results revealed some new insight into whooping crane 

habitat use during migration (e.g., roosting and feeding site 

characterization). 

Based on the large number of sightings along the central Platte 

River in Nebraska during 1820-1948, Allen (1952) believed that 

whooping cranes made that area a major stopover, remaining in the 

area for some days. In 1978, the USFWS designated an 88 km 

portion of the Platte River in central Nebraska as critical 

habitat. 

As a result of reduced channel width, loss of adjacent wet 

meadows, and encroachment of the channel by woody vegetation 

brought on by diversion and storage of water for irrigation and 

power generation (USFWS 1981), 128 km of Platte River channel 

habitat has been lost. In the remaining 120 km of the Platte 

River channel that crosses the breadth of the migration path, 

there has been a 58 to 87% reduction in channel area due to 

encroachment of woody vegetation and a 70% loss in the average 

annual flow since 1930. As much as 97% of suitable crane 

roosting habitat has been lost in some river segments. Woody 

vegetation is still expanding and channel width declining on the 

Platte River (Currier 1997). Over 73% of native grasslands and 

wetlands adjacent to the river channel have been lost due to 

declines in river flows, construction of drainage systems, and 

C-11
DRAFT Whooping Crane Recovery Plan 2005 

conversion to cropland (Currier et al. 1985). 

The need to prevent further deterioration of habitat along the 

Platte River has been identified (USFWS 1981). Areas for cranes 

should be managed to prevent further channel shrinkage and 

encroachment by woody vegetation. Such actions are being 

initiated by the states of Wyoming, Colorado, and Nebraska and 

the U.S. Department of the Interior. In 1997 they signed a 

"Cooperative Agreement for Platte River Research and Other 

Efforts Relating to Endangered Species Habitats Along the Central 

Platte River, Nebraska" (Derby and Strickland 2001). The 

cooperators agreed to implement certain management activities for 

four target endangered or threatened species (whooping crane, 

piping plover, interior least tern, and pallid sturgeon) and 

their associated habitats, including federally designated 

critical habitat for the whooping crane. The signatories are 

currently working to implement a basin-wide Platte River Recovery 

Implementation Program to recover the river to benefit the target 

species. One objective is to acquire and restore 4,047 ha in 

the first 10-13 years and ultimately 11,736 ha of Platte River 

habitat for the three bird species (Derby et al. 2000). 

Along the Platte River, roosting habitat suitability criteria 

(Ward and Anderson 1987, Armbruster 1990), combined with 

hydraulic simulations of Instream Flow Incremental Methodology 

(IFIM), have been used to identify the relationship between river 

discharge and roosting habitat (Platte River Management Joint 

Study 1990, Ziewitz 1992, Platte River Management Joint Study 

1993). The IFIM consists of a collection of computer models 

including the Physical Habitat Simulation Model and analytical 

procedures designed to predict incremental changes of habitat 

resulting from incremental changes in river discharge. The 

models that have been developed with this methodology are based 

solely on physical features of Platte River roosting habitat. 

The models select river discharges that will provide the required 

quantity and quality of crane roosting habitat. A review and 

update of the current whooping crane model is being done by the 

Fort Collins Science Center under contract with the Service. 

The USFWS recommended target flows for the central Platte River, 

Nebraska, to the Federal Energy Regulatory Commission. These 

recommendations are designed to rehabilitate and maintain the 

structure, patterns, processes, and habitat of the central Platte 

River ecosystem. Flow recommendations are generally prioritized 

by time period in the following order: a) pulse flows during late 

spring (May and June) and late winter (February and March); b) 

summer; c) spring migration; and d) fall migration. 

C-12
DRAFT Whooping Crane Recovery Plan 2005 

A river management plan was prepared by the Biology Workgroup of 

the Platte River Management Joint Study, a group of 

representatives from the USFWS, Bureau of Reclamation, Corps of 

Engineers, States of Wyoming, Colorado, and Nebraska, water 

development interests, and environmental groups. The plan 

identified management alternatives that could be implemented in 

the Platte River basin as an aid to future management (Platte 

River Management Joint Study 1990). Currier et al. (1985) and 

Strom (1987) described management programs to preserve, 

rehabilitate, and restore river habitat. Other research 

conducted along the Platte River (Hurr 1983, Wesche et al. 1990, 

Henszey and Wesche 1993) indicates river discharge and stage is a 

dominant factor affecting groundwater levels in wet meadow 

grasslands. Reasonable in-stream flows are required to maintain 

the wet meadows used by cranes. 

Nebraska Game and Parks Commission, under authority of a State 

law that allows protection of in-stream flows for fish and 

wildlife, was granted an in-stream flow right permit for the 

central Platte River. This permit, from the Nebraska Department 

of Natural Resources, will help maintain remaining river roosting 

habitat and adjacent wetland meadows. However, the approved instream flow right is less than the flows that were requested by 

the Commission. 

The Platte River Whooping Crane Habitat Maintenance Trust (PRT) 

began implementing their habitat restoration program in the early 

1980s. The PRT has acquired land through fee title acquisition 

and conservation easements. Restoration activities include 

clearing and maintaining river roost sites free of trees and 

shrubs and restoring and rehabilitating wetland meadows and 

marshes adjacent to the river channel. Human activity near river 

roosts and wetland meadows is restricted during the migration 

periods. 

Wintering Grounds Management and Research 

Despite intensive studies of whooping cranes on the wintering 

grounds by Allen in the late 1940s, some important questions 

remained unanswered. More detailed information was needed on 

food habits, food availability in relation to climatic 

conditions, spatial requirements and territorial behavior in an 

expanding population, and on the effects of increasing human 

activities in and around the cranes' habitat. With more of this 

information available, better management planning and evaluation 

would be possible. 

C-13
DRAFT Whooping Crane Recovery Plan 2005 

Potential whooping crane food organisms and related physical 

factors were studied in 1963 and 1964 by Bill Van Tries and 

Gordon Folzenlogen of the Service. In November 1970, the NAS 

assigned David Blankinship to conduct research on wintering 

whooping cranes at ANWR and adjacent areas. Findings on 

territorial behavior, subadult flocks, adult-young relationships, 

feeding ecology, parasites, and other aspects of wintering 

ecology have been published (Blankinship 1976, Forrester et al. 

1978, Bishop and Blankinship 1982, Bishop 1984, Blankinship 

1987). 

Hunt (1987) studied upland habitats at ANWR to identify 

environmental conditions associated with crane use, the effect of 

management on uplands, and the importance of food items consumed 

there. Whooping cranes used portions of upland pastures that 

were open, close to the wetland edge, and away from sources of 

human disturbance. Periodic upland burning increased visual 

openness of habitat, oak stem density, and availability of acorns 

(Hunt 1987). 

Winter territories of whooping cranes on the Texas coast place 

the birds in close proximity to several human-induced disturbance 

factors, which were studied by Lewis and Slack (1992). These 

factors included whooping crane tour boats, boat and barge 

traffic along the GIWW, recreation and commercial traffic 

(including hunting, angling, crabbing, and oystering), and aerial 

overflights. The extent to which whooping cranes were exposed to 

disturbance varied among the different use localities. In the 

winter of 1985-86, Mabie et al. (1989) examined the response of 4 

whooping crane family groups on Matagorda Island to several 

staged hunting and boating activities. Direct harassment by 

airboat caused the only significant difference in behavior 

pattern (percent of time alert) when compared to control 

observations. The cranes responded to disturbances at distances 

ranging from 25 to 550 m. Response ranged from alert posture to 

walking away to flying away to a maximum distance of 2,150 m. 

Whooping crane response was generally short-term, with a return 

to normal behavior patterns by the second hour of observation. 

Irby (1990) observed whooping cranes on Welder Flats for 365 

hours during 1990, using scan sampling and focal bird sampling 

techniques, and noted all events that caused disturbance. Of the 

365 hours of observation, cranes spent 47 minutes responding to 

non-observer human-induced disturbance. Irby (1990) made several 

recommendations resulting from his observations. Barge mooring 

may represent a dangerous threat. A coordinated plan needs to be 

developed to protect the area from pollution, and to designate 

C-14
DRAFT Whooping Crane Recovery Plan 2005 

safe barge mooring areas. 

Refuge and coastal wetland users should be encouraged to minimize 

disturbance to whooping cranes. Damage caused to submerged 

vegetation by boating activities should be reduced. Support of 

private landowners in minimizing disturbance and maximizing 

protection should be recognized and encouraged. It is difficult 

to assess the total impacts of disturbance upon whooping cranes 

in terms of fitness, productivity, and survival. As the AWBP 

continues to expand, a decrease in territory sizes and expansion 

into new wintering areas is likely to continue. The effects of 

increased population density and/or exposure to disturbances 

could be compounded by an increase in frequency or severity of 

disturbance. Levels of disturbance should be monitored on the 

wintering grounds and steps taken to minimize detrimental 

activities. 

Management of ANWR is a sizeable and complex operation (Johnson 

1976). Prime habitat is limited and natural foods may be in 

short supply at times. Two 40-ha fenced enclosures were 

developed during 1964-1968, in which various cereal and root 

crops were grown. Some whooping cranes used these fields but 

sandhill cranes and Canada geese (Branta canadensis) ate most of 

the food (Shields and Benham 1969). Another management strategy 

was the diking of a 28-ha impoundment equipped with a high 

volume, low-lift pump designed to bring large quantities of 

saline water and marine life into the basin; the exit of live 

food items was prevented by screens at spillway outlets. Limited 

use by whooping cranes was achieved during 1 winter when they 

were attracted to the site by "bait" grains, but in subsequent 

years whooping cranes did not use the artificial impoundment. 

During the mid-1960s, whooping cranes were attracted to grains 

spread for their use. Such supplemental food has since been 

avoided because concentrating the birds increases the potential 

for a disease outbreak or the spread of parasites, and changes 

distribution of the cranes. Supplemental feeding could be 

attempted to attract cranes from the tidal areas in certain 

emergency situations, such as during oil or chemical spills, or 

periods of food scarcity. 

Chavez-Ramirez (1996) analyzed whooping crane winter foods during 

the 1992-93 and 1993-94 winters. He evaluated standing biomass 

of blue crabs, clams and wolfberries, human and wildlife 

competition for these principal foods, and compared the nutritive 

composition of winter foods to the commercial rations used for 

the captive flocks (Nelson 1995, Chavez-Ramirez et al. 1997). 

C-15
DRAFT Whooping Crane Recovery Plan 2005 

Prescribed burning is used to reduce height and density of 

grasses, remove brush, and to modify plant composition on uplands 

to make them more attractive to whooping cranes. Management in 

the past included mechanical cutting and grazing by livestock. 

Whooping cranes almost immediately use the burned areas (Hunt 

1987). Currently, 15 prescribed burn units averaging 322 ha are 

located in the crane area at ANWR. Depending on the acorn crop, 

the units are burned on a 3-year rotation. Additional burning is 

done on Matagorda Island, as well as on private lands on San Jose 

Island and Welder Flats. 

About 30 freshwater ponds are present on ANWR and Matagorda 

Island near areas used by cranes. Cranes drink at upland 

freshwater ponds where surrounding vegetation is kept low to the 

ground and aquatic emergent or floating vegetation is sparse or 

absent. Such ponds provide a source of fresh water when coastal 

waters are highly saline above 23 parts per thousand and may 

encourage cranes to utilize upland food resources. 

The most complete census of the AWBP is made during winter. 

Aerial censuses are made weekly from the time the first whooping 

cranes appear, approximately twice a month during mid-winter, and 

again weekly until the last cranes depart. Flights provide 

information on mortality, habitat use, pair formation, territory 

establishment, and population age structure by identifying all 

color-banded birds present. These flights serve to alert the 

refuge staff to hazards or harassment of cranes resulting from 

human activity. If a crane is determined to be "missing," then a 

ground search may be initiated to locate the carcass. 

Whooping cranes use marshes bordering Matagorda Island, a barrier 

island 60.8 km long by 1.2 to 7.2 km wide. In 1942, the Federal 

government purchased approximately 7,700 ha of Island uplands, 

and leased 2,400 ha from the State of Texas, to establish an 

airbase and bombing range. In 1971, a Memorandum of Agreement 

with USFWS established the Matagorda Island Unit of ANWR. The 

upland area was declared excess property by the Air Force in 

1975. The property was transferred to USFWS as part of the NWR 

system in 1978. In 1988, USFWS and Texas General Land Office 

exchanged easements and signed a management agreement that 

established Matagorda Island State Park and Wildlife Management 

Area. In 1988, the USFWS purchased 2,232 ha on the south end of 

the Island. A new agreement between USFWS and the State of Texas 

enabling joint management of the entire island was signed in 1994 

and is reviewed every 5 years. It established the Matagorda 

Island NWR and State Park and includes a separation of duties. 

C-16
DRAFT Whooping Crane Recovery Plan 2005 

USFWS has the lead for wildlife and habitat management, and Texas 

Parks and Wildlife Department manage public use and environmental 

education. 

Additional protection of some winter habitat has been provided by 

NAS's leasing Ayres, Roddy, and a portion of Rattlesnake islands 

from the State of Texas. The leasing arrangement substantially 

reduces the potential for disturbing or harassing cranes 

wintering in these areas. 

Construction of the GIWW in the early 1940s through the heart of 

marshes on ANWR, subsequent erosion by wind and boat wakes, and 

deposition of dredged material, resulted in loss of 11% of 

wintering habitat (Sherrod and Medina 1992). In 1983-1984, 

shoreline erosion along the GIWW was measured at a loss of 1 m 

per year, amounting to destruction of 0.8 ha of whooping crane 

habitat along 13.6 km of critical habitat shoreline (Stehn 1987). 

In 1985, the U.S. Army Corps of Engineers (USACE) formed an 

interagency committee to study the impacts of the GIWW on 

critical habitat of whooping cranes. Boats and barges plying the 

GIWW create wakes and surges that erode marsh bordering the 

channel (U.S. Army Corps of Engineers 1988). Ponds and sloughs 

in the marsh are destroyed as erosion breaches their margins. 

Between 1989-1992, volunteers built walls using more than 57,000 

sacks of cement to protect 2,652 m of shoreline. In 1992, USACE 

used 610 m of interlocking cement mats to stop erosion. USACE 

agreed in 1993 to armor approximately 4.8 km of the most 

critically eroding shoreline, and to continue to armor 610 m 

annually until all areas were adequately protected. The USACE’s 

Section 216 Study provided a permanent solution to the habitat 

erosion problem. In 1998-2000, the Corps used flexible cement 

mats to protect 25.6 km of shoreline at ANWR and 8.3 km at Welder 

Flats. They also protected 471 m at Welder Flats using geotubes, 

and purchased equipment stored on the refuge to respond to an oil 

spill. Total project costs were $15.43 million. 

Deposition of dredged material from periodic maintenance dredging 

of the channel has destroyed additional marsh and, accidentally, 

created some new marsh. Dredged material disposal sites along 

the GIWW have been nearly fully utilized. The problem of future 

disposal of dredged material is critical. 

In the summer of 1991, Mitchell Energy created a dike around 5 ha 

of open shallow bay and filled the area with dredge material. 

Vegetation was planted in the created shallows and the first 

whooping crane use was documented in January 1992. Mitchell 

C-17
DRAFT Whooping Crane Recovery Plan 2005 

Energy constructed additional marsh acreage in 1993 and 1995 

totaling 8 ha. The USACE has evaluated beneficial uses of dredge 

material to create new coastal marsh habitat for whooping cranes. 

In 1995, the USACE created 2 wetland areas using dredged material 

totaling 18 ha (Evans and Stehn 1997). The USACE new dredge 

material disposal plan calls for creation of 654 ha of marsh 

habitat over the next 50 years. The USACE is working 

cooperatively with other agencies on design and location of these 

new marshes. 

Several studies have characterized whooping crane winter habitat. 

Darnell et al. (1997) studied influence of landscape features on 

bird use of marsh habitat created for whooping cranes. Although 

the created marshes were successful in providing avian habitat, 

design modifications were suggested to increase the similarity of 

created and natural marshes (Darnell et al. 1997). Bonds 

(2000), using GIS and remote sensing, characterized whooping 

crane territories from 1992-1997. Bonds (2000) recommended landcover composition of whooping crane areas to be 50% salt marsh 

(5-6.5 patches/ha), 30-40% salt marsh open water (10-16 

patches/ha), and up to 10% grasslands (8.9 patches/ha). 

Vocalizations of whooping cranes have been studied by several 

researchers. Initial vocal analysis of alarm calls was not 

sufficiently accurate (64.4%) to identify individual birds 

(Carlson 1991), but recordings of unison calls allows for 

identification of individuals (Bernhard Wessling, pers. comm.). 

Wessling (2000) recorded the unison calls for 27 pairs on winter 

territories at ANWR in winter 1999-2000. In the summer of 2000, 

Brian Johns recorded unison calls of 9 pairs on the breeding 

grounds. From the comparisons, it was possible to identify 

several of the nesting pairs on their winter territories (Brian 

Johns, pers. comm.). 

Captive Propagation 

 

Whooping cranes are propagated to save the genetic material of 

the species and to establish additional wild populations. In 

1998, the Recovery Team adopted the following allocation of 

captive-produced chicks listed in order of priority: maintenance 

of captive flocks; Florida releases; Wisconsin/Manitoba releases; 

off-corridor experiments considered essential to Florida, 

Wisconsin, or propagation; education; other approved populations; 

and other experiments. 

C-18
DRAFT Whooping Crane Recovery Plan 2005 

Research and Propagation at Patuxent Wildlife Research Center

Before research was carried out at PWRC, successful attempts to 

propagate whooping cranes involved only 4 birds - 2 females 

(Josephine and Rosie) and 2 males (Crip and Pete) (McNulty 1966, 

Doughty 1989) (Fig. 5). Josephine, who in 1941 was captured and 

placed in captivity at Audubon Park Zoo in New Orleans, 

Louisiana, became the last survivor of the non-migratory, 

southwestern Louisiana population. Crip, Pete, and Rosie, 

flightless due to injuries, were from the migratory population 

(McNulty 1966, Maroldo 1980). Three other birds in poor health 

(1 from Louisiana and 2 from Aransas) were rescued from the wild 

but all died soon after capture. 

 

Josephine, in captivity from 1941 to 1965, produced 13 chicks. 

Four lived for more than a decade but left no survivors. Pete 

lived for 13 years in captivity but also left no survivors. In 

1949, Pete and Josephine nested unsuccessfully in an enclosure at 

ANWR. After Pete died at Aransas in 1949, Josephine was repaired with Crip. The pair hatched one chick in 1950 at ANWR but 

a predator took it a few days after hatch. After nesting 

unsuccessfully in 1951, Crip and Josephine were transferred to 

Audubon Park Zoo. Josephine died in 1965 and Rosie was paired 

with Crip. After an unsuccessful nesting attempt in 1966, they 

were moved to the San Antonio Zoo in Texas. Rosie, in captivity 

from 1956 to 1971, produced 1 line with Crip that survives today 

(Gee Whiz). Crip, in captivity from 1949 to 1979, produced 13 

chicks with Josephine, 3 with Rosie, and 1 with Ektu. Ektu, 

hatched and reared at PWRC from an egg taken from WBNP in 1967, 

died in 1984, and produced 1 chick with Crip that died the same 

year (Fig. 5). 

C-19
DRAFT Whooping Crane Recovery Plan 2005 

Figure 5. Whooping crane captive propagation, 1941-1979.

C-20
DRAFT Whooping Crane Recovery Plan 2005 

Experimentation with bringing sandhill cranes into captivity 

began in 1961. Immature lesser and greater sandhill cranes were 

captured in 1961 and 1962, respectively, and greater sandhill 

crane eggs and downy chicks were collected in 1962. These cranes 

were housed in temporary facilities at Monte Vista NWR, Colorado. 

Initial results of this research indicated that egg collecting 

was the safest and most convenient method of obtaining and 

transporting wild stock (McNulty 1966, Doughty 1989). In 

subsequent years, only eggs were taken from the wild at Malheur 

NWR, Oregon and Grays Lake NWR, Idaho, several locations in 

peninsular Florida, Jackson County, Mississippi, and central 

Wisconsin. 

A male whooping crane named CAN-US, captured as a chick in WBNP 

in 1964 with an injured wing (Novakowski 1965), was the only 

whooper in the flock. In 1966, U.S. Senator Karl Mundt sponsored 

a supplemental appropriation to establish the Endangered Wildlife 

Research Program and to develop permanent facilities at the PWRC 

in Laurel, Maryland. The WCCA was influential in acquiring the 

first project funding at PWRC (Erickson 1968). The single 

whooping crane, sandhill cranes, and Aleutian Canada geese were 

transferred to Maryland in spring 1966.

Although some propagation techniques developed for sandhill 

cranes can be applied to whooping cranes, the latter have 

required certain procedural modifications. Whooping cranes are 

more difficult to rear than sandhills, and most mortality has 

occurred within one month of hatching as a result of bacterial 

infections, coccidiosis, congenital abnormalities, and leg 

disorders resulting from rapid growth (Kepler 1978). All 

mortalities in the captive flock have been summarized from 1967 

to 1981 (Carpenter and Derrickson 1982) and from 1982 to 1995 

(Olsen et al. 1997). 

Whooping crane eggs were first produced at PWRC in 1975 when 1 

female laid 3 eggs. Although 2 females produced eggs when they 

were 5 years old, most captive females have not laid until they 

were 7-10 years old (Table 3). At CZ, 1 female produced eggs 

when she was 4 years old (Dwight Knapik, pers. comm.) and 2 

females when 5 years old. ICF had 2 females produce eggs at 4 

years of age (Mike Putnam, pers. comm.). 

C-21
DRAFT Whooping Crane Recovery Plan 2005 

Table 3. Age of captive whooping cranes when they first produced 

eggs, Patuxent Wildlife Research Center, 1975-1993. 

Age Producing Percent 

(years) Femalesab Femalesc Producing 

5 28 5 17

6 22 8 36

7 15 8 53

8 13 10 76

9 10 9 90

10 9 9 100

a

 Does not include birds transferred between centers before 

maturation. Transfers delayed egg production. 

b

 Females reaching or passing through that age class by 1993. 

c

 Females producing eggs in that age class. 

__________ 

C-22
DRAFT Whooping Crane Recovery Plan 2005 

Possible factors responsible for delaying reproduction in the 

captive flock include photoperiod, rainfall, rearing conditions, 

dominance relationships, age of separation of potential pairs 

from a bachelor flock, sexual compatibility, inadequate pen size, 

lack of access to ponds, and stress associated with handling and 

disturbance (Kepler 1976, 1978, Derrickson and Carpenter 1982, 

Ellis et al. 1996, Mirande et al. 1996). Besides delayed sexual 

maturity, other factors reduce reproductive potential in the 

captive flock. Most birds, after they start, lay eggs every 

year. Some pairs lay every other year, some more occasionally, 

and some lay small or misshapen eggs. Between 1975 and 2003, the 

captive flock at PWRC produced 845 eggs (Table 4). 

C-23
DRAFT Whooping Crane Recovery Plan 2005 

Table 4. Size and productivity of the captive whooping crane 

flock at Patuxent Wildlife Research Center, 1975-2003. 

Eggs retained at PWRC

Year AHYa

Birds 

31 Dec.

HYb

Birds 

31 Dec.

Females

Laying

Total

Eggsc

No. Fertile Hatched Chicks

Fledged

1975 20 0 1 3 3 2 1 0

1976 18 1 2 5 3 1 1 1

1977 19 2 4 22 8 4 3 2

1978d 19 3 3 23 8 8 7 3

1979e 22 4 4 21 16 10 8 4

1980 22 0 2 6 4 1 0 0

1981 19 1 2 11 11 5 3 1

1982 19 7 5 28 15 12 9 6

1983 25 10 5 34 22 18 14 8

1984 27 5 5 31 21 16 12 4

1985 31 7 3 13 13 8 7 6

1986f 36 2 0 0 0 0 0 0

1987 35 6 5 7 7 3 2 1

1988 37 9 6 15 15 8 7 3

1989 30 2 5 19 19 14 9 8

1990 32 3 4 14 14 5 4 3

1991 35 5 5 21 21 9 5 2

1992 36 13 8 48 48g 11 9 8

1993 37 19 8 35 35 16 15 10

1994 40 16 9 48 48 29 21 18

1995 37 35 8 48 48 35 31 26

1996 39 21 8 44 44 27 25 18

1997 42 18 8 55 55 30 29 18

1998 40 27 10 55 55 35 30 27

1999 44 30 8 52 52 32 29 26

2000 47 25 8 51 51 35 35 32

2001 46 17 10 52 52 31 29 25

2002 53 15 10 43 43 26 22 21

2003 51 8 9 41 41 31 30 29

 a AHY = After Hatch Year

 b HY = Hatch Year 

c

 Includes 73 eggs transferred to Grays Lake National Wildlife 

Refuge in 1976-1984. Fertility determined for unhatched eggs 

by examination of egg contents. Examination occurred after 

full-term incubation and eggs containing no detectable embryo 

were considered infertile, therefore, the number of fertile 

eggs listed is considered a minimum estimate. 

d

 All eggs retained at PWRC were incubated and hatched under 

C-24
DRAFT Whooping Crane Recovery Plan 2005 

sandhill cranes and chicks were "foster-parent" reared. All 

eggs transferred to GL were artificially incubated until 

transfer. e

 All eggs retained at PWRC were incubated under sandhill cranes 

and chicks were hand-reared or foster parent-reared by 

sandhill cranes. All eggs transferred to GL were incubated 

under captive pairs of sandhill cranes at Patuxent until 

transfer this year and subsequent years. 

f

 No eggs were produced in 1986. Breeding birds were moved 

temporarily to pens in summer 1985 during construction of new 

pens. The birds were moved into the new pens in November 1985. 

These movements were believed to be the disturbance that 

disrupted the 1986 breeding cycle. 

g

 Six new pairs broke the 19 eggs they produced. 

__________ 

C-25
DRAFT Whooping Crane Recovery Plan 2005 

Breeding pair numbers and egg fertility have been the primary 

factors limiting annual production (Gee and Temple 1978). 

Successful natural copulations were not observed until 1991 when 

a full-winged pair laid a fertile egg (Nicolich et al. 2001). 

There has been no difference in the number of eggs produced by 

naturally fertile pairs and artificially inseminated birds at 

Patuxent. From 1991 to 1999, 8 pairs produced chicks by natural 

breeding, but egg fertility (54%) was less than from females 

artificially inseminated (76%). Natural fertility, which reduces 

the risk of injury due to handling, is good in some pairs but 

overall is less than in pairs artificially inseminated. Some 

pairs, although they copulate, fail to lay a high percentage of 

fertile eggs or do not reliably lay fertile eggs every year. In 

these pairs, artificial insemination before they lay the first 

egg may increase natural fertility and increase total fertile 

production in the captive flock (Bakst 1988). To get fertile 

eggs from badly imprinted or handicapped individuals, the females 

have been artificially inseminated using the massage technique 

(Gee and Mirande 1996). To condition pairs to this procedure, 

collection of semen from males and the handling of females begins 

well before laying. After their pubic bones begin to spread, 

females are inseminated 3 times weekly and after each oviposition 

until laying ceases. 

From 1975 through 2000 at PWRC, fertility of eggs (233 of 268) 

from whooping cranes artificially inseminated averaged 87%. 

From 1975 through 2003, the PWRC flock produced 845 eggs of which 

462 were fertile (54%). From these 462 fertile eggs, and 136 

other fertile eggs obtained from WBNP, PWRC fledged 310 birds 

(51%). 

From 1993 to 2000, 239 of 378 eggs (63%) from the PWRC flock were 

fertile. From these 239 eggs, 176 (74%) were fledged. Of these, 

164 were sent to the Florida reintroduction. Although PWRC 

fledged about 1 chick per pair before 1993, consistent 

improvements in rearing techniques since then increased the 

fledging rate to 3 chicks per pair annually. PWRC avoids 

imprinting problems by parent-rearing chicks or hand-rearing them 

in visual and auditory contact with a subadult whooping crane 

role model. 

 

Seventy-three whooping crane eggs were transferred from PWRC to 

Grays Lake between 1976 and 1984. PWRC shipped 22 birds to ICF 

in 1989 and 11 birds to Calgary in 1992 and 1993 to help 

establish other captive flocks. The flock was split several 

times to reduce the risk of disease outbreaks decimating the 

C-26
DRAFT Whooping Crane Recovery Plan 2005 

entire captive population. 

Hatchability of whooping crane eggs incubated by cranes exceeds 

that of eggs placed in incubators, probably because of less than 

optimum incubation regimes. In 1978, hatchability of the 8 eggs 

retained at PWRC and incubated under sandhill cranes was 88%, 

while only 5 of 11 fertile eggs incubated artificially before 

their transfer to GL hatched. As a result, since 1979 all 

whooping crane eggs at PWRC have been incubated under sandhill 

cranes or whooping cranes. Since these modifications were 

undertaken, hatchability and chick survival has equaled that 

observed in eggs and chicks from the AWBP (Table 4). 

A study of the pedigree effect on survival in captivity and in 

Florida found that some families do not produce eggs or fertile 

eggs. Some produce many chicks but few survive well in captivity 

and after wild release, some fledge many chicks and they survive 

well in captivity and after wild release, and some families carry 

genetic defects (e.g. scoliosis) (George Gee, pers. comm.). 

Infection with coccidia (Eimeria spp.) has been a major morbidity 

and mortality factor for chicks at PWRC, in some years resulting 

in up to 20% mortality of the hatched chicks (Carpenter et. al 

1980). Control programs, including better pen design, improved 

pen husbandry, pen rotation, and development and use of new 

coccidiostats in the feed, have now reduced the mortality to 

zero. 

A disease outbreak can cause a serious setback to the captive 

breeding program. In the fall of 1984, 7 whooping cranes in the 

captive flock at PWRC died from EEE, of which 5 were females. 

The January 1985 sex ratio in the surviving adult captive 

population was 10 males to 4 females. Sandhill cranes at PWRC 

also were exposed to the virus, but no mortality occurred 

(Carpenter et al. 1987). Whooping cranes appear especially 

susceptible to EEE; consequently the potential impact of this 

disease will be considered when selecting any site for additional 

whooping crane populations. 

Thirteen of the 32 whooping cranes at PWRC were exposed naturally 

to the EEE virus and all developed antibody titers. Ongoing 

unpublished research has shown that use of an EEE vaccine 

protects against infection and should reduce the risk of this 

disease in the future. Actions taken in 1985 and continued 

annually to prevent another outbreak of EEE at PWRC include: (1) 

a surveillance and control program for the principal mosquito 

(Culiseta melanura), vector of the disease; (2) testing EEE 

C-27
DRAFT Whooping Crane Recovery Plan 2005 

vaccines and developing a more effective vaccine for whooping 

cranes; and (3) continuing serological monitoring of the captive 

flock for antibody titers. Now that the etiology of the whooping 

crane deaths at PWRC is known, the disease threat can be 

minimized in captivity by initiating appropriate mosquito control 

measures and the use of EEE vaccines. However, the long-term 

efficacy of the vaccine is unknown and annual booster shots are 

required. The Whooping Crane Health Advisory Team recommended 

that the breeder cranes at all captive facilities in EEE 

geographic areas, including ICF and PWRC, be vaccinated. EEE 

vaccination research is also being done to test its usefulness 

when whooping cranes are released into EEE areas like Florida. 

As part of an experimental strategy, chicks transported from PWRC 

to Florida for release are vaccinated, but those coming from ICF 

and other northern captive centers are usually not vaccinated. 

In September-October 1987, a mycotoxin in commercially prepared 

crane feed poisoned about 240 of the 300 captive cranes at PWRC. 

Fifteen cranes died (5% of the flock), including 3 whooping 

cranes. Laboratories found a trichothecene in the feed that may 

have been the toxic agent (Valente 1992). A small sample of each 

commercial food shipment is now fed to bobwhites (Colinus 

virginianus) before being offered to cranes. Food consumption, 

body weight changes, and mortality in the quail are used to 

detect toxins in the feed. 

WNV, a form of encephalitis newly arrived from Africa and first 

detected in the New York area in 1999, has been spreading across 

the U.S. and Canada. It may pose a threat, which needs to be 

assessed, to the cranes at PWRC and soon to all the whooping 

crane populations (Robert McLean, pers. comm.). Research on WNV 

and the efficacy of vaccination in sandhill cranes was carried 

out by PWRC and NWHC in 2002. Preliminary results show that 

sandhill cranes didn’t die or develop obvious clinical signs when 

challenged with WNV, but they did have a subclinical infection. 

Vaccination appears to be particularly effective in protecting 

sandhill cranes, reducing virus shedding. 

Recent significant studies at PWRC include: use of monensin and 

vaccine as an improved treatment for disseminated visceral 

coccidiosis; estimates of diversity in the major 

histocompatibility complex; ways to establish migratory crane 

populations using trucks, ultralight aircraft, and other 

techniques; ingested metal treatment (Olsen and Wise 2001), blood 

studies (Olsen et al. 2001), and comparisons between individual 

crane behaviors and survival in Florida (Kreger et al. 2001, Gee 

et al. 2001), and experiments involving fertilization timing of 

C-28
DRAFT Whooping Crane Recovery Plan 2005 

artificially inseminated cranes (Jones and Nicolich 2001; Jones 

et al. in prep b). 

The pen facilities at PWRC were modernized in the early 1990's 

but major maintenance and replacement needs exist at present. 

These new facilities should help establish breeder pairs on a 

territory without the disturbances associated with pen 

maintenance experienced in earlier complexes. 

Propagation at International Crane Foundation

The ICF is a private conservation organization dedicated to the 

study and preservation of cranes worldwide. Captive propagation 

expertise was developed during the 1970s with several crane 

species, including whooping cranes (Doughty 1989). ICF employs 

thirty full-time staff members and ten additional people on 

project funding. The Crane Conservation Department, which 

manages the whooping crane flock and also assists with the 

eastern migratory reintroduction, consists of 6 employees. In 

addition, a veterinarian and veterinary technician, under the 

Department of Conservation Services, provide clinical care to the 

captive flock. 

 

In 1989, the U.S. Whooping Crane Recovery Team decided to split 

the captive flock to reduce the risk of disease. ICF received 22 

whooping cranes from PWRC and an injured adult male from the RMP. 

Two cranes died shortly after their arrival. Two experienced 

pairs failed to lay in 1990, probably due to the disruption 

caused by the move. Cranes, especially whooping cranes, are 

sensitive to disturbance and pen changes (Mirande et al. 1997b). 

Three females laid 9 eggs in 1991, and 1 chick was parent-reared, 

the start of captive whooping crane production at ICF. From 

1991-2003, the flock at ICF has laid 268 eggs, of which 132 were 

fertile, 103 hatched, and 84 fledged (Table 5). Fifty-five have 

been sent to Florida for reintroduction. Eighteen were kept at 

ICF to build the flock and for genetic management. 

C-29
DRAFT Whooping Crane Recovery Plan 2005 

Table 5. Size and productivity of the captive whooping crane 

flock at International Crane Foundation, 1989-2002. 

Year All

Birds, 

Jan. 1 

Females 

Laying 

Eggs Fertile

Eggs 

Chicks 

Hatched

Chicks 

Fledged 

Chicks 

Sent to 

Florida

1989 23a - - - - - -

1990 21 0 0 0 0 0 0

1991 30 3 9 2 2 1 0

1992 28 3 16 8 6 6 1

1993 37 3 9 5 5 5 2

1994 28 5 14 6 6 6 4

1995 34 5 21 10 8 5 2

1996 34 6 23 15 12 10 10

1997 32 5 23b 13 8c 7 7

1998 30 6 22 13 11 7 6

1999 30 4 20 9 8 7 6

2000 28 7 26 12 5 5 4

2001 28 5 21 6 5 2 1

2002 28 7 33 16b 13c 11d 4

2003 32 8 31 17 14 12 8

TOTALS 268 132

(49.3%)

103 

(78.0%)

84 

(81.6%) 

55 

a

 22 birds arrived at ICF in fall of ‘89 

b

 Three of these eggs sent to PWRC. 

c

 Three eggs hatched at PWRC. 

d

 Three chicks hatched at PWRC and fledged at Necedah NWR. 

__________ 

C-30
DRAFT Whooping Crane Recovery Plan 2005 

Eggs were also picked up from wild nests in Canada and shipped to 

ICF to build up the size of the captive flock or to support 

reintroductions. In May of 1990, 12 eggs were transferred from 

WBNP and 8 fledged to increase the size of the captive flock at 

ICF to 30. Between 1990 and 1996, 58 eggs from WBNP were 

transported to ICF, 49 hatched and 41 fledged (Table 6). 

Eighteen were sent to Florida for reintroduction, 4 to Idaho, 3 

to Calgary, and 16 retained in captivity for genetic management. 

C-31
DRAFT Whooping Crane Recovery Plan 2005 

Table 6. Hatching and fledging rates of AWBP eggs transferred to 

International Crane Foundation, 1990-1996.

Year Eggs

Received

Eggs 

Fertile

Eggs 

Hatched

Chicks 

Fledged

Chicks Sent 

to Florida

1990 12 11 11 8 0

1991 0 0 0 0 0

1992 11 10 10 7 6

1993 10 9 8a 7 0

1994 9 5 5 5 4

1995 10 10 10 9b 8 

1996 6c 5 5 5d 0 

TOTALS 58 50 49 41 18

a

 Four chicks sent to Grays Lake, Idaho; 2 chicks sent to 

Calgary Zoo. 

b

 One chick sent to the Calgary Zoo. 

c

 One egg arrived with a hole in it, late dead embryo. 

d

 All chicks retained at ICF for genetic management. 

__________ 

C-32
DRAFT Whooping Crane Recovery Plan 2005 

At ICF, chicks have been parent-reared, hand-reared, or costumereared. In costume-rearing, cranes are exposed to the human form 

only during negative, stressful situations and remain wary of 

people. From the time of hatching, costume-reared whooping 

cranes are exposed to live whooping crane role models in adjacent 

pens to avoid imprinting problems. 

Significant morbidity and mortality factors for captive whooping 

cranes at ICF have been orthopedic problems and metal foreign 

body ingestion (Langenberg, unpubl. reports to the Recovery 

Team). Developmental wing and leg deformities, and handlingassociated leg fractures and joint injuries in chicks have 

contributed to low fledging or release rates at ICF in some 

years, especially in the early 1990s when production first 

started (Hartup et al. 2001a). Changes in handling protocols, 

information exchange with PWRC and other centers, and increased 

experience have decreased the impacts of these chick problems. 

The ICF flock has been free of significant infectious disease 

problems, probably the result of intensive husbandry practices 

and regular health monitoring. As the captive whooping crane 

population ages, the incidence of geriatric problems (such as leg 

joint arthritis) is increasing, and can be a particular problem 

in the captive facilities in colder regions, such as ICF. 

Beginning in 1990, closed circuit television proved to be an 

effective tool for monitoring and supervising the socialization 

of new pairs as well as for monitoring pairs that break their 

eggs. Through video monitoring, an egg could be retrieved within 

minutes of being laid. Currently ICF has five cameras. 

Seventeen crane pens are hardwired and ready for cameras, 

allowing staff to move cameras as needed. ICF has acquired 

software for analysis and storage-retrieval of its growing 

collection of video materials. 

The number of laying females at ICF has increased to 7 in 2002. 

ICF has facilities to house 15 breeder pairs. Research is 

ongoing to improve reproduction, rearing procedures, behavioral 

management, health care, and other topics that may directly 

benefit management and recovery (Gerencser 1997, 1998, Langenberg 

and Donoghue 1997, Langenberg et al. 1998, Hartup et al. 2001b, 

Bowman et al. 2002). A few of these topics are nutrition, 

effects of disturbance from human activity as well as neighboring 

cranes, dominant pair suppression and presence of ponds. 

One research and management theme is the importance of water. In 

1995, a whooping crane exhibit was built. The exhibit displays 

the birds in a large wetland (42 m x 22 m) with natural grasses 

C-33
DRAFT Whooping Crane Recovery Plan 2005 

and aquatic vegetation. Whooping crane pairs that have spent two 

breeding seasons in this exhibit have all laid eggs even though 

they are on public display. Water is believed to be one of the 

main reasons for this; therefore, ICF is investigating the 

presence of ponds, the size of the ponds and how they affect the 

behavior of pairs in the breeding season. In 1996 small ponds 

(2.5 m x 2.5 m) were created in pens of pairs that were of 

breeding age and had not bred. The breeding results of these 

pairs were mixed. During the fall of 2000, ponds were constructed 

in two Whooping Crane pairs' pens. The ponds are approximately 

7.5 m x 9 m and vary in depth from a few cm up to 45 cm. 

Reproductive behavior of the pairs in these pens will be compared 

with those with smaller ponds or no ponds at all. 

Water and exposure to the wetland environment is also 

incorporated into the rearing of the crane chicks for release. 

Pairs that raise young are provided with flooded areas. 

Isolation-reared chicks are also provided with pools and flooded 

areas in their exercise yard. When the cohorts are formed and 

the youngest crane is thermo-regulating well, they are moved to 

larger enclosures in crane city. These pens have ponds 

approximately 15 by 20 feet in size where the chicks are 

encouraged to roost in the ponds overnight. 

As part of ICF’s efforts to improve crane management, plans are 

in the works for building a new isolation rearing facility near 

to the breeding complex. This new facility would move the cranes 

from an area adjacent to the main office complex where it is 

difficult to isolate chicks from human sounds, to a low 

disturbance area. Wetlands next to the facility would allow the 

cranes access to a larger area allowing wide open vistas with 

fewer human artifacts. 

Since 1989, ICF has received support from Region 2 of USFWS to 

cover costs of maintaining and breeding its captive whooping 

cranes. Beginning in 2001, these funds have been appropriated 

from the Washington Office of USFWS. ICF raises additional funds 

from the private sector to support whooping crane conservation, 

over $200,000 in each of the last two years. Aside from research 

and crane management efforts, ICF emphasizes public education 

about cranes, their habitats, and conservation. Roughly 30,000 

visitors come to ICF each year, where they can see a pair of 

whooping cranes in a natural wetland setting. ICF staff members 

engage in outreach activities along the Wisconsin-to-Florida 

flyway, in Texas, and in other key crane areas, involving use of 

crane posters, audio-visual presentations, and Crane Trunks 

(boxes shipped on temporary loan to schools and containing a 

C-34
DRAFT Whooping Crane Recovery Plan 2005 

variety of crane artifacts and educational activities). ICF also 

has a school curriculum on crane migration available through 

registration on its website. 

 

Propagation at Calgary Zoo

The Calgary Zoological Society is a non-profit, charitable 

organization that operates the Calgary Botanical Gardens and 

Prehistoric Park in Calgary, Alberta, Canada. The Society houses 

a wide variety of living animals and plants, and participates in 

many threatened and endangered species breeding programs. In 

1988, the CWS called for bids from suitable organizations to 

manage a captive breeding flock of whooping cranes. In 1989, 

Calgary was chosen, and the Calgary Zoological Society signed an 

agreement with CWS to serve as the Canadian captive breeding 

center. 

In 1991, zoo staff visited ICF for training in captive husbandry. 

Funding was obtained from the Nat Christie Foundation in Calgary 

to build breeding enclosures, a chick-rearing building, and 

incubation facility. In November 1992, the first 2 whooping 

cranes arrived from ICF, with 11 sent from PWRC in 1993. In 

1994, the first chick was hatched from a wild egg from WBNP. In 

1995, Hope and Chinook produced the first eggs at Calgary. 

Chinook, at age 4 years and 14 days, was the youngest female to 

lay an egg in captivity. In 1996, the same pair produced the 

first fertile eggs laid at Calgary. Three chicks were reared to 

fledging, and were the first released to the wild at Kissimmee 

Prairie, Florida from this facility (Table 7). Between 1996-

2003, 15 chicks reared at Calgary were shipped to go to Florida. 

C-35
DRAFT Whooping Crane Recovery Plan 2005 

Table 7. Size and productivity of the captive whooping crane 

flock at Calgary Zoo, 1992-2002.

 

Year All

Birds 

Females 

Laying 

Eggs Fertile 

Eggs 

Chicks 

Hatched

Chicks 

Fledged 

Chicks 

Sent to 

Florida

1992 2 0 0 0 0 0 0

1993 13 0 0 0 0 0 0

1994 16 0 0 0 0 0 0

1995 18 2 5 0 0 0 0

1996 18 1 5 5 5 3 3

1997 20 2 12 1 1 0 0

1998 21 2 10 2 2 2 2

1999 21 3 13 6 2 2 2

2000 20 4 21 11 6 3 2

2001 20 6 28 5 5 3 3

2002 19 6 24 6 2 2 2

2003 17 4 21 8 3 2 1

TOTALS 139 44 26 17 15

__________ 

C-36
DRAFT Whooping Crane Recovery Plan 2005 

One hundred and thirty-nine whooping crane eggs have been laid at 

Calgary 1995-2003. Forty four were fertile, 26 hatched and 17 

chicks fledged (Table 7). Four eggs were received from WBNP in 

1994 and 2 in 1996, from which 2 chicks hatched in 1994 and 1 in 

1996. From those AWBP eggs, 1 chick fledged each year. All 

fertile eggs have been produced by natural fertilization, and 

this approach may be continued. Eggs are incubated using a 

combination of natural and artificial methods. Chicks are reared 

by parents or by costumed caretakers. 

Cross-fostering, Translocation, and Guide-bird Studies at Grays 

Lake NWR, Idaho

Survival prospects for the whooping crane would be greatly 

enhanced by establishing additional, separate populations. The 

first technique tried was cross-fostering whooping cranes to 

sandhill crane foster parents. Whooping crane eggs from the wild 

or from captive breeders were placed in sandhill crane nests, and 

the sandhill cranes incubated, hatched, reared, and introduced 

the whooping crane chicks into the wild. 

Cross fostering was tested at Grays Lake NWR in Idaho, on the 

western edge of the recent historical range of the whooping 

crane, where studies on the greater sandhill crane had been in 

progress (Fig. 6)(Drewien 1973, Drewien and Bizeau 1974). From 

1975 through 1988, 216 whooping crane eggs were transferred to GL 

from WBNP, and 73 from PWRC, and placed under pairs of sandhill 

cranes. Two hundred and ten eggs hatched and 84 chicks fledged 

(Table 8)(Drewien et al. 1989, Ellis et al. 1992b). The whooper 

chicks adapted to dietary and habitat differences and, in 

subsequent years, repeated the migration pattern of their foster 

parents. 

C-37
DRAFT Whooping Crane Recovery Plan 2005 

Figure 6. Summer and winter ranges and migration route of the 

reintroduced Rocky Mountain whooping crane population. 

As of 2002, this population ceased to exist. 

C-38
DRAFT Whooping Crane Recovery Plan 2005 

Table 8. Eggs transplanted, hatched and chicks fledged at Grays 

Lake, Idaho, 1975-1988. 

Year

Origin 

of Eggs

No. eggs

transplanted

No. eggs 

Hatched

No. chicks

Fledged

1975 Canada 14a 9 5

1976 Canada 15b 11 4

PWRC 2 0 0

1977 Canada 16 15 4

PWRC 14c 5 0

1978 Canada 13 9 3

PWRC 15d 5 0

1979 Canada 19 12 6

PWRCe 5 4 2

1980 Canada 13 10 4

PWRC 2 2 1

1981 Canada 12 5 0

1982 Canada 14 8 3

PWRC 13 11 4

1983 Canada 16f 15 11

PWRC 12f 11 8

1984 Canada 22g 19 10

PWRC 10f 6 2

1985 Canada 23h 20 11

1986 Canada 15i 11 2

1987 Canada 12 12 2

1988 Canada 12 10 2

Subtotal Canada 216 166 67

PWRC 73 44 17

Total 289 210 84

C-39
DRAFT Whooping Crane Recovery Plan 2005 

a

 Two of 14 eggs lost to predators. 

b

 Four of 15 eggs lost to predators. 

c

 Three eggs deserted after a snowstorm, one egg lost to a 

predator. 

d

 Examination of 10 eggs that did not hatch revealed that 4 were 

infertile, 2 contained early-dead embryos, and 4 contained 

late-dead embryos. e

 Poor hatchability of PWRC eggs during the period 1976-1978 was 

due largely to egg infertility (11 eggs) and artificial 

incubation (20 eggs). After 1978, only eggs containing viable 

embryos (as determined by flotation) were transferred and all 

eggs were incubated under sandhill cranes at PWRC before their 

transfer. 

f

 One egg lost to a predator before hatching. 

g

 Three eggs lost to predators before hatching. 

h

 Three eggs believed to be infertile or to contain early dead 

embryos at the time of transfer. 

 i Two eggs were eaten by predators and two failed to hatch. 

__________ 

C-40
DRAFT Whooping Crane Recovery Plan 2005 

High chick mortality was attributed to inclement weather at the 

time of hatching, poor habitat and food conditions during some 

years, and coyote predation (Drewien and Bizeau 1978, Drewien et 

al. 1985). Subadult and adult mortality rates were also high; 

birds were lost to fence and power line collisions (Brown et al. 

1987, Brown and Drewien 1995), disease (Snyder et al. 1987, 1992, 

Stroud et al. 1986), predation (Windingstad et al. 1981, Drewien 

et al. 1989), and other causes. High mortality and the absence 

of breeding resulted in a relatively small population that peaked 

at 33 individuals in winter 1985. 

Higher mortality rates among females apparently were the basis 

for unequal sex ratios among cross-fostered adults. In research 

in other locations, it had been documented that wild cranes can 

successfully pair with tame or captive individuals (Hyde 1968, 

Longley 1970, Nesbitt 1979). Experimentation was started to 

simultaneously augment the wild cross-fostered population at 

Grays Lake NWR with captive-reared individuals, rectify the maleskewed sex ratio, and hasten the onset of breeding in the wild 

population. In June 1981, a captive, 3-year-old, parent-reared 

female whooping crane was transferred from PWRC to GL and placed 

on a male whooper's territory (Drewien et al. 1989). Although 

the female rapidly adjusted to the wild and associated 

periodically with the male, a pair bond was never established. 

Successful migration seemed unlikely, so the female was captured 

and returned to PWRC in October (Drewien and Clegg 1992). The 

experiment was repeated in 1982. The same female quickly adapted 

to the wild and her presence stimulated increased territorial 

activities by the male (Drewien et al. 1989). Unfortunately, the 

male died after becoming entangled in a barbed wire fence. The 

female was recaptured and returned to PWRC. 

The experiment was repeated in 1989, but in May rather than June. 

A captive 6-year-old female from PWRC was placed in a pen on a 

male's territory at GL. The male exhibited much interest in the 

female and after 1 week she was released from the pen. Pairing 

behavior included unison calling and copulations. No nesting 

attempt was made, perhaps because it was somewhat late in the 

season. The male molted his flight feathers and secluded himself 

in the marsh. In early June, the female abandoned the flightless 

male but was joined by another wild male. The new pair remained 

together for over 4 months. From October 5-15, the male was 

observed initiating migratory flights on 5 occasions with the 

female following. However, the female was unable to keep up with 

the male and she always returned to the territory with the male 

following. 

On October 15 the male migrated alone. The only other whooper 

present, a male, immediately joined the female for 2 days until 

C-41
DRAFT Whooping Crane Recovery Plan 2005 

he migrated. Six years in captivity apparently made the female 

physically incapable of sustaining long flights. Attempts to 

capture her in late October were unsuccessful and she 

disappeared. The behavior of the males at GL demonstrated that 

they were highly responsive to the presence of a conspecific 

female during the breeding season. 

During the 1980s it became apparent that during summer older 

females did not return to GL or other areas occupied by 

territorial males. Experiments to enhance pair formation were 

carried out from 1986 through 1990 whereby 20 whooping cranes 

(some females were recaptured several times) were moved from 

isolated summer sites and released at GL near male whooping 

cranes (Drewien et al. 1989). Five (2 males, 3 females) were 

held for 1 to 4 months in a pen before being released. These 

experiments contributed to numerous associations and interactions 

between both sexes, but no permanent pair bonds developed. The 

longest associations lasted 2 to 4 months before males and 

females separated. The cross-fostered females exhibited minimal 

response to the presence of males. These results suggested that 

imprinting problems possibly existed in whooping cranes raised by 

sandhill cranes. 

Dr. Edward 0. Garton, biometrician at the University of Idaho, 

modeled the cross-fostered population to predict when it might 

become self-sustaining. The model assumed (1) cross-fostered 

females would be breeding at the same rate as the females in 

Canada and (2) survival of birds in their first year would be 

similar to that of first year birds in Canada. Despite these 

optimistic and unrealized assumptions, with the future transfer 

of 30 eggs per year, the population would only reach 6 nesting 

pairs after 50 years (Garton et al. 1989). "It is obvious from 

all scenarios modeled that egg transplants of less than 30 eggs 

per year will not suffice to establish a self-sustaining 

population in a reasonable period of time. Natural breeding will 

be essential to establish a self-sustaining population" (Garton 

et al. 1989). 

At the 1989 meeting of the U.S. Whooping Crane Recovery Team, the 

team recommended the cross-fostering be discontinued. Other 

research continued at GL until 1992, but cross-fostered females 

appeared incapable of normal breeding behavior. The average 

whooping crane at WBNP begins egg production in its 4th year 

(Ernie Kuyt, pers. comm., 1991). By the fall of 1992, crossfostered adult female whooping cranes of ages 4 through 12 years 

had passed through a nesting season on 34 occasions without 

pairing. 

C-42
DRAFT Whooping Crane Recovery Plan 2005 

In 1992, a wild cross-fostered male whooping crane paired with a 

female sandhill crane to produce a hybrid chick. The hybrid wild 

chick provided additional evidence that cross-fostering may break 

down behavioral barriers that normally discourage pairing between 

the 2 species. However, isolated cranes from one species may 

hybridize with the more common species found in the same area. 

The hybrid summered in Yellowstone National Park. It never 

produced offspring and was believed sterile. It was last seen in 

spring 1999 and is believed dead. 

Sexual imprinting of a foster-reared species on the foster-parent 

species had already been confirmed in foster-reared raptors, 

waterfowl, gulls, finches, and gallinaceous birds (Immelmann 

1972, Bird et al. 1985). An investigation of the potential 

imprinting problem in cranes occurred at ICF where sandhill 

cranes were foster-reared by red-crowned cranes (sample of 1), 

white-naped cranes (sample of 2), and Siberian cranes (sample of 

1). When given a choice the cross-fostered sandhill cranes 

socialized more with the foster species than with conspecifics. 

The 2 foster-reared females showed a stronger preference for the 

foster species than did the 2 foster-reared males (Mahan and 

Simmers 1992) lending further support to the theory of improper 

sexual imprinting, particularly in female cranes, being the 

reason for failure of pairing in the cross-fostered whooping 

cranes at GL. 

In 1993, 4 males (9-17 yr old) and 4 females (7-13 yr old) 

remained in the Rocky Mountains. A variety of observations 

suggested that these adults might adopt and rear whooping crane 

chicks. Cross-fostered males had built nests, intermittently 

incubated an empty nest and sandhill eggs placed in that nest, 

and assisted neighboring sandhill pairs in raising sandhill and 

whooper chicks. Penned male and female whoopers fed and 

temporarily reared sandhill crane chicks. 

In 1993 and 1994, an experiment was designed to determine if the 

cross-fostered adults would adopt and raise whooping crane chicks 

and teach them migration (Drewien et al. 1997). If successful, 

this procedure would overcome the imprinting problems that had 

prevented appropriate pairing. Four whooping crane chicks or 

eggs were provided to the project each year. Although parentchick bonds appeared to develop in captivity, adults did not 

remain with the chicks after release to the wild. The chicks did 

not permanently remain with any cranes nor migrate. Field 

research was ended after 1994. 

In 1997, the remnant Rocky Mountain whooping crane population was 

designated experimental nonessential to allow greater management 

C-43
DRAFT Whooping Crane Recovery Plan 2005 

flexibility and to permit crane research to be conducted using 

ultralight aircraft. In fall, 1997, Kent Clegg flew a mixed 

flock of 8 sandhills and 4 whooping cranes behind an ultralight 

aircraft between Grace, Idaho and Bosque del Apache NWR, New 

Mexico. The trip covered 1140 km in 9 days. Two of the whooping 

cranes were lost to predators on the wintering grounds, and two 

migrated north in the spring. The cross-fostered population in 

the Rockies declined to a single survivor in year 2000 along with 

one crane from the ultralight experiment. Both were dead by 

spring 2002.

Reintroducing A Non-migratory Population in Florida

A November 21, 1975, letter to members of the Whooping Crane 

Recovery Team from the Florida Game and Fresh Water Fish 

Commission suggested the possibility of re-establishing a nonmigratory whooping crane population in the eastern United States. 

No pure genetic representative of the non-migratory Louisiana 

flock remained in captivity. The letter proposed that Florida 

sandhill cranes might be used as surrogate parents to instill 

non-migratory behavior into cross-fostered whooping cranes with 

the goal of restoring a non-migratory flock in the Southeast. 

In 1977, John Allender (Audubon Park Zoological Garden) and 

George Archibald submitted a proposal to reintroduce whooping 

cranes to Louisiana. The proposal was tabled by USFWS because 

they did not wish to endorse other reintroduction efforts until 

the cross-fostering project was fully evaluated (letter of Lynn 

Greenwalt, Director, FWS to Regional Directors, May 1978). 

Louisiana Wildlife agency personnel were concerned that critical 

habitat might be designated within the State as a consequence of 

a release, a designation that might place unfavorable constraints 

on land and hunting management (March 1978 letter of J. Burton 

Angelle, Secretary, Louisiana Wildlife and Fisheries Commission 

to George Archibald). Resource agency personnel in Louisiana 

were also concerned that restrictions on hunting of geese and 

ducks might be imposed as a consequence of the presence of an 

endangered species (Gomez 1992). Federal concerns included the 

belief that local residents might not be instilled with a 

conservation ethic sufficient to permit success of the 

reintroduction (letter from D. L. Hall, Special Agent In Charge, 

USFWS, April, 1978). 

In 1979, the U.S. Whooping Crane Recovery Team contacted the 

Florida Commission to ask if they were still interested in 

evaluating the feasibility of establishing a non-migratory flock 

of whooping cranes. Research was needed to determine whether a 

migratory crane species, when reared by non-migratory Florida 

C-44
DRAFT Whooping Crane Recovery Plan 2005 

sandhill crane foster parents, would also be non-migratory. Any 

cranes cross-fostered in Florida would potentially be in 

association with migratory greater sandhill cranes that nest in 

the Great Lakes region but winter in southern Georgia and 

Florida. Such an association at the time of spring migration 

might trigger some inherent tendency to migrate. Research to 

address the question began in 1980. One member of each of 

several established pairs of Florida sandhill cranes was captured 

and instrumented with a radio transmitter. When nesting began, 

eggs of greater sandhill cranes, obtained from PWRC or from the 

wild in Wisconsin or Idaho, were substituted for the pair's 

natural clutch. Hatching and rearing of the young were monitored 

until the resultant chick/chicks were 55 to 60 days old. The 

young were then captured, radio-tagged, and plastic leg bands 

attached. Movements were monitored through 1 or 2 spring 

migrations following separation from their parents. 

Thirty-four greater sandhill crane eggs were transferred into 23 

Florida sandhill crane nests between 1982 and 1987. From these 

transfers 5 young were produced which survived to the age at 

which they separated from their parents. Twenty-seven captivereared young were released (4 cohorts) during 1986 and 1987. 

They were radio-instrumented and distinctly color banded. 

Eighteen survived through at least 1 spring migration and 2 fall 

migrations. Only southerly movements by some individuals (60 to 

120 km) exceeded normal dispersal of subadult Florida sandhill 

cranes. In the 1 instance of the 120 km movement south, the 

birds returned within 6 weeks to the general vicinity of release. 

The movements of the dispersing experimental birds did not differ 

significantly (P > 0.05), either in direction or date of movement 

from that of a control group (Nesbitt and Carpenter 1993). 

Research results all indicated that migration in sandhill cranes 

was learned from their parents and not genetically programmed. 

By the mid-1980's, questions began to arise concerning the lack 

of pairing behavior of whooping cranes cross-fostered by sandhill 

cranes. It was desirable to test an alternative reintroduction 

technique. Thus, in 1986, releases of captive-reared sandhill 

cranes began. Four cohorts of captive-reared greater sandhill 

cranes were soft-released in Florida during late winter or early 

spring (Nesbitt and Carpenter 1993). Concurrently a group of 

Florida sandhill cranes (1- or 2-year-olds) from known natal 

sites were captured, radio-instrumented, and monitored as a 

control to compare dispersal. 

In 1983, the U.S. Recovery Team met to select sites to evaluate 

for another wild population. Eastern sites were proposed because 

they would be discrete from the other wild populations, a 

C-45
DRAFT Whooping Crane Recovery Plan 2005 

requirement of endangered species re-introductions in the United 

States. Coastal Louisiana, where whooping cranes survived as a 

non-migratory population in the 1940s (McIlhenny 1943), was not 

considered due to its proximity to Texas wintering sites and 

potential conflicts with Louisiana’s extensive hunting of 

waterfowl. 

Sites selected for evaluation were Seney NWR and adjacent areas 

in the Upper Peninsula of Michigan and Ontario, Okefenokee NWR in 

southern Georgia, and 3 sites in Florida (Lewis and Cooch 1992). 

Three-year research projects began in 1984 and final reports on 

the eastern study sites were submitted in 1987-88 (Bennett and 

Bennett 1987, McMillen 1987, Bishop 1988, Nesbitt 1988). In 

summer 1988, the U.S. Whooping Crane Recovery Team recommended 

that the next reintroduction establish a non-migratory population 

in the Kissimmee Prairie of Florida. Reasons the Team chose to 

establish a non-migratory population included (1) failure of the 

cross-fostering technique in Idaho and (2) lack of any proven 

technique to establish a migratory population. Some Florida 

habitats are similar to habitats historically used in Louisiana. 

Florida has no goose or crane hunting so hunting conflicts were 

unlikely. The Canadian Recovery Team endorsed the Kissimmee 

Prairie site in fall 1988. The Director of USFWS and the 

Director General of CWS approved the project in 1989. 

Considerable progress had been made in developing reliable 

methods for reintroducing captive-produced cranes to the wild. 

Releases of isolation-reared sandhill cranes resulted in high 

post-release survival both in migratory and non-migratory 

situations (Ellis et al. 1992a). Isolation-rearing refers to 

rearing the birds separated from visual contact with humans. 

Ethologist Dr. Robert Horwich at ICF developed costume-rearing, 

and the release of such birds into flocks of wild cranes, in 

1986. These first experimental releases used captive-reared 

sandhill cranes (Nesbitt 1979, Drewien et al. 1981, Zwank and 

Derrickson 1981, Horwich 1986, Bizeau et al. 1987, Leach 1987, 

Zwank and Wilson 1987, Nesbitt 1988, Horwich 1989, Archibald and 

Archibald 1992, Ellis et al. 1992b, Horwich et al. 1992, Urbanek 

and Bookhout 1992, 1994, Nesbitt and Carpenter 1993) to test the 

techniques. Some were soft or gentle releases involving a 

gradual transition from life in captivity to the wild. The 

cranes were placed in large predator-proof enclosures containing 

food and water. Their wings were brailed to prevent flight 

(Ellis and Dein 1991). After an acclimation period of 1-2 weeks, 

the brails were removed and the cranes could fly from the pen. 

Urbanek and Bookhout (1992) noted the need for similar studies on 

captive-reared whooping cranes. 

C-46
DRAFT Whooping Crane Recovery Plan 2005 

The Florida release site, Kissimmee Prairie, consists of 

approximately 2,000 square kilometers of flat, open palmetto 

prairie interspersed with shallow wetlands and lakes (Fig. 7). 

On private ranch lands, much of the prairie has been converted to 

improved pasture. Land ownership includes 8 large ranches 

totaling 82,200 ha. Large private holdings range from 2,700 ha 

to 42,500 ha. Public lands range from 2,955 ha to 43,300 ha. 

Three Lakes WMA (22,450 ha) was identified by Bishop (1988) as 

the preferred release site with the best habitat lying between 

lakes Jackson and Kissimmee. 

C-47
DRAFT Whooping Crane Recovery Plan 2005 

Figure 7. The Florida peninsula, showing the primary range of the 

Florida non-migratory population. 

Release pens like those used successfully in releases of the 

endangered Mississippi sandhill crane (Grus c. pulla), at the 

Mississippi Sandhill Crane NWR, were built near Lake Jackson and 

C-48
DRAFT Whooping Crane Recovery Plan 2005 

Lake Marian. In January 1993, the first group of 14 juvenile 

whooping cranes were transferred to Florida in a soft-release 

managed like previous sandhill crane releases in Mississippi 

(Ellis et al. 1992b) and Florida. The whooping crane population 

in Florida was designated experimental nonessential to increase 

flexibility of management (Lewis and Finger 1993). The objective 

of the first release was to evaluate release techniques and 

response of whooping cranes to the Florida habitat. At regular 

intervals released birds were recaptured and samples taken to 

evaluate exposure to disease and parasites. 

Whooping cranes were released in Florida habitats similar to 

those used by Florida sandhill cranes (Nesbitt and Williams 

1990). Shallow palustrine wetlands were used for roosting, 

foraging, loafing, and nesting. They also frequented upland 

habitats for foraging. Open grassy fields, usually grazed by 

livestock and/or used for sod production, provided abundant 

invertebrate and vertebrate food items. Live oaks and laurel 

oaks (Quercus spp.) provided seasonally abundant acorns. 

Marsh/pasture ecotones and lake edges provided a diversity of 

aquatic, semiaquatic, and upland food resources. 

Upon arrival and prior to release from the pens, whooping cranes 

were examined and treated with antihelmenthics to reduce the 

chance for introduction of exotic parasites. Most were 

vaccinated for eastern equine encephalitis and provided feed 

containing a coccidiostat. Three exotic parasites were found in 

early releases (Spalding et al. 1996), but their occurrence 

declined with additional anthelmentic treatment in Florida of 

subsequent releases. 

Two diseases, eastern equine encephalitis (EEE) and disseminated 

visceral coccidiosis (DVC) are of particular concern for the 

recovery of whooping cranes in Florida. Released whooping cranes 

are partly protected from these diseases by the current release 

protocol. DVC is caused by infection with a protozoan, Eimeria

spp., transmitted by fecal contamination of food. This disease 

is very prevalent in local sandhill cranes but illness and 

mortality are rarely observed in this species. Whooping cranes 

are given feed containing a coccidiostat during the time that 

they are in the pens and while they continue to use the pen area. 

Although disseminated granulomatous lesions are frequently found 

in whooping cranes killed by bobcats, severe lesions have only 

been recorded a few times. In two cases, DVC may have caused 

mortality, or predisposed birds to predation. Exposure of chicks 

to DVC is expected to be high, and research to determine its 

impact on chicks is needed. 

C-49
DRAFT Whooping Crane Recovery Plan 2005 

EEE virus is endemic in central Florida, although more common in 

the panhandle. Transmission is by mosquitoes but varies greatly 

from year to year being more common in wet years. Most whooping 

cranes released in central Florida are vaccinated prior to 

release. The vaccine titer wanes after about 6 months. Several 

cranes are believed to have been temporarily ill from EEE virus 

and have recovered when given supportive care. Exposure of newly 

hatched chicks is likely in years with high transmission. 

Maternal antibodies may provide some protection in chicks but 

more research is needed to elucidate risk factors. The drought 

in Florida from 1998-2002 reduced transmission of the disease and 

also the ability to study it. 

From 1993-2003, 268 isolation-reared whooping cranes were 

released in Florida, mostly as juveniles, and 87 survived in 

December, 2003 (Table 9). Predation by bobcats has been the 

primary mortality factor (Nesbitt et al. 1997). Other mortality 

factors, roughly in order of importance are: wasting syndrome 

associated with Infectious Bursal Disease virus infection (Julie 

Langenburg, pers. comm.), power line collision and electrocution, 

roost disturbance at night by boats and airboats, alligator 

predation, ingestion of metal and other objects (Spalding et al. 

1997, Folk et al. 2001), coyote predation, and monofilament 

entanglement. 

Egg production started in 1999, with 7 pairs producing eggs 

through 2003. The first chick was fledged in 2002. Wetlands in 

Florida experienced a drought during 1998-2002, reducing the 

potential for suitable nesting conditions. 

The drought is believed to have increased the dispersal range in 

recent years. The birds have ranged over much of peninsular 

Florida from near the Georgia border (Baker County) to the 

latitude of Lake Okeechobee (Palm Beach County) (Nesbitt et al. 

2001)(Fig. 7). One pair spent the summer and fall of 2000 in 

Michigan, and 1 subadult spent nearly 2 months in Virginia in 

2001. However, all birds that have dispersed have returned to 

central Florida. Releases will be continued to maintain the 

population near 100 birds while the Team continues to evaluate 

the project’s potential for establishing a self-sustaining 

population.

C-50
DRAFT Whooping Crane Recovery Plan 2005 

C-51

Table 9. Number of birds released and surviving in the Florida 

nonmigratory population, 1993–2002. 

 

Year Number 

Released 

Age Year end 

Population

Number 

Pairs 

Nesting 

Pairs 

Chicks 

Hatched

Chicks 

Fledged

1993 14 all < 1year 8 0 0 0 0 

1994 19 all < 1year 16 0 0 0 0 

1995 19 all < 1year 25 0 0 0 0 

1996 47 5=1.5y, 43=<1y 56 1 0 0 0 

1997 28 all < 1year 60 1 0 0 0 

1998 22 all < 1year 57 7 0 0 0 

1999 28 all < 1year 65 10 2 0 0 

2000 30 all < 1year 82 15 3 2 0 

2001 21 all < 1year 86 15 2 0 0 

2002 27 8=1.5y, 19=<1y 85 16 7 2 1 

2003 13 all < 1year 87 18 7 8 2 

TOTAL 268 

__________ 
DRAFT Whooping Crane Recovery Plan 2005 

C-52

Research on Reintroducing Migratory Populations

After cross-fostering proved unsuitable as a technique for 

reintroducing migratory populations of whooping cranes, the 

Whooping Crane Recovery Team identified the need for testing 

other techniques (U.S. Fish and Wildlife Service 1994). Since 

then, various modifications of leading captive-reared cranes with 

trucks, ultralight aircraft, and releasing them with migratory 

sandhill populations, have been tested (Nagendran 1992, Urbanek 

and Bookhout 1994, Nagendran et al. 1996, Ellis et al. 1997, 

2001a, Lewis 1999, Duff et al. 2001). Some projects utilized 

isolation-rearing with caretakers in crane costumes and another 

project (Clegg et al. 1997, Clegg and Lewis 2001) used group 

rearing of chicks to promote proper imprinting. Formerly, 

aggression was thought to be so severe as to prevent group 

rearing. 

Cranes can be led long distances behind motorized craft (air and 

ground), and those led over most or the entire route will return 

north in spring and south in fall to and from the general area of 

training (Ellis et al. 1997, Ellis et al. 2001b, Mummert et al. 

2001). However, they may follow their own route. Groups 

transported south and only flown at intervals may not migrate. 

Trained birds will not home on a captive site where they hatched 

but rather will return to the site where they were flown free and 

began their migration. Cranes can also be expected to return to 

the same (or nearby) wintering area the following fall. All 

birds need not follow the entire route south to return north if 

flock mates know the route. 

If cranes are field-reared and are to be introduced into a wild 

flock, costumes may not be necessary and cranes quickly learn to 

avoid humans (Clegg et al. 1997). Crane decoys can be used to 

hold cranes at roost sites before and during migration and at the 

release site after migration. The threat of losses to predators 

can be reduced with these decoys by influencing the cranes 

selection of roost sites and feeding locations (Clegg et al. 

1997, Clegg and Lewis 2001). 

If certain protocol restrictions are followed, it is possible to 

make the costume-reared cranes exhibit some wild behavior. The 

most efficient way to make trained cranes wild (e.g., not 

approach humans) is to release them (after migration) with wild 

cranes. 
DRAFT Whooping Crane Recovery Plan 2005 

C-53

In the western United States, golden eagle (Aquila chrysaetos) 

attacks were a problem (Ellis et al. 1999) both for ultralightled and for truck-led migrations. A major problem in the 

trucking migrations was collisions with power lines. During the 

2 trucking migrations, 3 cranes died and about 15 non-lethal 

collisions were observed. However, techniques were developed to 

diminish or eliminate these hazards (Ellis et al. 1997). 

It appears possible to restore or supplement wild migratory 

populations of cranes by first leading small groups from chosen 

northern to southern sites. Abruptly releasing cranes after 

migration results in good survival if they are released 1 or 2 at 

a time into a wild flock (Ellis et al. 2001c) or a whole group 

into a large wild flock (Clegg et al. 1997, Clegg and Lewis 

2001). 

Proposed Migratory Reintroductions

In 1996, the Recovery Team decided to investigate the potential 

for another reintroduction site in the eastern United States with 

the intent of establishing an additional migratory population. 

Separation between a new flock and the AWBP was considered 

important as a protection if a catastrophe hits one of the 

populations, to avoid transmission of disease, crossbreeding 

between the 2 populations, and the behavioral influence that 

cranes reintroduced from captivity could have on the wild flock 

(U.S. Fish and Wildlife Service 2001). Also, under Section 10(j) 

of the Endangered Species Act, reintroductions of experimental 

nonessential populations must essentially be kept separate from 

endangered populations. 

After a study of potential wintering sites (Cannon 1998), the 

Team selected the Chassahowitzka NWR/St. Martin’s Marsh Aquatic 

Preserve near Crystal River, Florida as the top wintering site 

for a new migratory flock. Although the habitat at Marsh Island, 

Louisiana appeared to be excellent, its location closer to the 

AWBP migration corridor was a key negative factor resulting in 

the selection of a site in Florida. 

Based on concerns that a reintroduced population in Saskatchewan 

or Manitoba might mix with the wild AWBP (Melvin and Temple 1980, 

Melvin et al. 1990, May 1992, Lyon et al. 1995a,b, Burke 1996, 

Hjertaas et al. 1997, DeSobrino 1998, Sommerfeld and Scarth 

1998), the Team considered summering areas further to the east of 

the AWBP migration corridor and requested the investigation of 

suitable sites in Wisconsin. 
DRAFT Whooping Crane Recovery Plan 2005 

C-54

After a list of potential areas was compiled, studies evaluated 3 

potential release sites: Crex Meadows State Wildlife Management 

Area, central Wisconsin including Necedah NWR and several 

Wisconsin WMAs, and Horicon NWR (Cannon 1999). The Recovery Team 

in September, 1999 recommended that releases start in central 

Wisconsin (Fig. 8). This recommendation was based on the 

presence of suitable habitat, food resources, and favorable local 

attitudes. 

A partnership of 9 founder organizations comprised of public 

agencies and private nonprofit organizations was formed and 

referred to as the Whooping Crane Eastern Partnership (WCEP). 

Founding members (alphabetically) include: 

* International Crane Foundation 

* International Whooping Crane Recovery Team 

* National Fish and Wildlife Foundation 

* Natural Resources Foundation of Wisconsin 

* Operation Migration, Inc. 

* US Fish and Wildlife Service 

* USGS National Wildlife Health Center 

* USGS Patuxent Wildlife Research Center 

* Wisconsin Department of Natural Resources 

The partnership extends beyond the list above. The huge scope of 

this migration requires united efforts spanning twenty states, 

seven of which lie in the migration corridor. WCEP was divided 

into sub-teams of Bird, Budget, Outreach, Regulatory and Flyway 

teams. A Project Direction team with key representatives from 

each agency serves as the final decision making body. Federal 

environmental documents were prepared and after publication in 

the US Federal Register, the eastern migratory population of 

whooping cranes was declared experimental non-essential under 

section 10(j) of the ESA. This action provides for greater 

management flexibility and reduces the regulatory requirements. 
DRAFT Whooping Crane Recovery Plan 2005 

Figure 8. Eastern United States experimental nonessential 

population area, with 2001 migration route. 

C-55
DRAFT Whooping Crane Recovery Plan 2005 

C-56

The plan is to release annually 10 to 25 juvenile, captive-reared 

whooping cranes in central Wisconsin (Anonymous 2000). Cranes 

will be captive-reared to 20-40 days of age at PWRC or ICF, 

before transfer to facilities at the Wisconsin release site, 

where they will be conditioned for wild release to increase postrelease survival (Ellis et al. 1992b) and adaptability to wild 

foods. They will be radio-tagged at release and monitored to 

discern movements, habitat use, other behavior, and survival. 

They would be released in fall and taught to migrate. Several 

strategies may be used to teach migration including: (1) leading 

them by ultralight aircraft to the chosen wintering site in 

Florida (Clegg et al. 1997, Lishman et al. 1997, Clegg and Lewis 

2001), (2) release with migrating wild whooping cranes or 

sandhill cranes, or (3) some combination of these or other 

techniques. If initial results are favorable, the releases would 

continue for at least 10 years. Experience with the RMP and FP 

provides insight that a minimum of 20 years may be needed for 

attaining self-sustaining populations. Thus, a 20-year project 

duration is listed in the Implementation Schedule. 

In fall 2001, 8 cranes started the migration behind an ultralight 

from Necedah NWR in central Wisconsin (Table 10). One bird would 

not follow well enough and was placed daily in a crate and 

trucked to the next roost site. One crane died hitting a power 

line at night after a severe storm blew the pen down and the 

birds escaped. The migration included 26 stops, covered 1,987 

kilometers, and took 50 days. The longest flight day covered 154 

km, and the longest flight lasted 2.15 hours. The shortest 

migration leg only lasted 38 minutes. Total flight time of the 

birds between Wisconsin and Florida was 35.8 hours. Bobcats 

killed two cranes during the winter at Chassahowitzka NWR. The 

remaining five migrated back on their own to central Wisconsin in 

spring, 2002. Four summered right at or near Necedah NWR, and 

one female summered about 80 miles to the southeast at Horicon 

NWR. 

In 2002, 17 whooping cranes raised at Patuxent were shipped to 

Wisconsin and trained to follow ultralight aircraft. One of the 

young cranes died from injuries received colliding with the 

ultralight in migration; the remaining 16 were led Florida (Table 

10). In the fall of 2002, the 5 surviving whooping cranes 

reintroduced in 2001 migrated south on their own. One spent a 

considerable time at Hiwassee Wildlife Refuge in Tennessee before 

joining another ultralight whooping crane in Florida, whereas the 
DRAFT Whooping Crane Recovery Plan 2005 

C-57

other 4 returned to Chassahowitzka NWR. In December, 2002, one 

had joined the 16 juveniles wintering at the release pen at 

Chassahowitzka, 2 were together with sandhills about 125 miles 

northeast of Chassahowitzka, and 2 were about 30 miles southeast 

of the refuge. 
DRAFT Whooping Crane Recovery Plan 2005 

C-58

Table 10. Number of birds released and surviving in the eastern 

population, 2001–2003. 

Year # Eggs # Young # # # # # Year end 

Hatched Shipped to Fledged Starting Finishing Surviving Migrated Population

Wisconsin Migration Migration Winter North 

2001 11 10 8 8 7 5 5 5 

2002 18 17 17 17 16 16 16 21 

2003 19 17 17 16 16 16 16 36 

__________ 
UNITED STATES

U.S. Fish and Wildlife Service

Aransas National Wildlife Refuge

PO Box 100

Austwell, Texas 77950

361/286-3559

http://www.fws.gov

CANADA

Recovery Secretariat

Canadian Wildlife Service

4th Floor PVM, 351 Joseph Blvd

Hull, QC KIA 0h3

819/953-1410

http://www.speciesatrisk.gc.ca/species/publications/plans/index_e.cfm

January 2005