U.S. Fish & Wildlife Service

Draft Recovery Plan 

for the Columbia Basin 

Distinct Population Segment 

of the Pygmy Rabbit

(Brachylagus idahoensis)

Photo by John Musser, provided courtesy of the Washington Department of Fish and Wildlife.
Draft Recovery Plan 

for the 

Columbia Basin Distinct Population Segment 

of the 

Pygmy Rabbit (Brachylagus idahoensis) 

Region 1 

U.S. Fish and Wildlife Service 

Portland, Oregon 

Approved: XXXXXXXXXXXXXXXXXXXXXXXXXXXX

Regional Director, U.S. Fish and Wildlife Service 

Date: ________________________________________ 
DISCLAIMER

Recovery plans delineate actions that are determined to be necessary to recover 

federally listed species. Plans are published by the U.S. Fish and Wildlife 

Service, and are often prepared with the assistance of recovery teams, contractors, 

State agencies, and others. Objectives will be attained and any necessary funds 

made available subject to budgetary and other constraints affecting the parties 

involved, as well as the need to address other priorities. Costs indicated for 

recovery action implementation and/or time for achievement of recovery 

objectives are only estimates and are subject to change. Recovery plans do not 

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

or agencies involved in plan formulation, other than the U.S. Fish and Wildlife 

Service. They represent the official position of the U.S. Fish and Wildlife Service 

only after they have been signed by the Regional Director as approved. Approved 

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

species status, and completion of recovery tasks. 

This document should be cited as follows:

U.S. Fish and Wildlife Service. 2007. Draft Recovery Plan for the Columbia Basin 

Distinct Population Segment of the Pygmy Rabbit (Brachylagus 

 idahoensis). Portland, Oregon. 118 pp. 

An electronic copy of this plan will be made available at:

http://endangered.fws.gov/recovery/index.html

ii 
ACKNOWLEDGEMENTS 

Columbia Basin Pygmy Rabbit Recovery Team Membership and 

Expertise 

Chris Warren, U.S. Fish and Wildlife Service 

Federal Recovery Coordinator, Endangered Species 

 

David Hays, Washington Department of Fish and Wildlife 

State Recovery Coordinator, Endangered Species 

Beau Patterson, Washington Department of Fish and Wildlife 

Surveys / Rangeland Management 

Lisa Shipley, Washington State University 

Habitat Use / Wildlife Nutrition / Captive Breeding 

Rodney Sayler, Washington State University 

Reintroduction / Monitoring / Population Ecology 

Linda Hardesty, Washington State University 

Rangeland Management / Extension Specialist 

Neal Hedges, U.S. Bureau of Land Management 

Surveys / Rangeland Management 

Chuck Warner, The Nature Conservancy 

Rangeland Management / Recovery Emphasis Area Manager 

Britt Dudek, Foster Creek Conservation District 

Rangeland Management / Agricultural Practices / HCP Development 

John Fleckenstein, Washington Department of Natural Resources 

Surveys / Rangeland Management 

Kevin Guinn, U.S. Natural Resources Conservation Service 

Rangeland Management / Agricultural Practices 

iii 
Past Member Participation

Jan Steele, Oregon Zoo 

Todd Thompson, Bureau of Land Management

iv 
EXECUTIVE SUMMARY

Current Status: The Columbia Basin distinct population segment of the pygmy 

rabbit (Brachylagus idahoensis) was listed as an endangered species by the U.S. Fish 

and Wildlife Service under an emergency regulation in 2001 (U.S. Fish and Wildlife 

Service [USFWS] 2001). The species was confirmed listed as endangered in 2003, 

without designation of critical habitat (USFWS 2003). The recovery priority number 

for the Columbia Basin pygmy rabbit is 3, on a scale from 1C (highest) to 18 

(lowest). The Washington Department of Fish and Wildlife began a captive breeding 

program for the Columbia Basin pygmy rabbit in 2001 (Washington Department of 

Fish and Wildlife [WDFW] 2001a). The Columbia Basin pygmy rabbit was 

considered to be extirpated from the wild in mid-2004. On March 13, 2007, 20 

captive-bred animals were reintroduced to habitats historically occupied by the

species in the Columbia Basin of central Washington. These captive-bred animals 

experienced a high level of predation over the first several weeks following their

release, and as of May 15, 2007, five of them remained alive. Just prior to the release 

effort there were 86 individuals included in a captive breeding program, 3 of which 

were purebred Columbia Basin animals. At least one wild-born, and likely captivebred kit (approximately 1-month old) has been documented at the release site. The 

remaining captive-bred female was also seen displaying nesting behavior. The

balance of the captive population and those recently released to the wild consist of 

intercross progeny from controlled matings between Columbia Basin pygmy rabbits 

and pygmy rabbits of the same taxonomic classification from a discrete population in 

Idaho. Intercross breeding has helped facilitate genetic restoration of the Columbia 

Basin pygmy rabbit and is considered essential for recovery efforts (USFWS 2006a). 

Currently, proposed measures to recover the Columbia Basin pygmy rabbit in the 

wild include additional releases of captive-bred progeny with at least 75 percent 

Columbia Basin ancestry. 

Habitat Requirements: Pygmy rabbits occur in the semiarid shrub steppe biome 

of the Great Basin and adjacent intermountain regions of the western United States. 

Within this broad biome, pygmy rabbits are typically found in habitat types that 

include tall, dense stands of sagebrush (Artemesia spp.), upon which they are 

highly dependent on for food and shelter throughout the year. The pygmy rabbit 

is one of only two rabbit species in North America that digs its own burrows and, 

therefore, is most often found in areas that also include relatively deep, loose soils 

that allow burrowing. 

v 
Historical Distribution: The pygmy rabbit has been present within the Columbia 

Basin ecosystem, a geographic area that extends from northern Oregon through 

central Washington, for over 100,000 years. This distinct population segment of the 

pygmy rabbit, which is the subject of this Draft Recovery Plan, is believed to have 

been disjunct from the remainder of the species’ range for at least 10,000 years, as 

suggested by the fossil record, and possibly as long as 40,000 to 115,000 years, as 

suggested by population genetic analyses. Museum specimens and sighting records 

indicate that the Columbia Basin pygmy rabbit likely occurred in portions of six 

Washington counties during the first half of the 1900s, including Douglas, Grant, 

Lincoln, Adams, Franklin, and Benton. 

Threats to Recovery: Large-scale loss and fragmentation of native shrub steppe 

habitats, primarily for agricultural development, likely played a primary role in the

long-term decline of the Columbia Basin pygmy rabbit. However, it is unlikely that 

these factors directly influenced the eventual extirpation of all known subpopulations 

from the wild. Once a population declines below a certain threshold, it is at risk of 

extirpation from a number of influences including chance environmental events (e.g., 

extreme weather), catastrophic habitat loss or resource failure (e.g., from wildfire or 

insect infestations), predation, disease, demographic limitations, loss of genetic 

diversity, and inbreeding. To varying degrees, all of these influences have impacted 

the Columbia Basin pygmy rabbit and, in combination, have led to the population’s 

endangered status. At the time of the U.S. Fish and Wildlife Service’s emergency 

listing action in 2001, the Columbia Basin pygmy rabbit was imminently threatened 

by its small population size, loss of genetic diversity, and inbreeding depression, 

coupled with a lack of suitable, protected habitats in the wild. 

Recovery Strategy: Due to a number of information gaps and other 

uncertainties in the available information, a phased approach for recovery 

planning has been proposed in this Draft Recovery Plan. The three general phases 

are: 1) removal or abatement of imminent threats to prevent the extinction of the 

Columbia Basin pygmy rabbit; 2) reestablishment of an appropriate number and 

distribution of free-ranging subpopulations over the near term; and 3) 

establishment and protection of a sufficiently resilient, free-ranging population 

that would be expected to withstand foreseeable long-term threats. The identified 

recovery strategy relies on effective adaptive management and is meant to be a 

dynamic process. To facilitate such a strategy, specific near-term (i.e., 2007 to 

vi 
2016) and more general long-term objectives and criteria have been established. 

In addition, revised implementation schedules will be developed, as necessary, to 

reflect the knowledge gained, accomplishments met, potential future constraints 

encountered, and consequent refinements to near-term recovery objectives, 

criteria, and/or actions as recovery progresses. 

Recovery Goal and Objective: The goal of this Federal recovery effort is to 

sufficiently abate threats to free-ranging Columbia Basin pygmy rabbits to ensure 

a high probability of the population’s persistence within their historical 

distribution over the foreseeable future. The long-term recovery objective is to 

increase the number, distribution, and security of free-ranging subpopulations of 

the endangered Columbia Basin pygmy rabbit so that it may be reclassified as 

threatened and ultimately removed from the List of Endangered and Threatened 

Wildlife and Plants pursuant to the Endangered Species Act. 

Recovery Criteria 

Downlisting Criteria: We will consider downlisting the Columbia Basin pygmy

rabbit if any of the following criteria have been met: (1) subpopulations at two 

recovery emphasis areas each have a five-year average Ne of at least 375 

individuals, and a third recovery emphasis area has been formally established 

through completion of one or more appropriate cooperative agreements and is 

available for initial reintroduction efforts; (2) a subpopulation at one recovery 

emphasis area has a five-year average Ne of at least of 250 individuals, and 

subpopulations at two other recovery emphasis areas each have a five-year 

average Ne of at least 125 individuals; or (3) a single subpopulation with a fiveyear average Ne of at least of 750 individuals has been reestablished through 

dispersal and range expansion from one or more recovery emphasis areas, and 

appropriate cooperative agreements have been reached to include the newly 

occupied habitats within the recovery emphasis area(s) involved and/or 

management measures to protect identified dispersal corridors have been 

implemented. 

Delisting Criteria: We have determined that defining credible delisting criteria is 

not possible at this time, given the uncertainties associated with the Columbia 

Basin pygmy rabbit, which include, in part, identifying appropriate density 

estimates, effective population size(s), dispersal corridor habitat and management 

vii 
conditions, effects of disease and predation, seasonal movement patterns, and the 

effectiveness of future captive breeding, genetics management, and reintroduction 

efforts. However, near term recovery objectives have been identified and 

appropriate recovery actions developed that would help provide this information, 

including: (1) ongoing surveys for free-ranging individuals or subpopulations; (2) 

augmenting the captive population with additional purebred Columbia Basin 

pygmy rabbits as available; (3) monitoring survival and movement of newly 

released Columbia Basin pygmy rabbits; (4) addressing existing constraints or 

management needs within recovery emphasis areas and appropriate intervening 

properties; and (5) annually updating specific methods and techniques in the 

Captive Breeding and Genetics Management Plan and Reintroduction Plan. 

Recovery Actions: 

Action 1: Manage the captive breeding program for the Columbia Basin 

pygmy rabbit. 

Action 2: Manage the genetic characteristics of the Columbia Basin 

pygmy rabbit. 

Action 3: Survey for and monitor free-ranging Columbia Basin pygmy 

rabbits. 

Action 4: Reestablish free-ranging Columbia Basin pygmy rabbit 

subpopulations within their historical distribution. 

Action 5: Protect free-ranging Columbia Basin pygmy rabbits. 

Action 6: Manage habitats at recovery emphasis areas to support stable, 

self-sustaining subpopulations of free-ranging Columbia Basin 

pygmy rabbits. 

Action 7: Pursue cooperative agreements for conservation of the 

Columbia Basin pygmy rabbit with landowners and managers 

within the population’s historical distribution. 

Action 8: Exchange information with stakeholders and the general public 

to address concerns and increase support for Columbia Basin

pygmy rabbit recovery efforts. 

Action 9: Secure funding for Columbia Basin pygmy rabbit recovery 

efforts. 

Action 10: Revise the Recovery Plan to facilitate implementation of 

adaptive management measures considered necessary to achieve 

the phased recovery strategy. 

viii 
Date of Recovery: It is not currently possible to estimate a date of recovery of this 

population because it is likely that only a few Columbia Basin pygmy rabbits 

currently survive in the wild, there are roughly only 100 individuals in captivity, and 

future reproduction of the captive animals and success of reintroduction efforts cannot 

yet be accurately predicted. 

Total Estimated Cost of Recovery: It is not currently possible to estimate 

the total cost of recovery. The estimated cost to implement all recovery actions

described in the Implementation Schedule over the next 10 years is $2,403,000. It 

may be assumed that continued, intensive management would be required for at

least the following decade at roughly half the cost.

Recovery Plan Time and Costs ($1000's) 

Table 1 

Recovery 

Action 

2007 2008 2009 2010 2011 2012 - 2016 TOTAL

1 172 172 172 81 81 250 928

2 9 9 9 7 14 7 55

3 5 10 15 10 10 25 75

4 77 77 77 47 57 210 545

5 10 10 10 30

6 16 31 36 26 61 140 310

7 60 85 59 34 34 80 352

8 5 5 5 5 5 25 50

9 5 5 5 5 5 25 50

10 2 2 2 2 8

TOTAL 359 206 390 217 269 762 $2,403

ix 
TABLE OF CONTENTS

DISCLAIMER ..................................................................................................ii 

ACKNOWLEDGEMENTS..............................................................................iii 

EXECUTIVE SUMMARY................................................................................ v 

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

A. Brief Overview and Status Summary ................................................ 1

B. Structure of the Draft Recovery Plan ................................................ 5

C. Species Description and Life History ............................................... 6

1. Taxonomy......................................................................................... 6

2. Physical Description ......................................................................... 7

3. Distribution........................................................................................ 7

4. Habitat and Diet................................................................................ 9

5. Burrowing Behavior ........................................................................ 10

6. Reproduction .................................................................................. 11

7. Home Range and Movements........................................................ 12

8. Mortality.......................................................................................... 13

D. Recovery Setting .............................................................................. 14

1. Geography...................................................................................... 14

2. Vegetation ...................................................................................... 14

3. Land Ownership and Use ............................................................... 16

E. Threats............................................................................................... 18 

F. Conservation Measures .................................................................... 26 

II. RECOVERY STRATEGY ........................................................................ 50 

III. RECOVERY GOALS, OBJECTIVES, AND CRITERIA.......................... 56 

A. Goal.................................................................................................... 57 

B. Objectives.......................................................................................... 57 

1. Near-term (2007-2016)................................................................... 57 

2. Long-term ....................................................................................... 58 

C. Recovery Criteria ............................................................................... 58 

1. Reclassification from Endangered to Threatened Status................ 60 

2. Removal from the List of Endangered and Threatened Wildlife and 

Plants ............................................................................................. 61 

x 
IV. RECOVERY PROGRAM........................................................................ 62 

Action 1: Manage the captive breeding program for the Columbia Basin 

pygmy rabbit. ...................................................................................... 62 

Action 2: Manage genetic characteristics of the Columbia Basin pygmy 

rabbit................................................................................................... 66 

Action 3: Survey for and monitor free-ranging Columbia Basin pygmy 

rabbits. ................................................................................................ 68 

Action 4: Reestablish free-ranging Columbia Basin pygmy rabbit 

subpopulations within their historical distribution. ............................... 70 

Action 5: Protect free-ranging Columbia Basin pygmy rabbits................ 75 

Action 6: Manage habitats at recovery emphasis areas to support 

stable, self-sustaining subpopulations of free-ranging Columbia Basin 

pygmy rabbits...................................................................................... 76 

Action 7: Pursue cooperative agreements for the Columbia Basin pygmy 

rabbit with land owners and managers of intervening properties within 

the population’s historical distribution. ................................................ 80 

Action 8: Exchange information with stakeholders and the general public 

to address concerns and increase support for Columbia Basin pygmy 

rabbit recovery efforts. ........................................................................ 82 

Action 9. Secure funding for Columbia Basin pygmy rabbit recovery 

efforts.................................................................................................. 83 

Action 10: Revise the Federal Recovery Plan to facilitate 

implementation of adaptive management measures considered 

necessary to achieve the phased recovery strategy. .......................... 84 

V. RECOVERY IMPLEMENTATION ........................................................... 85 

A. Definition of Action Priorities ............................................................... 86 

B. Listing, Reclassification, and Delisting Factors ................................... 86 

C. Action Duration and Responsible Parties ........................................... 87 

D. Estimated Costs for Recovery Actions................................................ 87 

E. Implementation Schedule ................................................................... 89 

VI. GLOSSARY ......................................................................................... 104 

VII. LITERATURE CITED .......................................................................... 107 

xi 
FIGURES AND TABLES 

Figure 1. Historic distribution of the pygmy rabbit......................................................3

Figure 2. Historic distribution of the Columbia Basin pygmy rabbit, appropriate 

soils and habitat intersect layers, which represent potentially occupied area, and 

recovery emphasis areas with 5-mile buffers...................................................................4

Figure 3. Genetic diversity of the purebred Columbia Basin population 

compared to the total captive population in the Columbia Basin pygmy rabbit 

captive breeding program, and genetic diversity of pygmy rabbits with different 

percentages of Columbia Basin ancestry ...............................................................................39 

Table 1. Recovery Plan Time and Costs, ($1,000s)......................................................viii 

Table 2. Columbia Basin pygmy rabbit captive breeding program by pygmy 

rabbit cohort, as of December 31, 2006...........................................................................29 

xii 
I. Background

A. BRIEF OVERVIEW AND STATUS SUMMARY 

The pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit species in North 

America. Historically, pygmy rabbits were found throughout the semiarid 

sagebrush steppe biome of the Great Basin and adjacent intermountain regions of 

the western United States, including portions of Oregon, California, Nevada, 

Utah, Idaho, Montana, Wyoming, and Washington (Figure 1). Pygmy rabbits in 

Washington represent the only population that occurs within the Columbia Basin 

ecosystem, an area that extends from north-central Oregon through central 

Washington (Quigley et al. 1997). This population, referred to as the Columbia 

Basin pygmy rabbit, has been discrete from the remainder of the species’ range 

for tens of thousands of years, and has been determined to be a distinct population 

segment under the Endangered Species Act of 1973, as amended (16 United 

States Code 1531 et. seq.) (United States Fish and Wildlife Service [USFWS]

2001). This determination is based on its genetic characteristics, which differ 

markedly from other population segments; its occurrence in the unique ecological 

setting of the Columbia Basin; and the significant gap in the current and historic 

range of the taxon that the loss of this population segment would represent 

(USFWS 2003a). 

Museum specimens and reliable sighting records indicate that the Columbia Basin 

pygmy rabbit probably occurred in portions of six Washington counties during the 

first half of the 1900s, including Douglas, Grant, Lincoln, Adams, Franklin, and 

Benton (Figure 2). This range has gradually diminished over the last century, 

until the few remaining subpopulations suffered a precipitous decline beginning in 

the late 1990s. Since 2004, no Columbia Basin pygmy rabbits have been found in 

the wild. The Washington Department of Fish and Wildlife (WDFW) initiated a 

captive breeding program for the Columbia Basin pygmy rabbit in 2001 (WDFW 

2001a). Just prior to release efforts, there were 86 individuals included in the

captive breeding program, 3 of which were purebred Columbia Basin animals. The 

balance of the captive population consists of intercross progeny from controlled 

matings between Columbia Basin pygmy rabbits and pygmy rabbits of the same

taxonomic classification from a discrete population in Idaho. 

1 
The Washington Wildlife Commission classified the pygmy rabbit as a State 

threatened species in 1990 (Washington Administrative Code (WAC) 232-12-

011), and reclassified the species as State endangered in 1993 (WAC 

232-12-014). 

On November 30, 2001, we, the U.S. Fish and Wildlife Service (Service), 

published an emergency rule to federally list the Columbia Basin pygmy rabbit as 

endangered (USFWS 2001). On March 5, 2003, we published a final rule listing 

the Columbia Basin pygmy rabbit as endangered, without critical habitat (USFWS 

2003a). Shortly after final listing, we assembled a multi-party Columbia Basin 

Pygmy Rabbit Recovery Team (Recovery Team) to assist with development of

this Draft Recovery Plan, and to otherwise advise us concerning Federal 

conservation measures for the Columbia Basin pygmy rabbit (see 

Acknowledgements, page iii, for Recovery Team membership and expertise). 

The recovery priority number for the Columbia Basin pygmy rabbit is 3, on a scale of 

1C (highest) to 18 (lowest) (USFWS 1983a and 1983b). This ranking is based on a 

high degree of threat, high potential for recovery, and classification as a distinct 

population segment under the Endangered Species Act. 

Definitions of key terms referenced within this Draft Recovery Plan are provided in 

the Glossary. 

2 
Figure 1. Historic distribution of the pygmy rabbit. 

3 
 

Figure 2. Historic distribution of the Columbia Basin pygmy rabbit, 

potentially occupied habitat (i.e., appropriate soils and habitat intersect 

layers), and recovery emphasis areas with 5-mile buffers (see text).

4 
B. STRUCTURE OF THE DRAFT RECOVERY PLAN 

There are currently a number of significant information gaps in our knowledge 

about pygmy rabbits in general and, more specifically, about how the Columbia 

Basin pygmy rabbit will respond to the ongoing and developing conservation 

strategies documented in this Draft Recovery Plan. As such, the available 

information does not currently allow for a long-term recovery plan to be 

developed or specific criteria to be defined that, when met, could ensure the 

population’s full recovery. Therefore, this Draft Recovery Plan prescribes a 

phased approach for recovery planning. This phased approach will allow for 

formulation and implementation of appropriate adaptive management measures as 

the information base concerning the Columbia Basin pygmy rabbit improves. 

Recovery of the Columbia Basin pygmy rabbit will require both effective 

adaptive management to determine optimal means to reestablish free-ranging 

subpopulations and sustained conservation measures to ensure the population’s 

long-term viability in the wild. 

The balance of this section documents the available information on the biology of 

the species as a whole, provides an overview of the recovery environment as 

context for this Draft Recovery Plan, and describes the current status of the 

Columbia Basin population. The remainder of the Draft Recovery Plan is divided 

into four main sections, as follows: 

Recovery Strategy: This section outlines the overall recovery strategy for 

the Columbia Basin pygmy rabbit. 

Recovery Goals, Objectives, and Criteria: This section establishes the 

general, long-term goal and objective that we anticipate will remain in place 

throughout the recovery process for the Columbia Basin pygmy rabbit. This 

section also establishes specific near-term (i.e., 2007 to 2016) recovery 

objectives. Finally, this section establishes a range of recovery criteria that, 

when met, could initiate Federal reclassification of the Columbia Basin 

pygmy rabbit from endangered to threatened status. 

Recovery Program: This section defines the detailed, near-term recovery 

actions that are considered necessary to advance the recovery process for the 

Columbia Basin pygmy rabbit to the next phase of recovery. 

5 
Recovery Implementation: This section documents the planned 

implementation of near-term recovery actions, including the parties likely 

responsible for implementing the actions; estimated costs, anticipated timing, 

and priorities for the actions; and which of the five listing factors will be

addressed by the actions. This section also documents the first of what will 

become a series of near-term Implementation Schedules. We will prepare 

revised Implementation Schedules, as necessary, to reflect the knowledge 

gained, accomplishments met, potential future constraints encountered, and

consequent refinements to near-term recovery objectives and/or actions as 

recovery progresses. The Implementation Schedule also provides a means to 

easily track the progress of the identified recovery actions. 

We plan to finalize this Draft Recovery Plan for the Columbia Basin pygmy 

rabbit following expert peer review, public comment, and incorporation of any 

necessary changes within 1 year of its publication. The Final Recovery Plan will 

be reviewed and updated periodically, as necessary, as research and management 

activities progress and as we gain further knowledge of the ecology and 

population biology of this species. The need for requisite data necessary to 

develop more precise and biologically accurate recovery criteria is recognized as 

a high priority, and specific actions to obtain this information have been 

identified. 

C. SPECIES DESCRIPTION AND LIFE HISTORY 

1. Taxonomy

The pygmy rabbit is a member of the family Leporidae, which includes hares and 

rabbits. The species has been placed in several genera since it was first classified 

in 1891 as Lepus idahoensis (WDFW 1995). In 1904, it was reclassified and 

placed in the genus Brachylagus, and in 1930, it was again reclassified and placed 

in the genus Sylvilagus. More recent examination of dentition (Hibbard 1963) 

and analysis of blood proteins (Johnson 1968) suggest that the pygmy rabbit 

differs significantly from species within either the Lepus or Sylvilagus genera. 

The pygmy rabbit is now generally considered to be within the monotypic genus 

Brachylagus, and is again classified as B. idahoensis (Green and Flinders 1980a; 

6 
WDFW 1995). There are no recognized subspecies of the pygmy rabbit 

(Dalquest 1948; Green and Flinders 1980a). 

2. Physical Description

The pygmy rabbit is the smallest Leporid in North America, with mean adult 

weights from 375 to about 500 grams (0.83 to 1.1 pounds), and lengths from 23.5 

to 29.5 centimeters (cm) (9.3 to 11.6 inches (in)) (Orr 1940; Janson 1946; Wilde 

1978; Gahr 1993; WDFW 1995; T. Katzner, Arizona State University, pers. 

comm. 2002). Females tend to be slightly larger than males. Pygmy rabbits 

undergo an annual molt. Their overall color is slate-gray tipped with brown. 

Their legs, chest, and nape (back of neck) are tawny cinnamon-brown, their 

bellies are whitish, and the entire edges of their ears are pale buff. Their ears are 

short (3.5 to 5.2 cm (1.4 to 2.0 in)), rounded, and thickly furred outside. Their 

tails are small (1.5 to 2.4 cm (0.6 to 0.9 in)), uniform in color, and nearly 

unnoticeable in the wild (Orr 1940; Janson 1946; WDFW 1995). The pygmy 

rabbit is distinguishable from other rabbit species by its small size, short ears, 

gray color, small hind legs, and lack of white on the tail. 

3. Distribution

The historical distribution of the pygmy rabbit included much of the semiarid, 

shrub steppe biome of the Great Basin and adjacent intermountain regions of the 

western United States (Green and Flinders 1980a), and included portions of 

Montana, Idaho, Wyoming, Utah, Nevada, California, Oregon, and Washington 

(Figure 1). Pygmy rabbits are not currently distributed continuously across their 

range, nor were they in the past. Rather, they are found in areas within their 

broader distribution where suitable habitats occur. The local distribution of 

suitable habitat patches, and thus pygmy rabbits, likely shifts across the landscape 

in response to various sources of disturbance (e.g., fire, flooding, grazing, crop 

production) combined with long- and short-term weather patterns. In the past, 

more dense vegetation along permanent and intermittent stream channels, alluvial 

fans, and sagebrush plains provided travel corridors and dispersal habitat for 

pygmy rabbits between appropriate use areas (Green and Flinders 1980a; Weiss 

and Verts 1984; WDFW 1995). Since European settlement of the western United 

States, more dense vegetation associated with human activities (e.g., fence rows, 

roadway shoulders, crop margins, abandoned fields) likely also provide avenues 

7 
for dispersal between local populations of pygmy rabbits (Green and Flinders 

1980a; Pritchett et al. 1987). 

The pygmy rabbit has been present within the Columbia Basin for over 100,000 

years (Lyman 1991; Lyman 2004). This population segment is believed to have 

been disjunct from the remainder of the species’ range since at least the early 

Holocene (10,000 to 7,000 years before present), as suggested by the fossil record 

(Grayson 1987; Lyman 1991; Lyman 2004), and possibly as long as 40,000 to 

115,000 years before present, as suggested by population genetic analyses 

(WDFW 2001a; K. Warheit, WDFW, pers. comm. 2002). The Columbia Basin 

pygmy rabbit likely had a broader distribution during the mid-Holocene (roughly 

7,000 to 3,000 years before present) (Lyman 1991; Lyman 2004). Gradual 

climate change affecting the distribution and composition of sagebrush habitat 

types is thought to have resulted in a reduction of the Columbia Basin pygmy 

rabbit’s range during the late Holocene (3,000 years BP to present) (Grayson 

1987; Lyman 1991; Lyman 2004). 

Columbia Basin pygmy rabbits were considered rare with local areas of 

occurrence within the Columbia Basin during the early 1900s (Dalquest 1948), 

although there is little comprehensive information available regarding their 

historical distribution and abundance within this region (WDFW 1995). Museum

specimens and reliable sighting records indicate that Columbia Basin pygmy 

rabbits probably occurred in portions of Douglas, Grant, Lincoln, Adams, 

Franklin, and Benton Counties, Washington, during the first half of the 1900s 

(Figure 2). 

Columbia Basin pygmy rabbits were thought to be extirpated from Washington 

during the mid-1900s, until a sighting was documented in Benton County in 1979. 

Intensive surveys in 1987 and 1988 located five small subpopulations in southern 

Douglas County. Three of the subpopulations were found on State lands and two 

were found on private lands (WDFW 1995). With the exception of the Benton 

County record, Columbia Basin pygmy rabbits have only been found in southern 

Douglas and northern Grant counties since the mid-1900s (WDFW 2000). 

The number of Columbia Basin pygmy rabbit subpopulations and active burrows 

in Washington has declined over the past two decades (WDFW 2001a). Four of 

the 5 subpopulations located in 1987 and 1988 were very small, with fewer than 

8 
100 estimated active burrows (WDFW 1995). The largest known subpopulation, 

located at the Sagebrush Flat site, had an estimated 588 active burrows in 1993, 

when it was considered to support fewer than 150 pygmy rabbits (Gahr 1993). 

While an additional subpopulation was discovered on private land in northern 

Grant County in 1997, three of the small subpopulations located in 1987 and 1988 

were extirpated during the 1990s, leaving just three known subpopulations in 

1999 (WDFW 2001a). 

 

One of the three remaining sites experienced a catastrophic fire in 1999 and 

declined to three active burrows, while the newly discovered site in Grant County 

declined for unknown reasons to two active burrows following the winter of 

1999-2000. These two subpopulations are now considered to be extirpated 

(WDFW 2001a). In addition, during the winter of 1997-1998, the number of 

active Columbia Basin pygmy rabbit burrows at the Sagebrush Flat site declined 

by approximately 50 percent, and continued to decline in following years 

(WDFW 2001a). Surveys of this last known subpopulation did not detect any 

animals in July 2004 (B. Patterson, WDFW, pers. comm. 2006), indicating that 

the Columbia Basin pygmy rabbit may have been extirpated from the wild. 

A captive breeding program for the Columbia Basin pygmy rabbit was initiated 

by the Washington Department of Fish and Wildlife in 2001 (WDFW 2001a). On 

March 13, 2007, 20 captive-bred animals were reintroduced to habitats 

historically occupied by the species in the Columbia Basin of central Washington. 

These captive-bred animals experienced a high level of predation over the first 

several weeks following their release, and as of May 15, 2007, five of them 

remained alive. Just prior to the initial release effort, there were 86 individuals

included in the captive breeding program, 3 of which were purebred Columbia Basin 

animals (USFWS 2007). The balance of the captive population and those recently 

released to the wild consist of intercross progeny from controlled matings between 

Columbia Basin pygmy rabbits and pygmy rabbits of the same taxonomic 

classification from a discrete population in Idaho (see Conservation Measures, p. 26). 

4. Habitat and Diet

Pygmy rabbits occur in a variety of semiarid, shrub steppe habitat types that are 

found throughout their historical distribution. Within these habitat types, pygmy

rabbits are typically found in areas that include the tallest (e.g., greater than 91 cm

9 
(36 in)), most dense (e.g., greater than 25 percent cover) stands of sagebrush 

(Artemisia spp.). Pygmy rabbits are highly dependent on sagebrush to provide 

both food and shelter throughout the year (Bailey 1936, Orr 1940, Green and 

Flinders 1980a, Weiss and Verts 1984, WDFW 1995, Davila 2004). 

The winter diet of pygmy rabbits is comprised of up to 99 percent sagebrush 

(Wilde 1978), which is unique among Leporids (White et al. 1982). During 

spring and summer in parts of their historical range, their diets consist of up to 51 

percent sagebrush, 39 percent grasses (particularly native bunch grasses, such as 

Agropyron spp. and Poa spp.), and 10 percent forbs (herbaceous plants) (Green 

and Flinders 1980b). There is evidence that pygmy rabbits preferentially select 

native grasses as forage during this period in comparison to other available foods. 

In addition, total grass cover relative to forbs and shrubs may be reduced within 

the immediate areas occupied by pygmy rabbits as a result of its use as a food 

source during spring and summer (Green and Flinders 1980b). The diets of 

pygmy rabbit populations likely change depending on the regions and specific 

habitat types they occupy (T. Katzner, pers. comm. 2002). 

5. Burrowing Behavior

The pygmy rabbit is one of only two Leporids in North America that digs its own 

burrows (Nelson 1909, Green and Flinders 1980a, WDFW 1995), the other being 

the volcano rabbit (Romerolagus diazi) found in central Mexico (Durrell and 

Mallinson 1970). As such, pygmy rabbits are most often found in areas that 

contain relatively deep (e.g., greater than 51 cm (20 in)), loose soils of windborne or water-borne origin that allow burrowing (Nelson 1909, Green and 

Flinders 1980a, WDFW 1995). Pygmy rabbits occasionally make use of natural 

cavities, holes in volcanic rock, rock piles, artificial structures, or burrows 

abandoned by other species, such as the yellow-bellied marmot (Marmota

flaviventris) or badger (Taxidea taxus) (Wilde 1978; Green and Flinders 1980a; 

WDFW 1995). As a result, pygmy rabbits may occur in areas of shallower or 

more compact soils that support sufficient shrub cover (Bradfield 1974). These 

atypical burrow sites, which are most often adjacent to areas containing dense 

sagebrush stands and deep soil conditions, may facilitate dispersal behavior and 

function as corridors between suitable habitats. During winter, pygmy rabbits 

make extensive use of snow burrows to access sagebrush forage (Bradfield 1974) 

10 
and to provide thermal cover while traveling among their underground burrows 

(Katzner and Parker 1997). 

Pygmy rabbits typically dig their burrows into gentle slopes or mound/intermound areas of more level or dissected topography (Wilde 1978; U.S. 

Department of Agriculture [USDA] 1991; Gahr 1993). Burrows frequently have 

multiple entrances, some of which are concealed at the base of large sagebrush 

plants (Janson 1946; Wilde 1978; Green 1979; Gahr 1993). Otherwise, individual 

burrows are relatively simple and shallow, often no more than 2 meters (6.6 feet) 

in length and usually less than 1 meter (3.3 feet) deep with no distinct chambers 

(Bradfield 1974; Green and Flinders 1980a; Gahr 1993). The diameter of burrow 

entrances in Washington averaged 19 centimeters (8 inches) (Gahr 1993). Small, 

shallow trenches typically found at burrow entrances are referred to as runways. 

Pygmy rabbits, especially juveniles, likely use their burrows as protection from

predators and inclement weather (Bailey 1936; Bradfield 1974). In general, the 

number of active burrows in an area increases over the summer as the number of 

juveniles increases. However, the number of active burrows is not directly related 

to the number of individuals in a given area because some individual pygmy 

rabbits appear to maintain multiple burrows, while some individual burrows are 

used by multiple individuals (Gahr 1993; WDFW 1995). 

6. Reproduction

Pygmy rabbits begin breeding the year following their birth and, in Washington, 

breeding occurs from February through June (Gahr 1993). Gestation of captive 

pygmy rabbits is from 22 to 24 days (Elias 2004), and females can produce from

one to four litters per year (Green 1978; Wilde 1978; Elias 2004). Kits emerge 

from their burrows at roughly 2 weeks of age, and average annual litter sizes in 

captivity ranged from 3.3 to 3.6 kits per litter at the time of emergence (Elias 

2004). Breeding appears to be highly synchronous in a given area, and juveniles 

are often identifiable to cohorts (Wilde 1978; Fisher 1979). 

Recent information on captive and wild pygmy rabbits indicates that females 

excavate specialized, cryptic “natal” burrows that are disassociated from their 

resident burrow systems (P. Swenson, Oregon Zoo, pers. comm. 2001; Elias 

2004; Rachlow et al. 2005). Recorded lengths of natal burrows from entrance to 

11 
nest ranged from 16.5 to 35.5 centimeters (7 to 14 inches). In the wild, natal 

burrows typically consist of a single entrance under a large sagebrush plant 

(Rachlow et al. 2005). Females begin to dig and supply nesting material (e.g., 

plucked fur, grass clippings) to these burrows several days prior to giving birth, 

and may give birth and nurse their young in the runway to the burrow’s entrance. 

After nursing, the young return to the burrow and the female fills the burrow 

entrance with loose soil and otherwise disguises the immediate area to avoid 

detection (Elias 2004; Rachlow et al. 2005). Captive pygmy rabbit females 

sometimes construct other “dead-end” burrows that appear to be associated with 

their natal burrows, and female pygmy rabbits may alter their defecation and 

latrine habits while pregnant or nursing (P. Swenson, pers. comm. 2001). 

Ongoing work with captive and wild pygmy rabbits should provide additional 

information concerning details of their reproductive strategy. 

7. Home Range and Movements

Pygmy rabbits have relatively small home ranges during winter, remaining within 

roughly 30 meters (98 feet) of their burrows (Orr 1940; Janson 1946; Gahr 1993; 

Katzner and Parker 1997), although some snow burrows may extend outward over 

100 meters (328 feet) (Bradfield 1974). Pygmy rabbits have larger home ranges 

during spring and summer (Orr 1940; Janson 1946; Gahr 1993; Katzner and 

Parker 1997). During the breeding season in Washington, females tend to make 

relatively short movements within a small core area and have home ranges 

covering roughly 3 hectares (7 acres); while males tend to make longer 

movements during this period, possibly in response to seeking out estrous 

females, resulting in home ranges covering roughly 20 hectares (50 acres) (Gahr 

1993). These home range estimates in Washington are considerably larger than 

for pygmy rabbits in other portions of their historical distribution (WDFW 1995; 

Katzner and Parker 1997). 

Recent records from studies in Idaho indicate that juvenile pygmy rabbits often 

undertake a single, rapid dispersal movement at 6 to 10 weeks of age, and that 

some juvenile animals may disperse over 10 kilometers (6 miles) during this 

period (Rachlow and Estes-Zumpf 2005). In addition, adult pygmy rabbits may 

disperse over 12 km (7.5 mi) between their more restricted, seasonal use sites. 

While these movements are considerably longer than those documented in 

previous studies (e.g., Green and Flinders 1979; Katzner and Parker 1998), it 

12 
should be noted that these are maximum estimates and there appear to be large 

differences in the propensity of individual pygmy rabbits to disperse, with many 

animals remaining relatively sedentary. Reflecting this, median recorded 

dispersal distances in Idaho were 1.1 kilometers (0.7 miles) and 3.0 kilometers 

(1.9 miles) for males and females, respectively (Rachlow and Estes-Zumpf 2005). 

Pygmy rabbits maintain a low stance, have a deliberate gait, and are relatively 

vulnerable in more open areas. They can evade predators by maneuvering 

through the dense shrub cover of their preferred habitats, often along established 

trails, or by escaping into their burrows (Bailey 1936; Severaid 1950; Bradfield 

1974). 

8. Mortality

The annual mortality rate of adult pygmy rabbits may be as high as 88 percent, 

and over 50 percent of juveniles may die within roughly 5 weeks of their 

emergence (Wilde 1978; WDFW 1995). However, the mortality rates of adult 

and juvenile pygmy rabbits can vary considerably between years, and even 

between juvenile cohorts within years (Wilde 1978). Starvation and 

environmental stress likely account for some mortality in wild pygmy rabbits 

(Wilde 1978), however, predation is generally considered to be the main cause of 

mortality (Wilde 1978; Green 1979). Potential predators include fossorial and 

terrestrial mammals, such as badgers, long-tailed weasels (Mustela frenata), 

coyotes (Canis latrans), and bobcats (Felis rufus), and a variety of avian 

predators, such as great horned owls (Bubo virginianus), long-eared owls (Asio 

otus), ferruginous hawks (Buteo regalis), northern harriers (Circus cyaneus), and 

common ravens (Corvus corax) (Janson 1946; Gashwiler et al. 1960; Green 1978; 

Wilde 1978; WDFW 1995; M. Hallet, WDFW, pers. comm. 2002). 

Population cycles are not known in pygmy rabbits, although local, rapid 

population declines have been noted in several states (Bradfield 1974; Weiss and 

Verts 1984; WDFW 1995). After initial declines, pygmy rabbit populations may 

not have the same capacity for rapid increases in numbers as other Leporids due 

to their close association with specific components of sagebrush ecosystems, and 

the relatively limited availability of their preferred habitats (Wilde 1978; Green 

and Flinders 1980b; WDFW 1995). 

13 
D. RECOVERY SETTING 

1. Geography

Elevations within the historical distribution of the Columbia Basin pygmy rabbit 

range from 113 meters (370 feet) above sea level at the Columbia River in 

northern Benton County to over 1,067 meters (3,500 feet) on the Waterville 

Plateau in Douglas County (Figure 2). The northern portion of this area has been 

heavily influenced by glacial activity and contains several large and numerous 

smaller coulees (i.e., ravine networks). Soils are typically thinner here than 

elsewhere in the area and contain numerous rocky outcrops. The Columbia River 

and its system of palisades and steep draws bound the western edge of the area. 

The central portion of the area is dissected by three east-west oriented ridge 

systems, which are the Beezley Hills to the north, the Frenchman Hills in the 

central region, and the Saddle Mountains to the south. The area between these 

ridge systems is generally flat to gently rolling and contains several dune 

complexes. The eastern portion of the area contains moderately rolling slopes, 

and several coulees transect the region, draining to the southwest. Finally, in the 

southern portion, the area is flat to gently rolling along the Columbia River, but 

rises into the Rattlesnake Hills at its extreme southern extent.

The Columbia Basin ecosystem lies within the rain shadow of the Cascade Range 

to the west and represents the northern-most extent of the semiarid, shrub steppe 

biome of the western United States. Precipitation is relatively light, ranging from

roughly 18 cm (7 in) in the southwest and lower elevations to over 30 cm (12 in) 

in the northeast and higher elevations. Approximately 65 percent of the 

precipitation falls from October through March. Average minimum and 

maximum daily temperatures are roughly -7 o and 2o

 Celsius (20o and 35o

Fahrenheit) in January and 13o

 and 31o C (55o and 88o F) in July (USFWS 1997). 

2. Vegetation

Native vegetation communities within the historical distribution of the Columbia 

Basin pygmy rabbit include a variety of arid and semiarid shrub steppe habitats, 

as well as sparsely scattered wetland and riparian habitats. In addition to naturally 

occurring vegetation, large expanses of irrigated crop fields and considerably 

more wetland and riparian habitat have been created as a result of the federally14 
sponsored Columbia Basin Irrigation Project that draws water from the Columbia 

River at Grand Coulee Dam (U.S. Bureau of Reclamation (USBR) 1998). Large 

dryland (i.e., non-irrigated) agricultural fields and smaller fields irrigated by 

private wells also occur within the population’s historical distribution, especially 

in the northern and eastern portions. 

Daubenmire (1988) classified the various native shrub steppe habitat types of the 

Columbia Basin ecosystem into zonal and edaphic (i.e., soil characteristics) series, 

as well as other unique types of plant associations including those found on talus 

slopes, cliffs, and dunes. The zonal habitat types occur on deep loamy soils and 

represent climatic climax communities. The edaphic habitat types are found 

within these zonal communities and differentiate at distinct soil type boundaries 

and/or gradate along geologic and climatic influences. The zonal habitat types 

and their management are of primary importance with regard to conservation of 

the Columbia Basin pygmy rabbit. 

Nearly the entire historical distribution of the Columbia Basin pygmy rabbit lies 

within the big sagebrush (Artemisia tridentata) – bluebunch wheatgrass 

(Agropyron spicatum) zonal habitat type. This habitat type consists of four well 

defined vegetation layers. The most prominent layer consists of various shrub 

species, principally big sagebrush, that are intermixed with a second layer 

comprised of a variety of tall perennial grasses, principally bluebunch wheatgrass. 

The third layer consists of low-lying perennial and annual grasses and forbs, 

which are usually less than 10.16 centimeters (4 inches) in height. Finally, the 

fourth vegetative layer is made up of a thin, fragile crust, called the cryptogam,

which occurs directly on the surface of the soil. Various lichen, moss, and 

liverwort species comprise this layer, which has important influences with regard 

to erosion susceptibility, moisture retention, and nutrient cycling. A small fraction 

of the population’s historical distribution, in the extreme northern portion, is 

within the threetip sagebrush (A. tripartita) - Idaho fescue (Festuca idahoensis) 

zone. This habitat type differs primarily by the substitution of the dominant shrub 

and grass species, but otherwise has similar characteristics to that of the big 

sagebrush - bluebunch wheatgrass zone. 

Cheat grass (Bromus tectorum), an exotic annual grass from Eurasia, has become

very widespread throughout the Columbia Basin ecosystem. In some areas it has 

replaced the native grass species amid the native shrubs and forbs, and can persist 

15 
indefinitely within these habitat types (Cassidy 1997). In other areas, shrubs are 

completely absent and cheat grass is essentially the only grass species that occurs. 

Such sites now represent newly formed grassland communities in portions of the 

population’s historical distribution (USFWS 1995). Cheat grass may affect the 

suitability of habitats used by the Columbia Basin pygmy rabbit (see Threats, p. 

18). 

Most of the non-irrigated agricultural lands within the population’s historical 

distribution are farmed to produce winter wheat and other small-grain crops, such 

as barley. A wide variety of crops are grown on the lands receiving irrigation and 

include wheat, alfalfa, corn, beans, potatoes, mint, apples, and grapes. These 

agricultural developments and the other broad-scale changes to the vegetation 

communities within the Columbia Basin have also had significant impacts on the 

assortment and relative abundance of various upland species. Some of these 

species are potential predators of the Columbia Basin pygmy rabbit, such as the 

coyote and common raven, which have done well with the land use changes in the 

region and their populations have likely increased from historical levels (see 

Threats, p. 18). 

3. Land Ownership and Use

Prior to European settlement and wide-spread development of agricultural fields 

within the Columbia Basin ecosystem, nearly the entire region consisted of native 

shrub steppe habitats. Presently, as much as 70 percent of these original native 

habitats within the population’s historical distribution have been converted for 

various uses, including agricultural, residential, industrial, and urban 

developments (Dobler 1996). In addition, most of the remaining undeveloped 

land within the population’s historical distribution is subject to a variety of other 

human influences, including livestock grazing, recreation, altered fire frequencies, 

and exotic species invasion. Much of the remaining undeveloped land within the 

population’s historical distribution is located on public properties managed by 

various Federal and State agencies. 

Major Federal lands within the historical distribution of the Columbia Basin 

pygmy rabbit include the Hanford Reach National Monument and the Saddle 

Mountain and Columbia National Wildlife Refuges managed by the Service; 

scattered ownership within the Jameson Lake, Douglas Creek, and Saddle 

16 
Mountains Management Areas managed by the U.S. Bureau of Land Management 

(BLM); scattered ownership associated with the Columbia Basin Irrigation 

Project managed by the U.S. Bureau of Reclamation; and the Hanford Site 

managed by the U.S. Fish and Wildlife Service and U.S. Department of Energy. 

Major State lands within the historical distribution of the Columbia Basin pygmy

rabbit include the Sagebrush Flat, Gloyd Seeps, Potholes, and Crab Creek 

Wildlife Areas managed by Washington Department of Fish and Wildlife; and 

scattered ownership managed by the Washington Department of Natural 

Resources. The Sagebrush Flat Wildlife Area was the last site known to support 

Columbia Basin pygmy rabbits in the wild. Most of these undeveloped public 

lands are managed to protect their natural resource values. Other major 

management objectives for these properties include oversight of livestock grazing 

leases, primarily by the Bureau of Land Management and the Washington 

Department of Natural Resources, and operating buffer zones for various sensitive 

Federal facilities, primarily by the U.S. Bureau of Reclamation and the U.S. 

Department of Energy. 

Non-governmental organizations and private land owners currently contributing 

to Columbia Basin pygmy rabbit recovery efforts (see Conservation Measures, p. 

26) include The Nature Conservancy in Douglas and Grant Counties and the 

Lancaster Family in northern Grant County. Most of the remaining area within 

the historical distribution of the Columbia Basin pygmy rabbit is in private 

ownership and managed primarily for irrigated and dryland crop production, 

livestock operations, and urban and rural developments (e.g., housing, 

commercial / industrial facilities, transportation corridors). 

17 
E. THREATS

Threats to the Columbia Basin pygmy rabbit are classified according to the five 

factors identified in section 4(a)(1) of the Endangered Species Act for 

consideration in listing, reclassification, and delisting decisions. The available 

information addressing each of these five factors is summarized below. 

Factor A – Present or threatened destruction, modification, or curtailment of 

habitat or range: Dryland and irrigated crop production has converted and 

fragmented large portions of the native shrub steppe habitats that were originally 

present within the Columbia Basin (Daubenmire 1988; Franklin and Dyrness 

1988; Dobler 1996; WDFW 1995; USBR 1998). In addition, urban and rural 

developments permanently remove native shrub steppe habitats. Columbia Basin 

pygmy rabbits cannot occupy these converted sites and, due to their relatively 

restricted movements, fragmentation of shrub steppe habitats severely limits the 

pygmy rabbit’s ability to disperse (Green and Flinders 1980b). The potential for 

maintenance, enhancement, and connectivity of appropriate shrub steppe habitats 

was an important near and long-term consideration during development of the 

recovery actions prescribed by this Draft Recovery Plan. 

A number of other, often interacting influences affect the remaining native shrub 

steppe habitats within the Columbia Basin, including altered fire frequencies, 

establishment of invasive plant species, recreational activities, and livestock 

grazing, as follows: 

Sagebrush is easily killed by fire, and when it occurs at increased frequency, fire 

can remove sagebrush from the vegetation community (Daubenmire 1988; 

WDFW 1995). Fire frequency has increased over portions of the remaining shrub 

steppe habitats within the Columbia Basin as a result of various influences, 

including the establishment of invasive plant species, unimproved road access, 

and certain recreational activities. Due to their reliance on tall, dense stands of 

sagebrush and associated shrub steppe vegetation, Columbia Basin pygmy rabbits 

cannot occupy frequently burned sites. Various nonnative, invasive plant species, 

such as cheatgrass (Bromus tectorum) and knapweed (Centauria spp.), have 

become well established throughout the Columbia Basin (Daubenmire 1988; 

Franklin and Dyrness 1988). Areas with dense cover of cheatgrass are apparently 

avoided by pygmy rabbits in Oregon (Weiss and Verts 1984), and these newly 

18 
established plant communities often provide fine fuels that can carry fires. 

Combined with widespread unimproved road access and informal recreational 

activities that can provide multiple sources of ignition, the establishment of nonnative, invasive plant species increases the risk of fire, and reduces the security 

and suitability of areas that could potentially support the Columbia Basin pygmy

rabbit (WDFW 1995). Controlling fire, the establishment of invasive plant 

species, and inappropriate recreational activities in areas potentially occupied by 

Columbia Basin pygmy rabbits were important considerations during 

development of the recovery actions proposed in this Draft Recovery Plan. 

Under certain circumstances, livestock grazing can negatively impact the 

Columbia Basin pygmy rabbit. The effects may depend on a variety of factors 

including livestock type, timing and duration of grazing, stocking densities, 

locations of water or mineral blocks, and other factors that may concentrate 

livestock use. Impacts to pygmy rabbits may include damage to burrow systems 

and possible direct mortality due to trampling (Rauscher 1997; N. Siegel, 

Washington State University, pers. comm. 2001; M. Hallet, pers. comm. 2002), 

altered movement and behavioral patterns (Gahr 1993; Siegel 2002), fewer 

available burrows (Siegel 2002), and decreased quantity and nutritional quality of 

forage species in grazed areas (Siegel 2004). It is currently unknown if humanaltered densities, distributions, or behaviors of other native or introduced species 

may negatively affect pygmy rabbits. For example, range management measures 

for deer (Odocoileus spp.) could concentrate their habitat use patterns, or 

providing water sources for various game-bird species could indirectly affect 

predator densities. Further study to develop appropriate recommendations for 

livestock grazing that could help avoid or minimize its potential impacts, as well 

as to monitor for any effects potentially due to management activities for other 

native or introduced species, were important considerations during development 

of the recovery actions proposed in this Draft Recovery Plan. 

Factor B – Overutilization for commercial, recreational, scientific, or educational 

purposes: We are currently unaware of any commercial use of pygmy rabbits, 

however, there are potential threats to the species due to inappropriate 

recreational, scientific, and/or educational management activities, as follows: 

Pygmy rabbits are often difficult to distinguish from species of cottontail rabbits 

(Sylvilagus spp.) (Garber 1993; WDFW 1995). Because of this, accidental 

19 
shooting of Columbia Basin pygmy rabbits may occur in association with hunting 

of other small game species in Washington (WDFW 1979). The use of hunting 

dogs in areas occupied by Columbia Basin pygmy rabbits may pose additional 

risks from harassment or direct injury. However, due to their typically restricted 

distribution and preference for dense habitats, combined with relatively few small 

game hunters in areas potentially occupied by Columbia Basin pygmy rabbits, the 

risks from accidental shooting by hunters or harassment and harm from hunting 

dogs is currently considered to be low (WDFW 1995). Near and long-term 

measures to monitor and protect Columbia Basin pygmy rabbits from hunting 

related impacts were considered during development of the recovery actions 

proposed in this Draft Recovery Plan. 

Investigations that require trapping, handling, translocation, and/or captivity of 

pygmy rabbits can result in mortality from several causes, including exposure 

(due to excessively high or low temperatures), direct injury from entanglement in 

traps, trap predation, intra-specific fighting, and capture stress (Bailey 1936; 

Severaid 1950; Wilde 1978; Gahr 1993; Rauscher 1997). Capture-related 

mortality rates (including recaptures) reported for pygmy rabbits are roughly 3 

percent (Gahr 1993), 5 percent (Wilde 1978), and 13 percent (Rauscher 1997). 

The mortality rate for one study approached 19 percent when records for 

recaptured animals were disregarded (11 deaths of 58 individuals), and all of the 

mortalities in this study occurred in just one portion of the study area (Rauscher 

1997). Trapping methods, daily and seasonal timing, study location, holding 

facilities, site security, and husbandry techniques may all affect the level of

capture-related mortality incurred. 

Currently, the Washington Department of Fish and Wildlife is leading efforts to 

manage a captive breeding program for the Columbia Basin pygmy rabbit (see 

Conservation Measures, p. 26). As of December 31, 2006, the estimated annual 

mortality of all captive pygmy rabbits that may be attributed to the captive 

breeding program, at least in part, is approximately 4 percent. Since only a few, 

recently released captive-bred individuals are believed to occur in the wild (see 

Reintroduction, p. 38), the captive breeding program is still essential to help 

ensure the long-term survival of the Columbia Basin pygmy rabbit, and the 

incidental mortality incurred in captivity is considered within acceptable limits 

with regard to Federal recovery objectives (USFWS 2003b). As we learn more 

20 
about this species, captive breeding protocols will be refined in an effort to further 

lower the incidental mortality rate associated with these activities. 

Some pygmy rabbit burrows are relatively shallow and may collapse when 

walked on by humans (Wilde 1978). In addition, some past investigations of 

pygmy rabbits have entailed the purposeful destruction of individual burrows 

and/or secondary disturbance to occupied areas while measuring vegetation and 

other site characteristics in the vicinity of active burrow systems (Janson 1946; 

Bradfield 1974; Green 1978; Wilde 1978; Gahr 1993; Gabler 1997; Rauscher 

1997). Human activity in occupied habitats may also attract the attention of 

predators, livestock, or other managed wildlife species, which could pose 

additional risks to Columbia Basin pygmy rabbits in the local area. It is unlikely 

that these activities have played a significant role in the long-term population 

decline and range reduction of the Columbia Basin pygmy rabbit. However, due 

to the projected near-term vulnerability of the population, these sources of 

potential disturbance and mortality were considered during development of the 

recovery actions proposed in this Draft Recovery Plan. 

Factor C –Disease and Predation: Pygmy rabbits often harbor a high parasite 

load (Gahr 1993; WDFW 1995), and some of these parasites, including ticks, 

fleas, and lice, can be vectors of disease. Episodes of plague and tularemia from

these vectors have been reported in populations of other rabbit species and often 

spread rapidly with high rates of mortality (Quan 1993). Severe disease 

epidemics have not been reported in pygmy rabbits, and parasites have not been 

viewed as a significant threat to the species (Green 1979; Gahr 1993). However, 

epizootics in wild animals are often very difficult to detect and disease can not be 

ruled out as a significant risk factor (D. Biggins, U.S. Geological Survey, pers. 

comm. 2002). 

A number of captive Columbia Basin pygmy rabbits have died as a result of 

various diseases, especially mycobacteriosis and coccidiosis (WDFW 2005a; 

Harrenstien et al. 2006). The bacterium that causes mycobacteriosis 

(Mycobacterium avium) commonly exists in soil and water, and can survive for 

long periods of time in soil. High numbers of the bacterium can also be shed in 

feces and urine. The incubation period for mycobacteriosis can be weeks to 

months, and detection of infected individuals is difficult. Preventive measures 

that have been taken for mycobacteriosis include regular monitoring of captive 

21 
pygmy rabbits to try and detect those that may be subclinically infected, 

quarantine of infected animals, removal of soil from contaminated pens, careful 

selection and testing of replacement soils, design changes to holding pens so that 

soils can be replenished more readily, husbandry and captive breeding of pygmy

rabbits in soil-free pens, use of larger holding sites that better mimic density 

conditions in the wild, dietary changes to improve the overall condition of the 

captive animals, and development of an appropriate treatment regimen. 

Comparisons of immune system function (i.e., lymphocyte stimulation and 

cytokine assays) among the Columbia Basin and Idaho pygmy rabbits, as well as 

the riparian brush rabbit (Sylvilagus bachmani riparius) and domestic rabbits 

(Oryctolagus spp.), have been undertaken (Harrenstien et al. 2006). In general, 

Columbia Basin pygmy rabbits had a significantly poorer immune response to 

mycobacteriosis than pygmy rabbits from Idaho and the other lagomorph species. 

A partially-ineffective cell-mediated immune response appears to be the most 

likely cause of their high mortality resulting from mycobacteriosis. A relationship 

between diminished genetic diversity (see Factor E, p. 25) and higher 

susceptibility to mycobacteriosis has been demonstrated for a number of other 

endangered species (Harrenstien et al. 2006). 

Coccidiosis is caused by a protozoan (likely Eimeria spp.) that occurs in soil and 

feces, and which invades the intestines and other tissues of animals. Coccidiosis 

may be most detrimental in neonate pygmy rabbits, as both adult and young 

animals can apparently remain free of the disease while harboring high levels of 

the coccidia. In addition to the soil treatments discussed above for 

mycobacteriosis, other preventative measures for coccidiosis include regular 

monitoring of coccidia levels and the prophylactic treatment of the captive pygmy 

rabbits, including breeding females, with antibiotics. If elevated coccidia levels 

are documented in any captive pygmy rabbits, they are further treated with 

antibiotics. The above measures appear to be effective at decreasing the 

incidence of coccidiosis in the captive population. Future monitoring for the 

occurrence and possible control of disease outbreaks in the wild and captive 

portions of the Columbia Basin pygmy rabbit population were important 

considerations during development of the recovery actions proposed in this Draft 

Recovery Plan. 

22 
Skeletal abnormalities have been detected in one wild-caught and ten captive-born 

Columbia Basin pygmy rabbits, as well as one intercross individual (WDFW

2004a). These abnormalities consist of missing or malformed metacarpal and 

metatarsal bones of the fore and hind feet, respectively. This unusual condition 

(i.e., brachydactyla) may be a result of inbreeding (Green 1935), and analyses to 

determine if, and to what extent, there may be a genetic component to the 

condition are ongoing. Preliminary assessment indicates that this condition is not 

a simple (i.e., single gene autosomal) recessive genetic trait. It is currently 

unclear whether the condition may be persistent within the captive population, or 

if it may represent any significant concerns for the fitness of affected individuals. 

A subset of pygmy rabbits remaining alive in the captive breeding program and, 

as feasible, all dead specimens are radiographed to further document the 

occurrence, extent, and possible cause of these abnormalities. 

Predation is thought to be the major cause of mortality among pygmy rabbits 

(Green 1979; Wilde 1978). However, pygmy rabbits have adapted to the presence 

of a wide variety of avian and terrestrial predators that occur throughout their 

historical distribution (Janson 1946; Gashwiler et al. 1960; Green 1978; Wilde 

1978; WDFW 1995). In relatively large, well distributed pygmy rabbit 

populations, predation is not likely to represent a significant threat to their longterm security. In contrast, due to the extremely small size and localized 

occurrence of the Columbia Basin pygmy rabbit population, altered predation 

patterns, or even natural levels of predation, currently represent a significant 

threat to reestablishment of this population segment in the wild and could impair 

ongoing conservation efforts. Habitat enhancement measures to provide 

appropriate cover, provision of artificial structures, and/or temporary predator 

control were important considerations during development of the recovery actions 

proposed in this Draft Recovery Plan. 

Factor D – Inadequacy of existing regulatory mechanisms: Washington 

classification of the pygmy rabbit as a State endangered species makes it illegal to 

hunt, possess, maliciously harass or kill, or to maliciously destroy the nests of 

pygmy rabbits, unless otherwise authorized by the Washington Wildlife 

Commission (Revised Code of Washington 77.15.120). However, this State 

designation does not provide regulatory protection from activities that may 

incidentally harm the Columbia Basin pygmy rabbit, nor does it provide 

regulatory mechanisms to protect habitat that may be considered essential to its 

23 
long-term security. Washington legislation (i.e., House Bill 1309) prescribes 

ecosystem standards for State-owned agricultural and grazing lands to maintain 

and restore fish and wildlife habitat by improving overall ecosystem health. 

However, these standards do not specifically address protection and conservation 

of the Columbia Basin pygmy rabbit, and are only mandated for lands under the 

jurisdiction of the Washington Department of Fish and Wildlife and the 

Washington Department of Natural Resources. In addition, application of the 

standards on lands managed by the Washington Department of Natural Resources 

must be consistent with the agency’s fiduciary obligations. 

Large areas of privately owned land within the historical distribution of the 

Columbia Basin pygmy rabbit have been withdrawn from crop production and 

planted to native and non-native cover under the Federal Conservation Reserve 

Program administered by the U.S. Department of Agriculture. Current 

revegetation standards under this program promote the improvement of habitats 

potentially used by the Columbia Basin pygmy rabbit. The program also restricts 

livestock grazing on contract lands except under severe drought conditions (M. 

Ruud, Farm Service Agency, pers. comm. 2001). However, the measures 

prescribed under this program do not specifically address conservation of the 

Columbia Basin pygmy rabbit, participation is voluntary, contracts expire after 10 

years, and changes to program requirements and management objectives at each 

renewal period are common (US Department of Agriculture [USDA] 1998). 

Presently, it is unclear what effects recent program changes have had, or future 

changes may have, on recovery efforts for the Columbia Basin pygmy rabbit. 

We are currently providing technical assistance to the Foster Creek Conservation 

District toward development of a county-wide Habitat Conservation Plan (HCP) 

for private agricultural interests (i.e., irrigated and dryland crops, fruit orchards, 

vineyards, and livestock ranching) throughout Douglas County, Washington. The 

plan would include protection measures for a number of important wildlife 

species, including the Columbia Basin pygmy rabbit, and the management 

measures it prescribes would complement other, ongoing conservation efforts in 

central Washington. However, the conservation measures prescribed by the plan 

have not yet been formally adopted, and would only apply to a portion of the 

historical distribution of the Columbia Basin pygmy rabbit if finalized. 

24 
The establishment, protection, maintenance, and enhancement of recovery 

emphasis areas for the Columbia Basin pygmy rabbit (see Conservation 

Measures, p. 26), as well as other shrub steppe habitats on Federal and nonFederal lands that may help facilitate recovery efforts, were important 

considerations during development of the recovery actions proposed in this Draft 

Recovery Plan. 

Factor E – Other natural or human-caused factors affecting the population’s 

continued existence: The most immediate concerns for the Columbia Basin 

pygmy rabbit are associated with the population’s extremely small size and 

possible extirpation from the wild (USFWS 2003a). Small populations are highly 

susceptible to random environmental events (e.g., severe storms, prolonged 

drought, extreme cold spells), abrupt changes in cover or food resources (e.g., 

from wildfire or insect infestations), altered predator or parasite populations, 

disease outbreaks, and fire. These influences represent a significant risk to the 

population’s potential reestablishment and long-term security in the wild (WDFW 

1995). Small populations are also more susceptible to demographic and genetic 

limitations (Shaffer 1981). These threat factors, which may act in concert, 

include natural variation in survival and reproductive success of individuals, 

chance disequilibrium of sex ratios, changes in gene frequencies due to genetic 

drift, and diminished genetic diversity and associated effects due to inbreeding. 

The captive, purebred Columbia Basin pygmy rabbits have not reproduced well 

enough to accommodate reintroduction efforts, and only a minimal number of 

purebred animals have been available for breeding efforts since the program’s 

first breeding season in 2002. In addition, the captive, purebred portion of the 

Columbia Basin pygmy rabbit population has experienced a loss of genetic 

diversity as a result of inbreeding (i.e., loss of genetic heterozygosity) and genetic 

drift (i.e., loss of alleles) (WDFW 2004a). The successful implementation of a 

captive breeding program and a comprehensive reintroduction program, both of 

which include appropriate genetics management planning (see Conservation 

Measures, p. 26), were important considerations during development of the 

recovery actions proposed in this Draft Recovery Plan. 

Threats Summary: The large-scale loss and fragmentation of native shrub steppe

habitats, primarily for agricultural development, have likely played a primary role in

the long-term decline of the Columbia Basin pygmy rabbit. However, it is unlikely 

25 
that these factors directly influenced the eventual extirpation of all known 

subpopulations from the wild. Once a population declines below a certain threshold, 

it is at risk of extirpation from a number of influences including chance

environmental events, catastrophic habitat loss or resource failure, predation, disease, 

demographic limitations, loss of genetic diversity, and inbreeding depression. To 

varying degrees, all of these influences have impacted the Columbia Basin pygmy 

rabbit and, in combination, have led to the population’s endangered status. At the 

time of our emergency listing action in 2001, the Columbia Basin pygmy rabbit was 

imminently threatened by its small population size, loss of genetic diversity, and 

inbreeding depression, coupled with a lack of suitable, protected habitats in the wild. 

F. CONSERVATION MEASURES 

As the State agency responsible for managing wildlife species, the Washington 

Department of Fish and Wildlife has undertaken a variety of conservation 

measures for pygmy rabbits since 1979. These efforts have included population 

surveys, habitat inventory, land acquisition, habitat restoration, land management 

agreements, initial studies on the effects of livestock grazing, and predator 

control. Despite these efforts, in 2001 they concluded that attempting to manage 

the State’s remaining pygmy rabbits in the wild would encumber the population 

with extreme risk due to the array of threats it faced. To address this risk, the 

agency determined that intervention, by way of a captive breeding program and 

reintroduction efforts, was necessary to prevent the extirpation of pygmy rabbits 

from the State. They have since contracted with captive breeding facilities at 

Washington State University, the Oregon Zoo, and Northwest Trek Wildlife Park 

to assist with captive breeding efforts. Washington Department of Fish and 

Wildlife also convened a multi-party Science Team comprised of individuals from

the captive breeding facilities, the Washington Department of Fish and Wildlife, 

and the Service to provide technical advice for the pygmy rabbit conservation 

program. Science Team members provide expertise in a broad range of 

disciplines, including husbandry, veterinary medicine, genetics, wildlife nutrition, 

population biology, ecology, and endangered species conservation. As necessary, 

the Science Team also consults on an ad hoc basis with experts from other 

research institutions. 

Following Federal listing of the Columbia Basin pygmy rabbit in 2001, we issued 

an endangered species recovery permit (TE-050644-3) to the Washington 

26 
Department of Fish and Wildlife pursuant to section 10(a)(1)(A) of the 

Endangered Species Act (USFWS 2003b). The recovery permit exempts 

incidental take of the Columbia Basin pygmy rabbit, that could occur as a result 

of the State's captive breeding efforts, which would otherwise be prohibited by 

section 9 of the Endangered Species Act. The recovery permit includes a 

requirement for annual reporting of activities conducted under the permit. The 

Annual reports include, in part, an introduction addressing reasons and objectives 

for taking the species; a methodology section addressing data collection and 

analysis procedures; a results section that provides the data collected, including 

information on any other federally listed species detected while conducting 

activities pursuant to the permit; and a conclusion section that specifically 

provides recommendations for recovery of the Columbia Basin pygmy rabbit. 

Captive Breeding: During fall 2000, the Washington Department of Fish and 

Wildlife, in cooperation with the Oregon Zoo, initiated studies of husbandry and 

captive breeding techniques using seven wild-caught pygmy rabbits (three female, 

four male) from southeastern Idaho (WDFW 2001a). These studies were 

undertaken to improve the information base for anticipated captive breeding and 

reintroduction efforts for the Columbia Basin pygmy rabbit. Due to concerns 

over limited housing capacity for all of the offspring at the Oregon Zoo, and to 

further develop pygmy rabbit husbandry expertise, a number of captive Idaho 

pygmy rabbits were moved to facilities at Washington State University and 

Northwest Trek Wildlife Park. In 2002, Washington State University also 

initiated studies to investigate reintroduction techniques using the Idaho pygmy

rabbits (see Reintroduction, p. 38). Over three breeding seasons from 2001 

through 2003, the 7 wild-caught Idaho pygmy rabbits and their progeny produced 

roughly 30 litters, totaling approximately 90 offspring (Science Team, 2004). 

During spring 2001, the Washington Department of Fish and Wildlife, in 

cooperation with Washington State University, expedited their captive breeding 

program for the Columbia Basin pygmy rabbit (WDFW 2001a). The program

was expedited due to the sudden extirpation of five of the last six subpopulations 

and the dramatic decline in the last known subpopulation of Columbia Basin 

pygmy rabbits during the winter of 2000 to 2001. The immediate goal of the 

program was to capture up to 20 reproductively active Columbia Basin pygmy

rabbits to establish a captive breeding population. The actual number and type 

(i.e., gender, age) of animals taken from the wild was based partly on information 

27 
28 

from the concurrent studies of Idaho pygmy rabbits, partly on preliminary 

estimates of what was needed to appropriately manage this population’s unique 

genetic profile, and partly on the availability of animals for capture. At the time, 

the Columbia Basin pygmy rabbits that were left in the wild were not considered 

essential to the captive breeding program, and ongoing efforts to manage them in 

place were continued. 

Between May 7, 2001, and January 15, 2002, 16 Columbia Basin pygmy rabbits 

(9 female, 7 male) were captured and removed from the last known subpopulation 

as an initial source for captive breeding efforts. Shortly after her capture, one 

female also gave birth to a litter of five offspring (two female, three male) that 

were conceived in the wild. Three of these 21 animals died prior to the first 

breeding season, bringing the total number of Columbia Basin pygmy rabbits 

available for initial captive breeding efforts to 18. In order to reduce the risk of 

catastrophic loss of the single captive population at Washington State University 

(e.g., from disease epidemic, predator access, vandalism) and to improve the 

efficiency of captive rearing efforts, seven of the wild-caught Columbia Basin 

pygmy rabbits were placed at the Oregon Zoo facility prior to the 2002 breeding 

season. Northwest Trek Wildlife Park was added as a third captive breeding 

facility for the Columbia Basin pygmy rabbit prior to the 2004 breeding season. 

These additional facilities provided the needed capacity to house a sufficient 

number of animals for the captive breeding program, improved the efficiency of 

captive rearing efforts, and further reduced the risk of losing a large proportion of 

the captive population at any one facility. 

Over 4 breeding seasons from 2002 through 2005, the 18 Columbia Basin pygmy 

rabbits entering the initial captive breeding season and their progeny have 

produced roughly 22 purebred litters, totaling approximately 79 offspring. As of 

December 31, 2006, 92 purebred Columbia Basin pygmy rabbits in the captive 

breeding program have died from a variety causes, leaving just 3 purebred 

animals available for the 2007 breeding season (Table 2). 

Various procedures have been implemented at the captive breeding facilities to 

reduce the risk of mortality to the captive pygmy rabbits, including updated 

protocols to reduce distress in newly captive animals, design changes to holding 

and breeding pens, regular replenishment of soils, soil-free rearing, antiseptic 

washing of water bowls and the use of distilled water, dietary adjustments, 
Table 2. Causes of mortality in the Columbia Basin pygmy rabbit captive breeding program by pygmy rabb

as of December 31, 2006. 

 Cohort →Cause of Death ↓

Wildbred 

[21] 

2002 

CB

[19] 

2003 

CB

[17] 

2004 

CB 

[26] 

2005*

CB 

[12] 

2003 

B1+ 

[23] 

2004 

B1+ 

[9] 

2005 

B1+ 

[24] 

2006 

B1+ 

[2] 

2004 

B2+

[34] 

20

B

[9

Disease

 Mycobacteriosis 15 5 3 3 0 4 0 0 0 0 

Coccidiosis 0 4 1 0 0 2 1 0 0 3 

 Other Disease 1 0 1 0 0 0 0 0 0 0 Maternal Neglect 0 0 3 5 5 9 0 0 0 3 1Trauma 2 2 1 2 0 3 4 1 0 0 Unknown 3 8 7 14 7 5 3 15 2 21 4Total Deaths 21 19 16 24 12 23 8 16 2 27 6Remaining Alive 0 0 1 2 0 0 1 8 0 7 2

B1+ = > 50 percent < 75 percent Columbia Basin Ancestry; 

CB = Captive-bred Columbia Basin Pygmy Rabbits 

* = No purebred progeny were produced in 2006. 

B2+ = > 75 percent Columbia Basin Ancestry. 

[n] = Total number in cohort. 

29
research on disease in pygmy rabbits and development of appropriate treatment 

regimens, and increased scrutiny and outreach to prevent undue disturbance of the 

captive animals. Prior to 2007, the annual mortality of all captive pygmy rabbits 

(exclusive of the purebred Idaho animals) that may be at least partially attributed 

to the captive breeding program (e.g., trauma, escape) is roughly 4 percent 

(USFWS 2007). This level of incidental mortality is considered within acceptable 

limits with regard to Federal recovery objectives (USFWS 2003b). As new 

information becomes available, captive breeding protocols will continue to be 

refined to further lower the incidental mortality associated with these activities, as 

feasible. 

Since the captive breeding program began, only a minimal number of purebred 

Columbia Basin pygmy rabbits have been available each breeding season,

primarily because the captive animals have not been reproducing as well as 

expected (Elias 2004; WDFW 2005a). For comparative purposes, 78 percent of 

all wild-caught Idaho pygmy rabbits contributed to reproduction, versus only 44 

percent of all wild-caught Columbia Basin pygmy rabbits (WDFW 2006). In 

addition, 66 percent of the Idaho pairings resulted in confirmed pregnancies, 

versus only 20 percent for the Columbia Basin pairings. Behaviorally, Columbia 

Basin pygmy rabbits also take eight times longer after initial pairing to begin 

reproductive behaviors, and spend five times longer performing reproductive 

behaviors once started. Finally, the period of successful breeding was roughly 1.5 

months longer for the captive Idaho pygmy rabbits (March to early June) 

compared to the captive Columbia Basin pygmy rabbits (March to mid-April). As 

a result, while the size and survival of litters were similar between the two groups, 

the total number of kits produced relative to the number of females in each 

captive population was nearly 2.5 times greater for the Idaho females. 

There are several lines of evidence from ongoing studies that suggest the 

Columbia Basin pygmy rabbit is suffering from inbreeding depression, including 

the poor reproductive performance discussed above, the potential for increased 

susceptibility to disease compared to Idaho pygmy rabbits and other lagomorph 

species (WDFW 2005a; Harrenstien et al. 2006), the existence of unusual skeletal 

abnormalities (WDFW 2004a), the documented decline in genetic diversity in the 

wild, and the continued loss of genetic variability in captivity (see Genetics 

Management, p. 31). Given the constraints that became apparent during the first 

30
several years of the captive breeding program, reintroduction planning for the 

Columbia Basin pygmy rabbit was postponed until these constraints could be 

further investigated and appropriate management measures implemented to 

address them. 

Genetics Management: In 2000, the Washington Department of Fish and Wildlife 

began population genetic analyses of contemporary pygmy rabbit samples from

Washington, Idaho, and Montana, and museum skin samples from Washington, 

Idaho, and Oregon (WDFW 2001b). Analyses have included both mitochondrial 

and nuclear DNA markers. Results of the genetic analyses indicate that the 

Columbia Basin pygmy rabbit is genetically distinct from, and has reduced 

genetic diversity compared with, the other pygmy rabbit populations. Analyses 

also indicate that the Columbia Basin pygmy rabbit likely had lower genetic 

diversity historically compared to the other populations. 

Information regarding the genetic characteristics of the Columbia Basin pygmy

rabbit within its historical distribution is limited. However, based on comparisons 

of museum and contemporary samples, the genetic diversity of the Columbia 

Basin pygmy rabbit in the wild has declined over the past 50 years (WDFW

2001b). In addition, the genetic characteristics of the offspring from the single 

wild-caught pregnant female demonstrate the probable inbred nature of the last 

known subpopulation of the Columbia Basin pygmy rabbit. Analyses of these 

offspring show that their genetic markers were identical, and this single 

documented genotype in the offspring was nearly identical to that of their mother. 

This strongly suggests that the wild parents of this litter were closely related. 

Ongoing genetic analyses of the captive-bred animals, initiated in 2001, indicate 

that the genetic diversity of purebred Columbia Basin pygmy rabbits has 

continued to decline in the captive population. As a result, the captive, purebred 

portion of the Columbia Basin pygmy rabbit population has experienced a loss of 

genetic diversity as a result of inbreeding and genetic drift (WDFW 2004a). 

Due to the poor demographic, behavioral, physiological, and genetic outlook for 

pure Columbia Basin pygmy rabbit breeding efforts, the Washington Department 

of Fish and Wildlife undertook initial attempts to intercross Columbia Basin 

pygmy rabbits with Idaho pygmy rabbits during the 2003 breeding season 

(WDFW 2003). These initial intercross breeding efforts were proposed on an 

experimental basis to address several basic issues, including the behavioral and 

31
reproductive compatibility between the two populations and the viability of any 

resulting intercrossed progeny. Results from the 2003 breeding season indicated 

that the reproductive behaviors and physiology of the two populations were 

compatible and that they could produce viable intercrossed progeny. These initial 

efforts followed the recommendations of the Science Team, and were closely 

coordinated with us to ensure consistency with our controlled propagation policy. 

The policy requires, in part, that captive breeding strategies are only employed 

when efforts to maintain or improve a listed species' status in the wild have failed, 

are determined to be likely to fail, are shown to be ineffective in overcoming 

extant factors limiting recovery, or would be insufficient to achieve full recovery 

(USFWS 2000). The initial intercross breeding efforts were undertaken to better 

assess the full range of possible recovery measures that could be pursued for the 

Columbia Basin pygmy rabbit. Results of these efforts confirmed the potential 

for genetic restoration of the Columbia Basin pygmy rabbit through careful, 

controlled efforts to compensate for the lack of genetic variability in the purebred 

population. 

Following further coordination with the Science Team, Service, Recovery Team, 

and the Washington Department of Fish and Wildlife, the scope of the intercross 

strategy beginning with the 2004 breeding season was broadened (WDFW 

2004a). The 2006 management priorities for the captive breeding program 

(WDFW 2006) were to: 1) maintain the genetic diversity present within the 

founding purebred Columbia Basin animals by pairing the most genetically 

appropriate (e.g., underrepresented, less closely related) animals; 2) produce 

additional purebred Columbia Basin pygmy rabbits to help ensure the 

population’s continued contribution to the captive breeding program; 3) produce 

additional 75 percent or greater intercross progeny by pairing purebred Columbia 

Basin pygmy rabbits and/or later-generation intercross progeny; 4) de-emphasize 

breeding individuals that are disproportionately related to the founding Idaho 

pygmy rabbits; and 5) conduct additional experimental breeding efforts to 

improve the success of the program (e.g., alternate breeding pen configurations, 

off-soil breeding, artificial insemination). Presently, there are no plans to conduct 

additional first-generation intercross pairings (i.e., produce additional 50 percent 

progeny) (WDFW 2006). As of December 31, 2006, the captive breeding 

program for the Columbia Basin pygmy rabbit consisted of 3 purebred animals 

and 95 intercross animals, of which 86 have at least 75 percent Columbia Basin 

ancestry (Table 2). 

32
In general terms, the phenomenon of “genetic rescue” involves an increase in 

fitness of a genetically compromised population by the infusion of increased 

genetic variation from immigrants of a donor population. Efforts to affect and/or 

document genetic rescue have been undertaken for isolated populations of various 

taxa (Tallmon et al. 2004), including the Florida panther (Puma concolor coryi) 

(Hedrick 1995), prairie chicken (Tympanuchus cupido) (Westermeier et al. 1998), 

Atlantic salmon (Salmo salar) (Waser and Strobeck 1998), adder (Vipera berus) 

(Madsen et al. 1999), white campion (Silene alba) (Richards 2000a), an 

Amazonian tree (Dinizia excelsa) (Dick 2001), Scandinavian wolf (Canis lupus) 

(Vila et al. 2003), and Eurasian otter (Lutra lutra) (Arrendal et al. 2004). This 

phenomenon has also been widely documented in a variety of animals and plants 

under experimental settings and for numerous domesticated animal breeds and 

plant varieties (Vogt et al. 1993; Richards 2000b; Hartwell 2003; Tallmon et al.

2004; Northcutt et al. 2004; Waite et al. 2005; Dalton 2005). 

In the classic sense, genetic rescue implies the removal of inbreeding depression 

from a population (i.e., elimination of the effects from deleterious genetic 

variants). However, concerns have been expressed regarding this limited 

interpretation of genetic rescue as a management strategy for imperiled taxa 

(Hedrick 2005). These concerns have encompassed the potential effects due to 

outbreeding depression from genetic rescue efforts (i.e., loss or reduction of 

locally adaptive genetic variants) (Maehr and Lacy 2002; Pimm et al. 2006), and 

the complex nature, management discretion, and potential controversy inherent to 

many naturally occurring and human-facilitated intercross events (Allendorf et al.

2001; Tallmon et al. 2004; Cowlishaw et al. 2006). Concerns have also been 

expressed regarding the potential for inappropriate management decisions if 

genetic factors are not sufficiently identified and addressed during recovery 

efforts for imperiled species (Frankham 2003). Hedrick (2005) promoted the 

more comprehensive management strategy of “genetic restoration”, which 

explicitly addresses levels of gene flow from donor to recipient populations and 

the interrelated objectives of eliminating inbreeding depression (genetic rescue), 

increasing levels of neutral genetic variation, which could potentially be adaptive 

or indicative of adaptive variants under future conditions, and avoiding or 

minimizing the potential effects from outbreeding depression. 

33
Some of the primary threats to the Columbia Basin pygmy rabbit are likely 

associated with inbreeding depression, including the population’s reduced 

reproductive success and compromised immune response. Early experimental 

results indicated that the use of intercross breeding would be beneficial in 

addressing these conditions. Accordingly, and in close coordination with 

Washington Department of Fish and Wildlife, the Science Team, and the 

Recovery Team, we have adopted an intercross breeding strategy as a key 

component of Federal recovery efforts for the Columbia Basin pygmy rabbit 

(USFWS 2006a). This approach has been taken because a successful purebred 

breeding strategy is not possible without a sufficient number of additional wild, 

reproductively active Columbia Basin pygmy rabbits for the captive breeding 

program. However, based on the available information, we have determined that 

it is highly unlikely that adequate numbers of purebred animals remain in the 

wild. 

The ultimate goal of the intercross breeding strategy for the Columbia Basin 

pygmy rabbit is to affect the population’s genetic restoration to help ensure its 

long-term viability. The three primary aims of the intercross strategy that will 

assist in the recovery of this critically imperiled population are: 

1) Conserve all of the remaining unique genetic characteristics of the Columbia 

Basin pygmy rabbit (i.e., minimize genetic drift). The genetic distinctiveness 

of the Columbia Basin pygmy rabbit is an important component of the taxon’s 

evolutionary legacy (Moritz 2002; USFWS 2003a), and conserving genetic 

resources is a primary objective of our implementation of the Endangered 

Species Act (USFWS 1996). Pairing purebred Columbia Basin pygmy rabbits 

has been a priority for the captive breeding program since it began in 2001 

(WDFW 2005a). However, due to the unavailability of additional purebred 

animals and the observed symptoms likely due to severe inbreeding depression, 

intercross breeding currently represents the most practicable approach to 

ensure that the unique genetic resources still inherent to the Columbia Basin 

pygmy rabbit are conserved. 

2) Ensure that the Columbia Basin pygmy rabbit population contains enough 

genetic diversity to remain viable for the foreseeable future (e.g., minimize

inbreeding). Loss of genetic diversity represents a significant threat to small 

populations due to the increased risks of inbreeding depression (Reed and 

34
Frankham 2003). Increasing the Columbia Basin pygmy rabbit’s genetic 

diversity through intercrossing with Idaho pygmy rabbits could help ameliorate 

the negative effects potentially due to inbreeding, including the poor 

reproductive performance, diminished immune response, and skeletal 

abnormalities that have been documented in the population. The available 

results of the captive breeding program indicate that this is the case (see 

below). 

3) Ensure that the unique genetic characteristics of the Columbia Basin pygmy

rabbit do not become attenuated through over-representation of genetic 

material from foreign pygmy rabbit populations (i.e., minimize the potential for 

outbreeding depression). The unique genotype of this distinct population 

segment, which has evolved in the Columbia Basin ecosystem, may include 

adaptive advantages for the taxon within this ecological setting (Storfer 1999; 

Moritz 2002; Manel et al. 2003). To the extent possible, maximizing the 

genetic representation of the Columbia Basin pygmy rabbit within the captive 

population may hold important implications for the recovery of the species in 

the region. 

The extent to which intercross breeding for the Columbia Basin pygmy rabbit is 

appropriate will be a balance between the above aims. The available information 

from the captive breeding program with regard to achieving the above aims

follows. 

Prior to the 2006 breeding season, the captive breeding program for Columbia 

Basin pygmy rabbit had successfully retained roughly 68 percent of the Columbia 

Basin founder (i.e., wild-caught) genomes in the captive population (K. Warheit, 

pers. comm. 2006). While there has been an overall loss of genetic diversity from

the founding population, this is nonetheless an encouraging result considering the 

limited reproductive success of the purebred animals, and also demonstrates the 

expertise and efficiency of personnel managing the captive breeding program. 

With regard to the available breeding scenarios, the captive breeding program is 

maximizing aim number 1 above. 

Prior to the 2006 breeding season, the pygmy rabbits included in the captive 

breeding program for the Columbia Basin population (all purebred Columbia 

Basin animals plus all intercrossed progeny remaining alive) had roughly 42 

35
percent greater gene diversity compared with the founding Columbia Basin 

animals, and 68 percent greater gene diversity compared to the remaining 

purebred Columbia Basin animals alone (K. Warheit, pers. comm. 2006). In 

addition, the expected and observed heterozygosity (based on analysis of 

microsatellites) of all the captive pygmy rabbits remaining alive in the program

prior to the 2006 breeding season (exclusive of the purebred Idaho animals) were 

24 percent and 43 percent greater, respectively, than the historical levels (circa

1950) documented for the Columbia Basin population through analyses of 

museum specimens (K. Warheit, pers. comm. 2006). These results indicate that 

the captive breeding program has largely achieved aim number 2 above. 

Considering the relative contributions of the Columbia Basin and Idaho pygmy 

rabbits founding the intercross progeny prior to the 2005 breeding season, the 

Columbia Basin population’s input is much greater than that of the Idaho 

population, and this result is consistent among a number of different founder 

statistics analyzed (WDFW 2005a). These analyses also demonstrated 

disproportionate contributions to the intercross progeny among the individual 

founders. Specific breeding scenarios implemented during the 2005 breeding 

season were intended to de-emphasize disproportionately represented Idaho 

founders (aim #3, above), as well as to better balance the relative contributions 

among the founding Columbia Basin animals (aim number 3, above). Breeding 

scenarios implemented during the 2006 breeding season further deemphasized the 

Idaho animals’ contributions to the program, and improved the balance among the 

founding Columbia Basin animals (WDFW 2006). These results indicate that the 

program has addressed, and made significant progress to achieve, aim number 3 

above. 

Some encouraging results of the captive breeding program to date indicate that the 

intercross pygmy rabbits (all ancestry percentages combined) have markedly 

increased reproductive success compared to the purebred Columbia Basin

animals, and possibly even the purebred Idaho animals (WDFW 2005a; R. Sayler, 

Washington State University, pers. comm. 2006). In addition, there are 

indications that the general immune response of the intercross animals is superior 

to that of the purebred Columbia Basin pygmy rabbits, and possibly even the 

purebred Idaho pygmy rabbits (Harrenstien et al. 2006). These results suggest 

that, at least in the near term, the captive breeding program is succeeding in 

36
reducing or eliminating inbreeding depression in the Columbia Basin pygmy 

rabbit (i.e., genetic rescue). 

With regard to genetic restoration of the Columbia Basin pygmy rabbit, the 

captive breeding program is at least succeeding in achieving the genetic indicators 

of increased, potentially adaptive genetic variation and the avoidance or 

minimization of potential outbreeding depression. However, it is currently 

unknown if the improvements documented thus far in reproductive success and 

general immune response, among other possible indicators, will ultimately 

translate into successive generations (i.e., improved population fitness) of the 

Columbia Basin pygmy rabbit. The extent to which the more comprehensive 

objectives of genetic restoration may be achieved will take into account the results 

of future captive-breeding seasons and the performance of captive-bred pygmy 

rabbits following their release to the wild. 

Proposed measures to recover the Columbia Basin pygmy rabbit in the wild include 

release of captive-bred progeny with at least 75 percent Columbia Basin ancestry. 

This desired level of genetic representation is based on the results of the captive 

breeding program and genetics management investigations to date. Achieving 

intercross levels greatly exceeding 75 percent appears to be of little added benefit 

and, given the available breeding scenarios, may be very difficult and time 

consuming (i.e., require multiple breeding seasons). For example, no purebred 

Columbia Basin pygmy rabbits have been recruited to the population since the 2004 

breeding season (Table 2), even though purebred pairings remained a priority for the 

program (WDFW 2006). In addition, a large proportion of the purebred Columbia 

Basin animals entering the 2006 breeding season had clinical signs of disease that 

may have negatively influenced their breeding success, were over 4 years of age,

and/or were already well represented genetically by their intercross progeny (WDFW

2006). Finally, estimates of genetic diversity in the captive population decline 

dramatically if only the captive purebred animals and those with 87.5 percent 

Columbia Basin ancestry are considered together, and these estimates are roughly 

equal to those of the founding purebred animals (Figure 3). However, these estimates 

increase significantly when the captive animals with 75 percent Columbia Basin

ancestry are included, with relatively little further improvements gained by 

considering the captive animals with less than 75 percent Columbia Basin ancestry. 

37
38

Several factors may influence future management decisions regarding the specific 

level of intercrossing considered necessary to ultimately affect genetic restoration of 

the Columbia Basin pygmy rabbit. These factors include, but are not limited to: 1) 

additional wild Columbia Basin pygmy rabbits may be located and secured for 

captive breeding efforts, and/or directly translocated to recovery emphasis areas (see 

Reintroduction, below); 2) differences in the reproductive success or other population 

fitness indicators between different intercross generations (i.e., ancestry percentages) 

in the captive pygmy rabbits may become apparent; and 3) the documented future 

responses (e.g., survival, reproductive success, habitat use) of free-ranging captivebred pygmy rabbits and their progeny. Future measures to monitor and adjust 

intercross levels, as feasible, in both the captive and wild portions of the Columbia 

Basin pygmy rabbit population were important considerations during development of 

the recovery actions proposed in this Draft Recovery Plan. 

Reintroduction: To test reintroduction techniques for the Columbia Basin pygmy 

rabbit, 42 captive-bred Idaho pygmy rabbits were used as surrogates and 

experimentally released into suitable habitats in southeastern Idaho during 4 separate 

release efforts conducted in August and September 2002, July 2003, and February 

2004 (Westra 2004). The Idaho pygmy rabbits were closely monitored following 

their release, and valuable information was generated for planning Columbia Basin 

pygmy rabbit reintroduction efforts. Various techniques were investigated during this 

work, including the use of large pre-release pens to acclimate the release groups and 

temporary containment fencing, supplemental feeding, and provision of artificial 

burrows at the release sites. Key results of these studies provided valuable 

information on the importance of seasonal timing of releases and the movement 

patterns, vulnerability to predation, habitat use, and over-winter survival of captivebred pygmy rabbits following their release. Successful reproduction in the wild by 

the captive-bred Idaho pygmy rabbits was also confirmed during the 2003 breeding 

season. 

Ultimately, the goal of the captive breeding program for the Columbia Basin pygmy 

rabbit is to release captive-bred animals at suitable sites within the population’s 

historical distribution to begin the process of its recovery in the wild. Any such 

suitable sites, referred to as “recovery emphasis areas”, will be evaluated to determine 

whether the area is considered of sufficient size and habitat quality currently, or 

potentially through appropriate enhancement measures, to support a viable 

subpopulation of Columbia Basin pygmy rabbits. Recovery emphasis areas represent
39

Figure 3. Genetic diversity of the purebred Columbia Basin population (circles) compared to the total captive population (trian

purebred Idaho animals) in the Columbia Basin pygmy rabbit captive breeding program, and genetic diversity of py

different percentages of Columbia Basin ancestry (diamonds).
sites that will be actively managed to help conserve the Columbia Basin pygmy 

rabbit in the wild and where long-term recovery objectives (i.e., beyond 10 years) are 

to be attained (see Recovery Strategy, p. 50). 

 

In 2002, the Washington Department of Fish and Wildlife undertook initial efforts to

identify and prioritize possible reintroduction sites throughout the historical

distribution of the Columbia Basin pygmy rabbit (Recovery Team 2004). These 

initial efforts considered each candidate site’s general habitat conditions, soil types, 

land ownership, and past records of Columbia Basin pygmy rabbit occurrence. All 

candidate sites identified were located on properties managed by Federal, State,

and/or one or more willing land owner interests. Ten of the candidate sites were 

further assessed by the Recovery Team through field visits in May, 2004, regarding 

their potential to help meet long-term recovery objectives for the Columbia Basin

pygmy rabbit. Further assessment of the 10 sites considered their existing habitat 

conditions and land uses, site impacts, management flexibility, necessary protection 

or enhancement measures, surrounding land uses and ownership patterns, and 

minimum size estimates. Two of the 10 sites assessed, 1 in the central Moses 

Coulee area of southern Douglas County and 1 in the Beezley Hills area of 

northern Grant County, were identified by the Recovery Team as the top priority 

sites to consider for near-term recovery objectives, including initial reintroduction 

efforts. These two sites represent the only recovery emphasis areas formally 

identified to date. 

The Washington Department of Fish and Wildlife currently manages the site in 

southern Douglas county, which totals approximately 1,515 hectares (3,740 

acres), to support recovery efforts for the Columbia Basin pygmy rabbit (WDFW 

1998 and 2001c). The Nature Conservancy, in cooperation with the Lancaster 

family, has also acquired or obtained easements on approximately 1,374 ha (3,390 

ac) of high quality shrub steppe habitat, which comprise the site in northern Grant 

County, specifically to support Columbia Basin pygmy rabbit recovery efforts. 

Other Federal (i.e., Bureau of Land Management) lands and properties managed 

by The Nature Conservancy within 8 km (5 mi) of the recovery emphasis areas 

total approximately 2,836 ha (7,000 ac) in the broader Moses Coulee area and 

approximately 4,862 ha (12,000 ac) in the broader Beezley Hills area. 

Management of these other lands will be consistent with recovery efforts for the 

Columbia Basin pygmy rabbit to the extent feasible, considering overall program

40 
objectives of the Bureau of Land Management and The Nature Conservancy (N. 

Hedges, BLM, pers. comm. 2006; C. Warner, The Nature Conservancy, pers. 

comm. 2006). Portions of the remaining shrub steppe habitat throughout the 

population’s historical distribution are administered by various Federal and State 

agencies and non-governmental conservation interests, including some private 

land owners. Conservation measures for the Columbia Basin pygmy rabbit may 

be considered in future management programs on these lands, including the 

potential identification of additional recovery emphasis areas (see Recovery 

Strategy, p. 50). 

Researchers at Washington State University, through coordination with us and the 

Washington Department of Fish and Wildlife, have developed a Reintroduction 

Plan that identifies specific procedures for release and monitoring of captive-bred 

Columbia Basin pygmy rabbits (Sayler et al. 2007). A draft of the Reintroduction 

Plan was distributed to the Science Team and Recovery Team for review and the 

plan was finalized prior to initial release efforts (see below). The Reintroduction 

Plan was largely based on the investigations of Idaho pygmy rabbits and the 

results of other ongoing recovery planning efforts for the Columbia Basin pygmy

rabbit (e.g., captive breeding, genetics management, evaluation of recovery 

emphasis areas, population modeling). The Reintroduction Plan generally defines 

the appropriate makeup for release groups, seasonal timing for initial releases, 

post-release monitoring actions, and projected timing for subsequent releases, as 

well as other specific release procedures (e.g., provision of temporary holding 

pens, artificial burrows, supplemental feeding). The Reintroduction Plan will also 

be revised annually, as necessary, to accommodate applicable adaptive 

management measures that have been identified (see Recovery Strategy, p. 50). 

An initial release of captive-bred pygmy rabbits took place on March 13, 2007, at 

the Sagebrush Flat site. The initial release group included 20 animals (8 females, 

12 males). Population modeling indicates that the likely success of reintroduction 

efforts for the Columbia Basin pygmy rabbit is greatly improved by undertaking 

multiple releases of captive-bred animals over multiple years (Sayler et al. 2007). 

Until a sufficient number of free-ranging animals can be established at one or 

more of the recovery emphasis areas (see Recovery Strategy, page 34), 

management emphasis will remain on ensuring that the captive breeding program

is secure and can continue to accommodate future reintroduction efforts (WDFW 

2007). 

41 
Stakeholder Involvement: We developed, with the Washington Department of 

Fish and Wildlife, a Template Safe Harbor Agreement for the Columbia Basin 

Pygmy Rabbit (Agreement) (USFWS 2006b). The Agreement provides a process 

for non-Federal and non-Washington Department of Fish and Wildlife land 

owners and managers, referred to as Participants, to voluntarily contribute to State 

and Federal recovery efforts for the Columbia Basin pygmy rabbit without 

incurring additional regulatory burdens for “incidental take”. In exchange for 

implementing conservation measures that would be expected to benefit the 

Columbia Basin pygmy rabbit, Participants are provided with regulatory 

assurances that they will not be subject to future land-use restrictions or additional 

management requirements if their voluntary actions result in increased numbers or 

distribution of Columbia Basin pygmy rabbits on their enrolled property. These 

assurances allow Participants to develop or make any other lawful use of their 

enrolled property, even if such activity results in the incidental take of Columbia 

Basin pygmy rabbits to such an extent that the enrolled property returns to the 

agreed-upon “baseline” conditions. However, these assurances are contingent on 

the Participant having maintained the agreed-upon baseline conditions, only 

engaging in take that is incidental to otherwise lawful activities, and being in full 

compliance with the Agreement and their associated “Site Plan”. Covered

activities may include, but are not limited to, those associated with ranching, 

farming, recreation, residential upkeep, conservation programs for the covered 

species, and direct management of shrub steppe habitat, including maintenance, 

enhancement, restoration, and conversion. 

The Agreement clarifies the management responsibilities and expectations of us, 

the Washington Department of Fish and Wildlife, and prospective Participants, 

and will serve as the basis for us to issue Federal Enhancement of Survival 

Permits (Permits) to Participants pursuant to section 10(a)(1)(A) of the Act. To 

receive a Permit, each prospective Participant would need to complete and submit 

to us a Federal Fish and Wildlife Permit Application. In addition to submitting a 

Permit application, each prospective Participant to the Agreement would also 

need to complete a Site Plan that identifies the specific properties to be enrolled 

and documents the baseline conditions, existing and, as available, proposed future 

land-use activities, and agreed-upon conservation measures that would be 

expected to benefit the Columbia Basin pygmy rabbit on the enrolled properties. 

Each prospective Participant would need to agree upon and sign the Site Plan 

42 
along with us, prior to issuance of the associated Permit. Once issued, Permits 

would exempt incidental take of Columbia Basin pygmy rabbits, which would 

otherwise be prohibited by section 9 of the Endangered Species Act, that are 

above the baseline conditions of the enrolled property. 

Conceptually, baseline represents the number of Columbia Basin pygmy rabbits 

on a given property at the time it is enrolled under the Agreement. However, for 

most species including pygmy rabbits, it is often difficult or impossible to 

determine the precise number of individuals in a given occupied area. Therefore, 

in practice, baseline is typically expressed as “population estimates and 

distribution” of the covered species or “habitat characteristics and determined area 

that sustain seasonal or permanent use” by the covered species on enrolled 

property. 

All non-Federal and non-Washington Department of Fish and Wildlife properties 

within the historical distribution of the Columbia Basin pygmy rabbit that could 

be voluntarily managed to provide a net conservation benefit to the population are 

eligible for enrollment under the Agreement, including lands that have been 

applied for or are currently enrolled under various programs administered by the 

U.S. Department of Agriculture (e.g., the Conservation Reserve Program). 

Eligible properties will primarily include those that represent shrub steppe habitat 

and/or soil conditions that may be capable of supporting the species, either 

currently or in the foreseeable future. The specific properties being considered 

for enrollment under the Agreement would be detailed in the Site Plans of 

prospective Participants. Public lands under the jurisdiction of State agencies 

other than the Washington Department of Fish and Wildlife may be enrolled 

under the Agreement. 

Non-Federal and non-Washington Department of Fish and Wildlife properties that 

are eligible for inclusion under the Agreement fall into two main categories. The 

first category is made up of intervening properties outside of the recovery 

emphasis areas. While intervening properties are not necessarily actively 

managed to conserve the Columbia Basin pygmy rabbit, they may nevertheless 

contribute to recovery efforts (see Recovery Strategy, p. 50). The second 

category includes those properties that comprise, in whole or in part, the recovery 

emphasis areas, which will be managed first and foremost to support viable 

subpopulations of this species. Reflecting this broad approach for recovery 

43 
efforts, the process for determining baseline conditions for intervening properties 

and recovery emphasis areas will vary, as described below. 

Determining the number of active burrows present currently represents the most 

reliable way to estimate pygmy rabbit population abundance and distribution in a 

given area, and is the most efficient method for documenting the species’ overall 

presence or absence in an area (see Survey and Capture, p. 45). As such, baseline 

conditions for intervening properties will be established in terms of the number of 

active Columbia Basin pygmy rabbit burrows present at the time the property is 

enrolled under the Agreement, or as otherwise determined beforehand through 

issuance of baseline description letters issued by us. 

Key features of recovery emphasis areas are the existing, or potential, habitat 

conditions they contain that would contribute to supporting long term recovery 

efforts for the Columbia Basin pygmy rabbit. As such, baseline conditions of 

eligible properties contributing to recovery emphasis areas will be established in 

terms of the amount and type(s) of habitat that currently exist on the properties 

that would contribute to sustaining a viable subpopulation of Columbia Basin 

pygmy rabbits (see Recovery Strategy, p. 50). Baseline determinations for 

recovery emphasis areas will require more detailed documentation and/or followup field assessments to evaluate existing habitat conditions. Therefore, 

information needed to establish baseline conditions for these properties will be

addressed on a case-by-case basis and documented within each Participant’s Site 

Plan. We will discuss with each prospective Participant the general criteria that 

will be used for existing habitat documentation or, as necessary, guidance and 

assistance for conducting follow-up habitat assessments for baseline 

determinations at recovery emphasis areas. At the discretion of owners and 

managers of properties contributing to recovery emphasis areas, and with our 

concurrence and that of the Washington Department of Fish and Wildlife, these 

baseline conditions may apply whether or not any additional wild Columbia Basin 

pygmy rabbits are documented during future surveys of these properties. 

Measures to pursue and secure cooperative agreements with non-Federal land 

owners and managers, as well as other stakeholders potentially affected by

recovery efforts for the Columbia Basin pygmy rabbit, were important 

considerations during development of the recovery actions proposed in this Draft 

Recovery Plan. 

44 
Survey and Capture: The Washington Department of Fish and Wildlife has 

developed three survey methods for Columbia Basin pygmy rabbits (WDFW

2004b). These methods employ different techniques, require varying levels of 

effort to perform, and have different applications depending on the information 

sought. The least intensive of these methods is referred to as “evidence searches”. 

Briefly, evidence searches entail qualified personnel walking transects across 

“survey habitat” looking for Columbia Basin pygmy rabbits or their sign, such as 

active burrow systems, tracks, or pellets. As with the other survey methods 

described below, detailed surveys are not necessary in any areas that do not 

contain survey habitat, and these sites can be documented through cursory visual 

assessment. Evidence searches are primarily used as an initial approximation to 

determine the species’ presence or absence in a given area. Since the mid-1980s, 

evidence searches have been used extensively by biologists to survey large 

portions of the remaining shrub steppe habitat throughout the population’s 

historical distribution. Evidence searches will also be the primary method used to 

conduct baseline surveys for intervening properties pursuant to the Agreement 

(see Stakeholder Involvement, p. 42). 

If evidence searches indicate that Columbia Basin pygmy rabbits might be present 

in an area, more intensive follow-up surveys, referred to as “complete area 

searches”, would be conducted. This method is primarily used to confirm the 

species’ presence in an area, more precisely document the specific sites occupied, 

and to estimate the species’ relative abundance by locating as many active burrow 

systems as possible. In addition to walking transects, as described above for 

evidence searches, complete area searches would also involve concerted efforts to 

obtain visual observations of live animals, closely monitoring potentially active 

burrow systems, collecting pellet samples for genetic testing, and/or revisiting 

sites on subsequent surveys. Complete area searches are typically applied where 

relatively few (e.g., less than 10) pygmy rabbits are thought to remain in an area, 

and/or when there is a need to accurately estimate the number of active burrows 

that may be present. This survey method was used by Washington Department of 

Fish and Wildlife at the last known occupied sites, which confirmed the 

extirpation of Columbia Basin pygmy rabbits from the local area. In the event 

that any additional wild Columbia Basin pygmy rabbits are located in conjunction 

with evidence searches, this method will also be important for future capture 

operations that may be conducted pursuant to the Agreement, and for determining 

45 
baseline conditions for intervening properties that may harbor Columbia Basin 

pygmy rabbits. 

The final survey method is referred to as the “Skalski monitoring method” 

(Skalski 1996). The main objective of this method is to systematically census 

active burrow systems at sites known to be occupied by Columbia Basin pygmy

rabbits. This repeatable survey method is primarily used as an index to monitor 

changes in a local subpopulation’s abundance and distribution over time. This 

method may also be used to assess different “treatments” in an occupied area 

(e.g., habitat condition, land use activity, experimental manipulation) to make 

inferences about their affects on various pygmy rabbit life history parameters 

(e.g., density estimates, movement patterns, habitat use). In general, this method 

involves identifying a stratified random sample of permanently marked plots 

throughout a specified area. Trained personnel then survey each plot for active 

burrow systems. The number of active burrow systems documented can be 

extrapolated to generate an index of pygmy rabbit abundance and relative 

distribution. Repeated surveys, in turn, can then be used to document trends over 

time and/or to infer changes in life history parameters attributed to various 

treatments. This method was used by the Washington Department of Fish and 

Wildlife at the last known occupied site to monitor the status of the local 

subpopulation and document its decline. This method, or a similar method based 

on the same objectives, will be the primary means to monitor the status of any 

reestablished free-ranging subpopulations over time and their response to future 

research and/or adaptive management measures. Information that is routinely 

recorded for each of the three survey methods described above includes site 

descriptions, surveyed area, habitat conditions, predator sign, land-use activities, 

and the presence of other wildlife species. The locations and results of survey 

efforts are compiled by the Washington Department of Fish and Wildlife, and the 

maintenance and use of these data will be important for the monitoring objectives 

and other recovery actions recommended in this Draft Recovery Plan. 

We along with the Washington Department of Fish and Wildlife, consider it very 

unlikely that any purebred Columbia Basin pygmy rabbits remain in the wild. 

However, not all potentially suitable habitats have been surveyed, and it is 

possible that there are still some free-ranging purebred animals within the 

population’s historic distribution. Therefore, there are ongoing survey efforts to 

locate and, as opportunities may arise, capture additional purebred Columbia 

46 
Basin pygmy rabbits from the wild so that they can be included in the captive 

breeding program and/or translocated directly to one or more recovery emphasis 

areas. All future capture and transportation operations would be conducted 

pursuant to the Washington Department of Fish and Wildlife's existing recovery 

permit (USFWS 2003b). Securing additional purebred Columbia Basin animals, 

and/or confirming their continued existence in the wild, would improve the 

overall recovery outlook for this population (see Recovery Strategy, p. 50), and 

were important considerations during development of the recovery actions 

proposed in this Draft Recovery Plan. 

Currently, the number of additional Columbia Basin pygmy rabbits considered 

appropriate to remove from the wild is 30. This preliminary estimate is based on 

the original program goal of capturing 20 reproductively active Columbia Basin 

pygmy rabbits, while only 9 of the 21 wild-bred animals (43 percent) have 

actually contributed to reproduction (4 of 11 females, 5 of 10 males). Thirty 

additional wild-caught animals is a minimum estimate for several reasons, 

including: 1) it is now apparent that the genetic diversity of the Columbia Basin 

pygmy rabbit in the wild had been declining over the past several decades; 2) the 

contemporary wild population was likely suffering from inbreeding depression; 3) 

five of the wild-bred pygmy rabbits in the captive breeding program were 

siblings, and only the parents of this litter represent founding animals; 4) the 

captive population has continued to lose genetic diversity; and 5) the reproductive 

success of the purebred population has declined commensurately. In addition to 

captive breeding considerations, under certain circumstances it may also be 

appropriate to translocate wild animals at currently occupied sites directly to one 

or more recovery emphasis areas. Such instances may include, but are not limited 

to: 1) too few animals would be left at the site to be considered viable following 

capture operations; 2) the occupied area is small, surrounded by unsuitable 

habitat, and immigration from, or emigration to surrounding areas due to natural 

dispersal would be precluded; and 3) direct translocation may offer a more 

efficient and effective means to manipulate the demographic make up and/or 

future intercross levels of the managed subpopulation(s) at recovery emphasis 

areas. The number of Columbia Basin pygmy rabbits that may be appropriate to 

remove from the wild and/or translocate between occupied sites will be reassessed 

as any additional free-ranging purebred animals may be located and secured for 

the captive breeding program.

47 
Public Outreach: We distributed information packages to a wide range of 

interested parties following publication of the proposed rule to list the Columbia 

Basin pygmy rabbit in 2001 (USFWS 2001). The information packages and, as 

requested, copies of the proposed rule were sent to State and Federal resource 

agencies, elected officials, the scientific community, industry groups, nongovernmental organizations, Native American Tribes, and the general public to 

request comments or suggestions concerning development of a final listing rule 

for the Columbia Basin pygmy rabbit. We also held a public meeting to solicit 

input from interested parties in February, 2002, following publication of the 

proposed rule. All substantive comments received as a result of these outreach 

efforts were addressed in the final listing rule for the Columbia Basin pygmy 

rabbit, published in 2003 (USFWS 2003a). The final listing rule and a Recovery 

Outline developed by us in November 2004 (USFWS 2004), also specify general 

conservation measures that we determined to be appropriate to initiate recovery of 

the Columbia Basin pygmy rabbit. Information packages and, as requested, 

copies of the final rule and the Recovery Outline were also distributed to 

interested parties upon their completion. 

Since publication of the final listing rule, and through coordination with the 

Washington Department of Fish and Wildlife and other Recovery Team members, 

we have held or otherwise attended a number of meetings with various 

stakeholders to discuss recovery planning efforts for the Columbia Basin pygmy

rabbit. Stakeholder groups involved in these discussions included the Douglas 

and Grant County Commissioners, Washington Wheat Growers Association, 

Washington Cattlemen’s Association, Society for Range Management, Foster 

Creek Conservation District, The Nature Conservancy, various State and Federal 

resource agencies (e.g., Bureau of Land Managment, Washington Department of 

Natural Resources), and concerned citizens. We, the Washington Department of 

Fish and Wildlife, and other Recovery Team members have also maintained an 

effective outreach program with local, State, and national media outlets regarding 

ongoing conservation efforts for the Columbia Basin pygmy rabbit. Ensuring 

continued formal and informal public outreach to encourage stakeholder 

involvement in recovery efforts for the Columbia Basin pygmy rabbit was an 

important consideration during development of the recovery actions described in 

this Draft Recovery Plan. 

48 
Predator Control: The Washington Department of Fish and Wildlife 

implemented a predator control program during the fall-winter periods of 1998 to 

1999 and 1999 to 2000 due to confirmed evidence of coyote predation of 

Columbia Basin pygmy rabbits (WDFW 2000). Numerous coyotes and several 

long-tailed weasels were removed by shooting or trapping over approximately 52 

square kilometers (20 square miles) around and including the last known occupied 

site at the Sagebrush Flat Wildlife Area. The level of effort to control terrestrial 

predators varied among years and areas, and the efficacy of this program to 

protect Columbia Basin pygmy rabbits is unknown. There are also a variety of 

avian predators that may occur at sites occupied by Columbia Basin pygmy 

rabbits. In an effort to help control the occurrence of common ravens and other 

predatory birds, the Washington Department of Fish and Wildlife removed 

obsolete structures from the last known occupied site that could have been used 

for perching or nesting by avian predators (WDFW 2003). 

To further address the future threat of predation at the recovery emphasis areas, 

additional measures have been implemented or are being considered, including 

controlling artificial food sources (e.g., spilled grain, trash, carnivore baits), 

additional removal of unnecessary structures potentially used as perch sites by 

avian species (e.g., old fencing), and providing appropriate exclusion fencing 

(WDFW 2003; C. Warner pers. comm. 2006; R. Sayler pers. comm. 2006). In 

addition, several measures, such as containment fencing, security and predator 

monitoring, and provision of artificial burrows, have been taken or are being 

considered to reduce the risk of predation of captive pygmy rabbits at pre-release 

sites and at the captive breeding facilities (R. Sayler pers. comm. 2001; L. 

Shipley, pers. comm. 2001; Westra 2004). 

49 
II. Recovery Strategy

We have worked closely with the Washington Department of Fish and Wildlife to 

address the conservation needs of the Columbia Basin pygmy rabbit since 

dramatic declines in the population were documented during the late 1990s. One 

of our main objectives during this period has been to ensure that Federal recovery 

planning efforts are consistent with and complement existing and developing 

State conservation measures, as appropriate. We also assembled a multi-party 

Recovery Team in 2003 (see Acknowledgements, page iii) to assist with 

development of this Draft Recovery Plan, and to otherwise advise us concerning 

recovery actions for the Columbia Basin pygmy rabbit. In addition, we have 

undertaken a number of efforts to involve various stakeholders and other interest 

groups in recovery planning for the Columbia Basin pygmy rabbit, which has 

contributed to the development of the following proposed recovery strategy, as 

well as the recovery objectives, criteria, and actions described below. 

Due to a number of information gaps in the available information, including 

uncertainties regarding how the Columbia Basin population may respond to 

ongoing and developing conservation measures, the Recovery Team has 

recommended a phased approach for recovery planning. The three phases reflect 

our proposed recovery strategy for this population, and include: 1) removal or 

abatement of imminent threats to the Columbia Basin pygmy rabbit in order to 

prevent the extinction of the population; 2) reestablishment of an appropriate 

number and distribution of free-ranging subpopulations to further reduce threats 

over the near term (10 years); and 3) establishment and protection of a sufficiently 

resilient, free-ranging population that would be expected to withstand foreseeable 

long-term threats. 

Our recovery strategy for the Columbia Basin pygmy rabbit is meant to be a 

dynamic process. The phased approach proposed in this Draft Recovery Plan 

provides for the development and implementation of appropriate adaptive 

management measures as the information base concerning the Columbia Basin 

pygmy rabbit improves. Adaptive management is a continual process of 

investigation, planning, implementation, monitoring, and evaluation of recovery 

actions so that future adjustments to management practices can be made to fully 

achieve recovery objectives. The currently identified near-term recovery 

objectives and criteria are limited by the available information, which is reflected 

50 
in the phased approach to recovery. In turn, many of the identified recovery 

actions address the early stages of adaptive management and are designed 

primarily toward information gathering and initial assessment needs. In addition, 

while the three identified recovery phases are logical from a management 

perspective, they largely represent artificial delineations of a continuous process. 

As such, the recovery actions developed to address each phase are not necessarily 

mutually exclusive and may overlap chronologically and/or functionally. The 

recovery actions are also expected to evolve over time in response to adaptive 

management. 

To facilitate the phased recovery strategy and implementation of adaptive 

management measures, the current Implementation Schedule (see p. 89) 

represents the first of what will become a series of near-term implementation 

plans. We will revise the implementation schedules as appropriate to reflect the 

knowledge gained, accomplishments met, potential future constraints encountered 

(e.g., lack of funding, changing management priorities), and consequent 

refinements to near-term recovery objectives, criteria, and/or actions as recovery 

progresses. 

The original objective of the captive breeding program for the Columbia Basin 

pygmy rabbit was to achieve necessary population growth by augmenting 

existing, free-ranging subpopulations with captive-bred animals as soon as 

possible (WDFW 2001a). At the time, this was determined to be the most 

efficient, cost-effective strategy. However, this approach is no longer possible 

due to the sudden extirpation of all known wild subpopulations and the poor 

reproductive performance of the captive, purebred Columbia Basin pygmy 

rabbits, which is presumably due mainly to inbreeding depression (see Captive 

Breeding, p. 27). As a result, the captive, purebred population was ultimately 

represented by only nine founders, and underwent a loss of genetic diversity (see 

Genetics Management, p. 31). 

It is now considered likely that the last known subpopulation of Columbia Basin 

pygmy rabbits, which was used to found the captive population, was already 

experiencing a significant level of inbreeding by the late 1990s, resulting in 

diminished genetic variability. Securing additional purebred Columbia Basin 

pygmy rabbits from the wild, if any still exist, remains a high priority for the 

captive breeding program, as well as for other recovery considerations (see 

51 
Conservation Measures, p. 50). However, the available information indicates that 

substantially increasing the genetic diversity of the captive population through the 

inclusion of additional purebred animals is very unlikely. Therefore, intercross

breeding with Idaho pygmy rabbits of the same taxonomic classification, yet from

a different geographic area, was determined to be necessary to facilitate genetic 

restoration of the Columbia Basin population, and is currently considered essential to 

meet Federal recovery objectives (USFWS 2006a). Based on results of the captive 

breeding program and genetics management efforts to date (see Genetics

Management, p. 31), proposed measures to recover the Columbia Basin pygmy rabbit 

in the wild will require release of captive-bred progeny with at least 75 percent

Columbia Basin ancestry.

At the time of our emergency listing action in 2001, the Columbia Basin pygmy

rabbit was imminently threatened by its small population size, loss of genetic 

diversity, and inbreeding depression, coupled with a lack of suitable, protected 

habitats in the wild. Since emergency listing, the captive breeding program, genetics

management efforts, habitat acquisition, and identification of appropriate recovery 

emphasis areas undertaken to date have reduced the immediacy of these threats. 

Accordingly, objectives established to address the first phase of recovery have largely 

been accomplished (see below). However, as addressed above, many of the 

associated actions initiated during the first phase of recovery will be necessary to 

continue and/or revise in subsequent phases as recovery progresses. 

Recovery objectives that have been accomplished to date include: 

• Abatement of imminent threats to the Columbia Basin pygmy rabbit 

population due to inbreeding and small population size through 

appropriate implementation of captive breeding and genetics management

measures. 

• Establishment of a captive population of Columbia Basin pygmy rabbits 

that can ensure maintenance of the population’s genetic and demographic 

status, as appropriate, and which is also considered capable of supporting 

future reintroduction and augmentation efforts. 

52 
• Identification of two recovery emphasis areas capable of supporting 

reintroduced, free-ranging subpopulations of Columbia Basin pygmy

rabbits that would be considered secure over the near-term (10 years). 

• Development of a Reintroduction Plan that identifies specific techniques 

to be undertaken during future release efforts, as well as generally 

identifying appropriate post-release monitoring measures and future 

research objectives (Sayler et al. 2007). 

• Development and implementation of appropriate measures to engage the 

full range of potential stakeholders and other interested parties in 

voluntary, proactive conservation efforts for the Columbia Basin pygmy 

rabbit. 

A key objective for the second phase of recovery planning is to release and 

establish an appropriate number and type (gender, age, ancestry) of captive-bred 

pygmy rabbits at one or more recovery emphasis areas to begin the process of 

recovering the Columbia Basin pygmy rabbit in the wild. However, even with 

successful genetic restoration and initial reintroduction efforts, any free-ranging 

subpopulations of Columbia Basin pygmy rabbits will face continuing risks from

inbreeding and loss of genetic diversity if they remain small and isolated (Lande 

and Barrowclough 1987). Therefore, it will be important to increase the numbers 

and distribution of free-ranging Columbia Basin pygmy rabbits as soon as 

possible to prevent future inbreeding, to retain their increased genetic diversity, 

and to reduce their vulnerability to stochastic events. As such, two important, 

near-term considerations for reintroduction efforts are the desired number of freeranging animals to be reestablished at recovery emphasis areas and, in turn, a 

minimum size estimate for recovery emphasis areas that would be considered 

necessary to support them. Ensuring long term protection of these areas is also an 

important consideration. Simultaneously, it will be important to maintain a 

sufficient number and demographic composition of pygmy rabbits in captivity to 

ensure that the captive breeding program remains secure until appropriate, freeranging subpopulations can be reestablished. 

In the absence of more species-specific life history data, a common, general 

approximation of minimum viable population sizes is referred to as the 50 / 500 

rule (Soulé 1980; Hunter 1996). This rule states that an effective population (Ne) 

53 
of 50 individuals is the minimum size required to avoid imminent risks from

inbreeding. Ne represents the number of animals in a population that actually 

contribute to reproduction, and is often much smaller than the census, or total, 

number of individuals in the population (N). Furthermore, the rule states that the 

long-term fitness of a population requires an Ne of at least 500 individuals so that 

it will not lose its genetic diversity over time and will maintain an enhanced 

capacity to adapt to changing conditions. Recovery emphasis areas, therefore, 

must be large enough and contain a sufficient quantity and quality of shrub steppe 

habitat currently, or potentially through appropriate enhancement measures, to be 

considered capable of supporting a viable subpopulation of Columbia Basin 

pygmy rabbits over the long-term. 

Rachlow and Witham (2004) calculated density estimates for pygmy rabbits 

occupying sites under variable habitat conditions. These estimates ranged from

0.38 to 2.72 pygmy rabbits per hectare (0.15 to 1.10 per acre). Considering these 

density estimates as an initial approximation of the range in area required by 

pygmy rabbits, a subpopulation of at least 500 individuals would require an area 

of suitable habitat between roughly 184 and 1,316 hectares (454 and 3,250 acres). 

The two currently identified recovery emphasis areas (see Reintroduction, p. p. 

38) total 1,515 hectares (3,740 acres) and 1,374 hectares (3,390 acres). As such, 

these areas are consistent with the above population density estimates and are 

considered of an appropriate size necessary to help achieve the recovery 

objectives and criteria that are currently established for the Columbia Basin 

pygmy rabbit (see Recovery Goals, Objectives, and Criteria, p. 56). 

A conservative density estimate was considered appropriate for establishing the 

minimum size of recovery emphasis areas (i.e., 1, 316 hectares (3,250 acres)) for 

several reasons, including: 1) the referenced study involved a discrete population 

in Idaho occupying a different ecological setting; 2) one study specifically 

addressing the Columbia Basin pygmy rabbit (Gahr 1993) suggested even lower 

densities, although this study was not specifically designed to evaluate pygmy 

rabbit population densities and likely occurred during a period of population 

decline; 3) not all of the existing or potential habitat within the identified recovery 

emphasis areas may be considered appropriate or currently available for pygmy

rabbits; 4) the Ne of free-ranging Columbia Basin pygmy rabbit subpopulations 

may be substantially less than N; and 5) it is currently unclear to what extent 

54 
lands outside of recovery emphasis areas may contribute to recovery objectives 

(see below).

Intervening non-Federal and non-Washington Department of Fish and Wildlife 

properties outside of recovery emphasis areas, while not actively managed to 

conserve the Columbia Basin pygmy rabbit, may nevertheless contribute to 

recovery efforts. Any such property that could be voluntarily managed to provide 

a net conservation benefit to the population will be considered eligible for 

inclusion under the existing Safe Harbor Agreement for the Columbia Basin 

pygmy rabbit (see Stakeholder Involvement, p. 42). In addition, Federal agencies 

with management authority over intervening properties outside of recovery 

emphasis areas must consider the contributions that their Federal authority may 

provide towards the survival and recovery of the Columbia Basin pygmy rabbit. 

Potential benefits that could be realized on intervening properties include: 

• Suitable habitat on intervening properties would be available for use by 

Columbia Basin pygmy rabbits released to recovery emphasis areas. 

• Undeveloped habitats on intervening properties would facilitate dispersal 

of newly released animals and enhance connectivity of recovery emphasis 

areas and other potentially occupied sites. 

• New subpopulations may form on intervening properties through natural 

expansion. 

• Additional purebred Columbia Basin pygmy rabbits may be located on 

intervening properties and be secured for captive breeding efforts and/or 

translocated directly to one or more recovery emphasis areas. 

• Monitoring and future collection of biological information (e.g., dispersal, 

survival, productivity, habitat use) would be improved through 

cooperative management efforts on intervening properties. 

• Research and adaptive management measures could be made more 

comprehensive if implemented at a broader scale through the inclusion of, 

and facilitated access to, intervening properties. 

55 
• The successful implementation of cooperative, proactive management 

measures on intervening properties would increase public awareness and 

support for the Columbia Basin pygmy rabbit recovery program.

The voluntary management measures that would be expected to provide one or 

more of the above conservation benefits on intervening non-Federal and nonWashington Department of Fish and Wildlife properties will be identified and 

documented as specific properties are enrolled under the Agreement (see 

Stakeholder Involvement, p. 42). On intervening properties where Federal 

management authority exists, measures that could potentially contribute to 

recovery of the Columbia Basin pygmy rabbit will be evaluated in accordance 

with our and other Federal agencies’ requirements pursuant to section 7 of the 

Endangered Species Act (i.e., Interagency Cooperation). Section 7 requires that 

Federal agencies, in consultation with us, utilize their authorities to further the 

purposes of the Endangered Species Act, and carry out programs for the 

conservation of endangered and threatened species. Section 7 also requires that 

Federal agencies consult with us to ensure that their proposed actions are not 

likely to jeopardize the continued existence of any listed species or adversely 

modify designated critical habitat. 

As the near-term (i.e., 2007 to 2016) objectives currently identified for the second 

phase of recovery are accomplished and met, revised implementation schedules 

will be developed to identify updated, specific recovery objectives, criteria, and 

actions considered necessary to advance to the final phase of the overall recovery 

strategy. 

III. Recovery Goals, Objectives, and Criteria

The goal of Federal recovery planning is to recover a listed species to the point 

that protections under the Endangered Species Act are no longer required (i.e., to 

delist the species), which may include an interim goal of downlisting a species 

from endangered to threatened status. Recovery goals are subdivided into discrete 

component objectives, which collectively describe the conditions for achieving 

downlisting or delisting. Recovery objectives are therefore the recovery goal 

parameters, and the criteria are the values of those parameters. The Endangered 

Species Act states that each recovery plan shall incorporate, to the maximum 

extent practicable, "...objective, measurable criteria which, when met, would 

56 
result in a determination . . . that the species be removed from the list." 

Accordingly, the recovery criteria represent the standards upon which a decision 

to reclassify or delist a species is based, in light of the five listing factors (see 

Threats, p. 18). Recovery criteria (delisting or downlisting) can be viewed as the 

targets or values by which progress toward achieving recovery objectives can be 

measured. Based on the best available information and overall recovery strategy 

identified above, we establish the following recovery goal, objectives, and criteria 

for recovering the Columbia Basin pygmy rabbit pursuant to the Endangered 

Species Act.

A. GOAL

The ultimate goal of this recovery plan is to identify recovery actions that, when 

implemented, will remove threats to the Columbia Basin pygmy rabbit to the 

extent that it is no longer in danger of extinction. At that point, the species may 

be reclassified as threatened and, ultimately, be removed from the Federal List of 

Endangered and Threatened Wildlife and Plants. In order to achieve this goal, 

threats to free-ranging Columbia Basin pygmy rabbits will need to be sufficiently 

abated such that there is a high probability of the population’s persistence within 

their historical distribution over the foreseeable future. 

B. OBJECTIVES 

1. Near-term (2007 to 2016)

a. The Reintroduction Plan, which identifies specific procedures for release 

efforts and identifies the current monitoring measures and research 

objectives for free-ranging Columbia Basin pygmy rabbits, is revised 

annually to account for adaptive management measures. 

b. Captive pygmy rabbits available for release to recovery emphasis areas 

represent at least 75 percent Columbia Basin ancestry, are considered fit 

for release by veterinary staff, and otherwise satisfy requirements of the 

most current Captive Breeding and Genetics Management Plan and 

Reintroduction Plan (e.g., relatedness, age, sex ratios). 

57 
c. Two recovery emphasis areas of at least 1,316 hectares (3,250 acres) each 

are formally established through completion of one or more appropriate 

cooperative agreements, and are available for reintroduction and/or 

augmentation efforts. 

d. Reestablished subpopulations at two recovery emphasis areas each have a 

5-year average Ne of at least 125 individuals. 

e. Future investigations are undertaken to develop appropriate, updated 

estimators of Columbia Basin pygmy rabbit overall abundance (N), 

effective population size (Ne), and dispersal corridor habitat and 

management conditions. These updated estimators, in turn, will make it 

possible to identify the appropriate size, number, status, and configuration 

of Columbia Basin pygmy rabbit subpopulations necessary to ensure the 

population’s long term viability (i.e., establish delisting criteria). 

f. As necessary to meet objective 5 above, additional recovery emphasis areas 

and/or dispersal corridors are identified, prioritized, and formally 

established through completion of one or more appropriate cooperative 

agreements. 

g. Appropriate cooperative agreements that lead to proactive, voluntary 

conservation efforts with land owners, managers, and other interested 

parties within the historical distribution of the Columbia Basin pygmy

rabbit are developed and implemented. 

2. Long-term 

Increase the size, number, distribution, and security of free-ranging 

subpopulations of the Columbia Basin pygmy rabbit so that the population may be 

reclassified as threatened and, ultimately, be removed from the List of 

Endangered and Threatened Wildlife and Plants pursuant to the Endangered 

Species Act.

C. RECOVERY CRITERIA 

58 
We establish recovery criteria to serve as objective, measurable guidelines to 

assist us in determining when an endangered species has recovered to the point 

that it may be downlisted to threatened, or that the protections afforded by the 

Endangered Species Act are no longer necessary and the species may be delisted. 

The following discussion summarizes the relationship between the listing factors 

established by the Endangered Species Act and the recovery actions developed to 

address the threats to the Columbia Basin pygmy rabbit (see Recovery Program,

p. 62). 

Listing Factor A: The present or threatened destruction, modification, or 

curtailment of the species habitat or range: In order to ensure that the long-term

recovery needs of the Columbia Basin pygmy rabbit are met, threats to the 

population’s habitat must be reduced or removed. Maintaining, enhancing, and 

restoring connectivity of appropriate shrub steppe habitats are important near term

and long term considerations for this species, and would be addressed by the 

recovery actions directed at habitat management efforts. 

Listing Factor B: Overutilization for commercial, scientific, or educational 

purposes: The Columbia Basin pygmy rabbit captive breeding and reintroduction 

programs are essential to ensuring the long-term survival of this population, 

although incidental mortality and certain other negative impacts have occurred as 

a result of activities associated with these efforts. Potential threats to the 

population due to scientific and educational management activities would be 

addressed by the recovery actions through implementation of adaptive 

management measures to refine captive breeding, release, monitoring, and 

research protocols as we learn more about this species biological requirements. 

Listing Factor C: Disease or Predation: A number of Columbia Basin pygmy 

rabbits have died in captivity as a result of various diseases. Preventative 

measures to address this threat include, among other things, regular monitoring 

and quarantine of infected animals, decontaminating holding pen areas when 

necessary, redesigning holding pens to more closely mimic density conditions in 

the wild, and prophylactic treatment of captive pygmy rabbits with antibiotics. 

Predation is thought to be the major cause of mortality among free-ranging pygmy

rabbits (Green 1979; Wild 1978), and would be addressed by recovery actions 

directed at habitat enhancement measures and/or establishing temporary predator 

control programs. 

59 
Listing Factor D: Inadequacy of existing regulatory mechanisms: Although 

Washington State regulations make it illegal to hunt, possess, maliciously harass 

or kill, or to maliciously destroy the nests of pygmy rabbits, they do not prohibit 

incidental take of the species nor do they provide regulatory protection of habitats 

considered essential to the Columbia Basin pygmy rabbit’s long-term security. 

There are also areas of private land within the species' historical distribution 

enrolled under the Conservation Reserve Program, which incorporates standards 

to promote the improvement of habitats potentially used by the Columbia Basin 

pygmy rabbit. However, the prescribed standards do not specifically address 

conservation of this species, participation is voluntary, and contracts expire after 

10 years. This threat would be addressed by the recovery actions through the 

establishment and support of recovery emphasis areas and implementation of a 

Safe Harbor Agreement that has been established to promote the recovery of the 

population. In addition, intervening Federal properties outside of recovery 

emphasis areas will contribute to recovery efforts. 

Listing Factor E: Other natural or manmade factors affecting the population’s 

continued existence: The most immediate concerns for the Columbia Basin 

pygmy rabbit are associated with the population’s small size and possible 

extirpation from the wild, since small populations are highly susceptible to 

random environmental events and demographic and genetic limitations (Shaffer 

1981). This threat would be addressed by the recovery actions through successful 

implementation of the Captive Breeding and Genetics Management Plan and 

Reintroduction Plan. 

1. Reclassification from Endangered to Threatened Status

Because of uncertainties with regard to how recovery of the Columbia Basin 

pygmy rabbit will progress as recovery actions are implemented, several recovery 

criteria based on the above threat factors and overall recovery strategy have been 

identified. In addition, recovery criteria may be met in the near or long term, 

depending on the overall effectiveness of recovery efforts. We will consider 

reclassification of the Columbia Basin pygmy rabbit pursuant to the measures 

prescribed by the Endangered Species Act if any one of the following criteria 

have been met: 

60 
a. Subpopulations at two recovery emphasis areas each have a 5-year average Ne

of at least 375 individuals, and a third recovery emphasis area has been 

formally established through completion of one or more appropriate 

cooperative agreements and is available for initial reintroduction efforts. 

b. A subpopulation at one recovery emphasis area has a 5-year average Ne of at 

least of 250 individuals, and subpopulations at two other recovery emphasis 

areas each have a five-year average Ne of at least 125 individuals. 

c. A single subpopulation with a 5-year average Ne of at least of 750 individuals 

has been reestablished through dispersal and range expansion from one or 

more recovery emphasis areas, and appropriate cooperative agreements have 

been reached to include the newly occupied habitats within the recovery 

emphasis area(s) involved and/or management measures to protect identified 

dispersal corridors have been implemented. 

2. Removal from the List of Endangered and Threatened Wildlife and 

Plants 

We have determined that defining credible delisting criteria is not possible at this 

time, given the uncertainties associated with the Columbia Basin pygmy rabbit, 

which include, in part, identifying appropriate density estimates, effective 

population size(s), dispersal corridor habitat and management conditions, effects 

of disease and predation, seasonal movement patterns, and the effectiveness of 

future captive breeding, genetics management, and reintroduction efforts. 

However, near term recovery objectives have been identified (see Recovery 

Objectives, p. 57) and appropriate recovery actions developed that would help 

provide this information. These recovery actions include, in part, ongoing 

surveys for free-ranging individuals or subpopulations, augmenting the captive 

population with additional purebred Columbia Basin pygmy rabbits, as available, 

to maximize their genetic representation within the captive breeding program, 

monitoring survival and movement of newly released Columbia Basin pygmy 

rabbits, addressing existing constraints or management needs within recovery 

emphasis areas and appropriate intervening properties, and annually updating 

specific methods and techniques in the Captive Breeding and Genetics 

Management Plan and Reintroduction Plan. 

61 
IV. Recovery Program

Based on the best available information and the near-term recovery objectives and 

criteria established above, we have identified the following recovery actions that 

are considered necessary to advance Federal recovery of the Columbia Basin 

pygmy rabbit. 

Action 1: Manage the captive breeding program for the Columbia 

Basin pygmy rabbit. 

1.1 – Identify and produce an appropriate number and type of pygmy

rabbits needed to maintain a viable captive population (also see action 

2.1). 

 

The captive breeding facilities currently contributing to recovery efforts include 

the Oregon Zoo, Washington State University, and Northwest Trek Wildlife Park. 

WE provide coordination among the facilities along with the Washington 

Department of Fish and Wildlife. A Captive Breeding and Genetics Management 

Plan guides the breeding efforts and is updated annually (WDFW 2007). Current 

estimates indicate a captive population of approximately 70 animals entering the 

breeding season will maintain its genetic diversity. Further assessment of the 

captive population will be ongoing and this target number will be refined, as 

necessary. 

 

1.2 – Identify and produce an appropriate number and type of pygmy

rabbits needed to support reintroduction and augmentation efforts (also 

see action 4.3). 

The appropriate number and type of captive-bred pygmy rabbits needed for 

reintroduction and augmentation efforts will be estimated from developing 

population viability analyses (WDFW 2005b; Sayler et al. 2007), studies of 

captive-bred Idaho pygmy rabbits released in Idaho under experimental 

conditions, and, ultimately, from monitoring of release efforts in Washington. A 

Reintroduction Plan has been developed by researchers at Washington State 

University in cooperation with the Washington Department of Fish and Wildlife 

(Sayler et al. 2007). This plan and the Captive Breeding and Genetics 

Management Plan help define the appropriate makeup for release groups, seasonal 

62 
timing for initial releases, post-release monitoring actions, and projected timing 

for subsequent releases, as well as other specific release procedures (e.g., 

provision of temporary holding pens, artificial burrows, supplemental feeding). 

1.3 – Identify and maintain appropriate configuration of captive breeding 

facilities to support actions 1.1 and 1.2. 

Captive breeding efforts are currently distributed between three facilities to 

provide sufficient space and the necessary expertise to support an appropriate 

captive population, and to reduce the risk of disease transmission or other 

potential threats at a single facility. Washington State University, as a research 

facility, will eventually reduce captive breeding efforts over time. As necessary, 

additional captive breeding facilities will be established to maintain the program

until it is no longer needed to ensure recovery. 

1.4 – Continue to develop and test new techniques to improve husbandry 

of captive pygmy rabbits, and implement as appropriate. 

This includes a wide variety of investigations, including work to improve the diet, 

veterinary procedures, and breeding strategies for captive pygmy rabbits. As it 

often takes a number of years to accumulate large enough sample sizes to 

determine if one method may have advantages over another, it is expected that 

continued refinements of husbandry and breeding techniques will be implemented 

throughout the initial phases of recovery. 

 

1.5 – Improve reproductive success of captive pygmy rabbits. 

1.5.1 – Determine whether captive animals can breed in soil-free 

pens. 

The captive breeding facilities are in the preliminary stages of investigating soilfree breeding, and have had small-scale experiments to refine captive breeding of 

pygmy rabbits in non-soil environments. Off-soil husbandry and breeding could 

help address disease issues and improve survival and reproductive success of 

captive pygmy rabbits. Additional investigations will be conducted and, as 

available, improvements will be implemented over the next several years. 

63 
1.5.2 – Determine whether larger breeding pens can: a) allow 

multiple animals to be successfully held and bred at the same 

time; and b) increase reproductive performance. 

Initial experiments in 2005 and 2006 suggest that two males can be held and bred 

with one female in a larger pen, but experiments with two females in one large 

pen were inconclusive. Reproductive performance of captive pygmy rabbits was 

improved with breeding in larger pens versus smaller pens. However, due to 

small, initial sample sizes, additional testing will be needed and investigations 

will continue in future breeding seasons. 

1.5.3 – Continue to investigate progesterone monitoring for 

early pregnancy detection. 

Laboratory analyses from 2002 through 2004 showed that progesterone can be 

detected in pygmy rabbit feces, but progesterone levels vary across the 

reproductive cycle. Further work to accurately measure a combination of fecal 

hormones in captive and wild pygmy rabbits may help develop techniques for 

assessing the reproductive status of free-ranging animals. 

 

1.5.4 – Continue to investigate the use of artificial insemination. 

The poor reproductive performance of Columbia Basin pygmy rabbits resulted in 

several genetically important animals dying without successfully reproducing. 

The purpose of this research is to develop artificial insemination techniques to 

help maintain genetic diversity within the captive Columbia Basin pygmy rabbits 

through direct reproductive intervention. Preliminary investigations in 2004 

showed some promise for further developing this technique. As feasible (e.g., 

considering funding needs, available animals), additional research will be

conducted to refine necessary procedures. 

1.5.5 – Continue to identify, prioritize, and pursue other 

reproductive research objectives. 

Poor reproduction of purebred Columbia Basin pygmy rabbits in captivity has 

limited growth of the population and delayed reintroduction efforts. Further work 

is necessary to examine the cause(s) of the poor reproduction and to develop 

64 
adaptive solutions to increase reproductive success of the captive animals. Some

of the topics that will be examined include links between reproductive success 

and nutrition, stress, and social groupings, harvesting and preserving ovaries of

genetically important females at death, and further investigations of pygmy rabbit 

reproductive behaviors. 

1.6 – Improve survival of captive pygmy rabbits. 

1.6.1 – Develop effective disease prevention and treatment 

measures for captive pygmy rabbits (also see actions 1.5.1, 

2.1.2, and 4.2.2). 

Infectious disease (e.g., mycobacteriosis) and intestinal parasitism (e.g., 

coccidiosis) are two of the major causes of mortality in captive adult and juvenile 

pygmy rabbits, respectively. Clinical trials over the past several years have led to 

the development of prevention and treatment methods that have met with some

success. Refinement of these methods and continued investigation into additional 

methods will be necessary to maximize the contributions that genetically valuable 

adults make to the captive population and to increase the survival of juveniles. 

1.6.2 – Continue to investigate mortalities of captive pygmy 

rabbits and implement available measures to minimize future 

threats. 

 

In order to manage the health of captive pygmy rabbits, it is necessary to know 

the causes of morbidity and mortality in the population. This can most effectively 

be done by routinely screening the health of live pygmy rabbits and by thoroughly 

investigating all mortalities for which the cause of death is not immediately 

apparent. 

 

1.7 – Update Captive Breeding and Genetics Management Plan annually 

(also see action 2). 

The Captive Breeding and Genetics Management Plan is a document that 

identifies the most genetically important individuals and guides priorities for 

pygmy rabbit pairings each year. Computer software designed for endangered 

species conservation applications (American Zoological and Aquarium

65 
Association Population Management 2000) is used to help develop the breeding 

priorities and planned pairings. This software integrates tools for demographic 

and genetic analysis of pedigrees, and guides users through management 

decisions for meeting demographic objectives while maintaining genetic diversity 

in closed populations of rare animals 

(http://www.ansci.cornell.edu/cat/completed.html). Lists of compatible 

individuals are sent to the captive breeding facilities, which use the lists to 

manage available pairings throughout the breeding season. As necessary to 

accommodate important pairings, captive pygmy rabbits may be moved among 

the facilities. However, movements between facilities are minimized to the extent

possible and veterinary screening of any pygmy rabbits involved is undertaken to 

further reduce the risk of incidental disease transmission. 

Action 2: Manage genetic characteristics of the Columbia Basin 

pygmy rabbit.

2.1 – Optimize genetic diversity of the captive population. 

The genetic characteristics of all captive pygmy rabbit offspring are assessed by 

the Washington Department of Fish and Wildlife following each breeding season 

(WDFW 2006). Several methods are undertaken to optimize the genetic diversity 

of the captive Columbia Basin pygmy rabbit population, including: a) attempting 

to equalize representation among the Columbia Basin founders; b) careful 

introduction and assessment of non-Columbia Basin pygmy rabbits into the 

captive breeding program (i.e., intercrossing); and c) refining population genetics 

modeling, which will facilitate minor changes in breeding scenarios each year to 

improve the captive population’s genetic diversity, and will also lead to better 

understanding of the long-term implications of captive breeding and genetics 

management results. 

2.1.1 – Maintain unique genetic characteristics of the Columbia 

Basin pygmy rabbit within the captive population. 

Strategies to accomplish this include selecting individuals with the desired genetic 

makeup to breed with one another, allowing one male to mate with multiple 

females, and providing larger pens for breeding. 

66 
2.1.2 – Implement intercross breeding to ensure that the captive 

population has sufficient genetic diversity, while minimizing the 

genetic representation of foreign pygmy rabbit populations. 

This is a critical task undertaken by the Washington Department of Fish and 

Wildlife geneticists, and is addressed and documented in annual updates of the 

Captive Breeding and Genetics Management Plan (WDFW 2007). 

2.1.3 – Augment captive population with additional wild 

Columbia Basin pygmy rabbits, as available, to maximize their 

genetic representation within the captive breeding program. 

Columbia Basin pygmy rabbits are believed to be extirpated from the wild. 

However, if additional wild Columbia Basin pygmy rabbits are located during 

future surveys, they will be secured, as appropriate (see Survey and Capture, p. 

45), to help maintain or improve the genetic diversity of the captive population. 

2.1.4 – Evaluate and manage the genetic characteristics of the 

captive population to determine appropriate animals to maintain 

in captivity each year. 

Computer software has been developed by conservation geneticists and 

population biologists in conjunction with the American Zoological and Aquarium

Association for use in endangered species management (Population Management 

2000). Use of this software is helpful for both the captive breeding and genetics 

management aspects of recovery efforts for the Columbia Basin pygmy rabbit. 

2.2 – Manage genetic diversity of free-ranging subpopulations. 

2.2.1 – Obtain tissue samples of free-ranging animals, as 

necessary, to assess and/or monitor the genetic characteristics of 

all known free-ranging subpopulations. 

Any remaining and/or reestablished free-ranging subpopulations will be sampled 

for both genetic and population monitoring purposes. Initially, 50 percent of the 

estimated population (both re-captures of released animals and new offspring) 

will be sampled over the first 2 years; the appropriate percentage will be 

67 
reevaluated for future efforts. The molecular diversity in the free-ranging 

population will be evaluated for changes over time to determine if, and to what 

extent, the free ranging population(s) become differentiated from the captive 

population. 

2.2.2 – Augment free-ranging subpopulations with captive 

animals and/or translocate pygmy rabbits from other occupied 

sites, as appropriate (see Survey and Capture, p. 45), to maintain 

appropriate genetic characteristics in the wild. 

In the unlikely event that one or more large, free-ranging subpopulations are 

located during future surveys, the genetic health of the subpopulation will be 

evaluated (see action 2.2.1) and appropriate management measures undertaken 

(e.g., capture, translocation, protection) to maximize the genetic diversity of the 

Columbia Basin pygmy rabbit and to otherwise accomplish the near-term 

recovery objectives that have been identified. 

Action 3: Survey for and monitor free-ranging Columbia Basin 

pygmy rabbits.

3.1 – Search for new subpopulations. 

If any additional free-ranging, purebred Columbia Basin pygmy rabbits persist, 

they could provide a significant benefit to conservation of this population. Much 

of the remaining shrub steppe habitat within the population’s historical 

distribution has been surveyed without locating any additional wild pygmy rabbits 

since 2004. However, the possibility still exists that free-ranging subpopulations 

may remain in areas that have not yet been surveyed. 

3.1.1 – Prioritize and document potential search areas based on 

likelihood of identifying previously unknown occurrences. 

 

Mapping exercises have been undertaken, using existing databases, to identify 

areas of appropriate soils and habitat conditions to prioritize areas of public and 

private lands for ongoing search efforts for the Columbia Basin pygmy rabbit. 

Private lands are only surveyed with the consent of individual land owners and/or 

68 
appropriately designated managers (also see Stakeholder Involvement, p. 42; 

action 7). 

3.1.2 – Continue to survey public properties within the highest 

priority area(s). 

3.1.3 – Continue to contact land owners and managers within 

the highest priority area(s) and pursue cooperative agreements to 

undertake surveys and, as appropriate, implement monitoring 

and management measures for the Columbia Basin pygmy 

rabbit. 

 

3.1.4 – Consolidate and document updated survey results and 

cooperative agreement measures annually. 

 

3.2 – Monitor free-ranging subpopulations and document their status 

annually. 

Free-ranging pygmy rabbits will be monitored using the Skalski monitoring 

method, or similar method(s) (see Survey and Capture, p. 45). Initially, freeranging subpopulations will be monitored annually. The monitoring method used 

and frequency of monitoring will be continually assessed and, as necessary, 

updated and included within a revised Reintroduction Plan (see action 4.8). 

3.2.1 – Coordinate survey data collection, maintenance, and 

reporting among affected parties. 

3.2.2 – Continue to develop and improve abundance indices of 

overall and effective population sizes based on counts of active 

burrows, and to refine appropriate survey and monitoring 

techniques for free-ranging subpopulations. 

Appropriate indices based upon counts of active burrows will be needed to 

evaluate the annual status and trends of free-ranging subpopulations, and/or to 

infer changes in life history parameters attributed to various experimental 

treatments or adaptive management measures. Updated survey and monitoring 

techniques are being investigated for pygmy rabbits throughout the species’ 

69 
range. This work, along with ongoing investigations of newly released Columbia 

Basin pygmy rabbits, will facilitate continued improvement of these techniques. 

3.2.3 – Develop and continue to refine criteria for evaluating 

and establishing appropriate management and habitat conditions 

for pygmy rabbit dispersal corridors.

Criteria based upon appropriate management and habitat conditions will be 

needed to evaluate the potential contributions of intervening properties to 

facilitate dispersal and/or expansion of free-ranging subpopulations beyond 

recovery emphasis areas. 

Action 4: Reestablish free-ranging Columbia Basin pygmy rabbit 

subpopulations within their historical distribution. 

4.1 – Formally establish (i.e., enroll under a cooperative agreement, see 

action 7) and continue to manage recovery emphasis areas that have 

been identified. 

Two high priority recovery emphasis areas have been identified and are currently 

being managed to accommodate initial reintroduction efforts for captive-bred 

Columbia Basin pygmy rabbits (see Reintroduction, p. 38). These areas are 

comprised of lands under Washington Department of Fish and Wildlife, nongovernmental organization, and private ownership or management authority. 

4.1.1 – Continue to pursue cooperative agreements with parties 

interested in having pygmy rabbits released on their properties 

and/or including their properties within one or more recovery 

emphasis area(s) (see action 7). 

4.1.2 – Through annual review and, as appropriate, revision, 

ensure that all conservation measures prescribed by existing 

cooperative agreements are active and adequate to accommodate 

Federal recovery efforts for the Columbia Basin pygmy rabbit. 

70 
4.2 – Prepare recovery emphasis areas for reintroduction and/or 

augmentation of captive-bred Columbia Basin pygmy rabbits (also see 

action 4.8). 

A Reintroduction Plan has been developed that identifies specific procedures for 

release and monitoring of captive-bred Columbia Basin pygmy rabbits (see 

Reintroduction, p. 38). Preparation of recovery emphasis areas may also include 

prior monitoring and, as feasible, control of disease vectors and predator 

occurrences that may negatively affect newly released Columbia Basin pygmy

rabbits. 

4.2.1 – Monitor predators at release sites and, as feasible (e.g., 

contingent on Agreement conditions), implement interim

predator control measures to minimize loss of novice animals 

(also see actions 5.1 and 6.3). 

Monitoring and, as feasible, implementing appropriate measures to control 

predators will be one of the biggest challenges of initial release efforts. Principal 

predators of concern include coyotes, weasels, badgers, ravens, and various raptor 

species. It may be feasible and effective to control only one or two key predators, 

or simply monitor their abundance, during initial release efforts. Various 

measures have previously been implemented at the identified recovery emphasis 

areas to address predators (see Predator Control, p. 49). Weasels have been 

observed in and around pygmy rabbit burrows in the past, and have successfully 

preyed upon newly released Idaho pygmy rabbits. Coyotes were observed 

bedding directly adjacent to active Columbia Basin pygmy rabbit burrows at the 

last known occupied site in southern Douglas County. As feasible, preventive 

control will be conducted prior to and through the first breeding season. Further 

evaluation of predation effects by predator species and survival / habitat 

relationships (e.g., key contributing habitat features) of newly released Columbia 

Basin pygmy rabbits will be conducted to determine the efficacy of any initial, 

and possible need for continuing, predator control measures at recovery emphasis 

areas. 

4.2.2 – Monitor for disease vectors at release sites and, as 

feasible, implement measures to reduce the risk of infection and 

transmission in free-ranging Columbia Basin pygmy rabbits. 

71 
Monitoring for diseases at reintroduction sites will be undertaken approximately 6 

months prior to release. The presence of significant disease vectors at a release 

site may preclude immediate release of captive-bred animals to the area. As 

available, preventive measures (e.g., flea treatments) would be taken prior to 

release. 

4.2.3 – Provide supplemental features at release sites (e.g., prerelease pens, artificial burrows, feeding stations) to improve the 

survival of novice animals, as necessary. 

Pre-release pens and supplemental feeding were used in the experimental releases 

of Idaho pygmy rabbits, and may be used to acclimate some Columbia Basin 

pygmy rabbit release groups at release sites. Artificial burrows have been used 

successfully in the conservation of a number of fossorial species, including blackfooted ferrets (Mustela nigripes), giant kangaroo rats (Dipodomys ingens), prairie 

dogs (Cynomys spp.), and burrowing owls (Athene cunicularia). Provision of 

artificial burrows also appeared to increase survival of Idaho pygmy rabbits 

during experimental releases in Idaho, and they will be provided at recovery 

emphasis areas for Columbia Basin pygmy rabbit releases. 

4.3 – Determine the appropriate captive animals to be released into the 

wild each year by evaluating the genetic characteristics and 

demographics of any free-ranging subpopulations and the captive 

population (also see actions 2 and 4.8). 

4.4 – Conduct reintroduction, augmentation, and/or translocation efforts at 

the highest priority recovery emphasis area(s) (also see action 2.2.2). 

Of several potential sites evaluated (see Reintroduction, p. 38), the two currently 

identified recovery emphasis areas have the highest quality habitat, supported 

pygmy rabbits in the recent past, and have various other management advantages 

that would facilitate pygmy rabbit conservation (e.g., controlled recreation, 

reduced disturbance, exclusion fencing, predator and fire abatement measures, 

existing road management). 

72 
4.5 – Monitor survival and movement of newly released Columbia Basin 

pygmy rabbits (also see action 4.8). 

4.5.1 – As feasible considering equipment and workforce 

availability, all or an appropriate proportion of Columbia Basin 

pygmy rabbits released at recovery emphasis areas will be fitted 

with radio transmitters to monitor their movements, habitat use 

patterns (see action 6.1.1), and causes of mortality. 

Radio-transmitters have been used successfully for pygmy rabbit research over a 

number of years and throughout the range of the species, including the 

experimental releases in Idaho. Risk of mortality due to the transmitters is low. 

Radio-telemetry monitoring is the primary means by which movements, habitat 

use patterns, and mortality factors of released animals can be assessed. 

4.5.2 – Develop and follow protocols to manage Columbia 

Basin pygmy rabbits that may disperse beyond recovery 

emphasis areas (also see action 7). 

Newly released Columbia Basin pygmy rabbits will likely continue to disperse 

beyond recovery emphasis areas. Appropriate measures will be implemented to 

contact and pursue cooperative agreements with land owners and managers of 

intervening properties. Initially, workloads will be prioritized to address 

intervening properties within 8 km (5 mi) of the recovery emphasis area(s) used 

for initial reintroductions, and other as-yet unsurveyed properties that contain 

“survey habitat” (see Glossary, p. 101) and that have the greatest potential to still 

harbor free-ranging Columbia Basin pygmy rabbits. As resources and workloads 

allow, pursuing cooperative agreements for other intervening properties within the 

historical distribution of the Columbia Basin pygmy rabbit will be addressed. 

4.6 – Continue to investigate, identify, and address existing constraints or 

management needs of recovery emphasis areas and, as feasible (i.e., 

contingent on cooperative agreement conditions), intervening 

properties that support additional occupied habitats or identified 

dispersal corridors of newly released Columbia Basin pygmy rabbits 

(also see actions 5, 6, and 7). 

73 
4.7 – Continue to assess and identify the appropriate sizes, number, 

distribution, and configuration of free-ranging subpopulations 

necessary to delist the Columbia Basin pygmy rabbit pursuant to the 

Endangered Species Act, and define criteria that would demonstrate 

that threats to the population are sufficiently ameliorated (also see 

actions 5, 6, and 7). 

Areas that are of sufficient size and that contain appropriate shrub steppe habitat 

and soil conditions that would be considered capable of supporting a viable 

subpopulation of Columbia Basin pygmy rabbits are relatively rare. To be 

consistent with the identified recovery strategy, potential sites would also need to 

represent willing public or private conservation management authority and 

flexibility to support long-term conservation efforts for the Columbia Basin 

pygmy rabbit. Other considerations include current information gaps, such as 

appropriate density estimates and other population modeling parameters, future 

effects of diseases and predation, and the habitat use, seasonal movement, and 

dispersal behaviors of newly released animals. The management direction 

currently identified emphasizes protection and enhancement of habitat conditions 

at existing recovery emphasis areas and, as feasible, maintaining habitat 

conditions and implementing appropriate protection measures on intervening 

properties. Additional recovery emphasis areas will be identified, prioritized, and 

formally established, and/or appropriate intervening properties will be protected 

as the information base concerning the Columbia Basin pygmy rabbit improves, 

and as feasible through appropriate cooperative agreements, in order to meet the 

identified near-term recovery objectives and reclassification criteria. 

4.8 – Update the specific methods and techniques in the Reintroduction 

Plan annually. 

The number of captive-bred Columbia Basin pygmy rabbits required to be 

released annually will ultimately be based on the survival and reproductive 

success of previously released animals and the overall status of subpopulations at 

recovery emphasis areas. There will be an annual reiterative process of refining 

the number of animals to be released each year, as well as release techniques and 

post-release monitoring strategies. Other information needs include evaluating 

potential effects of pre-release pens, supplemental feeding, seasonality and timing 

of releases, predator control, and differing make-up of release groups. Ongoing 

74 
investigations will lead to an increasingly consistent, effective approach to 

reestablish subpopulations of Columbia Basin pygmy rabbits. 

Action 5: Protect free-ranging Columbia Basin pygmy rabbits. 

5.1 – Evaluate and address, as feasible, the potential effects of predators 

on free-ranging Columbia Basin pygmy rabbits (also see action 

4.2.1). 

If predation appears to be limiting initial reestablishment or growth of Columbia 

Basin pygmy rabbit subpopulations, control measures will be implemented to 

maintain and increase existing subpopulations. 

5.1.1 – Remove or manage potential predator attractants that 

could be used as perches, cover, or supplemental food sources 

(e.g., power poles, old fences, outbuildings, unused equipment, 

spilled grain, refuse) to reduce the occurrence of local predators, 

as necessary (see Predator Control, p. 49). 

5.1.2 – Continue annual surveys to determine relative abundance 

of predators at recovery emphasis areas. 

5.2 – Identify and minimize effects of human activities on Columbia 

Basin pygmy rabbits at recovery emphasis areas and, as feasible (i.e., 

contingent on cooperative agreement conditions), intervening 

properties. 

A variety of land management activities have the potential to negatively affect 

pygmy rabbits. Further investigation and adaptive management measures to 

address potential risks from various land management activities will be

undertaken as opportunities arise. For example, additional information will help 

clarify the compatibility of various recreational activities (e.g., hunting), 

infrastructure management (e.g., roads, power lines), grazing plans, fire control 

measures, and research investigations with pygmy rabbit conservation objectives. 

75 
5.2.1 – Avoid development of new, or expansion of existing 

roads and trails, and restore habitats on obsolete roads and trails 

in occupied areas. 

5.2.3 – Protect burrow complexes at occupied sites from

disturbances and direct impacts due to existing and proposed 

land use practices (e.g., grazing management, recreational use, 

research projects), except under experimental conditions 

designed to further evaluate the practice(s). 

5.3 – Enforce Federal regulations that protect Columbia Basin pygmy 

rabbits from unauthorized “take” (e.g., killing, harm, harassment [see 

Glossary, page 72]). 

Action 6: Manage habitats at recovery emphasis areas to support 

stable, self-sustaining subpopulations of free-ranging 

Columbia Basin pygmy rabbits. 

6.1 – Continue to investigate and refine estimates of the quantity and 

quality of habitats needed to support a viable subpopulation of freeranging Columbia Basin pygmy rabbits (also see action 4.8). 

Future planned research of reestablished, free-ranging Columbia Basin pygmy 

rabbit subpopulations will improve habitat assessments and population density 

estimates that, in turn, will facilitate refinements of the Federal recovery 

objectives, criteria, and actions currently identified for the Columbia Basin pygmy 

rabbit. 

6.1.1 – Document habitat use patterns of free-ranging Columbia 

Basin pygmy rabbits at recovery emphasis areas (e.g., forage 

selection, condition, and quality; cover requirements; seasonal 

movements). 

This is an integral part of initial research planning and monitoring needs for freeranging Columbia Basin pygmy rabbit subpopulations. 

76 
6.1.2 – As feasible (i.e., contingent on cooperative agreement 

conditions), evaluate contributions to recovery emphasis areas 

from available habitats on intervening properties, including any 

that are managed pursuant to programs administered by the U.S. 

Department of Agriculture (e.g., Conservation Reserve Program 

(CRP)). 

In the past, Columbia Basin pygmy rabbits have been observed using lands 

enrolled under the Conservation Reserve Program directly adjacent to shrub 

steppe habitat. However, it is currently unknown how and to what extent 

reestablished subpopulations of Columbia Basin pygmy rabbits may use these 

lands or other altered habitats within or adjacent to recovery emphasis areas, or 

which components of these alternative habitats may function as pygmy rabbit 

habitat. 

6.1.3 – Develop and refine habitat models (e.g., Habitat 

Suitability Index) for Columbia Basin pygmy rabbits at both 

local and landscape scales. 

 

Efforts to develop and refine habitat models for Columbia Basin pygmy rabbits 

will allow for improvements in identified recovery actions and management of

available habitats. 

6.1.4 – Through coordination with the Science Team and 

Recovery Team, solicit expertise (e.g., biological, ecological, 

management) to identify and prioritize appropriate research 

objectives and methodologies that will inform continuing 

development and refinement of habitat and population 

estimators and modeling exercises. 

6.2 – Protect habitats at recovery emphasis areas and, as feasible (i.e., 

contingent on cooperative agreement conditions) intervening 

properties (see action 7). 

6.2.1 – Monitor changes in habitats through remote sensing, 

ground surveys, and mapping. 

77 
A variety of remote sensing techniques have been developed to assess habitat 

quality. These techniques are being tested at several sites in the Columbia Basin. 

Ground-based sampling to monitor habitat quality was conducted in the past, and 

will continue to be conducted at various intervals (e.g., 5 to 10 years) unless more 

effective techniques are developed. Habitat maps will be produced for recovery 

emphasis areas and other potentially used intervening properties pursuant to any 

existing cooperative agreements (see action 7). 

 

6.2.2 – Continue to work with local land owners and managers 

to develop fire management plans and, as appropriate, 

implement measures to reduce the risk of catastrophic loss of

important shrub steppe habitat (e.g., provide firebreaks, monitor 

and control ignition sources, develop agreements with local fire 

districts). 

A fire management plan has been developed or is in the process of being 

developed for each of the currently identified recovery emphasis areas. 

Firebreaks have been constructed and are currently maintained at one recovery 

emphasis area. 

6.2.3 – As necessary, provide exclusion fencing at recovery 

emphasis areas to protect habitats from unauthorized access and 

potentially negative impacts. 

Perimeter fencing has been installed and maintained at key sites on both recovery 

emphasis areas to help manage unauthorized access. 

6.3 – Continue to investigate and, as feasible, implement enhancement 

and restoration measures to improve habitat quantity and quality for 

Columbia Basin pygmy rabbit subpopulations at recovery emphasis 

areas. 

As ongoing research improves our understanding of shrub steppe habitat 

components required by free-ranging Columbia Basin pygmy rabbits, adaptive 

management measures will be implemented, as available, to appropriately 

manipulate available habitats. 

78 
6.4 – Document methods, treatments, timing, and results of all habitat 

enhancement, restoration, and protection projects undertaken for freeranging Columbia Basin pygmy rabbits and maintain those records to 

facilitate long-term habitat monitoring (also see action 4.8). 

Maintaining adequate records will allow future assessments of what specific 

management measures contribute to successful shrub steppe habitat manipulation 

projects. 

6.5 – As necessary to achieve near-term recovery objectives, continue to 

identify, assess, and prioritize potential recovery emphasis areas and, 

as appropriate, formally establish and provide recommendations to 

address habitat management needs at these sites (also see actions 4.7 

and 6.1). 

Potential future recovery emphasis areas on public and willing land owner or 

manager properties will be identified, assessed, and prioritized, as necessary. Key 

areas that can be formally established will be managed to accommodate future 

reintroductions and reestablishment of Columbia Basin pygmy rabbit 

subpopulations. Management recommendations for these sites (e.g., habitat 

enhancement and/or protection measures, exclusion fencing) will be developed 

and provided for future planning considerations. 

6.5.1 – Continue to collect site-specific habitat information at all 

potential recovery emphasis areas. 

Habitat information specifically addressing Columbia Basin pygmy rabbit 

conservation needs (e.g., shrub cover, height, and distribution; soil characteristics) 

will be collected. Other important considerations for potential future sites 

include, but are not limited to, their overall size, available slopes, presence of 

weedy species, existing road systems, fire history, and management access. 

6.5.2 – Review management plans for public lands and, as 

feasible (e.g., contingent on cooperative agreement conditions), 

other intervening properties affecting potential recovery 

emphasis areas to determine compatibility of the site(s) with 

pygmy rabbit conservation measures (also see action 7). 

79 
Provide public land managers and other neighboring land owners and managers 

information regarding compatibility of near and long term management 

considerations for Columbia Basin pygmy rabbit recovery efforts. 

6.6 – As feasible through cooperative agreements (see action 7), 

incentives, conservation easements, and/or willing acquisition or 

exchange, increase the size of recovery emphasis areas or otherwise 

develop and implement habitat protection measures at key occupied 

sites and/or identified dispersal corridors beyond established recovery 

emphasis area boundaries. 

While intervening properties may not be actively managed to conserve the 

Columbia Basin pygmy rabbit, they may nevertheless contribute to recovery 

efforts (see Recovery Strategy, p. 50). Early identification of future needs and 

available options for managing additional habitat for reestablished Columbia 

Basin pygmy rabbit subpopulations will be important for achieving the identified 

recovery objectives. The successful implementation of cooperative agreements 

and proactive management measures may play an important role in providing 

sufficient habitats for recovery, and will increase public awareness and support 

for the Columbia Basin pygmy rabbit recovery program. 

Action 7: Pursue cooperative agreements for the Columbia Basin 

pygmy rabbit with land owners and managers of intervening 

properties within the population’s historical distribution. 

7.1 – Develop Site Plans under the existing Agreement and issue 

associated Permits to non-Federal and non-WDFW land owners and 

managers of eligible properties whose ongoing management may 

provide a net conservation benefit for recovery efforts, yet whose land 

use practices may also result in incidental take of free-ranging 

Columbia Basin pygmy rabbits (see Stakeholder Involvement, p. 42). 

7.1.1 – Contact land owners and managers generally within 8 

kilometers (5 miles) of recovery emphasis areas to provide 

information on recovery efforts for the Columbia Basin pygmy 

80 
rabbit and to address future management options for 

reintroduced animals that may disperse onto their properties. 

Land owners and managers in the vicinity of identified recovery emphasis areas 

will be contacted and notified of any future releases of Columbia Basin pygmy

rabbits, and invited to take part in the Agreement. 

7.1.2 – Determine baseline conditions and monitoring protocols, 

as necessary, for properties of any land owners or managers 

interested in participating in the Agreement. 

Baseline conditions will be established through surveys carried out by qualified 

personnel and at the discretion of the interested land owner or manager. 

7.2 – Develop and provide guidelines and technical assistance to 

interested land owners and managers to address management practices 

that could potentially affect free-ranging Columbia Basin pygmy 

rabbits (e.g., grazing regimes, recreational activities, restoration 

projects). 

7.3 – Assist interested non-Federal and non-Washington Department of 

Fish and Wildlife land owners and managers develop new Habitat 

Conservation Plans, or otherwise assist with participation in existing 

Habitat Conservation Plans, with regard to management practices that 

may result in the incidental take of free-ranging Columbia Basin 

pygmy rabbits. 

7.3.1 – Develop measures to minimize and mitigate incidental 

take of Columbia Basin pygmy rabbits to the maximum extent 

practicable. 

Appropriate management guidelines will be developed and incorporated into a 

multi-species Habitat Conservation Plan that is currently being developed by the 

Foster Creek Conservation District. If finalized, incorporation of these guidelines 

will ensure that impacts to the Columbia Basin pygmy rabbit resulting from

otherwise lawful activities conducted on private, agricultural lands throughout 

Douglas County are mitigated to the maximum extent practicable. These 

81 
guidelines will also assist with management considerations for Columbia Basin 

pygmy rabbits that may occur on private, agricultural lands throughout the 

population’s historical distribution. 

7.3.2 – Assist with development of Certificates of Inclusion for 

land owners and managers interested in participating in new or 

existing Habitat Conservation Plans. 

7.4 – Continue to coordinate recovery efforts with various Federal 

agencies (e.g., Bureau of Land Management, U.S. Fish and Wildlife 

Service, Bureau of Reclamation, Department of Energy) pursuant to 

the requirements of section 7 of the Endangered Species Act and, as 

opportunities arise, develop and implement cooperative agreements to 

address Federal conservation initiatives for the Columbia Basin 

pygmy rabbit. 

7.5 – Continue to identify and secure funding sources to assist interested 

land owners and managers with development of cooperative 

agreements, implementation of recovery actions, and/or to otherwise 

provide incentives for participating in conservation efforts for the 

Columbia Basin pygmy rabbit (also see action 9). 

Action 8: Exchange information with stakeholders and the general 

public to address concerns and increase support for 

Columbia Basin pygmy rabbit recovery efforts. 

8.1 – Continue to identify stakeholders and address issues of concern. 

By identifying all potential stakeholders, specific outreach efforts can be focused 

to better communicate significant resource issues concerning the Columbia Basin 

pygmy rabbit and to respond to stakeholder concerns. 

8.1.1 – Review history of comments at meetings, letters to the 

editor, and news stories to identify primary issues of concern to 

the general public regarding Columbia Basin pygmy rabbit 

recovery. 

82 
8.1.2 – Continue to develop and maintain lists of interested 

parties through public meeting sign-in sheets and submitted 

comments. Use these lists to develop notices for future 

meetings and/or targeted information mailings. 

 

8.2 – Meet or otherwise contact stakeholders and other concerned parties 

to communicate recovery information and to solicit input. 

Solicit input from stakeholders, other interested parties, and the general public 

through public meetings, targeted mailings, and other means. Conduct field trips 

for land owners and managers of intervening properties within the vicinity of 

recovery emphasis areas to discuss recovery planning for the Columbia Basin 

pygmy rabbit. 

8.2.1 – Initiate and respond to communications with 

stakeholders. 

8.2.2 – Organize and participate in additional public 

informational meetings with various stakeholders (e.g., county 

commissioners, industry groups, conservation organizations) at 

appropriate benchmarks, such as public comment periods and 

implementation of significant recovery actions. 

8.2.3 – Develop targeted mailings to key stakeholders to 

communicate as new information warrants and/or to solicit 

further input. 

8.3 – Engage local media through news releases and invitations to 

scheduled events to inform the public concerning recovery efforts for 

the Columbia Basin pygmy rabbit. 

Action 9. Secure funding for Columbia Basin pygmy rabbit recovery

efforts. 

9.1 – Continue cooperative efforts with a diverse group of stakeholders, 

other interested parties, and the general public in recovery planning 

for the Columbia Basin pygmy rabbit, including land owners and 

83 
managers of existing and potential future recovery emphasis areas and 

intervening properties. 

Both public and private land owners and managers may have interests in recovery 

of the Columbia Basin pygmy rabbit. Efforts to seek active involvement from

both the public and private sectors will be ongoing. Private land owners can 

obtain funds for conservation of Columbia Basin pygmy rabbits that may be 

separate from those that support State or Federal conservation efforts. 

9.2 – Establish a cooperative framework for matching and cost-sharing 

Federal and non-Federal funding sources. 

Various funding sources exist for conservation measures on private, State, and 

Federal properties. Cooperative projects will be better positioned to receive funds 

through successful integration of these sources for Columbia Basin pygmy rabbit 

recovery efforts. 

9.3 – Establish research and management connections between experts in 

pygmy rabbit biology and the greater shrub steppe ecosystem through 

publications and presentations addressing pygmy rabbits and their 

associated habitats. 

Pygmy rabbits are only one of a number of species of concern in the broader, 

semiarid shrub steppe biome. Additional funding opportunities are potentially 

available for research and management that incorporates multiple species. 

Through publications and presentations, a wider range of concerned managers and 

researchers will have a better understanding of the conservation needs of pygmy

rabbits which, in turn, will make their inclusion in future management and/or 

research programs more likely. 

Action 10: Revise the Federal Recovery Plan to facilitate 

implementation of adaptive management measures 

considered necessary to achieve the phased recovery

strategy. 

This Recovery Plan for the Columbia Basin pygmy rabbit should be reviewed and 

updated periodically, as necessary, as research and management activities 

84 
progress and as we gain further knowledge of the ecology and population biology 

of this species. The need for requisite data necessary to develop more precise and 

biologically accurate recovery criteria is recognized as a high priority. 

10.1 – Revise Implementation Schedule. 

Revised Implementation Schedules will be prepared, as necessary, to reflect the 

knowledge gained, accomplishments met, potential future constraints encountered 

(e.g., lack of funding, changing management priorities), and consequent 

refinements to near-term recovery objectives, criteria, and/or actions as recovery 

progresses. Annual updates of the Captive Breeding and Genetics Management 

Plan (see action 1.7) and the Reintroduction Plan (see action 4.8) will provide key 

information to assist with preparation of revised Implementation Schedules. In 

addition, monitoring and reporting measures associated with implementation of 

cooperative agreements with various stakeholders (see action 7) will also be used 

to help develop revised Implementation Schedules. 

V. Recovery Implementation 

The Implementation Schedule that follows lists the actions and estimated costs 

associated with the recovery program for the Columbia Basin pygmy rabbit. It is 

a guide for meeting the recovery goals outlined in this plan. Parties with

authority, responsibility, or expressed interest to implement a specific recovery 

action are identified in the Implementation Schedule. The listing of a party in the 

Implementation Schedule does not require, nor imply a requirement, that the 

identified party has agreed to implement the action(s) or to secure funding for 

implementing the action(s). However, parties willing to participate may benefit 

by being able to show in their budgets that their funding request is for a recovery 

action identified in an approved recovery plan and is therefore considered a 

necessary action for the overall coordinated effort to recover the Columbia Basin 

pygmy rabbit. Also, section 7(a)(1) of the Endangered Species Act directs all 

Federal agencies to utilize their authorities in furtherance of the purposes of the 

Endangered Species Act by carrying out programs for the conservation of 

endangered and threatened species. 

The following Implementation Schedule lists actions from the above Recovery 

Program that require funding. Various action statements identified in the 

85 
Recovery Program represent general recovery activities that do not lend 

themselves to specific funding estimates, rely on future adaptive management 

measures to refine them, and/or their costs and associated workloads are 

incorporated into a higher-order action of the same priority. As such, these 

actions are not repeated in the Implementation Schedule, but are described in the 

Recovery Program section. In addition to the cost estimates provided, the 

Implementation Schedule assigns priorities to the identified actions, lists which of

the five listing factors will be addressed by the proposed actions, estimates the 

duration of the actions, and identifies likely responsible parties for implementing 

the actions. 

A. DEFINITION OF ACTION PRIORITIES 

Recovery actions in the Implementation Schedule have been prioritized, with each 

action being assigned a "priority number" based on the following definitions. The 

Implementation Schedule identifies which of the following priorities applies to 

each recovery action:

Priority 1: Actions that must be taken to prevent the extinction of the species, or 

to prevent the species from declining irreversibly; 

Priority 2: Actions that must be taken to prevent a significant decline in the 

species’ abundance or distribution, or some other significant negative 

impact short of extinction; and 

Priority 3: All other actions necessary to provide for full recovery of the species. 

B. LISTING, RECLASSIFICATION, AND DELISTING FACTORS

We consider the role of five potential factors affecting a species (see Threats, p. 

18) in order to list, delist, or reclassify the species. The Implementation Schedule 

identifies which of the following factors will be addressed by each recovery 

action:

Factor A: The present or threatened destruction, modification, or curtailment of 

habitat or range; 

86 
Factor B: Overutilization for commercial, recreational, scientific, or educational 

purposes; 

Factor C: Disease or predation; 

Factor D: The inadequacy of existing regulatory mechanisms; and 

Factor E: Other natural or human-caused factors affecting the population’s 

continued existence. 

C. ACTION DURATION AND RESPONSIBLE PARTIES 

Only Federal agencies are mandated to take part in recovery efforts for the 

Columbia Basin pygmy rabbit, and we have a statutory responsibility to 

implement this Draft Recovery Plan. However, we anticipate that recovery of the 

Columbia Basin pygmy rabbit will require the involvement and cooperation of 

Federal, State, local, and private interests. We provide an estimated duration for 

each recovery action identified in the Implementation Schedule and identify the 

primary Federal and State agencies having the authority to implement the 

identified actions, as well as other stakeholder groups and partnerships who are 

actively involved in recovery implementation. However, the list of possible 

stakeholders is not limited to those identified below, and others may participate. 

Key to Responsible Parties Identified in the Implementation Schedule:

FCCD Foster Creek Conservation District 

NWT Northwest Trek Wildlife Park 

OZ Oregon Zoo 

USFWS U.S. Fish and Wildlife Service 

WDFW Washington Department of Fish and Wildlife 

WSU Washington State University 

D. ESTIMATED COSTS FOR RECOVERY ACTIONS 

The Implementation Schedule provides the estimated annual costs of 

implementing the identified recovery actions from 2007 to 2011 and, as feasible, 

an estimated cost for the time period from 2012 to 2016. Estimates for recovery 

actions are based on average costs of similar actions implemented to date for a 

variety of recovery activities (e.g., captive breeding, genetics management, 

87 
88 

reintroduction, monitoring, habitat management, stakeholder involvement, public 

outreach, predator control). 

Estimated overall cost by year: 

 2007: $359,000 2010: $217,000 

 2008: $406,000 2011: $269,000 

 2009: $390,000 2012 - 2016: $762,000 

The total estimated cost to implement near-term recovery actions is $2,403,000.
E. Implementation Schedule for the Draft Recovery Plan for the Columbia Basin DPS of Pygmy Rabbit 

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

1 1 C, E Manage captive

breeding program forthe Columbia Basin pygmy rabbit.

10 years WDFW, 

USFWS,Washington StateUniversity, OZ, NWT

150 150 150 75 75 250 

1 1.6 C, E Improve survival of 

captive pygmy rabbits. 

5 years " " 10 10 10 2 2 

1 2 C, E Manage genetic

characteristics of the Columbia Basin pygmy rabbit.

10 years WDFW 

7 7 7 7 7 TBD 

89
90

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

1 2.1.3 C, E Augment captive

population withadditional wildColumbia Basinpygmy rabbits, as available, to maximize their genetic representation within the captive breeding program. 

3 years " " 

2 2 2 

1 2.2 C, E Manage genetic 

diversity of freeranging subpopulations. 

2 years " " 

7 7 

1 3 C, E Survey for and

monitor free-ranging Columbia Basin pygmy rabbits.

10 years WDFW, 

USFWS 

* * * * * *
91

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

1 3.1 C, E Search for new

subpopulations. 

3 years WDFW 5 5 5 

1 4 A, E Reestablish freeranging Columbia 

Basin pygmy rabbit subpopulationswithin their historicaldistribution.

10 years WDFW, 

USFWS,WSU, Land Owners and Managers ofRecovery Emphasis Areas

* * * * * *

1 4.1 A, E Formally establish and 

continue to manage recovery emphasis areas that have been identified.

10 years " " 

15 15 15 5 5 40 

1 4.2 A, E Prepare recovery

emphasis areas for reintroduction and/or augmentation ofcaptive-bred ColumbiaBasin pygmy rabbits. 

4 years " " 

10 10 10 10 
92

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

1 4.4 A, E Conduct

reintroduction,augmentation, and/or translocation efforts atthe highest priorityrecovery emphasis area(s). 

10 years " " 

10 10 10 5 5 25 

1 4.5 A, E Monitor survival and 

movement of newlyreleased rabbits 

10 years " " 

30 30 30 30 30 100 

1 5 A, B, C Protect free-ranging 

Columbia Basin pygmy rabbits.

10 years USFWS, 

WDFW, other Federal Agencies, Participants to the Agreement 

* * * * * *
93

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

1 5.1 A, B, C Evaluate and address, 

as feasible, the potential effects of predators on freeranging Columbia Basin pygmy rabbits. 

3 years " " 

7 7 7 TBD 

1 6.2 A, E Protect habitats at 

recovery emphasis areas and, as feasible,intervening properties. 

10 years " " 

5 5 5 5 5 25 

1 7 A, D, E Pursue cooperative 

agreements for the Columbia Basin pygmy rabbit with land owners and managers of intervening properties within the population’s historical 

10 years USFWS, 

WDFW, other Federal Agencies, Prospective Participants to the Agreement 

* * * * * *
94

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

distribution. 

1 7.1 A, D, E Develop Site Plans 

under the existing Agreement and issue associated Permits to non-Federal and nonWDFW land owners and managers ofeligible properties whose ongoing management mayprovide a conservationbenefit for recoveryefforts, yet whose land 

10 years " " 

50 75 50 25 25 50 
95

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

use practices may alsoresult in incidental takeof free-rangingColumbia Basinpygmy rabbits. 

1 7.4 A, D, E Continue to coordinate 

recovery efforts with various Federal agencies pursuant tothe requirements of section 7 of the Act and, as opportunitiesarise, develop and implement cooperative agreements to addressFederal conservation initiatives for the Columbia Basinpygmy rabbit. 

10 years USFWS, 

other Federal Agencies

5 5 5 5 5 10 

1 7.4 A, D, E Continue to coordinate 

recovery efforts with various Federal agencies pursuant tothe requirements of 

10 years USFWS, 

other Federal Agencies 5 5 5 5 5 10 
96

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

section 7 of the Act and, as opportunitiesarise, develop and implement cooperative agreements to addressFederal conservation initiatives for the Columbia Basinpygmy rabbit. 

1 9 A, C, E Secure funding for

Columbia Basin pygmy rabbit recovery efforts.

10 years USFWS, 

WDFW, other Federal Agencies, Prospective Participants to the Agreement 

5 5 5 5 5 25 

1 10 A, B, C, 

D, E 

Revise the Federal Recovery Plan tofacilitate implementation of adaptive management 

10 years USFWS, 

WDFW, other Recovery Team Members

2 2 2 2 TBD 
97

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

measures considerednecessary to achieve the phased recoverystrategy.

and Stakeholders

2 1.5 C, E Improve reproductive 

success of captivepygmy rabbits. 

5 years " " 

10 10 10 2 2 

2 1.7 C, E Update Captive 

Breeding and GeneticsManagement Plan annually. 

5 years WDFW

2 2 2 2 2 

2. 3.2 C, E Monitor free-ranging 

subpopulations and document their status annually. 

8 years WDFW, 

USFWS 

5 10 10 10 25 

2 4.6 A, E Continue to 

investigate, identify,and address existing constraints or management needs of recovery emphasis areas and, as feasible,intervening properties that support additional 

10 years " " 

10 10 10 5 5 25 
98

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

occupied habitats or identified dispersal corridors of newlyreleased Columbia Basin pygmy rabbits. 

2 4.7 A, E Continue to assess and 

identify appropriatesizes, number,distribution, and configuration of freeranging subpopulationsand define criteria that would demonstrate that threats to thepopulation are sufficiently ameliorated.

2 years USFWS

10 10 

2 4.8 A, E Update the specific 

methods and techniques in theReintroduction Plan annually. 

3 years WDFW, 

USFWS,Washington State University

2 2 2 2 2 TBD 
99

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

2 5.2 A, B, C Identify and minimize 

effects of humanactivities on Columbia Basin pygmy rabbits at recovery emphasis areas and, as feasible,intervening properties. 

3 years " " 

3 3 3 TBD 

2 6 A, E Manage habitats at 

recovery emphasisareas to supportstable, self-sustaining subpopulations of free-ranging Columbia Basin pygmy rabbits.

10 years WDFW, 

USFWS,Land Owners and Managers ofRecovery Emphasis Areas

* * * * * *

2 6.1 A, E Continue to investigate 

and refine estimates ofthe quantity and quality of habitats 

10 years " " 

10 20 20 10 10 50 
100

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

needed to support a viable subpopulation of free-rangingColumbia Basinpygmy rabbits. 

2 6.2.1 A, E Monitor changes in 

habitats throughremote sensing, ground surveys, and mapping. 

2 years WDFW, 

USFWS 

10 10 

2 6.3 A, E Continue to investigate 

and, as available,implement enhancement and restoration measures to improve habitat quantity and qualityfor Columbia Basin pygmy rabbit subpopulations at 

10 years WDFW, 

USFWS,Land Owners and Managers ofRecoveryEmphasis Areas

5 10 10 10 25 
101

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

recovery emphasis areas. 

2 6.4 A, E Document methods, 

treatments, timing, andresults of all habitatenhancement, restoration, andprotection projects undertaken for freeranging Columbia Basin pygmy rabbits and maintain those records to facilitate long-term habitat monitoring. 

10 years WDFW, 

USFWS,Land Owners and Managers ofRecoveryEmphasis Areas

1 1 1 1 1 5 
102

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

2 6.5 A, E Continue to identify,

assess, and prioritize potential recoveryemphasis areas and, asappropriate, formallyestablish and provide recommendations to address habitat management needs at these sites.

2 years " " 

25 25 

2 7.2 A, D, E Develop and provide 

guidelines andtechnical assistance to interested land owners and managers toaddress management practices that could potentially affect freeranging Columbia Basin pygmy rabbits. 

10 years " " 

5 5 2 2 2 10 
103

Cost Estimates ($1,000 units) 

FY FY FY FY FY FY Action 

PriorityNumber 

Action Number 

Listing Factor Action Description 

Action Duration 

ResponsibleParties 

2007 2008 2009 2010 2011 

2012-2016 

ToAN

2 7.3 A, D, E Assist non-Federal and 

non-WDFW land owners and managers with developing new HCPs, or otherwise assist with participation in existing HCPs, with regard to management practices that may result in incidental takeof free-rangingColumbia Basinpygmy rabbits. 

10 years USFWS, 

WDFW,FCCD 

2 2 2 10 

2 8 A, D, E Exchange

information withstakeholders and the general public to address concerns and increase support for Columbia Basin pygmy rabbit recovery efforts.

10 years USFWS, 

WDFW 

5 5 5 5 5 25 

Annual Totals 359 406 390 217 269 762 
VI. Glossary 

Adaptive Management – Continual process of investigation, planning, 

implementation, monitoring, and evaluation of recovery actions so that 

future adjustments can be made to fully achieve recovery objectives. 

Agreement – Template Safe Harbor Agreement for the Columbia Basin Pygmy 

Rabbit developed in accordance with section 10(a)(1)(A) of the 

Endangered Species Act. 

Baseline – Number of Columbia Basin pygmy rabbits on eligible property at the 

time it is enrolled under the Agreement, or as otherwise determined 

beforehand through baseline description letters issued by the U.S. Fish 

and Wildlife Service. Baseline is typically expressed as an estimate of 

population abundance and distribution or amount and type(s) of habitat 

that sustain the covered species on an enrolled property. 

Columbia Basin Pygmy Rabbit – Includes any intercross pygmy rabbits in 

captivity that are considered essential for genetics management efforts; 

and all released, captive-bred, intercross pygmy rabbits, as well as their 

naturally reproduced progeny, that have some minor level (i.e., less than 

25 percent) of non-Columbia Basin pygmy rabbit ancestry. 

Conservation Measure – Voluntary management commitment of a Participant that 

is reasonably expected to result in a net conservation benefit to the 

Columbia Basin pygmy rabbit. 

Cooperative Agreement – Collective term to refer to any agreement (e.g., Section 

6 Cooperative Agreement, Safe Harbor Agreement, Habitat Conservation 

Plan, Conservation Agreement, Memorandum of Agreement, 

Memorandum of Understanding) between the U.S. Fish and Wildlife 

Service and another party developed to address conservation of the 

Columbia Basin pygmy rabbit. 

Enrolled Property – Property included under the Agreement through completed 

(i.e., signed) Site Plans of Participants. 

104 
HCP – Habitat Conservation Plan developed in accordance with section 

10(a)(1)(B) of the Endangered Species Act. 

Incidental Take – Take that is incidental to otherwise lawful activities. 

Intercross – Any exchange of genetic material (e.g., through mating, fertilization, 

or other means) between different species, subspecies, or distinct 

vertebrate population segments within a taxonomic species. 

Intervening Property – Properties outside of recovery emphasis areas that are not 

actively managed to conserve the Columbia Basin pygmy rabbit, but may 

nevertheless contribute to recovery efforts. 

Net Conservation Benefit – Result of a conservation measure that is reasonably 

expected to contribute to conservation of the Columbia Basin pygmy

rabbit. 

Participant – Non-Federal and non-Washington Department of Fish and Wildlife 

land owner or manager of property enrolled under the Agreement. 

Permit – A Federal Enhancement of Survival Permit issued to a Participant, in 

conjunction with the Agreement and their Site Plan, pursuant to section 

10(a)(1)(A) of Endangered Species Act. 

Recovery Emphasis Area – Sites that are actively managed to help conserve the 

Columbia Basin pygmy rabbit in the wild and where long term recovery 

objectives will be attained. Recovery emphasis areas contain habitat 

characteristics that currently, or potentially through appropriate 

enhancement measures, would be considered capable of sustaining a 

viable subpopulation of Columbia Basin pygmy rabbits. 

Release Site – Actual site within a recovery emphasis area that is prepared to 

receive newly released captive-bred or translocated pygmy rabbits. 

Release sites may encompass 20 to 30 hectares (50 to 75 acres) and 

contain from 25 to 50 artificial burrows, some or all of which may be 

surrounded by temporary containment fencing. 

105 
Regulatory Assurances – Federal regulatory certainty provided to Participants 

through their Site Plans and the Agreement, and reduction of their future 

management liability for incidental take of Columbia Basin pygmy rabbits 

on their enrolled properties. 

Site Plan – Document that formally identifies a Participant’s commitment to 

implement conservation measures to benefit the Columbia Basin pygmy 

rabbit, and enrolls the Participant’s property under the Agreement. 

Survey Habitat – Habitat that may be occupied by Columbia Basin pygmy rabbits. 

Survey habitat includes: 1) areas that contain greater than or equal to 10 

percent sagebrush cover that averages at least 51 centimeters (20 inches) 

tall by stand type (i.e., relatively continuous, uniform vegetation cover); 

and 2) thin-soil sites, or other sparsely vegetated areas, that contain habitat 

patches of at least 400 square feet (approximately 0.01 acres) that consist 

of greater than or equal to 20 percent sagebrush cover that averages at 

least 51 centimeters (20 inches) tall. 

Take – To harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect 

a species listed as threatened or endangered under the Endangered Species 

Act, or attempt to engage in any such conduct. 

106 
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