Threatened and Endangered Species - Recovery Plans
Date Published: August 2001
Number of Pages: 24
Publication Number: WDFW 775
Author(s): David W. Hays
This document summarizes the current status of pygmy rabbits in Washington, reassesses and prioritizes the strategies and tasks of the initial (1995) Washington State Recovery Plan for the Pygmy Rabbit and provides an overview of emergency measures needed to prevent extinction of Washington's pygmy rabbit.
The pygmy rabbit was listed as a threatened species in the state in 1990 and was reclassified to endangered status in 1993. It is a U.S. Fish and Wildlife Service species of concern. A state recovery plan for the rabbit was written in 1995 and efforts have been underway to implement the plan despite less than full funding. Recovery objectives are to increase pygmy rabbit numbers and distribution and manage habitat for long-term protection of features that support pygmy rabbits.
The number of populations and numbers of pygmy rabbits have been declining since 1997. In 1995, five pygmy rabbit populations were known to exist in Douglas County and a sixth population was found in 1997. Between 1997-2000 five of the six populations disappeared; by March 2001, only one area, Sagebrush Flat, was known to still have rabbits. Small populations at several sites were extirpated for unknown reasons, other populations were extirpated by known wildfires. Numbers of active burrows on standardized plots at Sagebrush Flat have declined from 229 in 1995 to zero in 2001. Random searches did reveal some active burrows at Sagebrush Flat in March and April 2001.
Genetic analyses of pygmy rabbits in Montana, Idaho, Oregon, and Washington have confirmed that the Washington population of pygmy rabbit is distinct and isolated from the rest of the species' range, and has been separated for thousands of years. These genetic differences more likely than not are similar to subspecific differences recognized in other mammals. Extinction of the Washington pygmy rabbit subspecies or race may occur at any time. The small remaining population is susceptible to disease, predation, and stochastic events.
With the apparent collapse of the pygmy rabbit population in the wild, the Department evaluated a number of options. Leaving a few remaining rabbits in the wild would encumber the population with extreme risk. There was only one option available to maintain the unique Washington pygmy rabbit - that was to initiate a captive breeding program to raise and release Washington pygmy rabbits. A decision was made by the Department in May 2001 to collect rabbits from the wild to begin a captive breeding program. The goal is to develop a captive population to ensure the maintenance of Washington's unique pygmy rabbits and to reintroduce sufficient numbers of captive-bred rabbits to re-establish populations in suitable habitat. Eleven of the remaining pygmy rabbits in Washington were captured and translocated to Washington State University. In addition, one female gave birth to 5 young in captivity.
The captive breeding program will begin with a cooperative project involving the WDFW (lead agency), Washington State University (where captive breeding will occur), the Oregon Zoo (where husbandry techniques are being developed), and Northwest Trek Wildlife Park. Other zoos may also be solicited to house small numbers of captive animals. A project biologist will be hired to conduct the captive rearing, release, and monitoring phases of the project. They will annually report on production, release and post-release survival phases of the project. Pygmy rabbits will be reintroduced into suitable habitat, provided with artificial burrows, and protected from predators with electric fencing. A Science Advisory Group will review all aspects of the project. Cost of a 3-year program is expected to be approximately $700,000 - 750,000. Long-term options will depend upon the success of the program.