Category: Recovery Plans
Published: July 1995
Author(s): Kelly R. McAllister
The pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit in North America. It is patchily distributed in the sagebrush-dominated areas of the Great Basin. This includes portions of Oregon, California, Nevada, Utah, Idaho, Montana, Wyoming, and Washington. Washington populations are disjunct from the core of the species' range, apparently separated for thousands of years. Paleontological evidence suggests that the species had a broader distribution in Washington thousands of years ago. Today, the known Washington range of the pygmy rabbit is greatly restricted. Museum specimen records and reliable sight records show that pygmy rabbits formerly occupied sagebrush habitat in five Washington counties: Benton, Adams, Grant, Lincoln, and Douglas. Currently, pygmy rabbits are known to survive in five isolated fragments of suitable habitat in Douglas County.
The current Washington population is estimated to be fewer than 250 rabbits. Of the five pygmy rabbit areas known to remain in Washington, the largest may be comprised of fewer than 150 rabbits. The other four populations are significantly smaller.
In 1990, the pygmy rabbit was listed as a threatened species by the Washington Wildlife Commission. The Commission reclassified the species to endangered in 1993. It is listed as a Candidate Category 2 species by the U.S. Fish and Wildlife Service.
The pygmy rabbit is the only rabbit native to North America that digs its own burrows. It is also uniquely dependent upon sagebrush, which comprises up to 99% of its winter diet. Dense sagebrush and relatively deep, loose soil are important characteristics of pygmy rabbit habitat. The primary factor contributing to the decline of the pygmy rabbit in Washington has been loss of habitat due to agricultural conversion.
Because of low numbers and limited distribution, pygmy rabbit populations in Washington are vulnerable to fire, disease, intense predation, and the random variation in birth and death rates, sex ratios, and combinations of demographic parameters that sometimes cause the collapse of small populations. Habitat degradation and loss are likely to continue without active prevention efforts. Before the pygmy rabbit can be considered at low risk of extirpation in Washington, numbers and distribution must be increased. In addition, adequate habitat must be managed for the long-term protection of features that support pygmy rabbits.
The recovery objectives for downlisting from State Endangered status are a minimum population of 1400 adult pygmy rabbits comprised of at least two areas supporting at least 500 adult pygmy rabbits and four additional areas that support at least 100 adult pygmy rabbits. All of the areas must be in secure habitat with long-term management plans in place which conserve pygmy rabbits and their habitat.
The recovery objectives for delisting from State Threatened status are a minimum population of 2800 adult pygmy rabbits comprised of at least four areas supporting at least 500 adult pygmy rabbits and eight additional areas with at least 100 adult pygmy rabbits. All of these areas must be in secure habitat with long-term management plans in place.
Recovery strategies for this species include protection of existing habitat, identification and management of lands for creation of new habitat, monitoring of the pygmy rabbit population, and research to better understand the effects of management actions. Grazing, if it occurs in pygmy rabbit areas, should be managed to be compatible with pygmy rabbit habitat needs. In all pygmy rabbit areas, steps should be taken to reduce the risk of range fire. To increase the extent of pygmy rabbit habitat, efforts should be directed at identifying lands where soil conditions are suitable for pygmy rabbits. If necessary, lands with appropriate soil conditions should be restored or enhanced to provide pygmy rabbit habitat. Pygmy rabbits should be introduced to selected vacant habitat. Other strategies, including enforcement, data management, cooperative work with landowners and other agencies, research, and public information should all play a role in pygmy rabbit recovery efforts.