The pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit in North America. It is also the only rabbit to dig its own burrows, using the deep loamy soils of habitat dominated by sagebrush, which also makes up most of its diet.
For over 100,000 years pygmy rabbits have lived in the Columbia Basin in Washington and the Columbia Plateau and Great Basin of the western U.S. (Oregon, California, Nevada, Utah, Idaho, Montana, and Wyoming). The rabbits in the Columbia Basin have been isolated from the rest of the population for at least 10,000 years, which has led to genetic differences between the rabbits in Washington and the other states. Since the mid-1900’s there has also been a loss of genetic diversity in Washington’s isolated populations.
The pygmy rabbit was state listed as a threatened species in Washington in 1990 because of population and distribution declines due to habitat changes. It was reclassified as state endangered in 1993 as declines continued, and except for a remnant population on the state’s Sagebrush Flats Wildlife Area, it was considered near extinct by 2001. The distinct population segment of the species known as the Columbia Basin pygmy rabbit was listed in 2003 as an endangered species under the federal Endangered Species Act (ESA).
A captive breeding program was initiated by the Washington Department of Fish and Wildlife (WDFW) and the U.S. Fish & Wildlife Service (USFWS) in 2001 with the intent of eventually reintroducing rabbits to the wild. Keeping rabbits healthy and alive in captivity was so challenging that the first trial release attempt on Sagebrush Flats was not until 2007, and none of the 20 animals released survived beyond a year.
In Spring 2011, a collaborative recovery effort was renewed with the Oregon Zoo, Washington State University, Northwest Trek Wildlife Park, USFWS and other state wildlife agencies. The recovery plan includes 1) translocating wild pygmy rabbits to Washington from other states to increase genetic diversity and numbers, 2) breeding pygmy rabbits in semi-wild conditions on the release site, and 3) releasing juvenile offspring of mixed lineage, and adult wild-caught pygmy rabbits from neighboring states.
Over the past two years, a team of biologists have translocated 110 pygmy rabbits from Nevada, Utah, Oregon and Wyoming to be included in recovery efforts. WDFW has developed techniques for breeding wild and captive bred pygmy rabbits in protected enclosures on the wildlife area to increase numbers of individuals for release. Due to very successful breeding in the enclosures, more than 170 pygmy rabbit offspring have been reintroduced to Sagebrush Flat Wildlife Area in Douglas County. Surveys this past December and January in the snow covering the release site showed a greater survival rate for released pygmy rabbits than wildlife biologists expected and a good start to recovering the species in Washington. Breeding and releases are already underway for the 2013 season. All released pygmy rabbits will continue to be closely monitored to collect data on breeding, habitat use, mortalities and other factors to modify reintroduction techniques and adaptively manage the newly-formed population.