Pygmy Rabbits from Nevada and Utah Boost Recovery of Endangered Population in Washington
Recent capture of pygmy rabbits in Nevada and Utah, and their relocation to Washington’s Columbia Basin, is aiding recovery efforts for this endangered population. Washington Department of Fish and Wildlife (WDFW) and U.S. Fish and Wildlife Service (USFWS) biologists worked last month with Nevada and Utah colleagues and other partners to bring a total of 42 pygmy rabbits to WDFW’s Sagebrush Flat Wildlife Area in Douglas County.
The rabbits were released within 48 hours of capture into two large (six- and 10-acre) enclosures on the wildlife area. The new rabbits joined captive-bred pygmy rabbits placed in the enclosures last year, rabbits born in the large enclosures last June, and wild rabbits translocated from Oregon and Nevada last October.
“Breeding season should be under way soon and we hope that this intermingling of pygmy rabbits from multiple sources will result in many kits born this year,” said WDFW research scientist Dr. Penny Becker, who is in charge of the recovery project. Keeping the rabbits in enclosures is expected to promote breeding opportunities to increase the number of rabbits for release. Interbreeding of wild and captive-bred rabbits should also boost the population’s genetic diversity.
“The large enclosures were also used to successfully hold wild and captive-bred pygmy rabbits over the winter,” Becker said. “Although survival was only about 23 percent, it is actually very similar to the over-winter survival of wild pygmy rabbit populations in other states.”
Both federal and state authorities list the pygmy rabbit (Brachylagus idahoensis) as endangered in the Columbia Basin of Washington (or “central Washington”). Sixteen of the last-known wild Columbia Basin pygmy rabbits were captured in 2002 and placed in breeding programs at Washington State University (WSU), Northwest Trek Wildlife Park, and Oregon Zoo.
Interbreeding of Columbia Basin pygmy rabbits with those from other states has been approved by USFWS.
Most landowners adjacent to Sagebrush Flat Wildlife Area have entered into "Safe Harbor Agreements" with USFWS and WDFW, holding them harmless under the Endangered Species Act (ESA) if rabbits disperse to their property and are accidentally injured or killed during routine land uses.
The Columbia Basin pygmy rabbit is the country’s smallest native rabbit and the only one to dig its own burrows, which makes it dependent on deep soils in shrub-steppe habitat in eastern Washington. It was listed as a state endangered species in 1993. After the state population dropped to fewer than 40 rabbits in Douglas County by 2001, it was listed as a federal endangered species in 2003.
Since pygmy rabbits are not listed as endangered elsewhere, other states with healthy populations such as Nevada and Utah are still able to help Washington by providing rabbits for reintroduction.
With the help of the Nevada Department of Wildlife, biologists captured rabbits in northeast Nevada’s Elko and White Pine counties March 4-13. Twenty of the Nevada-born rabbits were released at Sagebrush Flat Wildlife Area, and two male rabbits were placed at the Oregon Zoo temporarily for captive breeding efforts there this year. The other 22 translocated rabbits came from capture operations in south-central Utah’s Piute and Wayne counties and northeast Utah’s Rich County conducted March 16-21. Becker said the rabbits were captured with a team that included Utah Division of Wildlife Resources and Brigham Young University staff.
Becker explained that when rabbits are released to the wild at Washington’s Sagebrush Flat Wildlife Area, smaller and more temporary “soft-release pens” are used to acclimate the rabbits to the new environment and promote residency. Becker and others have already found multiple burrows of pygmy rabbit kits released in 2011. They are continuing surveys for additional rabbits established on Sagebrush Flat and surrounding lands this spring and summer. Starting in May, the wild adult rabbits in the enclosures, along with any kits born in the enclosures and at Oregon Zoo, will be released and closely monitored. USFWS and WDFW agree the recovery effort is challenging, but they are buoyed by the enthusiastic cooperation from the project’s many partners, who also include the U.S. Bureau of Land Management, several private veterinarians, and volunteers.