Surveillance | Land Management | Education | Research

Pygmy Rabbit Release 
on the INEEL

Weighing less than a pound, the pygmy rabbit (Brachylagus idahoensis) is the smallest North American rabbit species.  Pygmy rabbits may be found in sagebrushed areas of southern Idaho, Washington, eastern Oregon, northeastern California, Nevada, and Wyoming. 

Pygmy rabbits are sagebrush obligates, meaning they require sagebrush habitat to survive.  They are dependent upon sagebrush for food, which comprises 98% of their winter diet and a good portion of their spring and summer diet.

Pygmy rabbit numbers have drastically declined in the past decade, even in protected areas such as the INEEL.  This decline is primarily due to habitat loss and fragmentation through development and agricultural conversion.  Pygmy rabbits have been listed by the federal government as a species of concern and are a candidate for threatened and endangered species listing.  In Idaho they are listed as a species of concern.  

A subspecies of pygmy rabbit, the Great Basin pygmy rabbit, is near extinction.  The Great Basin pygmy rabbit is found only in eastern Washington.  Probably less than 50 rabbits of this subspecies remain.  Though genetically related to our native Idaho species, genetic studies by the Washington Department of Fish and Wildlife (WDFW) suggest that these rabbits have been isolated from Idaho and Oregon populations for as long as 7,000-10,000 years. Because of this, translocating rabbits from neighboring states isn't a good option to boost Washington populations.

To preserve the Washington's last remaining population of the Great Basin pygmy rabbit, rabbits were captured from eastern Washington and a captive breeding program was initiated to raise and release Washington pygmy rabbits into two protected areas in eastern Washington. 

Before scientists launched the captive breeding effort in Washington, they captured and bred more common Idaho pygmy rabbits so they could study and perfect rearing techniques.  Under the direction of Dr. Rod Sayler from Washington State University,  this model population of Idaho pygmy rabbits were reintroduced to the INEEL this fall.  Results from the Idaho reintroductions are intended to help improve the success of reintroductions for the endangered Columbia Basin pygmy rabbit, scheduled to begin in the summer of 2003.

"It is far too early to say much about the survival rates of these first released animals, but we are actually encouraged by what we’ve seen so far," said Dr. Sayler. "We would not have been surprised if we’d lost the majority of animals in the first week, but this did not happen."  

WSU graduate student Rob Westra and Stoller wildlife biologist Sue Vilord will continue to track the animals using the signals from the animals' radio collars, obtain precise GPS locations, and observe them and their habitat use directly.  The outcome of this research should provide valuable information to assist in the successful reintroduction of Great Basin pygmy rabbits.

ESER Wildlife Biologist Sue Vilord

The Great Basin pygmy rabbit captive breeding program is a cooperative project involving the Washington Department of Fish and Wildlife, Washington State University, the Oregon Zoo, and Northwest Trek Wildlife Park.  The Idaho reintroduction program is being conducted on the Idaho National Environmental Research Park through the ESER Program under the supervision of the Department of Energy-Idaho Operations Office.