Columbia Basin Pygmy Rabbit, Kathryn Curran

Columbia Basin Pygmy Rabbit

~The adorable creature at risk of extinction~

By Kathryn Curran, BIO 227-01

Columbia Basin Pygmy Rabbit; Photo by Oregon Zoo

Pygmy Rabbit; Photo by Betsy Demay

What is it & what does it do? ~

Species Description and Ecology- 

The Columbia Basin pygmy rabbit is part of the Leporidae family. This includes hares and rabbits. Though classification of the pygmy rabbit has been changed several times over the years, it is now generally classified as B. idahoensis, within the monotypic genus Brachylagus. The smallest leporid in North America, the pygmy rabbit has a mean adult weight ranging from .83 to 1.1 pounds and 23.5 to 29.5 centimeters long. Typically, female rabbits tend to be bigger than the males. 

Overall, the color of the pygmy rabbit is slate gray with slight hints of brown with whitish bellies. Unlike many rabbit species, their ears are short and rounded and their small tail lacks any white coloring. Pygmy rabbit’ main food source is sagebrush, which is also an essential part to the species’ shelter. They are typically known as shy creatures only visible during dawn and dusk. In terms of reproduction, females produce one to four litters each year, with roughly 3 to 4 kits with each litter.

Pygmy rabbits usually like loamy soils underneath sagebrush for their tunnel digging networks. In addition, they create runways throughout shrubs to connect burrows to each other. It is the only non-domesticated rabbit species that digs burrows for itself. The pygmy rabbit was once highly populated throughout the Great Basin and most northwest states in the big sagebrush, part of the bluebunch wheatgrass habitat type.

Map of Columbia River Basin

Where does it live? ~

Habitat

The pygmy rabbit population resides in the Columbia Basin ecosystem, stretching central Washington into the northern portion of Oregon. It is believed that the rabbit occurred in six portions of Washington during the first half of the 20th century, but has since been reduced.

How was it listed? ~

Classification and Date of Listing- The pygmy rabbit, or the Bracylagus idahoensis, was classified as threatened in 1990 by the state of Washington. It was reclassified three years later as endangered by the Washington Department of Fish and Wildlife. A recovery plan was finished by 1995, and has had several amendments over the past twenty years. It was finally federally listed as endangered in November of 2011, under the Endangered Species Act of 1973.

What went wrong? ~

Main Threats 

There are several key factors that contribute to the pygmy rabbits’ endangerment. 

1. Habitat Degradation and Destruction: Much of the native shrub habitats in the Columbia Basin have been converted for agricultural purposes and urban development. Approximately 60 percent of native shrub habitats have been converted for human purposes, and Columbia Basin pygmy rabbits are unable to live or disperse in these sites.
2. Harmful Recreation and Management Activities: The pygmy rabbit is difficult to distinguish from the commonly hunted cotton-tailed rabbit, making them easy targets for accidental shooting. In addition, scientific studying and captive breeding efforts to combat pygmy rabbit endangerment has unintentionally created disturbances amongst populations. 
3. Disease and Predation: The effects of parasitic diseases, like plague and tularemia, bacteria that causes coccidiosis and myco bacteriosis, and skeletal abnormalities possibly attributed to inbreeding, increase pygmy rabbit mortality. Predation from terrestrial avian vertebrates has contributed more to pygmy mortality as populations continue to shrink and become easier to capture.
4. Other Factors: The Columbia Basin pygmy rabbit’s small population size make it highly influence to random environmental changes. Alterations in food sources and cover can skew the sex ratio and diminish genetic diversity in the already diminished population.

What is being done? ~

Captive Breeding Program at Oregon Zoo; Photo by Oregon Zoo

Description of Recovery Plan- These plans were published by the US Fish and Wildlife Service under the Endangered Species Act of 1973. The recovery plan addresses seven main areas to improve the pygmy rabbit's chance of survival: captive breeding, genetics, reintroduction, predator control, survey and monitoring, stakeholder involvement, and public outreach. With the Oregon Zoo teaming up with the Washington Department of Fish and Wildlife, a captive breeding program for the Columbia Basin pygmy rabbit was started in 2001, as well as an intercross breeding strategy in 2003. The purpose of the intercross breeding was to restore genetic variation in the population, and was achieved by controlled breeding of the Columbia basin pygmy rabbit with other pygmy rabbis from a habitat in Idaho. These programs seemed to be effective, as 20 intercrossed rabbits were reintroduced to the Columbia Basin habitat by spring of 2007. However, these animals had a high mortality rate and were believed to have all died by 2008. More individuals were released in 2011, and these seem to have been more successful than the previous population. In addition, the recovery plan hopes to remove threats from the population and from its essential shrub steppe habitat. In recent years, the need for captive breeding has diminished; finally , all captive breeding programs were discontinued in 2012 as the population could now sustain itself. Surveys, complete area searches, and the censusing of active burrow systems known as the "Skalski monitoring method" allow biologists to monitor the population's progress. Currently, the Washington Department of Fish and Wildlife is supporting the Foster Creek Conservation District in an effort to create a Habitat Conservation Plan for Douglas County, Washington. This would protect the Columbia Basin pygmy rabbit, as well as a multitude of other species. 

Oregon Zoo Official Logo

WDFW Official Logo

What can YOU do? ~ 

Personal Action

Want to help? You can donate to the Oregon Zoo or the Washington Department of Fish and Wildlife. Both organization have actively worked

towards the pygmy rabbit's restoration, and greatly need some support. You can also volunteer at either of these organizations if you're nearby. Tell your friends, and the spread the conservation message!

Visit these websites to learn more about the Columbia Basin Pygmy rabbit or to donate!

~ Oregon Zoo: http://www.oregonzoo.org/conserve/fighting-extinction-pacific-northwest/columbia-basin-pygmy-rabbits

~Washington Department of Fish and Wildlife: https://fishhunt.dfw.wa.gov/wdfw/donate.html

~Foster Creek Conservation District: http://www.fostercreekcd.org/records-request/

Read the official recovery plan here! 

http://www.fws.gov/endangered/species/recovery-plans.html

Works Cited

"Columbia Basin Pygmy Rabbit." Oregon Zoo. Metro, n.d. Web. 23 Nov. 2015.

U.S. Fish and Wildlife Service. 2012. Recovery Plan for the Columbia Basin Distinct Population

           Segment of the Pygmy Rabbit (Brachylagus idahoensis). Portland, Oregon. ix + 109 pp.