Senin, 10 Januari 2011

Saving the Pygmy Rabbit


The pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit in North America and is able to fit in the palm of a hand. It is patchily distributed in the sagebrush-dominated areas of the Great Basin, which includes portions of Oregon, California, Nevada, Utah, Idaho, Montana, and Wyoming. An isolated subspecies of pygmy rabbit found in Washington State is near extinction.
Pygmy Rabbit 1 Saving the Pygmy Rabbit
Relatively little is known about this species, and scientists are still trying to figure out how best to estimate their population size. However, one thing we do know is that pygmy rabbits are closely associated with tall, dense stands of big sagebrush growing on deep, loose soil. Its dependence on sagebrush is the main reason for its decline.
Pygmy Rabbit 6 Saving the Pygmy Rabbit
Unlike all but one other North American rabbit, the pygmy rabbit digs its own burrows in deep, loose soil. Its burrow systems are typically constructed under clumps of big sagebrush and pygmy rabbits usually stay within a 100 foot radius of the burrow. Not only do they rely on sagebrush for shelter and protection from predators, but they depend on sagebrush for food. About 98 percent of their winter diet is composed of sagebrush and a good portion of their spring and summer diet is as well. They sometimes climb into tops of sagebrush to feed.
Pygmy Rabbit 4 Saving the Pygmy Rabbit
The pygmy rabbit is distinguishable from other rabbits by its small size, short ears, gray color, and small hind legs. Unlike the cottontail rabbit, it lacks white fur on the underside of their tail. It also has white ear margins, a characteristic that distinguishes it from a cottontail. Pygmy rabbits are active throughout the year in day or night, mainly at dusk and dawn.
Pygmy Rabbit 3 Saving the Pygmy Rabbit
Pygmy rabbits are preyed upon by weasels, coyotes, badgers, bobcats, birds of prey, owls, foxes, and sometimes humans (pygmy rabbits are sometimes difficult for hunters to distinguish from other rabbit species). Mortality is high for juveniles (one study found that 50 percent did not survive the first five weeks) and adults alike, and populations may experience an annual mortality rate up to 88 percent. Like other rabbits, pygmy rabbits mainly try to stay hidden and are cryptically colored to avoid predation. Although capable of short bursts of speed, pygmy rabbits are vulnerable to predators if caught in the open. They do not generally leap like other rabbits, but move by scampering close to the ground. This behavior helps them to avoid predators as they move rapidly through dense cover.
Pygmy Rabbit 5 Saving the Pygmy Rabbit
Because so much sagebrush habitat has been degraded or destroyed over the past 150 years due to agriculture and other human development, wildfires, and invasion of noxious weeds, many fear that pygmy rabbit numbers have declined drastically. However, it is difficult to know with certainty what their current status is because until recently wildlife agencies put little or no resources towards monitoring pygmy rabbit populations. In September, 2010, the U.S. Fish and Wildlife service determined that there is not enough evidence to warrant listing pygmy rabbit as threatened or endangered under the Endangered Species Act. Let’s hope that this decision spurs land users and wildlife agencies to take actions now to conserve quality sagebrush habitat and monitor pygmy rabbit populations so that this species will never have a need to be listed.

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