In a wildlife park in Eatonville, where large bison wander free and bighorn sheep climb the hills, a tiny animal is being carefully monitored. In a quiet enclosure, away from the curious eyes of the public, the endangered Columbia Basin pygmy rabbit is staging a comeback.
After nearly becoming extinct, the rabbits were listed as endangered in 2001. Disease, predation, habitat loss and a dwindling gene pool all contributed to the near demise of the population. They were dying off more quickly than they were reproducing, so scientists stepped in and all 16 of the last wild rabbits were captured and secured.
Now, a breeding program involving Northwest Trek Wildlife Park, Washington State University (WSU) and the Oregon Zoo is giving the bunny population a boost so they can be released back into the wild.
The rabbits are being crossbred with a stronger population of Idaho pygmy rabbits in an effort to fortify their immune systems. Because this population was isolated from other pygmy populations by the Columbia River, it’s possible that some inbreeding may have occurred. Also, as dams were built in the Columbia River, more land became usable for farmers, resulting in less land for the rabbits, according to The Scientist magazine.
In the wild, rabbits depend on sagebrush for food and soft soil for digging burrows. They are not just the smallest rabbit in North America, but the only one known to dig burrows. Other rabbits typically build nests above ground.
This sagebrush habitat is home to other animals besides the pygmy rabbit, including sage grouse, sage sparrows and Washington ground squirrels. The fact that pygmies are on the decline indicates that other animals could also be in danger. The dramatic decrease of this species from its historic range signals an unraveling of the ecosystem, said Dina Roberts, an endangered species biologist with the Washington Department of Fish and Wildlife, in a written statement.
The rabbits are not just cute, they are a vital part of the food chain and their absence can affect larger animals that in turn lose a food source, said Lisa Shipley, a wildlife ecologist at WSU. It may be difficult to see all that’s going on in arid Eastern Washington, but there is a desolate beauty if you look closer, she said.
"It’s not as charismatic but just as vitally important as some of our old-growth forests," Shipley said. Understanding how to maintain important species in ecosystems makes it possible to learn how to modify human actions and balance human needs with preserving Washington’s amazing natural diversity, Roberts said.
Things are looking up for this beleaguered bunny. With the Idaho rabbits introducing new genes into the population, the rabbits are beginning to multiply. It may seem strange to think that rabbits could have trouble with breeding, but the pygmies are a challenge.
Despite their cuddly appearance, they can be aggressive toward each other, and in the wild they prefer a solitary existence in their own territory. Becky Elias, a research assistant at WSU, said the females especially can become hostile after mating, and want nothing to do with their partners.
Ed Cleveland, the head animal care technician at Northwest Trek, said they can’t even keep two litters in the same enclosure because of the fighting that would ensue.
The pygmy rabbits also have a distinct breeding season and smaller litters, Elias said, which makes them different from other rabbits that breed all year round. A pygmy mother may have just two litters of four kits in a year, while other rabbit species might have a few litters of seven or eight kits. With such small numbers, the wildlife workers at the breeding facilities are especially vigilant in taking care of the rabbits.
"With endangered species breeding, every one counts," Elias said.
Health problems have also plagued the pygmy rabbits, so workers watch carefully for signs of trouble. Often, a rabbit might simply "look funny," Elias said, and workers will only have a few hours to step in and rescue a rabbit before it dies. They do rounds every day, checking how much each rabbit has eaten and looking for signs of illness. The pens at WSU are equipped with infrared cameras so workers can monitor the rabbits at night and intervene if there is trouble.
The life span is only about five years for a healthy rabbit, so anything the workers can do to keep them safe and healthy is beneficial. The rabbits are usually kept far from the noise and activity that visitors bring so that nothing can frighten them and throw off their breeding cycle. At Northwest Trek, Cleveland steps into a shallow pool of disinfectant before entering the area to aviod tracking in germs. They don’t use lawnmowers to maintain the grounds either, he said, since the noise might stress out the bunnies.
The workers try not to handle the rabbits too much, only entering the pens if there’s a problem with a sick rabbit or a mess that needs cleaning up.
"They’re wild animals and we want to keep them wild," Elias said.
Occasionally, however, a kit will need to be hand-raised because its mother has died, or a sick adult will need some attention, and then it’s difficult not to get attached. A full-grown pygmy only weighs about one pound, and these little balls of fuzz are pretty hard to resist.
"If I have to hand-raise any of them," Elias said, "I’m instantly in love with them."
The goal of the breeding program is to get enough healthy rabbits ready to go back into the wild so they can sustain their own population. In March 2007, 20 rabbits were released in Eastern Washington to see if they could survive and reproduce. Things did not go well, and within days most were picked off by predators—leaving only four females. There was some evidence that two litters were born, but there are no signs of any left in the wild.
There are no releases planned for this year because the numbers aren’t high enough. Since so many predators find the bunnies tasty, workers need to build their breeding stock to at least 100 or more rabbits before releasing them. Then, perhaps, enough of them can avoid the coyotes, badgers, foxes, owls, and bobcats long enough to reproduce successfully.
Shipley said some releases in Idaho with non-endangered rabbits helped workers understand what works and what doesn’t. Next time they might release pregnant rabbits and perhaps give them some supplemental food and create artificial burrows to give them a head start. Even the time of year might be an important factor.
"Obviously, you don’t want to put them out when there’s a hawk migration," Shipley said.
At WSU, expectant mother rabbits set up their natal burrows in a cozy greenhouse, since the warmer environment helps kits survive. All the rabbits get salads in the morning, made with fresh clover, dandelion and kale grown in greenhouses. At the Oregon Zoo, they’re growing sagebrush, the pygmy rabbits’ food of choice, because it’s difficult to find growing in the wild.
It may seem like a lot of fuss for just one animal, but it’s possible that by spending so much time learning about this unique rabbit and how to rescue it, an entire ecosystem might be saved. The pygmies are a warning sign.