PULLMAN, Wash. — Washington State University researchers feel like long-shot lottery winners after discovering that endangered Columbia Basin pygmy rabbits are once again breeding in the wild in Washington.
Len Zeoli, a WSU doctoral student in the Department of Natural Resource Sciences, was shocked recently while doing field studies to see a young pygmy rabbit hop out of a burrow and just sit there looking at him.
“I could hardly believe my eyes,” said Zeoli. “We have been studying these animals daily for months, but did not have a clue that a female already had given birth to a litter of kits.”
Twenty of the endangered rabbits, which are smaller than cottontail rabbits, were experimentally reintroduced to native sagebrush habitat in eastern Washington in March to determine if captive-reared females would breed in the wild after release. But within days, half of only eight females in the group were lost to predators, including coyotes, hawks and owls.
“Although the Washington Department of Fish and Wildlife quickly took steps to control predation, the odds of four female rabbits being able to survive the breeding season and reproduce were close to zero at that point,” according to Rod Sayler, conservation biologist at WSU. “We knew we were going to lose more rabbits and we did.”
Then, at the beginning of June, with only one female and one male surviving in the wild, Zeoli made two remarkable discoveries.
“Len came rushing into the Endangered Species Lab at WSU a week ago, jumping up and down like an excited little kid”, Sayler said. “He had just found the sole surviving female digging a natal burrow and lining it with grass, the last step before she gives birth and hides her litter underground for about two weeks while nursing.
“Now he discovers a partially grown juvenile from another litter. This means that at least two litters of pygmy rabbit kits have been born in the wild. We feel like we’ve won the lotto.”
Dave Hays, endangered species coordinator for WDFW, agreed. “With so few rabbits reintroduced to the wild, and so many natural odds to overcome, the birth of two litters is both unexpected and exciting,” he said. “Biologists viewed the initial release primarily as a learning tool to improve reintroduction techniques and boost survival rates in the future.
Hays added that faculty, students, and veterinarians from WSU, along with wildlife experts from the Oregon Zoo, and Northwest Trek near Tacoma, and biologists from WDFW and the U.S. Fish and Wildlife Service, have been working for years to rear enough pygmy rabbits in captivity to reintroduce them into the wild.
The few pygmy rabbits currently surviving from this first experimental release may not have to wait long for reinforcements. Sayler and Lisa Shipley, another WSU wildlife scientist, say that the captive-breeding program is already producing more kits to support future reintroduction efforts. Next time around, biologists will increase protection for released females and their offspring.
“The reintroduction of pygmy rabbits is a numbers game,” Sayler said, “because they are food for so many predators. To jump start a pygmy rabbit population in the wild, we must release many more rabbits, or provide better protection from natura predators.”
“We’re working on new ways to exclude predators and improve female survival,” said Zeoli. “It will still take many years, lots of hard work, and maybe some more luck to reach the ultimate goal of restoring a self-sustaining population of pygmy rabbits in Washington. But this baby step of seeing the first breeding in the wild by captive-reared animals renews hope for all of us that this endangered rabbit will not go extinct.”
Columbia Basin pygmy rabbits in Washington were declared endangered in 2001 under an emergency listing by the U.S. Fish and Wildlife Service, after the one remaining population crashed for unknown reasons. Biologists rescued 16 wild pygmy rabbits to begin a captive breeding program at WSU and the Oregon Zoo just before the last known animals disappeared in the wild.
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