Final effort to save tiny rabbits from extinction

June 13, 2011 - 3:45 AM

EPHRATA, Wash. (AP) — Wildlife experts are making one last effort to save the endangered Columbia Basin pygmy rabbit, believed extinct in the wild since mid-2004.

The pygmy rabbit is the smallest rabbit in North America, and can fit in a person's hand. Adults weigh about a pound and measure less than a foot in length. The previous effort to reintroduce the pygmy in 2007 ended badly when they were quickly gobbled by their many predators.

Some 100 pygmy rabbits are being released this time into large wire enclosures.

The rabbits — who were raised in captivity for this last-ditch effort — must learn quickly to find food, breed and avoid being eaten. The wire enclosures give them a fighting chance to survive, scientists say.

"If this doesn't work, I'm not sure what Plan B would be," said Matt Monda of the Washington Department of Fish and Wildlife, who has been working for years to save the endangered species.

Only the Columbia Basin pygmy rabbit is endangered. Pygmy rabbits thrive in other Western states and are not protected.

This recovery effort is not without some controversy.

A big concern was all the engineering that has gone into these animals, Monda said. The original goal was to preserve the genetics of the Columbia Basin rabbit, but that proved impossible because of small numbers and problems that resulted from inbreeding.

The animals in the new effort are the result of cross-breeding with other pygmy rabbits from Idaho and Oregon.

"That was a controversial idea, to bring non-endangered rabbits and make them endangered," Monda said.

Still, the U.S. Fish and Wildlife Service has approved the practice, said agency biologist Chris Warren, who is involved in the rescue effort.

A key feature of this new rescue effort is a six-acre enclosure with a 6-foot-tall wire fence is intended to keep out coyotes, badgers, weasels, snakes and to disrupt birds of prey. It has an electrified wire near the bottom to keep predators from digging under. The fence posts have spikes on top to prevent raptors from gaining a perch to hunt.

The enclosure surrounds plenty of sagebrush for food, and has dozens of artificial and real burrows where the rabbits can hide and, hopefully, breed.

Once the rabbits grow used to the big enclosure, they are being moved two at a time to smaller enclosures, where they are gradually introduced to predators through tunnels to the outside. Finally they are released outright.

Monda acknowledged the effort is somewhat unusual, in part because the rabbits bred in the safety of facilities at Washington State University, the Oregon Zoo and Northwest Trek have to be taught to fear predators. So far, the experiment appears to be a success, as some rabbits have already survived for weeks.

The project manager is Penny Becker, who was hired earlier this year after spending several years working on the recovery of wild dogs in South Africa.

Becker spends her days checking on her charges, including tracking those equipped with radio collars. A signal that doesn't move for six hours is presumed to be a dead rabbit.

Becker and assistant Chad Eidson travel to the many small enclosures as they chart the progress of each rabbit. All are numbered and some have names.

Predators aren't the only issue. Conventional mating is difficult because female pygmy rabbits will only briefly tolerate the presence of males, and often fight with them, the scientists say.

Monda estimated that researchers have spent up to $250,000 a year for 10 years on work to save the rabbits.

The exact reasons for the disappearance of the rabbits in the Columbia River Basin of eastern Washington state are not clear.

But the basin was extensively developed for wheat and potato farming after Grand Coulee Dam was finished in the 1940s. It turned out the soft soil the rabbits need was also the most prized by farmers. Rabbit numbers started to slump as their habitat disappeared. But Monda also suspects that disease or freak weather took a heavy toll because numbers dropped very quickly two decades ago.

"Seven distinct populations happened to die out at the same time," he said.

An environmental group that has advocated for the rabbits also believes there is no choice other than the current reintroduction.

"This is the last chance of saving any remnant of the pygmy rabbit,'" said Noah Greenwald of the Center for Biological Diversity in Portland, Ore.

But, Greenwald said, "We got to this point because we didn't take action to save the rabbit in the first place."

If enough survive to reproduce next year it will be a measure of the program's success, Monda said.

"We need a new explosion of kits (babies) on the ground," Monda said. "We need Washington genes on the ground."