By Zach Howard
CONWAY, Mass (Reuters) - The New England cottontail rabbit, in sharp decline for decades throughout the Northeast, is on the verge of disappearing from several states, with the reason somewhat a mystery, wildlife experts say.
The once prolific breeder, already no longer found in Vermont, has nearly vanished from Rhode Island and New Hampshire and exists in only negligible populations in Massachusetts, Connecticut, Maine and New York, according to biologists and U.S. officials.
The New England native apparently has been supplanted by a look-alike competitor -- the abundant eastern cottontail, of which more than 200,000 were introduced locally in the early 1900s for hunters, a Rhode Island study found this week.
Habitat loss and predation could partly explain this disappearing rabbit trick, although the eastern cottontail variety relies on similar habitats and must contend with the same predators, said the report's co-authors, Thomas Husband, natural resources science professor at University of Rhode Island and Brian Tefft, a state wildlife biologist.
After studying the rabbits for almost 20 years, they say the New England cottontail looks close to being wiped out in Rhode Island. A statewide survey of its habitat and breeding sites has found evidence of only one remaining animal.
A possible cause is predators including coyotes and bobcats returning in large numbers, lured by plentiful eastern cottontail for them to feed on, said Husband in a statement.
Another possible cause is subtle differences in the bunnies' bodies. New England cottontails have smaller eyes placed farther forward on their heads than their eastern cousins, giving them poor peripheral vision with which to spot predators. The eastern type also runs from approaching predators sooner than does the New England variety.
"But it's all speculation as to whether or not that's a factor," Husband added.
A new survey will be done in 2012 to confirm results, but biologists are brainstorming how to reintroduce the species. One possible future refuge could be on Patience Island in the middle of Narragansett Bay, which has never hosted a population of either cottontail in the past.
The New England cottontail, which was named as a candidate for the U.S. Endangered Species Act in 2006, is listed as endangered in Maine and New Hampshire.
Its entire range has shrunk by 86 percent since 1960 in areas east of the Hudson River in New York and across into New England, according to the U.S. Fish and Wildlife Service.
Its numbers are so diminished that it is no longer found in Vermont, and it exists in just a handful of smaller populations in its historic range, the FWS says.
Federal and New Hampshire officials in April pledged to help restore New England cottontail habitat on private and state-owned lands over the next 50 years.
The animal prefers early so-called successional forests, or "thickets," with dense and tangled vegetation. Once the forests age beyond 25 years and trees become larger, the shrub layer thins out, making the habitat unsuitable for the New England cottontail.
(Editing by Ellen Wulfhorst and Barbara Goldberg)