Rabbits are known for their reproductive prowess, but state officials are worried about the decline in Connecticut of the native New England cottontail.

This winter, the state Department of Environmental Protection plans to collar 20 New England cottontails and 20 nonnative Eastern cottontails and fit them with radio collars. It hopes to get a handle on the decline of the New England cottontail and the rise of the Eastern cottontail by learning their ranges and how they manage their lives.

“We want to track the rabbit’s movement, if not on a daily basis, then at least biweekly,” said Michael Gregonis, a DEP wildlife biologist.

Last year the DEP asked anyone who might come in close contact with rabbits in the state, such as hunters and wildlife rehabilitators, to tell them what they were seeing. The results were 90 percent Eastern, 10 percent New England, which is similar to what other studies have shown.

The Eastern cottontail is slightly smaller than its New England counterpart and the two have different markings. The New England cottontail lives in brushy, overgrown fields, while the Eastern cottontail is more adaptable and a more successful breeder because it can live anywhere, experts said.

The New England cottontail is not in danger of immediate extinction — 10 percent of all the rabbits in the state is still a lot of rabbits, Gregonis said. But there is the real threat that the New England cottontail will be marginalized by the increase in Eastern cottontails and the loss of the brushy areas it needs for a home.

The DEP’s work may eventually be part of an effort to add the New England cottontail to the nation’s list of endangered species. It could lead to efforts to preserve the scrub lots and brushy flood plains that New England cottontails and other species prefer.

Last year, four environmental groups petitioned the U.S. Fish and Wildlife Service to add the New England cottontail to the endangered species list. But there is now a federal moratorium in effect that blocks any additions to the list.

Around 1900, fish and game clubs brought Eastern cottontails to New England to add to the native rabbit population. Because they can live in many different habitats, they’re easier to find and shoot than the New England cottontail.

People should want to keep the New England cottontail from dying out because it is the native species of the region, said David Carle, executive director of the Conservation Action Project in Nashua, N.H.

“The New England cottontail has been here for eons and the habitat it needs to live has been here for eons as well,” he said. “But we’re letting it get lost.”

–Associated Press