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...