NEW ENGLAND COTTONTAIL REPOPULATION PROJECT

The rare New England cottontail (Sylvilagus transitionalis), a threatened species of native rabbit once abundant throughout the New England region, is getting much-needed help.Starting in 2011, biologists from the New England Cottontail Captive Breeding Working Group (NECCBWG) teamed up to restore populations by breeding these rabbits in human care and releasing them into their natural habitat. This program has made promising progress toward boosting cottontail numbers while the partners also work to protect and restore habitat throughout the range of this species.

RWPZ had dedicated space, staff, and veterinary care for the breeding program and continues to provide expertise to sustain a supply of healthy captive-born rabbits for the reintroduction and population augmentation initiative. Partners in Massachusetts, Connecticut, Maine, New Hampshire, and New York continue to provide wild adult cottontails for the breeding program. These are the “founder” rabbits that produce the offspring for reintroduction efforts and population augmentation. Genetic testing performed at the University of Rhode Island (URI) confirms the founders are indeed New England cottontails before they are added to the breeding program. From 2013 through 2022, the breeding and release program grew significantly, nearly doubling numbers achieved in each of the previous years, with young rabbits now being released in Rhode Island, New Hampshire, and Maine to create new populations and augment existing populations.

During the 2019 breeding season, 24-hour video footage was collected and analyzed by URI students to assess why some female rabbits were successfully birthing kits, while select female rabbits were not getting pregnant. Results found that those rabbits that were not getting pregnant did not copulate at all. In 2022, the Zoo rabbit breeding team and a URI masters student experimented with a mate choice study by allowing the female breeding rabbit to preview three different male rabbits before being paired to breed. The male rabbit that the female rabbit spent the most time with became the chosen mate. Since the mate choice study began, the results seem to indicated success with this past year resulting in one the greatest number of kits born in a single year since the program’s inception.