Sharing Science to Conserve New England's Native Cottontail

Sharing Science to Conserve New England's Native Cottontail

Federal, state, and university conservation partners met in Dover, N.H., January 17-19, 2018, to review progress in restoring the New England cottontail rabbit across the species’ six-state range. The focus of the event was the annual meeting of the New England Cottontail Technical Committee, composed of biologists from Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, and New York, plus representatives of the USDA Natural Resources Conservation Service, the U.S. Fish and Wildlife Service, and the Wildlife Management Institute. Scientists from the University of New Hampshire, University of Rhode Island, State University of New York College of Environmental Science and Forestry, and University of Connecticut also participated.

Biologist Jeff Tash radio-locates collared cottontails sheltering in thick habitat after a fresh snowfall at Wells National Estuarine Research Reserve, York County, Maine

The population of the New England cottontail – the region’s only native rabbit – has been falling for decades. This secretive creature, sometimes called a “woods rabbit,” lives in shrubby swamps, old fields overgrown with shrubs, and areas of thick young forest growing back following disturbances such as windstorms, fires, floods, or timber harvests. The New England cottontail (Sylvilagus transitionalis) was a candidate for placement on the federal endangered species list until 2015, when the U.S. Fish and Wildlife Service judged that efforts by partners carrying out a conservation strategy developed in 2012 had a “high certainty” of helping the cottontail population recover.

The conservation strategy calls for determining where New England cottontails live; creating and preserving thousands of acres of young forest and shrubland; developing a captive breeding program; and determining whether cottontails are occupying habitat created for them. Researchers are also studying whether the eastern cottontail (S. floridanus) competes with the New England cottontail and may exclude it from suitable habitat. A non-native species, the eastern cottontail was introduced to the region, mainly from populations in the Midwest, during the last century. It is better able to live in the small, highly fragmented habitats found in many parts of eastern New York and southern New England, the New England cottontail’s current range.

The Fish and Wildlife Service has set a goal of having 13,500 New England cottontails living on 27,000 acres of good habitat by 2030. Collectively, the six states with New England cottontails are striving to meet even higher population and habitat goals: 21,650 rabbits on 42,440 acres by 2030. The Great Thicket National Wildlife Refuge, established in 2016, will protect and manage shrubland and young forests for a range of wildlife, including New England cottontails, with the goal of conserving 15,000 acres.

At the Technical Committee meeting, scientists reported on research important to the conservation effort. One topic was how to best conduct fecal pellet surveys to detect the presence and abundance of New England cottontails on habitat sites. Another project seeks to learn how the species’ genetic health is affected when small sub-populations become isolated from one another, either by human development or as intervening areas of young forest become too old to offer the dense cover that lets young cottontails disperse from the areas where they were born. Presenters stressed the importance of maintaining large patches of suitable habitat – at least 25 acres for a sub-population of rabbits – by continuing to create new young forest and shrubland next to and between existing habitat patches.

Researchers studying wild New England cottontails in New York’s Hudson River Valley reported that radio-collared individuals will move as far as 500 meters and, on occasion, up to 4 kilometers from the sites where they were initially trapped and collared. Paved roads are significant barriers to their movement, as cottontails are wary of crossing these open, non-natural surfaces, and if they try to do so, they may be struck by vehicles and killed.

Another report focused on a small population of New England cottontails that conservationists have started at Bellamy River Wildlife Management Area near Dover, N.H. There, biologists have created and refreshed between 40 and 50 acres of habitat with good food and cover that protects cottontails from predators. New England cottontails released on the site came from a captive breeding program at Roger Williams Park Zoo in Providence and from offspring produced in an outdoor breeding facility at Great Bay National Wildlife Refuge in New Hampshire.

One researcher noted that it can take 7 to 8 years for habitat created through management efforts, such as clearcut timber harvests, to become dense enough to support cottontails. The habitat will stay thick enough for the rabbits for another 10 to 12 years, by which time the trees will have grown tall and broad enough to produce shade reducing the amount and quality of food and cover plants at ground level. Other reports to the Technical Committee covered the population of around 65 rabbits that conservationists have established on Patience Island in Rhode Island’s Narragansett Bay; New England cottontails reintroduced at Great Swamp Wildlife Management Area in southern Rhode Island; the potential negative health effects of ticks and endoparasites on cottontails in New York; and studies of eastern cottontails in Connecticut and how they interact with New England cottontails.

Each state’s representative to the Technical Committee presented a detailed report on efforts to make, refresh, and protect habitat within “focus areas” identified as the best places to concentrate habitat-creation efforts.

Meeting attendees also visited a 16-acre outdoor breeding pen at Great Bay National Wildlife Refuge in Newington, N.H. There, a 10-foot-tall fence surrounds an area of thick shrubs where conservationists have started a New England cottontail population using rabbits from the Patience Island breeding colony. (A similar breeding pen exists at Ninigret National Wildlife Refuge in Rhode Island.) Conservationists have used rabbits produced in the pen to bolster wild populations and to start new populations in areas of prime habitat where New England cottontails currently do not live.

A second stop on the field trip was Wells National Estuarine Research Reserve in York County, Maine, where biologists demonstrated the use of radio-telemetry equipment to confirm the presence of several radio-collared cottontails living in the habitat.

Photo Credit
Charles Fergus
February 14, 2018