Last February, we posted about our science department’s efforts to document if the New England cottontail (Sylvilagus transitionalis), a rare and elusive species of rabbit, is still present on Nantucket (see Searching for a Certain “Some Bunny”). We just recently learned the exciting news that a DNA sample from one of the rabbits that we captured on Foundation-owned property tested positive as a New England cottontail, indicating that this species still occurs on Nantucket!
We became involved with this project because the U.S. Fish and Wildlife Service (USFWS) recently ramped up its efforts to locate sites where there are still viable populations of New England cottontails due to concerns regarding drastic declines across their range. Nantucket was identified as one of the most likely sites where remnant populations may still exist. This is because they were known to have once occurred here and vast expanses of highly suitable, undeveloped habitat have been protected from development due to the success of Nantucket’s land conservation efforts.
Over the past several winters, we trapped rabbits using “Havahart” traps and collected fecal pellets (aka bunny poop) in order to obtain DNA samples needed to definitively distinguish this species from the more common, but introduced eastern cottontail (Sylvilagus floridanus). Eastern and New England cottontails look virtually identical in the field, so the only way to distinguish live animals is by analyzing their DNA, obtained from either a small drop of blood, and tiny sample of tissue obtained from the outer edge of the ear, or fecal pellets. Our sample that tested positive as a New England cottontail came from a rabbit that was trapped on Foundation’s Ram Pasture property in February of 2011 and was one of 55 samples that we submitted over a two year period.
So why is this important? The New England cottontail, which is the only cottontail rabbit native to the northeastern United States, has become extremely rare within the last 50 years. It was once found east of the Hudson River in New York, across all of Connecticut, Rhode Island and Massachusetts, north to southern Vermont and New Hampshire, and into southern Maine. This former range is believed to have declined by over 75%. Why? The introduction of the Eastern cottontail in the late 1800’s to provide game for hunters has certainly played a role, but the region-wide decline of its preferred dense shrubland habitat is also a significant factor.
On Nantucket, dense shrublands suitable for New England cottontails are rare priority habitats in and of themselves. Knowledge of the presence and the locations of population concentrations of this species within our coastal maritime shrublands and scrub oak barrens will enable us to better manage these ecologically important habitats. Also, grant money may be available for conducting habitat management efforts in areas where New England cottontails are known to occur. Funded projects are aimed at preventing shrublands from succeeding into forests, which are less suitable for New England cottontails. Now that we have documented the presence of this species on Foundation-owned lands, it is possible that we will be eligible for grant funding to conduct habitat management work that will benefit not only this species, but also others such as northern harriers, eastern whip-poor-wills, and numerous rare shrubland-associated moths.
What next? Now that we know that New England cottontail rabbits do in fact occur on Nantucket, we will focus our efforts on two main priorities: obtaining more information about the population and habitat use patterns of this species at the Ram Pasture site where it was found, and continuing our efforts to determine if there are additional population concentrations in other areas of the island. In the months ahead, we will be collecting additional DNA samples from rabbits at Ram Pasture and across the island, as well as meeting with biologists from the USFWS to coordinate with their region-wide species conservation efforts.
How can you help? There is one additional way that New England and Eastern cottontails can be differentiated: skull suture patterns. Skull sutures are junctions between the major bones of the skull. In New England cottontails, the skull suture lines between the frontal and nasal bones of the skull are irregular and jagged, while those of the Eastern cottontail are smooth. If you happen to be a rabbit hunter and are interested in “donating” the intact head of any rabbits you harvest, our department will gladly accept your contributions – just store each specimen in an individual Ziploc bag (with the name and contact info of the collector, date, and specific location where the rabbit was harvested recorded with permanent marker on the outside) and freeze it while it is still fresh. We will happily collect your specimens and store them until we are able to transfer them to a game biologist at the Mass Wildlife for identification. Please call our office at 508-228-2884 and ask for any member of the science staff for more information.