Environment DEC
From the April 2005 issue
Splitting Hares to Save a Species, or When is a Bunny Not Just Any Ol' Wabbit?
Mike Clark from the
Division of Fish, Wildlife
and Marine Resources
weighs a rabbit in
a capture bag
Of all the creatures in the animal kingdom, rabbits are most often associated with ... well, making more rabbits! So if someone told you there was a species of cottontail whose population was dwindling, you might be forgiven for being a bit skeptical. That's only one of many preconceptions that have to be overcome by Michael Clark of DEC's Division of Fish Wildlife and Marine Resources, as he and a team of DEC wildlife biologists study the decline of New England cottontails in New York. Clark recently presented a report on "Status and Distribution of the New England Cottontail" as part of a Fish and Wildlife Seminar.
Strong similarity of species a problem
Even upon close examination
it is very difficult to distinguish
Eastern cottontails from
New England cottontails
New England cottontails were identified as a distinct species from their more common cousins, Eastern cottontails, in the last quarter of the 19th Century. Biologists think they developed as a separate species due to the natural barrier of the Hudson River, which deterred them from migrating beyond New England. One reason that a red flag about declining populations of the species was not raised sooner is because Appalachian cottontails, which had been thought to be New Englands, were reclassified as a separate species in 1992. New Englands are also very similar to Eastern cottontails, so similar that positive identification-even with "bunny in hand" as Clark says-is extremely difficult. So he and his team have resorted to using sophisticated DNA analysis techniques to identify them.
New England cottontails may have
developed as a distinct species
because of the natural barrier
caused by the Hudson River
Until 2004, DNA samples were collected in one of two ways. The easy way was collecting fresh fecal (pellet) samples-preferably during winter when freezing temperatures and snow preserve the DNA better. The hard way was trapping a live animal and taking a tiny tissue sample before releasing it. Since 2004, DNA analysis technology has improved enough so that pellet sampling is now used exclusively.
These maps demonstrate how the range and abundance of
New England cottontails has declined over the last 40+ years
Reasons for decline unclear
In the early 20th Century, hunting clubs began stocking Eastern cottontails in New England to increase the number of game animals. Since then, the two species have competed for the same habitat, and New Englands appear to be losing ground. Around 1960, they were common from eastern New York through much of New England. Now they are scattered in small pockets over that area. The reasons for their decline are varied; chief among them is loss of habitat to development and replacement of thick scrub, which rabbits prefer, as farms have been abandoned, but other possible causes are also under investigation. One trait that makes studying New Englands difficult is that they are more secretive by nature than Easterns and so are simply harder to find, kind of like "Harvey", the invisible giant rabbit in the play by the same name-they're there, you just can't see them.
A "species of special concern"
New England cottontails are listed as a"species of special concern" in New York State but not in New England. The goal of ongoing research is to determine whether they should be similarly listed in New England. DEC is working cooperatively with neighboring states toward this goal. New Hampshire recently instituted hunting restrictions in areas that are currently dominated by New Englands in an attempt to shore up their numbers. Only time will tell if that strategy has the desired effect.
The future is uncertain for New England cottontails, but they have a better chance of surviving to see it thanks to the work of dedicated wildlife biologists like Michael Clark and DEC's Fish and Wildlife team.
