Wanted: Smooth Green Snakes
by Mya Wiles, Conservation Intern
There are 14 species of snakes in Massachusetts, with nine occurring in Berkshire County. Of those nine, two are listed by the Natural Heritage and Endangered Species Program (NHESP) as having an "undetermined status" due to infrequent observations and lack of information regarding their distribution or status in the state.
One of those species, the Smooth Green Snake (Opheodrys vernalis), is notoriously secretive. Very little is known about this beautiful little snake, and I just had to know more.
Over this past year, I had been working on an undergraduate senior thesis project designed to target green snakes. In general, snakes can be notoriously challenging to study because they are difficult to detect by visual observation. This has resulted in a deficit of information and research on snake ecology, but there are a few successful techniques for increasing detection.
For smaller snake species such as the Common Garter Snake (Thamnophis sirtalis), a technique called "artificial cover surveys" are particularly successful in northern climates. This relies on the snake's need to thermoregulate, which is often done by sheltering under warm, flat objects. Researchers can deliberately place cover, such as plywood boards or corrugated metal sheets in an area of interest. Cover boards are checked regularly by flipping them over and identifying and counting all of the individual snakes present.
With this technique, and permission from Mass Audubon to use three of their Berkshire sanctuaries as study sites, 81 plywood boards were set out this past summer to try and find Smooth Green Snakes.
After four months and 1,090 board visits I had recorded 541 snake observations. Not one of them was a green snake. A majority of observations were of Common Garter Snakes (T. sirtalis), but Dekay’s Brownsnakes (Storeria dekayi), Redbelly Snakes (S. occipitomaculata), Eastern Milksnakes (Lampropeltis triangulum), and a single Ring-necked Snake (Diadophis punctatus) were observed.
The lack of green snake observations was concerning, especially in conjunction with reports from local naturalists who shared similar stories of few or decreasing observations. Could these snakes be disappearing from the Berkshires? The state? It's unlikely that the survey failed to detect snakes that were present at the study sites because green snakes have been detected using artificial cover in previous surveys (e.g. Cox et al., 2008; Meshaka, 2010).
So where could they be?
Further efforts are needed to document the presence of green snakes and others so that the NHESP can assess their status in the state and decide their eligibility for listing. Snakes are seldom studied because of the challenges they pose, but they are important contributors to our ecosystems and represent over half of the state’s reptile biodiversity.
Snakes deserve as much protection and attention as other wildlife. So the next time you spot a snake, try to take a picture and report it to one (or more) of the following databases: