Funded in part by the New England Herpetological Society
The Black Rat Snake (Elaphe obsoleta) is listed as an endangered species in the state of Massachusetts due to its limited range and specific habitat requirements. This snake is known from only four populations in the state and accurate knowledge of this animal’s life history, spatial activity and habitat parameters are seen as essential elements towards the successful management of this species.
The researchers, Paul Metcalf of Herpetological Associates and Peter Mirick of the state Division of Fisheries & Wildlife, have utilized mark and recapture methods to begin to compile a database of information concerning individual snakes at one particular site, and hope to eventually facilitate an accurate population estimate from this method.
Micro-transmitters were implanted into the body cavity of the snakes (two males and one female) by Dr. Mark Pokras of Tufts Veterinary School’s Wildlife Clinic in Grafton MA. Each transmitter has an expected life of one year.
Once released, implanted snakes are located from between one and three times weekly from their release date until their ingress into the den crevices or until retrieval of the implanted transmitters is necessary. Each transmitter unit produces a unique pulsed frequency signal in the 164-165 or 150-151 MHZ range.
Transmitter signals are received using a Division of Fisheries & Wildlife-owned receiver calibrated to receive frequencies in the same range. The MDFW also provided a hand-held Yagi antenna and the necessary coaxial cable. Each transmitter has a local range of 200 to 1000 feet, depending on local topography and current consumption by the transmitter.
Through the use of radio-relocation methods, the researchers hope to also develop maximum, minimum and average range area estimates in addition to identifying specific E. obsoleta habitat requirements by collecting and comparing habitat parameters chosen by relocated snakes, to randomly chosen sites.
In addition to Paul Metcalf and Pete Mirick, a hardy collection of souls have ventured forth to assist in the assembling of data concerning this endangered snake. They include Joe Martinez, a Ph.D candidate and former President of the NEHS, Kurt Schatzl, a local naturalist and President of the NEHS, and Tom Palmer, former NEHS Librarian, noted naturalist and author of the book, “Landscape with Reptile.”