Evaluating the Effectiveness
of Headstarting Redbelly Turtles in Massachusetts

        ABSTRACT:  As part of the federal recovery plan for the endangered redbelly turtle, Pseudemys rubriventris, in Massachusetts, a headstart project was initiated in 1984 to increase numbers of turtles.  In this project, hatchlings are collected from a single donor population, raised in captivity (to increase their size) for about nine months, and subsequently released into one of several targeted ponds.  We evaluate the effectiveness of headstarting redbelly turtles in Massachusetts by assessing survival of headstarted (HS) turtles and their effect on turtle numbers.  The survival of headstarted turtles was assessed by determining (1) size-specific survival rates of HS turtles at one pond—Crooked (CR), and (2) average annual recapture rates of HS turtles at four ponds—Crooked (CR), Island (IS), Gunner’s Exchange-Hoyts’ (GH), and Federal (FE).  The effect of HS turtles in increasing turtle numbers was examined by determining post-release changes in population size of four populations.  Survival of HS turtles at CR Pond was lowest during the first year post-release, with substantial increases in following years.  Lower survival rates of HS turtles at CR Pond was size-related (carapace length <65 mm).  Higher survival rates, similar to rates observed for non-HS subadult and adult turtles, were observed for larger HS turtles (carapace length >95 mm).  Average annual recapture rates of HS turtles at CR, IS, GH, and FE ponds were highest (0.70–0.84) for the three smaller ponds (CR, IS, GH) and lower (0.44) for the largest pond (FE).  The observed difference in recapture rates was likely the result of variable trap effort, with more accurate rates observed for the smaller, more intensively trapped ponds.  Sufficient numbers of HS turtles are surviving to increase turtle numbers at the three smaller ponds (CR, IS, GH) but not at FE Pond.  Despite the increases in turtle numbers due to HS turtles, successful recovery requires the establishment of self-perpetuating populations.  Because factors limiting population growth of the Massachusetts redbelly turtle probably still exist, headstarting should not be considered an appropriate longterm conservation strategy.  Clearly, more research is needed to identify factors limiting natural recruitment if self-perpetuating populations are to be achieved.


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