Movements, overwintering, and mortality of hatchling Diamond-backed Terrapins (Malaclemys terrapin) at Jamaica Bay, New York

Abstract

As with other turtles, the postemergent movements, overwintering behaviours, and survivorship of hatchling Diamond-backed Terrapins ( Malaclemys terrapin (Schoepff, 1793)) are poorly known, but anecdotal reports suggest that they may spend more time on land than most aquatic turtles. We investigated this behaviour using drift fences with pitfall traps on the island of Ruler’s Bar, Jamaica Bay, New York, fall 2006 to spring 2008. We captured 324 live hatchling Terrapins, 95 were recaptured at least once, and we found 43 dead. After emergence from nests in the fall, most hatchlings moved upland away from the water; this pattern was reversed in the spring. Hatchling body sizes shrank during winter, probably owing to desiccation, and hatchlings were more likely to move on warmer days and days without precipitation. We recaptured some hatchlings on land as long as 9 months after emergence. As a result, hatchling M. terrapin were seen on land from April to December, well outside fall and spring during which they emerge from nests, and we found strong evidence that hatchling M. terrapin overwinter on land outside their nests. One important nest predator (raccoons, Procyon lotor (L., 1758)) was also an important hatchling predator, as were Norway rats ( Rattus norvegicus (Berkenhout, 1769)). Future work should investigate the terrestrial microhabitats used by hatchling M. terrapin, and management should protect hatchlings during this life stage.