Basic information on population demography and activity are essential for designing conservation plans for declining species.  In addition, seasonal variation in activity patterns of reptiles requires physiological and behavioural adjustments that influence both their ecology and life history.  A northern population of wood turtles (Glyptemys insculpta) in the Sudbury District, Ontario was surveyed in fall 2004 and a subset of adults (N = 5) radio-tracked during the winter of 2004-2005.  I examined population demography and size, winter movements and home range size, and characteristics of hibernation sites.  A total of nine turtles (4 females, 4 males, 1 juvenile) were captured.  Mean maximum carapace length for the 8 adults was 20.6cm for males and 21.2 cm for females.  Combining data from our survey and that of previous preliminary surveys, population size along an approximately 17 km stretch of river was estimated to be 120 turtles (95% CI = 51 to 189).  Turtles did not use distinct structures (e.g., root hollows, logjams, and holes in the riverbank) for hibernation, but instead rested relatively exposed on the riverbed at a depth of approximately 1 m and at a mean distance of 1 m from the riverbank.  Surprisingly, turtles made small movements during winter, typically in a direction parallel to the riverbank.  The findings of my study contribute to a better understanding of the over-wintering ecology of G. insculpta at its northern limit.  These data are especially important because G. insculpta is declining in numbers, and is particularly vulnerable to increases in adult mortality (that may occur during hibernation) because of slow growth, late maturity, and high mortality of eggs and juveniles.

© William F. Greaves