Ecology of Thamnophis sauritus (Eastern Ribbon Snake) at the northern limit of its range

In Canada, Thamnophis sauritus (Eastern Ribbon Snake) is found only in Southern Ontario and a small area Of Southwestern Nova Scotia. Although the Nova Scotia Population is nationally designated as threatened, its distribution, seasonal activity. movement patterns, and over-wintering sites remain undescribed. We used radio-telemetry, capture-mark recapture, and direct observation to: 1) assess abundance, summer activity, and movement: and 2) to locate and characterize a hibernaculum for Eastern Ribbon Snakes in Kejimkujik National Park, NS. A total of 105 individuals were marked: among these. 13 free-ranging adults were surgically implanted with radio-transmitters and tracked from June until mid-November 2001. From late May to September, snakes were always found within 5 m of water, with summer ranges on land that rarely exceeded 5 x 10 m. From September to mid-October, snakes moved LIP to 173 in away from the shoreline. Eleven observations of snakes feeding on anurans (Ranidae) and fish (Cyprinidae) were made at temporary pools, marginal to the lake. Despite the use of radio-telemetry, only one hibernaculum was found. Our observations indicate that the Eastern Ribbon Snake is relatively sedentary; its low activity rate and small activity range may make it vulnerable to local extinction.