Impacts of Translocation on Behavior and Survival of Timber Rattlesnakes, Crotalus horridus

The impact of translocation on timber rattlesnakes (Crotalus horridus) was assessed experi- mentally by moving 11 specimens distances of between 8 km and 172 km away from their native popula- tions and releasing them into a study area having a resident rattlesnake population. All translocated snakes were equipped with radio transmitters, and their behavior, survival, and interaction with resident snakes were observed. Eighteen resident snakes were also telemetrically monitored during the fouryear study. Six of the 11 (54.5%) translocated snakes are known to have died while only 2 of the 18 (11.1%) resident snakes experienced mortality during the period they were radiotracked. Of the six translocated specimens that died, three experienced overwinter mortality despite their location of resident hibernacula, two were killed by predators, and one died from disease. The mean daily survival rate of translocated snakes (0.9973) was significantly lower than that of resident snakes (0.9993). Translocated snakes selected habitats similar to that of residents, foraged successfully, and maintained body mass. However, translocated snakes exhibited atyp- ical movement patterns consisting of extensive and long-distance traveling. The six translocated male rat- tlesnakes averaged 15,017 m (SE = 2184.3) in total distance traveled from release until hibernation with daily movements of 123.8 m (SE = 19.40) and convex polygon activity range areas of 600.6 ha (SE = 253.0). Comparatively, the total active season distance traveled by the seven resident male rattlesnakes averaged only 5575 m (SE = 936.5) with mean daily movements of 36.9 m (SE = 5.36) and convex polygon activity ranges of 59.9 ha (SE = 13.04). Mean activity parameters 3 to 5 times larger than those of resident snakes were also typical for translocated female rattlesnakes. Translocated snakes located active hibernacula ap- parently by following resident snakes; however, their overwintering mortality was higher than that of res- idents. Translocated snakes that successfully survived the first overwinter period continued to exhibit more extensive movements in their second active season than did residents. However, there was evidence of the establishment of a more resident-like pattern of movement among these specimens during the second year. Translocation of adult snakes is not recommended as a standard conservation practice because of its im- mediate and long-term negative impacts.