Ranging behaviour of adders (Vipera berus) translocated from a development site

Translocation of animals from sites scheduled for development is a widespread but controversial intervention to resolve human-wildlife conflicts. Indeed, reptiles are very frequently the subject of such translocations, but there is a paucity of information on the fate of such animals or how their behaviour compares to residents. In 2014, a population of adders (Vipera berus) was translocated from a development site in Essex, UK. A sample of snakes was fitted with external radio tags and tracked for a period of 10 days during the spring. This exercise was repeated during the summer using a combination of translocated and resident individuals. Translocated males exhibited significantly greater average daily movements than resident conspecifics. Furthermore, all translocated males undertook long-distance, unidirectional movements away from the release site. In contrast, all translocated females remained within 50 m of the point of release. One of the males returned to the donor site, crossing large areas of unsuitable habitat in doing so. Translocated males also maintained significantly larger total ranges than resident conspecifics. No differences in range sizes were observed between translocated and resident females. The dispersal of male snakes from the release site may increase the risk of mortality of translocated snakes and reduces the likelihood of establishing a new population. Interventions to encourage the establishment of new home ranges within the boundaries of release sites may include mechanisms to prevent dispersal immediately following release.