Meeting Abstract
The range of Timber Rattlesnakes (Crotalus horridus) extends further north than most other rattlesnakes. In these colder, northern latitudes, gravid female C. horridus must use rare, open habitats (rookery sites) in order to elevate body temperatures necessary for successful embryonic development. Unfortunately, many of these rookery sites are becoming overgrown with vegetation and it is believed females occupying these sites will no longer be able to maintain preferred body temperatures and reproductive fitness will suffer. For the past three summers (2016, 2017, 2018) we radio-located gravid females at six rookery sites; four of which have become overgrown with vegetation. At each site, we monitored available operative temperatures, canopy cover, and presence of potential predators. We determined the body temperature of females throughout the entire summer, behaviors, date of parturition, and estimated litter size. During the winter 2016, we removed trees surrounding three of the six rookery sites using a targeted disturbance called “Daylighting”. Operative temperatures increased as canopies became more open. During the first summer (pre-Daylighting), gravid females at more enclosed rookery sites dropped litters at a slightly later date, abandoned rookery sites, aborted their litters, and mothers suffered increased mortality. Following Daylighting management, we gathered evidence for increased reproductive success and improved thermal conditions. However, risk of predation may also be higher. We will further discuss body temperatures maintained by females at rookery sites, and the efficacy of Daylighting management. Dependent on the success of this restoration technique, these management techniques can be applied throughout the species northern range to increase female reproductive success.
