Population Estimation of an Urban-Adapted Snake

Accurate estimation of the abundance of many snake species is often compromised by their secretive and elusive nature, which lowers the probability of recapturing marked individuals. However, urban-dwelling populations of Dekay’s Brownsnake ( Storeria dekayi ) often congregate at high densities in fragmented edge habitats, making them unusually good models for estimating abundance using mark–recapture techniques. We used a mark–recapture modeling approach to estimate the population size of S. dekayi in two roadside greenspaces at an urbanized site in central New Jersey, USA. We applied a robust design sampling scheme and incorporated temporary emigration and trap responses into our a priori candidate models. Snakes occurred at high densities in both sites, with constant capture probabilities in the early activity season, but with some evidence of trap-shy behavior. This study provides a useful guideline for monitoring and assessing the population size of snakes, especially abundant species in urban environments.