How age, sex, and reproductive condition affect retreat-site selection and emergence patterns in a temperate-zone lizard, Elgaria coerulea

Abstract

Minimising predation risk is critical to fitness in all animals. For animals that utilise retreat sites as an anti-predator strategy, there are many factors that influence retreat site selection and determine when to emerge from a hiding place. In this paper we test for seasonal and daily variation in cover use in a temperate-zone lizard (Elgaria coerulea). We also test for age- and sex-related differences in capture-site temperature, cover use, and sprint speed. We conducted a mark-recapture study on Elgaria coerulea in south-eastern British Columbia, Canada. We recorded temperature, precipitation, lizard’s position, proximity to cover, and rock size. The results showed seasonal variation in both retreat-site selection and emergence patterns. Lizards selected thicker rocks during the summer compared to spring, perhaps to avoid lethal high temperatures. Adult males used larger, thicker rocks than adult females and juveniles. Emergence patterns also differed between the sexes. The probability of capturing an adult female in the open steadily increased over the summer, while male emergence declined over the season. The tendency to be in the open also increased with the amount of rain that fell the previous day. This study shows that while remaining under cover is important in Elgaria coerulea, specific circumstances (lethal temperatures, reproduction, precipitation) will modify their cover use.