Trail cameras enhance understanding of lizard behaviour in a remote alpine environment

The number and type of threats that a species is exposed to is often influenced by their activity patterns. For ectotherms, environmental conditions are likely to strongly influence activity, given that external heat is needed to reach body temperatures that promote physiological functions, including locomotion. As a result, one might expect ectotherms to avoid cold environments, such as the alpine zone, known for large temperature variations and prolonged winters. However, many endemic lizards, including diurnal skinks (Oligosoma spp.), inhabit the alpine zone across Aotearoa, New Zealand. We used trail cameras to monitor the surface activity of skinks (likely to be predominantly McCann’s skinks, Oligosoma maccanni) in the alpine zone of the southern South Island (c. 44°S; 1150 to 1600 m a.s.l.) from spring until autumn. We asked: (1) under which environmental conditions do skinks emerge? (2) which temperatures and other weather variables promote the highest levels of surface activity? and (3) what sort and duration of activity are typical? We observed more skink activity when temperatures at basking locations were warm, with 95% of skink observations occurring when temperatures recorded at copper models were between 13.2 and 43.2°C; these patterns follow trends observed in McCann's skinks at lower elevation and in species of alpine skinks in Australia. Furthermore, skinks were most active when conditions were dry and sunny, with observations in mid-summer peaking in the late afternoon. When visible, skinks were very mobile, only remaining in the same position for 1–3 min. Our study increases understanding of a generalist skink in an alpine environment. During summer, activity of skinks is highly dependent on warm sunny conditions, and our study highlights trail cameras as an effective tool for monitoring behaviour (including potential predator exposure) in this remote environment.