Lizard burrows provide thermal refugia for larks in the Arabian Desert

Abstract

A common perception is that desert birds experience greater extremes of heat and aridity than their mammalian counterparts, in part, because birds do not use burrows as a refuge from the desert environment. We report observations of Dunn's Larks (Eremalauda dunni), Bar-tailed Desert Larks (Ammomanes cincturus), Black-crowned Finch Larks (Eremopterix nigriceps), and Hoopoe Larks (Alaemon alaudipes) using burrows of the large herbivorous lizard Uromastyx aegypticus as thermal refugia during hot summer days in the Arabian Desert. Continuous recordings of shade air temperature (T(a)), soil surface temperature (T(surface)), burrow air temperature (T(a-burrow)), and burrow substrate temperature (T(substrate)) showed that T(surface) exceeded 60°C on most days. T(a) typically exceeded 45°C, whereas T(a-burrow) was around 41°C during midday. Calculations of total evaporative water loss at different temperatures indicated that Hoopoe Larks can potentially reduce their water loss by as much as 81% by sheltering in Uromastyx burrows during the hottest periods of the summer day.