Behavioural thermoregulation of alpine birds in response to low temperature in early summer

Abstract

Thermoregulation in animals can be achieved physiologically and behaviourally. Alpine birds can obtain significant radiation benefits from the sun and to help conserve heat they adjust their behaviours such as perching. The aim of this study was to explore the preferences of alpine birds for temperature and illumination of perching sites. We measured the temperature and light intensity of both potential sites and actual sites where birds perched, and compared the distributions of temperature and illumination of these on cold and warm days among species. Results showed a non-random selection of temperatures on cold days and a slightly higher light preference on warm days. Among species, only the little raven (Corvus mellori) showed a preference for warmer and lighter perching sites, while other species either showed no predilection or perched in warmer places due to other factors of habitat selection. When perching, behaviours like sitting (hiding feet) and puffing were more frequent on cold days and no birds chose a shady site when the temperature was low. The influence of predation may explain the random selection of perch site in most birds. Finally, the results indicate that alpine birds may be more favoured by the warming of the alpine region.