Heat dissipation behaviour of birds in seasonally hot, arid-zones: are there global patterns?

Quantifying organismal sensitivity to heat stress provides one means for predicting vulnerability to climate change. Birds are ideal for investigating this approach, as they display quantifiable fitness consequences associated with behavioural and physiological responses to heat stress. We used a recently developed method that examines correlations between readily-observable behaviours and air temperature (Tair) to investigate interspecific variation in avian responses to heat stress in seasonally hot, arid regions on three continents: the southwestern United States, the Kalahari Desert of southern Africa and the Gascoyne region of Western Australia. We found substantial interspecific variation in heat dissipation behaviours (wing-drooping, panting, activity-reduction, shade-seeking) across all three regions. However, pooling the data revealed that little of this interspecific variation was systematically explained by organismal traits (foraging guild, diet, drinking dependency, body ma...