Cool birds: facultative use by an introduced species of mechanical air conditioning systems during extremely hot outdoor conditions

Rapid climate change across the globe is having dramatic effects on wildlife. Responses of organisms to shifting thermal conditions often include physiological and behavioural accommodations, but to date these have been largely viewed and studied as naturally evolved phenomena (e.g. heat avoidance, sweating, panting) and not necessarily as strategies where animals exploit other anthropogenic conditions or resources. Moreover, the degree to which native versus introduced species show thermal plasticity has generated much conservation and ecological interest. We previously have observed introduced rosy-faced lovebirds (Agapornis roseicollis) perching in the relief-air vents on building faces in the Phoenix, Arizona, USA metropolitan area, but doing so only during summer. Here we show that such vent-perching events are significantly associated with extreme outdoor summer temperatures (when daily local highs routinely exceed 40° C). In fact, the temperature threshold at which we detected lo...