Behavioural responses to heat in captive native Australian birds

Abstract

Australian birds are under threat from climate change and heatwaves. We investigated whether captive native Australian birds adjusted their time budgets, microsite selections or used thermoregulatory behaviours on typical or extremely hot summer days. We observed eight species of birds at Adelaide Zoo and found that the proportion of time spent on stationary behaviours, feeding, in the sun and on the ground differed amongst species of birds, between mornings and afternoons and day type. Wing-venting was used more frequently during the hottest observation periods. The smallest birds in the study utilised wing-venting more than other species of birds, possibly because it is more important for them to conserve water. Psittaciform birds spent less time feeding and more time resting in cooler microsites during hot periods. Columbiform birds continued feeding and spent more time in the sun rather than resting in cooler microsites. Whitebrowed Woodswallows spent a significantly lower proportion of time on stationary behaviours and a higher proportion of time feeding compared to the other species. Our results suggest that columbiform birds may have an advantage during heatwaves as they can continue feeding through high ambient temperatures, provided there is adequate access to food and water.

How to Stay Cool: Early Acoustic and Thermal Experience Alters Individual Behavioural Thermoregulation in the Heat

“…As expected, and documented in other species (Smit et al, 2013;Cunningham et al, 2015;Pattinson and Smit, 2017;Xie et al, 2017;Oswald et al, 2019), panting and use of cooler microsites (here, the floor) increased with temperature (measured as T air or T loc ). In addition, we found that, after controlling for microsite temperature, birds panted more, earlier in the day.…”

“…Yet, at any one place in time, selection by high temperatures does not operate equally across individuals. This is because individuals respond behaviourally to thermal challenges (Smit et al, 2016;Xie et al, 2017;Thompson et al, 2018;Pattinson et al, 2020). To avoid lethal hyperthermia, birds rely on thermoregulatory behaviours, such as panting, to dissipate heat.…”

Heat Shock Protein Expression is Upregulated after Acute Heat Exposure in Three Species of Australian Desert Birds

“…Columbiform birds generally have higher heat tolerance limits compared to passeriform and psittaciform birds (Whitfield et al, 2015;McKechnie et al, 2016McKechnie et al, , 2017Smith et al, 2015Smith et al, , 2017. In a captive situation, Diamond Doves (Geopelia cuneate, Columbiformes) have also been found not to alter their behaviour in response to heat, whereas Budgerigars (Melopsittacus undulatus, Psittaciformes) and White-browed Woodswallows (Artamus superciliosus, Passeriformes) increased the proportion of time spent stationary and decreased the proportion of time spent feeding in response to heat (Xie et al, 2017b). Zebra Finches (Taeniopygia guttata, Passeriformes) and Budgerigars also lack a corticosterone response when exposed to high temperatures, suggesting that they may be at a further disadvantage surviving during a heat wave when compared to Diamond Doves (Xie et al, 2017a).…”

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

“…There are numerous examples of natural microsite selections by terrestrial animals to mitigate extreme hot [14,15] and cold [16] outdoor temperatures (e.g. seeking cool tree shade by day, warm cavities overnight), but objectively documented cases where human resources/environments are used by wildlife for such thermal buffering are comparatively scarce.…”