Observations on the temperature regulation and water economy of the galah (Cacatua roseicapilla)

Abstract

1. 1. Galahs (Cacatua roseicapilla), like many other birds, undergo controlled hyperthermia in hot environments.2. 2. Basal metabolism of galahs (271 g) at night during summer averages 0.93 cm3O2 (g-hr)-1 vs 0.90 predicted.3. 3. They can evaporatively dissipate heat at 1.4-1.7 times the rate of metabolic heat production at high ambient temperatures (Ta).4. 4. Under moderate Ta and humidity, galahs must minimally drink 7.3 g H2O/24hr. Without water they lose 2.2% body mass/24 hr. Some of these birds benefited from drinking 0.3 M NaCl.5. 5. Galahs occupy arid Australia through good powers of heat defense, some resistance to dehydrating conditions, and mobility allowing them to reach both water and food.