PATTERNS OF CUTANEOUS WATER EVAPORATION BY AUSTRALIAN PIGEONS

Abstract

We examined thermoregulation and cutaneous evaporative cooling by heat-stressed desert columbids (diamond dove, flock bronzewing, rock pigeon, and spinifex pigeon), temperate-zone columbids (common and brush bronzewing, and crested pigeon), and rainforest columbids (wonga pigeon, Luzon bleeding heart, and emerald dove). Body temperature at a Ta of 47 oC was lower for desert birds (43.3 oC) than for temperate-zone birds (43.6 oC) and rainforest birds (44.4 oC). Body-skin temperature difference (DT) was only 0.2 oC for rainforest species; it was significantly higher at 0.4 oC for temperate-zone pigeons, and significantly higher again at 0.9 oC for arid-zone birds. Cutaneous water evaporation (CWE) was 2.1 mg H2O cm-2 h-1 for rainforest species; it was significantly higher at 5.6 mg H2O cm-2 h-1 for temperate-zone birds, and significantly higher again at 13.5 mg H2O cm-2 h-1 for arid-zone pigeons. CWE of young wonga and bleeding heart pigeons was similar to that of adults, but was very high for young birds o...