The acid base balance of Abdim's stork ( Sphenorhynchus abdimii) during thermal panting

Abstract

1. 1. The effect of long-term (8–10 hr) exposure to heat stress (40–45°C) on acid base balance of Abdim's stork ( Sphenorhynchus abdimii) was investigated. 2. 2. Body temperature reached a maximum of 41·15°C (at 45°C T a), as compared to about 40·0°C at 24–30°C T a. 3. 3. Normal respiratory rates (10 c/min) increased to 100–112 c/min at ambients of 40, 42 and 45°C. 4. 4. Normal arterial pH, P CO2 and [HCO 3 −]were 7·564, 27·9 and 25·09, respectively. After 10 hr of intensive panting, values were 7·571, 25·5 and 23·09. 5. 5. These results are discussed in relation to a possible shunt mechanism, effective in preventing washout of gas-exchange surfaces in a flying bird's lungs.