ADAPTATIONS TO DESERTS 



=> 400 



2 



i 



^- 300 

 < 



UJ 



t t 



I I I I I I I I I I I I I ' I I I I I ' I ' ' ' ' I ' I ' I ' li p 



10 15 20 25 30 



AMBIENT TEMPERATURE °C 



Figure 4. Heart rate of a Poor-will at different ambient temperatures. The 

 closed circles represent the heart rate of an inactive bird following at least 30 

 minutes of exposure to each ambient temperature. 



429 



