BIRD ADAPTATIONS 



>- 

 o 

 o 

 m 



17 18 19 20 21 22 23 24 I 2 3 4 5 6 7 8 9 



TIME 



Figure 1. Body temperatures of eight Evening Grosbeaks recorded by indwelling 

 thermocouples at a constant temperature of 30 C (0). a constant temperature of 

 -15 C (■), and outdoors during January at -6.8 C (•). 



293 



