Fig, 61. Chickadee at 

 n e s t- hole. Light-and- 

 shadow-pi ctu ring general- 

 ized obliterative pattern, 

 most potent in snowy win- 

 ter. Notice how the' black 

 head - markings ' in e r g e ' 

 with the dark hole beyond. 



Photographed from life by 

 Finlev and Bohlman. Courtesy 

 also of - The Condor." 



