PTARMIGAN IN NOVEMBER JUST AFTER COMPLETING WINTER PLUMAGE 



The conspicuousness of these birds in white winter plumage when seen against a dairk 

 background is an eloquent argument for the necessity of their seasonal changes in plumage, 

 the value of which is strikingly illustrated by the photographs on the preceding page and 

 below, where birds in summer and winter plumages respectively are shown with appro- 

 priate seasonal surroundings. 



PTARMIGAN IN WINTER PLUMAGE 



