BIRD STUDY 31 
Perhaps the most remarkable example of adaptive colora- 
tion in the bird world is found among the Ptarmigans or Snow 
Grouse, which, although having the Grouse colors in summer, 
turn pure white in winter. Mr. Frank M. Chapman calls atten- 
tion to the fact that Snowy Owls feed on Ptarmigans. It would 
appear, therefore, that the Ptarmigan’s colors mean conceal- 
ment for defense, while the Owl’s mean concealment for ap- 
proach and attack. The soft, quiet flight of Owls also assists 
them in coming upon their quarry unobserved. 
The same relation would seem to exist between whole 
classes of birds, for example, Hawks and Grouse. Both are 
modestly colored, the Grouse evidently for concealment and 
Hawks for attack. All Flycatchers also have modest colors. 
They can hardly be seen as they perch upon dead branches 
and doubtless this gives them advantage in darting out upon 
passing insects. 
It should be noted that all birds are lightest colored on 
their under parts, many of them white. This is an important 
element in protective coloring, since the under parts are always 
in shadow. They must therefore be lighter in order to make the 
color effect uniform. 
The whole matter of color protection is filled with diffi- 
cult questions, owing to the many exceptions, but it is a subject 
of intense interest for study, and one that comes under almost 
daily observation if our eyes are open to observe the facts. 
