COLOR A PROTECTION. 23 
upon the ground, are secreted from the searching eye 
of the Hawk and the Kite by their grey speckled 
plumage, which resembles the ground on which they 
move. The tawny feathers of the Whip-poor-will 
also afford it a means of protection, even from man, 
as it is extremely difficult to distinguish it from the 
log upon which it may be crouching, almost within 
our reach. The Ptarmigan, which inhabits very cold 
northern climates, in summer has its plumage marked 
with stripes of black or brown, which colors more 
nearly approach to those of the rocks and barrer 
heaths upon which it lives; but, did these hues re 
main during the winter, when the snow covers every 
object with a mantle of white, the place of its con- 
eealment would be readily discovered, and it would 
fall an easy prey to the Snowy Owl or the Gyr Fal- 
con. What then is the provision of Nature to guard 
against this danger? As the cold season advances, 
the feathers, by some unknown process, gradually 
become white, and the bird burrows fearlessly in the 
snow, in search of berries and’ leaves, comparatively 
secure from the eye of its enemy. 
Another object besides safety is gained from the 
concealment afforded by the peculiar colors and 
markings of the plumage; the support of the bird 
being sometimes dependent upon it. Thus the Crane 
and the Heron, and many other water birds, which 
depend upon their dexterity as fishers for their sup- 
ply of food, are clothed with feathers partly of white 
and partly of a bluish slate color, and the fish as they 
glide beneath the water recognize but little difference 
