The Willow Ptarmigan . 377 



are extremely hard to discern against the blank whiteness of their surround- 

 ings. Even when fresh foot-prints in the snow and occasional calls told of their 

 near vicinity, I have often found myself to be within but a few yards of the 

 birds before they would take flight with startling whirr of wings and hoarse 

 notes of alarm. Then, as a bird would alight at some distance, it would seem- 

 ingly vanish from the sight, not infrequently defying rediscovery altogether. 

 On the occasional cloudless day, when the sun shines unobstructedly, even 

 white objects are brought out in sharp relief by their long, dark shadows cast 

 upon the snow. If approached at right angles to the rays from the sun, the 

 Ptarmigan may then be discerned at several hundred yards distance. But 

 they are then shy, for they have a marvelous way of appearing to know 

 whether or not the hunter is actually aware of their exact whereabouts. 



During the eight-months winter season, the Willow Ptarmigan feed upon 

 the buds and tender terminal twigs of the dwarf alder and willow; this, and 

 practically nothing else, save that quartz gravel is regularly gathered from the 

 river-bars where the wind bares the ground of snow. 



The Willow Ptarmigan are by nature gregarious. Especially is this trait 

 exhibited in the autumn months, when in the most northern localities a partial 

 migration is undertaken a few hundred miles to the south, or into great val- 

 leys where more food and better cover are afforded. For the birds do show a 

 predilection for the vicinity of brush-patches, or even tracts of stunted spruce 

 trees in regions where these exist. Not infrequently they escape from the dash 

 of the Falcon by taking refuge in a bush, among whose stems the snow r.ests 

 lightly, and into which the frightened bird is able to plunge quite out of sight. 

 In the early spring, long before the thaw commences in earnest, the male 

 Ptarmigan begin to change to a rich chestnut-brown color on the head and 

 chest, and a bright red comb develops above each eye. For a time, in April 

 and early May, the males, with their deep brown mantles and white bodies, 

 are very conspicuous. They are then more noisy than at any other season, 

 uttering, at frequent intervals until late dusk, a low, harsh 'cackle,' roughly 

 imitated in the Eskimo name for the Willow Ptarmigan, A-kaze-rh-gak. 



The male Ptarmigan wear this special courting plumage until June, when 

 another change, involving the whole body plumage, leads to a brown-black- 

 and-buff plumage, which is worn until autumn. The females, meanwhile, 

 change rapidly in early May, about the time the snow begins to disappear, to 

 a mottled and barred, black-and- brown coloration. In this "summer pro- 

 tective" plumage the birds of both sexes are as difficult to see against the green, 

 brown and gray of the open tundra as they were in winter plumage, against 

 the white landscape. 



All these remarkable changes in appearance are the result of molts, by which 

 feathers of one color fall out and new ones of a difterent color grow in. In the 

 autumn, exactly the same process leads from the brown and mottled colora- 

 tion of both old birds and young-of-the-year to the pure white of winter dress. 



