crops of blueberries, heathberries, cranberries, and roseapples are 

 freely resorted to, and these fruits again become available the fol- 

 lowing spring, when the retreating snow leaves them exposed. 



The reader will already have marveled at the special and useful 

 modifications in the habits and structure of the ptarmigan, which 

 enable it to carry on a successful existence under such extremes 

 in winter climate. Perhaps the most wonderful thing about the bird 

 is its alternating adaptations to the opposite conditions of the short 

 summer period. Not only is the summer plumage of a totally dif- 

 ferent general color, as already described, but it is much less dense 

 than the winter plumage. The molts, however, do not affect the 

 feathers of every part of the body. The wing and tail feathers are 

 changed only at the time of the fall molt which, in fact, is the only 

 complete molt. The feathers of the feet and legs are not replaced in 

 the spring; but, as summer advances, the old feathers become brittle 

 and wear off, until midsummer finds the birds with almost naked 

 feet a heavy feathering at that season probably being not only need- 

 less but a hindrance, especially when wet. 



The toe-nails in winter are so long as to project considerably be- 

 yond the generous feathering of the feet and toes. They probably 

 serve as "ice-creepers," of great use in walking or wallowing in crusty 

 snow. But the extraordinary thing is that in summer the toe-nails 

 drop off, or molt, new ones growing from the quick! 



In winter plumage one set of feathers fails to conform to the 

 general whiteness the tail-feathers. When the bird is at rest the 

 very long upper and under tail-coverts almost completely conceal 

 these black tail-feathers, which are then closed together in narrow 

 ranks; but when the bird takes flight, the tail is widely spread, and 

 a black "directive" marking flashes forth against the white back- 

 ground. In summer, the wing-feathers, left unmolted from the winter 

 dress, are unnoticed in the bird at rest; but, as the wings are spread 

 in flight, they furnish again a conspicuous "directive" pattern against 

 the dark landscape, the black tail-feathers being then ineffective. 



The ptarmigans of the far northern frontier afford an even 

 more important game-resource than did the native birds in the early 

 days of the settlement of the States. The weight of a willow ptarmi- 

 gan is one and one-half pounds, so that each bird gives as much food 

 as four or five Bob-whites. It should be so cared for as to continue a 

 permanent game-resource in a country where the food-value of game- 

 birds is far more to be considered than any question of sport. 



67 



