coloration. In this "summer protective" 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 dif- 

 ferent color grow in. In the autumn exactly the same process leads 

 from the brown and mottled coloration of both old birds and young- 

 of-the-year to the pure white of winter dress. But while in the spring 

 molt the feathers of the head, neck, and back are the first to be re- 

 placed, in the fall these are the last tracts affected; so that by the 

 middle of October birds are to be seen with dark feathers still pre- 

 dominating in the head and back. This, of course, gives much the 

 same effect as at an early stage of the spring molt. 



The female ptarmigan selects the site for her nest during the 

 third week of May, and by the second week of June full sets of eggs 

 have been laid. The nest is a slight depression in the moss on the 

 open ground ; usually the summit of a hummock is selected, as being 

 a drier situation during the period of early summer rains. A scanty 

 lining of dry grasses in the nest keeps the eggs from actual contact 

 with the saturated moss of the foundation. 



The full set of eggs numbers from eleven to thirteen. They are 

 very deeply and closely spotted and blotched with chestnut-brown, 

 the effect being to render them difficult to distinguish from their sur- 

 roundings, even when lying in plain view but a few feet from the 

 observer. The female bird does all of the sitting, and when ap- 

 proached on the nest does not take flight until almost trodden upon. 

 She then exhibits the greatest solicitude, tumbling about within a 

 few yards of the intruder in the most distressing manner. The male 

 bird sometimes appears, but keeps discreetly at a much greater dis- 

 tance. 



After the eggs are hatched, the precocious youngsters are ac- 

 companied by both parents. They then have the facultv. so like that 

 of young quails and grouse, of concealing themselves at a moment's 

 notice, while the parents attempt to call the intruder's attention else- 

 where. The young are at first clothed with down, of vellow and 

 brown shades; but before they are half-grown this is entirely replaced 

 by loose-textured feathers, and even before half-grown they are able 

 to fly as readily as the adults. 



In summer, the willow ptarmigan's bill of fare includes many 

 sorts of insects, as well as green herbs. In the fall the abundant 



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