. The bird, its form and function . Fig. 33a.—Ptarmigan in the fall, showing the gray autumnal plumage (whichhas replaced the brown of summer on the upper parts of the body and wings),gradually giving place to the white of the coming winter feathers. Wildbirds in Alaska. (Harold Whealton, photographer.) homology is carried out in the method of shedding the dropping out of feathers one by one, as inother birds, these come off in flakes, like the skin of alizard. The feathers of the back loosen, shrivel up, andfade to a brownish hue before they peel away. 52 The Bird We have seen how
. The bird, its form and function . Fig. 33a.—Ptarmigan in the fall, showing the gray autumnal plumage (whichhas replaced the brown of summer on the upper parts of the body and wings),gradually giving place to the white of the coming winter feathers. Wildbirds in Alaska. (Harold Whealton, photographer.) homology is carried out in the method of shedding the dropping out of feathers one by one, as inother birds, these come off in flakes, like the skin of alizard. The feathers of the back loosen, shrivel up, andfade to a brownish hue before they peel away. 52 The Bird We have seen how birds, by moulting their feathers,change the colour of their plumage; in some cases severaltimes each year. There is, however, still another way inwhich the appearance of new colour is brought by increase of pigment, for the feather when oncefull grown is dead; but by the mere breaking or fraying. Fig. 34.—The three moults of the Ptarmigan, shown in three individuals.(Courtesy of American Museum.) of the edges of each feather. It is thus that the Snow-flake brushes off the rusty trimmings of his winters suitand returns to his home in the far North, dressed in spick-and-span black and white. A much more familiar exam-ple is to be seen at our very doorstep. The cock EnglishSparrow in midwinter is even more sombrely clad thanusual; but as spring approaches, although he can attainto no elaborate song or flowing plume, yet even this Feathers 53 commoner feels the call of love for beauty, and day byday the dusty brown tips of his throat-feathers wearaway one by one, and leave exposed the clear blackcentres; and behold, the vulgar frequenter of our streets
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyo, bookyear1906
