Identifier: birditsformfunct07beeb (find matches)
Title: The bird, its form and function
Year: 1906 (1900s)
Authors: Beebe, William, 1877-1962
Subjects: Birds Birds
Publisher: New York : Henry Holt
Contributing Library: Internet Archive
Digitizing Sponsor: Internet Archive

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Fig. 35.—Two male English Sparrows, showing the difference in colour caused bywear of the feather-tips between October and April. and alleys, flaunts a jet cravat before the eyes of his lady-love! Colour. The very interesting uses which the colours of birdsserve, the part they take in courtship, in evading danger,or in enabling birds to find each other, are many. Theseuses have been much written about, but of the natureand formation of colour less is known. Few of us have 54 The Bird probably ever given a thought to the colours themselvesWhy is that feather blue? Why—because it is blue! There are two principal ways in which colours areproduced in feathers: first, when a real colour-pigmentis present, and again when the structure of the feather ismore or less like miniature prisms in shape, breaking up
Text Appearing After Image:
Fig. 36.—Young Brown Pelicans in the downy plumage. 1/6 natural size. the rays—rainbow-like—into the iridescence of the spec-trum. In the case of almost all the beauties of Nature,the more closely we examine them, the more beautifulthey become. But this is not true of the iridescentcolours of birds such as hummingbirds, unless we con-sider the structure. The colour itself disappears underthe microscope, and only gray or black tints are seen.The black, red, brown, and yellow colours of feathers Feathers 55 are almost always due to pigment or colouring-matter inthe shaft or vane. If we take a black feather and holdit to the light, it will still look black; if we pound it witha hammer, it will not change. Green is never found as a pigment except in thefeathers of a small family of birds called plantain-eatersor turacous, which inhabit West Africa. For some timeit was thought that the natives dyed the birds artificially,as when these birds were kept captive, the magnificentscarlet p

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