Image from page 357 of “The bird, its form and function” (1906)
Image from page 357 of “The bird, its form and function” (1906) by Internet Archive Book Images
Title: The bird, its form and function
Year: 1906 (1900s)
Authors: Beebe, William, 1877-1962
Subjects: Birds — Anatomy Birds — Physiology
Publisher: New York, H. Holt and company
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library
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Text Appearing Before Image:
ion is compensated by adirect adaptation of the wing to the new conditions of life. In the ostriches and their near allies the extreme reduc-tion of wings is to be found, and yet in the true ostrichesand rheas the great expanse of soft feathers is a consid-erable help to the birds when running at full speed, actingas a sail or aeroplane to assist in the onward motion.But the contrast between a loose, open-w^ork feather fromthe wing of one of these birds and a compact, firmly vanedplume from a condors wing is very striking. The casso-wary has from four to six flight-feathers, but, far from 338 The Bird being of any use in supporting his great frame, they areso vestigial that they look exactly like black slate-pencilsprojecting in a row from the little fleshy flap which con-tains the evidence of his full-winged ancestors A full-grown ostrich was once imported to this countryfrom Abyssinia. When the native keepers learned that thebird was to be sent away, they surreptitiously plucked the
Text Appearing After Image:
Fig. 268.—Wing of Cassowary, showing degenerate flight-feathers. poor creature, until but few feathers were left on its body.The bird was tame, and, by keeping its attention busywith a basket of carrots, I inserted a piece of white card-board beneath one of its skinny, denuded wings and se-cured an excellent photograph (Fig. 269). This clearlyshows the black, curved claws on the first two fingers.In this same bird I noticed that occasionally the crookedforearm w^ould be raised, the claw at the end of the wing Wings 339 drawn up, and the ostrich would scratch its body or headwith this interesting finger rehc! When the plume feathersof the wing are full grown, the foot or leg is thus used,
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