File:The structure and life of birds (1895) (14770311063).jpg

Identifier: structurelifeofb00head (find matches)
Title: The structure and life of birds
Year: 1895 (1890s)
Authors: Headley, F. W. (Frederick Webb), 1856-1919
Subjects: Birds -- Anatomy Evolution
Publisher: London and New York, Macmillan and co.
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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etty appendagejutting out, and impudently spoiling the beautiful lineof the front margin of the wing from shoulder to tip.If you stand at the entrance to the British Museum(the Antiquarian Department at Bloomsbury) thiscurious phenomenon may easily be seen, as the Pigeonswhich are usually feeding in large numbers on theo-ravel in front fly up and settle overhead on thepediment. In two specimens of Kestrel Hawks whichI have examined, the extension of the wing necessarilyextended the bastard wing, the tendon within theanterior membrane attaching not only to the metacarpbut also to the thumb. The purpose of this is not clear,nor have I noticed anything of the kind in other birds. 254 THE STRUCTURE AND LIFE OF BIRDS chap. In Mr. Muybridges1 photographs of a Cockatoo onthe wing, both bastard wings may be seen to be slightlyraised, for what purpose it is hard to say. In thePigeon too they project during a vigorous stroke, butI have seen no other bird use them either for stoppingor striking.
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Fig 65.—Drawn from a photograph by Ottomar Anschutz, showing bastard wingextended during downstroke. The Centre of Gravity. In the bird the centre of gravity falls at a point lowdown in the body : the heavier organs are accumulatedthere, the lighter ones up above. Below are the greatbreastbone and the ponderous muscles of flight (the 1 See Mr. Muybridges Animal Locomotion, to be seen at theBrit sh Museum. VII FLIGHT 255 pair that lower the wings sometimes weighing onefifth of the whole weight of the body), and the entrails.High up, just under the backbone, come the lungswith their spacious air-sacks. This arrangement is nodoubt advantageous. Imagine a flying-machine withwings springing from a point many yards above theengine which supplied the motive power. It wouldhave a constant tendency to right itself if it capsized.In the same way the bird is helped in balancing bythe fact that his centre of gravity is low down, but toa much less extent, since the point lies only a littlebelow

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