Identifier: historyofbirds00pycr (find matches)
Title: A history of birds
Year: 1910 (1910s)
Authors: Pycraft, W. P. (William Plane), 1868-1942
Subjects: Birds
Publisher: London, Methuen and Co
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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nus Guttera. The pheno-mena here exhibited appear hitherto to have been passed withoutcomment, yet it is certainly remarkable that this keel, elsewhereamong birds a thin plate of bone, should in these Swans andCranes have developed into a cavernous receptacle, involvingalso the body of the sternum forming the roof of this space.What are the factors which have brought about the formationof this curious chamber ? The theory of natural selection hereseems inadequate; while the theory of mutation involving thesympathetic variation of two such dissimilar structures seems nomore helpful. For the capture of ants and other insects the Woodpeckershave developed a protrusible tongue—agreeing therein withmany ant-eating mammalia—and powerful salivary glands.Yet, without any such elaborate apparatus one of the King-fishers (^Halcyon cyanoleucus) of Liberia, which, after the fashionof his people, is almost tongueless, contrives to subsist on antswithout any special apparatus for their capture!
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6*^ Coverts III. 46A The upper surface of the wing of a Little Stint (Tringa miniita) toshow (a) the difference between the distal and proximal overlap-theformer shown by the major, the latter by the median coverts—and (b) the tault-incr which results in the formation of an intercalary row m diastataxic wmgs.° B, Upper surface of a portion of the forearm of an Owl to show the diasta-taxic condition of the wing. ADAPTATIONS 409 Here again is another instance of apparent over-elaborationin Nature. We say apparent advisedly, for the fact that so manywidely different creatures have developed a highly complexlingual mechanism for the capture of insect food shows thatthese exceptions require further study. By way of contrast we may site the case of the Red-headedWoodpecker (Melanerpes erythrocephald), which, like its con-geners, possesses a protrusible tongue ostensibly for the capture ofinsect prey, yet lives at any rate very largely, on eggs of otherbirds, even entering hen-roosts in i

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