Bird lore (1903) (14564174448) - Public domain zoological illustration

Identifier: birdlore51903nati (find matches)
Title: Bird lore
Year: 1899 (1890s)
Authors: National Committee of the Audubon Societies of America National Association of Audubon Societies for the Protection of Wild Birds and Animals National Audubon Society
Subjects: Birds Birds Ornithology
Publisher: New York City : Macmillan Co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library



Text Appearing Before Image:
158 Bird-Lore effect of wear is shown by photomicrographs of brown Purple Finch feathers,and the second is shown by the figures of Crossbill feathers. We haveillustrated also the effect of wear on a Meadow Lark, showing how thelighter-colored parts of feathers may disintegrate. The growth of each feather is a chapter by itself. The histologistwith microscope and cross-sections tells us how beneath the old feather,resting in a pit or follicle of the skin, certain cells group themselves andmultiply until a papilla or feather germ is formed. This pushes out the
Text Appearing After Image:
Fresh feather Worn feather PHOTOMICROGRAPHS OF CROSSBILL FEATHERS old feather and lengthens into a pulpy cylinder from the apex of whichthe pin-feather expands, being built by the pulp cells from the tipdownward and from the edges inward as the papilla elongates. This isbut a rude way of expressing the very elaborate process of feather-growthcompleted when, in the course of a few weeks, the pulp of the calamus,or quill-part of the feather, dries up. Each papilla produces a newfeather at the time of a molt (and also whenever one is accidentallypulled out) and enjoys a period of rest between times. The individualfeathers of the natal plumage, technically known as neossoptiles, are ex-ceptions and are continuous in growth with the tips of the feathers ofthe Juvenal plumage. A molting bird is as confusing to examine as any prize puzzle, but series How Birds Molt 159 ,iK h of specimens taken after the breeding season show that molt begins at defi-nite parts of the body and the reclothing e