File:Bird-life; a guide to the study of our common birds (1898) (14752534971).jpg

Identifier: birdlifeguid00chap (find matches)
Title: Bird-life; a guide to the study of our common birds
Year: 1898 (1890s)
Authors: Chapman, Frank M. (Frank Michler), 1864-1945 Seton, Ernest Thompson, 1860-1946
Subjects: Birds
Publisher: New York, D. Appleton and company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
at when you see a bird inthe bush it will not seem a mere automaton, but in eachmovement will give you evidence of a nice adjustmentto its surroundings. Remember, too, that evolution is athing of the present as well as of the past. We may notbe able to read the earlier pages in the history of a species,but the record of to-day is open to us if we can learn tointerpret it. This may be made clearer, and the importance of astudy of habit be emphasized, if I briefly outline the rela-tion between the wings, tail, feet, and bill of birds andthe manner in which they are used. We are in the field,not in the dissecting room; our instrument is a field glass,not a scalpel, and in learning the functions of these four FORM AND HABIT: THE WING. IT organs we shall direct our attention to their external formrather than their internal structure. The Wing.—Birds wings are primarily organs oflocomotion, but they are also used as weapons, as musicalinstruments, in expressing emotion, and they are some-
Text Appearing After Image:
Fig. 4. -Young Hoatzin, showing use of hooked fingers in climbing. (AfterLucas.) times the seat of sexual adornment. As an organ of loco-motion the wings most primitve use is doubtless forclimbing. Gallinules, for instance, have a small spur onthe wrist or bend of the wing, and the young birdsuse it to assist their progress among the reeds. A morestriking instance of this nature is shown by that singularSouth American bird, the Hoatzin (Opisthocomus oris-5 18 FORM AND HABIT: THE WING. tatus). The young of this bird have well-developed clawson the thumb and first finger, and long before they canfly they nse them as aids in clambering about the bushes,very much as we may imagine the Archaeopteryx did.In the adult these claws are wanting. Some eminently aquatic birds, as Grebes and Pen-guins, when on land, may use their wings as fore legs inscrambling awkwardly along ; while some flightless birds,for example, the Ostrich, spread their wings when run-ning. But let us consider the wing in

Note About Images