Peterson Reference Guide to Molt in North American Birds (Peterson Reference Guides)
Steve N.G. Howell
Language: English
Pages: 280
ISBN: 0547152353
Format: PDF / Kindle (mobi) / ePub
To most observers, molt seems an overwhelming subject. But birders use many aspects of molt more than they realize to distinguish juvenile birds from adults, to pick out an individual hummingbird from among dozens visiting a feeder, and much more. For those whose interest goes beyond simply identifying birds, questions such as What triggers molt to start? How fast do feathers grow? and How long do they last? offer a fascinating window into the lives of birds. Put plainly, molt relates in some way to everything a bird does, including where it lives, what it eats, and how far it migrates. Here, for the first time, molt is presented for the nonscientist. Molt is very orderly and built on only four underlying strategies: simple basic, complex basic, simple alternate, and complex alternate. This book clearly lays out these strategies, relates them to aspects of life history, such as habitat and migration, and makes this important subject accessible. 0.80 inches tall x 7.30 inches long x 10.20 inches wide
selections from this book, write to Perm issions, Houghton Mifflin Harcourt Publishing Company, 215 Park Avenue South, New York, New York 10003. www.hm hbooks.com P E T E R SO N F IE L D G U ID ES and P E T E R SO N FIELD G UID E S E R IE S are registered tradem arks of Houghton Mifflin Harcourt Publishing Company. Library of C o n g re ss Cataloging-in-Publication Data Howell, Steve N. G. in North Am erican birds/Steve N. G. H o w e ll; sponsored by the Roger Tory Peterson Institute and the
parasite loads than is the production of carotenoids, such that the extent or intensity of colors with different pigment bases may convey different information about a bird’s condition.89-90 Structural colors (such as blue and white) are pro duced by the interference of light rays by the finescale structure of the feather, and they can be either iridescent or non-iridescent. The most commonly observed “structural color” in the plumage of birds is white: keratin, the material of which feathers
naturally arises: do any North American herons have alter nate plumages? Certainly there is no evidence that bitterns and night-herons do, and neither do most herons and egrets. One possibility lies with the Cat tle Egret, adults of which in spring have bright or ange plumes on the crown, back, and chest, unlike the mostly white appearance they show in winter. The color of these plumage areas apparently inten sifies as the breeding season approaches, suggesting that the coloration is not
head and neck feathers, are presumed to occur in several species. However, as in other groups of birds such as ducks and quail, it is uncertain whether latewinter and spring molts in rails and coots are really prealternate or simply a continuation of suspended prebasic molts.1,2 P R E B A S I C MOL TS . A feature of the prebasic molt in Like m ost rails and gallinules, the P urple Gallinule apparently h a s the com plex basic m olt strategy. Follow ing the preform ative molt, young birds re se m
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