A Further Contribution To Knowledge Of The Host Relations Of The Parasitic Cowbirds

Excerpt from Host Relations of the Parasitic Cowbirds Inasmuch as the completeness of our knowledge varies with the different species of cowbirds, the detailed discussion of such biolog ical matters as host selection, the relative frequency with which different species of these hosts are utilized, the success rate with which these birds serve as fosterers, and the various reactions they give to the parasite and to the incidence of parasitism are all given in the account of each species of cowbird. As might be expected from the interest discussed above, the data are incomparably more extensive, and thus more amenable to analysis and interpretation, for the North American brown-headed cowbird than for any of the others. Because of this, the chief biological discussion and synthesis are given under that species, even though parts of the thoughts and conclusions are applicable to the others as well. The present study of the host-parasite relations of the cowbirds has been a long time in progress. Not only has a great mass of data been accumulating slowly over several decades, but newer insights and better methods of evaluating and interpreting the facts have been brought to bear as the material permitted. Much of the present data is due in large measure to the kind cooperation of many observ ers, collectors, and custodians of collections, all of whom have generously sent me numerous interesting records that otherwise would not have been available. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Cowbirds are an ideal group in which to study the biology of brood parasitism; within the six included species there are displayed all stages of the development of this mode of reproduction ranging from that of the non-parasitic bay-wing through those of the completely parasitic screaming, shiny, brown-headed, bronzed, and giant cowbirds. The present report deals only with their host relationships, as this is the aspect of their biology in which our knowledge has shown the greatest increase since the author's discussion was published in 1929.

In the past two centuries, cowbirds have increased in numbers and extended their range across North America, while many of the native songbird species whose nests they parasitize to raise their young have declined. This timely book collects forty essays by most of the principal authorities on the biology and management of cowbirds. The book's goals are to explore the biology of cowbirds, the threats they pose to host species and populations, and the management programs that are being undertaken to minimize these threats. The book is organized into five sections, each with an extended editors' introduction that places the contributions in a broad, up-to-date setting. The sections cover: The changing abundance of cowbirds and the ways in which their numbers can be estimated. Host choice by cowbirds, the negative effects of cowbirds on particular host species, and the daily patterns of cowbird behavior. Behavioral interactions between cowbirds and specific host species. Patterns of cowbird abundance and host use across varying landscapes. Management programs designed to control cowbirds and protect threatened songbirds.

The evolutionary, ecological and behavioral questions posed by obligate brood parasites are among the most intriguing of all contemporary ornithological topics. Avian brood parasites lay their eggs in the nests of other birds and may be a major contributing factor driving several species of songbirds to near extinction. As one of the first books to present a comprehensive overview of this fascinating phenomenon, this work discusses the comparative biology and co-evolutionary adaptations exhibited by the five families of birds that engage in such behavior. Several chapters dealing with the comparative biology of both intraspecific and interspecific brood parasites, are followed by individual accounts of all known species--nearly 100 altogether, primarily cowbirds and cuckoos. Some of the more remarkable behavioral and structural adaptations of these birds include egg mimicry, juvenile mimicry, elimination by starvation or actual attack of other nestlings or host eggs, and even the learning and partial mimicry of host song traits. An extended glossary, a list of Latin names, 400 literature citations and range maps of all parasitic species discussed are also included. Detailed line drawings by the author enhance this synthesis of biological and ecological information.

This fascinating study describes the natural histories of these brood parasites and examines many of the exciting questions they raise about the evolution of cheating and the arms race between parasites and their prey. Brood parasites fill their armoury with adaptations including exquisite egg mimicry, rapid laying, ejection of host eggs, murder of host young, chick mimicry and manipulative begging behaviour: ploys shown by recent research to have evolved in response to host defence behaviour or through competition among the parasites themselves. While many host species appear defenceless, accepting parasite eggs quite unlike their own, many are more discriminating against odd-looking eggs and some have evolved the ability to discriminate against odd-looking chicks as well. How is this arms race conducted? Will defenceless hosts develop defences in time, or are there constraints which limit the evolution and perfection of host defences? And why are so few species obliged only to lay eggs in host nests? Have host defences limited the success of brood parasitism, or is it in fact much more common than we suspect, but occurring mainly when birds parasitize the nest of their own kind? All of these puzzles are examined in descriptions of the natural history of each of the groups of parasites in turn. Here is a book with wide appeal, both to amateur naturalists fascinated by this most singular and macabre of behaviours and by ornithologists and ecologists interested in the evolution of ecology and behaviour. The story takes us from the classic field work by pioneer ornithologists such as Edgar Chance, Stuart Baker, Herbert Friedmann and others, through to the experimental field work and molecular techniques of today's leading scientists. We visit brood parasites in Europe, Asia, Japan, Africa, Australasia, and North and South America, to look at some of the world's most interesting birds and some of biology's most interesting questions, many of which still beg answers from ornithologists in the future. Brilliant illustrations by David Quinn illuminate the species discussed, showing many behaviours never before illustrated and conveying the thrill of watching these astonishing birds in the wild.

This volume assesses the current status of neotropical migratory birds in the USA, and analyzes the methods and strategies for conserving migrant populations.

The Brown-headed Cowbird is known to use the nests of more than 200 other bird species, and cowbirds in general are believed to play a role in the decline of some migratory songbird populations. These brood parasites—birds that lay their eggs in the nests of others—have long flourished in North America. In this timely book, Catherine Ortega summarizes and synthesizes a wealth of information on cowbirds from around the world that has appeared since the publication of Herbert Friedmann's classic 1929 monograph on these birds. Most of this information has appeared in the last quarter-century and reflects advances in our understanding of how brood parasitism influences, and is influenced by, host species. Ortega shows that in order to manage cowbirds without further damaging delicate balances in host-parasite relationships, it is necessary to understand such factors as behavior, reproduction, population dynamics, and response to landscape patterns. She examines and explains the origin, evolution, and costs of brood parasitism, and she discusses the philosophical and ecological considerations regarding the management of cowbirds—a controversial issue because of their perceived influence on threatened and endangered birds. Because brood parasitism has evolved independently in various bird families, information on this adaptive strategy is of great ecological interest and considerable value to wildlife management. Cowbirds and Other Brood Parasites is an important reference on these creatures that enhances our understanding of both their behavior and their part in the natural world.