Smith, J. N. M., Cook, T. L., Rothstein, S. I., Robinson, S. K. & Sealy, S. G. (eds) Ecology and Management of Cowbirds and their Hosts: Studies in the Conservation of North American Passerine Birds. 388 + ix pages. Austin: University of Texas Press, 2000. Hardcover, ISBN 0-292-77738-8.
In November 1993 several hundred ornithologists, land managers, and conservationists gathered in Austin, Texas, for a research workshop on the ecology and management of the brood parasitic cowbirds. Most of the chapters of this long-awaited volume derive from papers presented at that workshop, some in greatly modified form. It took seven years for these papers to be written, rewritten, edited, and published. Because early drafts of many of the manuscripts circulated widely, several of these chapters were cited repeatedly for years before they were published (e.g., in Robinson et al. 1995).
Despite the delay, this book is surprisingly relevant. Many of the papers have been updated with data from more recent field seasons and review much of the recent literature on cowbirds. Most of the chapters address the ecology and host relations of the Brown-headed Cowbird (Molothrus ater); two papers discuss Shiny Cowbirds (M. bonariensis). The book is organized in five parts. Part I includes chapters that analyze population trends of Brown-headed Cowbirds and their hosts and explore census methodology, as well as a look at the remarkable double invasion of Florida by Shiny and Brown-headed Cowbirds. Part II examines Brown-headed Cowbird spacing behavior and host selection, and also considers the effects of cowbird parasitism on the breeding success of their hosts. Part III addresses behavioral interactions between cowbirds and their hosts, such as nest defense by hosts, egg puncture by Shiny Cowbirds, and egg removal by Brown-headeds. Part IV includes fourteen chapters that consider how habitat variables and landscape composition affect Brown-headed Cowbird parasitism. The last part describes efforts to control cowbirds in the breeding areas of four endangered species.
As in any publication, there are errors. Some are trivial typesetting or editing mistakes; others may lead to more serious misinterpretations. For instance, in an otherwise insightful examination of the relative effects of brood parasitism and nest predation on seasonal fecundity, Grzybowski and Pease argue (pp. 151-152) that an increase in predation partially compensates for itself by causing nest failures to occur earlier in the nest cycle and thus use up less of the available breeding season. While this makes sense intuitively, the simulations they refer to (Figures 16.1 and 16.2) actually show proportionately greater losses in seasonal fecundity at higher levels of predation! Perhaps this occurs because renests are less likely to be successful at higher predation levels.
Most of the illustrations are of high quality, and the index is very complete. There is no general bibliography; each chapter includes its own References Cited section. This volume would be useful for researchers interested in the evolution and ecology of brood parasites, for North American land managers, and for anyone interested in avian conservation.
Robinson, S. K., Thompson, F. R., III, Donovan, T. M., Whitehead, D. R., and Faaborg, J. 1995. Regional forest fragmentation and the nesting success of migratory birds. Science 267:1987-1990.