The Ecology of Migrant Birds: A Neotropical Perspective. - book reviews

Ecology, Jan, 1997 by John P. Roche

Neotropical migrant birds hold a dual interest for ecologists. First, they provide examples of extraordinary evolutionary adaptations. In order to travel long distances to find suitable resources with which to breed, or to survive the winter, migrant bird populations have overcome many physiological and ecological obstacles. Second, neotropical migrants are important because many species are undergoing declines in the face of anthropogenic changes to both their wintering and breeding grounds. John Rappole, in his wide-ranging and thought-provoking book, The ecology of migrant birds: a neotropical perspective, addresses both the biological and conservation issues surrounding neotropical migrants.

Whereas some books attempting reviews of relatively broad subject areas simply review the information that has been discovered to date, Rappole provides us with both an astute summary of the past and a research blueprint for the future. He does an outstanding job of carefully weighing the rigor of alternative hypotheses and then steering the reader to an understanding of the specific research questions that must be addressed if we are to expand our understanding of migrant biology. Rappole employs an outline format that is common in books attempting to cover a large topic area comprehensively. Chapters address such topic areas as habitat, resource use, migrants in tropical communities, migration, the evolution of migration, a comparison of Old World and New World migration systems, population changes, and conservation. In each of these topic areas, Rappole proceeds to outline sub-topics of particular importance. The organizational style is generally effective, although in a couple of instances, where subheadings are followed by as few as 21 words, consolidation could have been used.

The book includes 39 pages of references; this list alone will be worth the purchase price for students of migrant ecology. In addition, Rappole has included five useful appendixes (he should be applauded for including a list of Spanish common names and their counterparts), as well as a number of informative tables within the text. These components all contribute to make the book a high-quality resource for investigators of avian migrants.

Rappole effectively reminds the reader that not all of the ecological folk-wisdom about migrants is necessarily true. He points out, for example, that not all migrants are wanderers in their tropical wintering grounds, that not all migrants utilize marginal habitats, and that in general, migrants do not seem to influence the breeding periods of residents. In the chapter on the evolution of migration, The ecology of migrant birds: a neotropical perspective makes a compelling argument for the hypothesis that neotropical migrants originated in the tropics, and later evolved migratory behavior to escape intense competition for breeding sites. In the chapter on population change, Rappole summarizes the state of migrant populations and some of the potential reasons why 109 neotropical migrants have shown significant declines in the last decade. He is careful to point out that procedural and statistical biases could potentially produce inaccurate estimates of population changes.

In the final chapter of the book, Rappole summarizes some ideas about what can be done to slow the decline of threatened migrant species. In this chapter Rappole points out the most important environmental problem facing society: human population growth. "This single factor," he writes, "is the ultimate cause underlying the complex myriad of proximate factors that threaten tropical biodiversity in general and avian migrants in particular." Rappole outlines a number of astute recommendations for conservation, including the importance of regulation, the dissemination of research results, education, and the preservation of critical habitats. Where Rappole effectively identifies the underlying cause of migrant declines, however, I felt that he fell short of identifying one of the most important cures. If the habitats upon which migrants depend are to be preserved, we must assign sustainable economic value to these ecosystems so that they can contribute to the standard of living of the citizens of the countries in which these habitats occur. Nevertheless, Rappole does provide many useful suggestions to help scientists and public officials contribute to the future health of tropical, and temperate, ecosystems.

The ecology of migrant birds: a neotropical perspective provides a well-rounded and astute summary of the ecology and conservation of neotropical migrants. By being so readable, so thoughtful in its treatment of alternative hypotheses, and so timely in the midst of a critical ecological problem, this book will positively influence the ideas of many scientists, and nonscientists, interested in avian biology and conservation.

JOHN P. ROCHE Indiana University Department of Biology Jordan Hall Bloomington, Indiana 47405