American Scientist

Restoring North America's Birds: Lessons from Landscape Ecology. Robert A. Askins. Illustrations by Julie Zickefoose. xiii + 320 pp. Yale University Press, 2000. $30.00.

Not so long ago, passenger pigeons, which once numbered in the billions, became extinct in the wild. Because of their sheer numbers, they had been thought to be one of the least likely birds to become extinct, but the severe alterations in North American landscape ecology since European settlement undoubtedly played a large part in sealing their fate. Thus it is not surprising to see that the conservation of neotropical migrant birds, which breed in North America and winter in the tropics, has attracted enormous attention, even though most are not yet considered endangered or even threatened. Many bird species are undoubtedly suffering population declines, the major causes for which may include the loss of habitats for breeding, wintering and migration stopovers. Birds are also threatened by more subtle ecological changes that degrade habitats, making them unsuitable for many species.

Although the causes and consequences of bird population fluctuations are extremely complex and difficult to study, during the past 20 years significant progress has been made, thanks primarily to arduous fieldwork. However, one problem with this new research is that its sheer quantity has resulted in a lack of synthesis and direction.

Restoring North America's Birds is well written and well researched. Robert Askins states in the preface that his goal is "to distill the voluminous research on bird conservation and present it in a form that is accessible and useful for foresters, wildlife managers, nature preserve managers, biologists with The Nature Conservancy and other conservation organizations, and the numerous citizens who donate their time and money for conservation." He describes the ecological principles associated with changes in bird populations and provides an overview of the history and present condition of North American birds in several terrestrial ecosystems, including floodplains, eastern and western forests, the Great Plains and mountain slopes. Askins's treatment of a wide variety of topics and species is consistently high in quality.

The book has two common themes: that understanding the concepts of landscape ecology and the history of prior extinctions will help prevent extinctions in the future, and that teamwork among many diverse groups, including private landowners, government agencies, the general public and industry, will be essential if we are to succeed in preserving avian diversity. Askins mingles history, natural history and science, providing thorough summaries of data and theories about avian population dynamics from a wide variety of published sources. Among the topics covered are habitat fragmentation, wintering-ground degradation, agricultural and clear-cutting practices, fire cycles, brood parasitism, nest predation and species-specific habitat requirements. Using studies of particular species of birds, including the Kirtland's warbler, the golden-cheeked warbler, the bobolink and the red crossbill, Askins clearly illustrates the basic principles of landscape ecology and their application to conservation biology. In doing so, he creates a framework for directing future avian conservation efforts in North America. The conservation of birds is highly contingent on a clear understanding of what their habitat requirements are and how their habitats are sustained.

This book is first-rate—very broad in scope and appeal, readable, and truly integrative in its coverage of landscape ecology and its implications for avian conservation biology. The illustrations and figures are inspiring and informative, respectively. The review of the literature is outstanding, and the integration of concepts in various chapters is flawless. This book will be of significant interest to researchers and students of conservation biology, ornithology and ecology; land managers; conservation agencies; and anyone with an interest in protecting the rich avian diversity of North America. One comes away from the book with a much better understanding of landscape ecology and how it ties in with avian conservation biology. Askins also offers direction and hope for the future.—Trevor E. Pitcher, Zoology, University of Toronto