This edited series has three principal goals. The first is to provide information in a relatively concise way for researchers needing an over view of specific disciplines. The second is to provide an update on specific schools of thought, bringing together ideas from colleagues whose works often appear in a variety of journals. And the third is to stimulate and suggest directions for new research. Volume 6 continues the tradition established by the previous editor and editorial board in providing new information, updating our understanding of specific dis ciplines, and stimulating new research. In the first chapter, Randall Breitwisch examines mortality patterns and sex ratios in monogamous birds. He argues that there are many more components to measuring parental investment than are often re alized; our knowledge is weak in several areas. Understanding the evo lution of mating systems depends on better distinguishing the different intensities of natural selection that operate on males and females. Greg ory Butcher and Sievert Rohwer develop a framework for assessing the role of colorfulness in birds. They propose several hypotheses to test and advocate evaluating more than one hypothesis at a time. Future work on the evolution of distinctive coloration and of sexual and age dimorphism must take these ideas into account.

As we assume the editorship of Current Ornithology, it seems useful to review the objectives of the series. We cannot improve on the state ments of our predecessors when they began their service as editors. In his preface to Volume 1 (1983), Richard F. Johnston wrote: The appearance of the first volume of a projected series is the occasion for comment on scope, aims, and genesis of the work. The scope of Current Or nithology is all of the biology of birds. Ornithology, as a whole-organism sci ence, is concerned with birds at every level of biological organization, from the molecular to the community, at least from the Jurassic to the present time, and over every scholarly discipline in which bird biology is done; to say this is merely to expand a dictionary definition of "ornithology. " The aim of the work, to be realized over several volumes, is to present reviews or position statements concerning the active fields of ornithological research. Dennis M. Power, who edited Volumes 6-12 (1989-1995), began his preface to Volume 6 (1989) as follows: This edited series has three principal goals. The first is to provide information in a relatively concise way for researchers needing an overview of specific disciplines. The second is to provide an update on specific schools of thought, bringing together ideas from colleagues whose works often appear in a variety of journals. And the third is to stimul&te and suggest directions for new re search.

If it is still true that more than 80% of the ornithologists in North America are primarily interested or engaged in ecological studies on birds (J. R. King and W. J. Bock, Final Report of the Workshop on a National Plan For Ornithology, 1978), then Volume 3 of Current Orni thology is preadapted for their consideration. All but one article in this volume are somehow concerned with the ecological aspects of the bi ology of birds. Variation in the scope of topical coverage is relatively broad, and includes conservation, reproduction, behavior, community structure, and evolutionary ecology. Three reviews concern the pervasive effects of man and industry on various bird populations of the world. Risebrough provides a de tailed description of the relationships between pesticides and bird pop ulations. Morrison ass es ses aspects of bird population numbers as in dicators of environmental change, and Temple outlines current research on endangered species. The broad spectrum of reproductive ecology of birds is variously treated in this volume. Jehl and Murray explore sexual selection and some of the resulting complexities in the evolution of sexual size di morphism, primarily in shorebirds. Lawton and Lawton are concerned with the relationships between social behavior and breeding systems in which variation is found in the age at which reproduction is first undertaken. Oring examines the wide-ranging variation in polyandrous breeding systems in birds, while Rohwer is concerned with adoption versus infanticide in birds, and their relationships to reproductive fit ness.