On my first day as a biologist, my supervisor told me that I would be studying the Bald Eagles (Haliaeetus leucocephalus) of Florida Bay. He then thrust into my hands a copy of Ian Newton's Population Ecology of Raptors (1979) and said, “Read this.” By that evening, I was a self-proclaimed raptor biologist.
Raptors bring out a uniquely intense passion in ornithologists and the public at large. People may fret over the decline of songbirds, but they will fight for the preservation of the Spotted Owl (Strix occidentalis) or Northern Goshawk (Accipiter gentilis; hereafter “goshawk”). It is no coincidence, therefore, that many of the long-term studies that are all too rare in ornithology are conducted by scientists dedicated to understanding the ecology of birds of prey. Two of these scientists—Richard Reynolds of the Rocky Mountain Research Station and Robert Kenward of the Centre for Ecology and Hydrology (Dorset, United Kingdom)—are well represented in The Northern Goshawk: A Technical Assessment of Its Status, Ecology, and Management. The full list of authors in this volume includes most of the prominent North American experts on the species. It is safe to say that The Northern Goshawk represents the state of the art in goshawk research as it stood in 2006.
More than a decade earlier, many of the same authors contributed to Studies in Avian Biology, no. 16 (1994, The Northern Goshawk: Ecology and Management, edited by William Block, Michael Morrison, and M. Hildegard Reiser), which was equally valuable in furthering the understanding of North American goshawk ecology. Comparing these two publications, one has a rare glimpse into the evolution of scientific knowledge. The 1994 work demonstrates predominantly basic knowledge (nest-site location, basic habitat descriptions, etc.), and the 2006 volume builds on these basics to explore the mechanisms driving goshawk populations, habitats, and resource use.
The only bothersome peculiarity of this book is the layout. Somewhat contrary to the subtitle, which lists “status, ecology, and management,” the book is organized in three sections: Regional, Ecology, and Management. When discussing the goshawk, placing regional contributions in a separate section is justified because the species exhibits some plasticity in its feeding and breeding behavior. Unfortunately, this arrangement puts an onus on the reader to jump between sections to get all of the information available. For example, one finds “Habitat, food habits, and productivity of Northern Goshawks nesting in Connecticut” by Becker et al. in Section I: Regional and “Northern Goshawk food habits and goshawk prey species habitats” by Drennan in Section II: Ecology. The Ecology section also has “Diet, prey delivery rates, and prey biomass of Northern Goshawks in east-central Arizona” by Rogers et al. Should that not be in the Regional section? This quirk of organization only slightly lessens the quality of the book.
The Regional section includes two papers focused on Europe and 10 on North America; only three of the latter concern goshawks east of the Mississippi. The Ecology section includes two papers on feeding ecology and three on movement and habitat use, one of which is focused on winter activity. Reynolds et al. conclude the Ecology section with an exceptionally good review of factors limiting goshawk populations. The final section, Management, includes a design for monitoring goshawks at the bioregional scale by Christina Hargis and Brian Woodbridge—a method that has been used successfully across the United States since the publication of this paper. Also in Management are a paper on using resource-selection function models and a description of an ecosystem-based conservation strategy. The final contribution in the volume is the obligatory discussion of “where do we go from here?”
The nearly two dozen contributions to this volume are required reading for anyone interested in the ecology of the goshawk in North America. I suspect that anyone involved in goshawk work already owns a copy, but those interested in raptor ecology in general will also find the book useful. Many of the techniques and references (44 full pages) are applicable across raptor taxa. Of 20 goshawk papers published in various journals since 2006, I found references to The Northern Goshawk in all of them. These were not just authors citing their own work; they included work from North America, Europe, and the recent cutting-edge papers written by Shigeki Asai of the Yamashina Institute for Ornithology in Chiba, Japan. Hopefully, in 10 more years, many of these same authors or their protégés will return with the same quality of knowledge to help us deal with the challenges on the horizon.
