Books and Other Resources on Hawk Identification and Migration
by Paul M. Roberts

Hawks can present unusual problems for field identification. How often have you tried to identify a silent, backlit warbler half a mile away? Let's compromise. How often have you tried to identify a sparrow when it's only a thousand feet away from you and flying south? How many thrushes have you seen perched or flying across the highway while driving down Interstate 95 or I-495 at 70+ miles an hour? How many of them have you identified? People, however, regularly try to do that with hawks.

That is, in part, why most people find that the standard birding guides are of little help when trying to identify hawks. The basic birding guides really help you only if you see the bird close, well enough to appreciate color. Most hawk sightings in the field, however, and especially in migration, entail seeing only dark gray blobs moving quickly against a light background. If you're lucky, you may see the silhouette of a bird soaring, and possibly pick up patterns of light and dark contrast on the bird. Thus arose the need for special hawk identification field guides.

Hawk Identification

The first real silhouette guide to hawks was done by Roger Tory Peterson in his first field guide, to the best of my knowledge, which is limited to North America for this time period. Peterson used black and white drawings of hawks almost as they would be seen when flying directly overhead. This was a major innovation, though the birds were not really depicted as soaring, so the silhouettes could be misleading. Peterson, however, showed major black or white field marks, what people were most likely to see.

The next major step came with the development of the ubiquitous A Field Guide for Hawks Seen in the North East (Hawks, 1972, 6 pp - now published by Hawk Mountain Sanctuary) The first popular inexpensive ($1.00+) silhouette guide, it describes the flight identification of 16 species seen in the northeast, with "side-on" as well as ventral views of the birds in flight. The drawings convey more field marks than Peterson's, but again are not realistic images of the birds in powered flight or soaring.

The first and only broad-based field guide to hawks is appropriately named Field Guide to Hawks, by William S. Clark and Brian K. Wheeler (Boston: Houghton Mifflin, Second Edition, 2001, 316 pp.). The text, by Bill Clark, is comprehensive in terms of identifying specific field marks. The species account for Golden Eagle reveals the basic format, divided into sections on Description, Adult, Juvenile, Older Immatures, Similar Species; Flight; Molt, Behavior; Status and Distribution; Fine Points; Subspecies; Etymology; and Measurements. The book covers 47 species, including vagrants. The detailed color plates by Brian Wheeler depict birds perched and in flight ( flying birds from above and below), by age set and gender where appropriate, and by race where possible. The plates are gathered in the front of the book for easy comparison, a page of plates facing a page of text highlighting the key field marks of each bird in the plate.

Clark and Wheeler is a true milestone in raptor publications. The second edition of this book includes significant improvements on the first. However, the first edition is a real classic and has many different plates. I'd recommend acquiring a copy of the first edition if you don't already have it, as well as the second edition.

Hawks in Flight by Pete Dunne, David Sibley, and Clay Sutton (Boston: Houghton Mifflin, 1988, 254 pp.) is a whole different kettle of fish. This classic employs Pete Dunne's prose to evoke vivid mental images of hawks as you usually see them in flight in the field, as dark objects in motion. It is of virtually no help in identifying hawks perched along the highway or near your feeders.) Dunne talks about jizz, impressions, something that Clark generally eschews. Hawks in Flight covers 23 species, basically those seen east of the Rockies. Excellent line drawings by David Sibley of each species (and age or gender as appropriate) from above and below are complemented by short summaries of key field marks. The book concludes with 76 pages of black and white photographs, most of which are apparently Sutton's. These photos are much larger than in the Clark and Wheeler guide, better reproduced, and much more helpful. A second edition of this book is also in preparation. Look for it to expand its scope and the little nuances that help identify backlit blobs at a quarter mile.

Clark and Wheeler show you what the birds look like, in fine detail; when you see the birds well. They focus on often subtle field marks to help age the bird, such as the shape or color of the secondaries on an eagle. Dunne, Sibley and Sutton show you what you are likely to actually see when hawks are in flight. Dunne helps you to make a reasonable guess as to what the hawk is when you don't see it well. If you could buy only one book, Clark and Wheeler should be it, but anyone really interested in hawk identification really needs both.

Did I say both? I meant to say "all three." In 1995 Brian Wheeler and Bill Clark published A Photographic Guide to North American Raptors (San Diego: Academic Press, 1995, 198 pp.). This spectacular book contains several hundred gorgeous full-color photographs of 43 species of North American hawks including various plumages of each species. There are 46 photographs of Red-tailed Hawk alone! The relatively brief text does not supplant that of the Field Guide, it complements the earlier guide, introducing more advanced identification guidelines for a number of species, including Red-tailed Hawk and Golden Eagle. The book closes with a special photo section on 14 raptor identification problems, such as "Pale Primary Panels on Back-lighted Underwings of Flying Buteos." One could buy this book for the photography alone.

Each species account includes one half to one page of text on the field marks, often with materially supplementing the Field Guide, and comparisons with similar species. (The operating assumption is that you've already read The Field Guide.) There are one to four gorgeous full-color photos per 6.5 in. x 9.75 in. page.

Quite simply, anyone interested in hawks should have all three guides. Each was revolutionary when it was first introduced. Each established a new standard for American guides, and each has an updated edition in the pipeline.

The most recently published field guide to hawks, The Raptors of Europe and The Middle East: A Handbook of Field Identification, by Dick Forsman (London: T & AD Poyser, 1999, 589 pp.), sets a new, higher standard for all field guides. The book covers 43 species of raptors, including 11 that have been reported in North America. Fourteen pages are devoted to the Golden Eagle alone. Each species section begins with a one-page overview on subspecies, distribution, habitat, population, movements, and hunting and prey. The identification portion starts with a summary, followed by "In flight, distant; in flight, closer; perched; bare parts; variation; and confusion species." That is followed by a major section on moult, and three pages on ageing and sexing. The species account concludes with 21 outstanding photographs, no more than 4 to an essentially 6 in. x 9 in. page. Captions focus on the distinctive field marks evident.

Published by Poyser, one of the truly great publishers of ornithological literature, this guide is a work of art, from concept, to design, to photography, to printing. I am not sufficiently well acquainted with European raptors to note possible subtle errors in text, but Forsman's book has established, in my mind, a new paradigm for any field identification guide. Although only about a dozen of these species have been in North America, this books merits inclusion in the library of any serious hawkwatcher. Last November, when one or more Gyrfalcons was reported from Plum Island over several weeks, this book was a constant reference with a 12-page species account, and 18 spectacular photographs, of Gyrfalcon.

There are a number of hawk videos on the market, incorporating some spectacular photography, but the best for field identification purposes is Hawk Watch: A Video Guide to Eastern Raptors, by Dick Walton and Greg Dodge (Brownbag Productions; 45 minutes) This video includes field footage of 19 species of hawks likely to be seen from Eastern hawk watches, with narration by Dick Walton. The images are the typical dark blobs, seen at some distance, so the field characters cited are based on many of the principles of hawk identification espoused in Hawks in Flight. The video comes with a brief booklet, and a humbling video quiz on flying hawks at the end of the tape. It provides excellent training for "real world" identification.

Hawk Watching & Migration

The best basic introduction to hawk watching and migration is Hawk Watch: A Guide for Beginners, by Pete Dunne, Debbie Keller and Rene Kochenberger (Cape May Point, NJ: Cape May Bird Observatory, 1984. 80 pp.). Hawk Watch is an outstanding guide for beginners, with chapters on hawk watching, diurnal raptors, equipment, how to observe hawks, interpreting data, and submitting reports on your observations. Excellent flight silhouettes by David Sibley and clear text describing key field marks of each species make easy to learn the 16 eastern species it covers. The book is not widely available commercially, but can be obtained at some Audubon shops or ordered directly from Cape May Bird Observatory and online booksellers. This book was the precursor to Hawks in Flight, developed to teach high school students. Get this downright cheap masterpiece before it goes out of print.

Raptor Migration Watch-site Manual, edited by Keith Bildstein and J. I. Zalles (Kempton, PA: Hawk Mountain Sanctuary Association, 1995, 177 pp.) is almost an extension to Hawk Watch. This all-prose guide to establishing a hawk watch site was developed to help biologists and hawk enthusiasts, particularly outside the U.S., to study hawk migration. The guide includes chapters on raptor migration and conservation biology, monitoring the abundance and distribution of migrating raptors, managing data, establishing membership programs and managing volunteer resources.

Raptor Watch: A Global Directory of Raptor Migration Sites (Cambridge, UK and Kempton, PA USA: Hawk Mountain Sanctuary Association, 2000, 419 pp.) is the first guide to the major documented hawk migration observation sites around the world. The book first provides overviews of what is known about hawk migration, country by country, for six continents, even where no regular watches are maintained. Three hundred eighty-eight known migration sites around the world are then described in terms of biogeography, description, land tenure and protected status, with information on the migration periods, raptor species seen (with peak counts an dates), and other migrants seen. Ten sites are described in detail for Massachusetts. Our own Wachusett Mountain is one of only 106 sites described worldwide, only three in New England, that average in excess of 10,000 hawks annually. Information is included on the migratory status of all hawks and the threats they face.

In essence, Raptor Watch is a detailed description of what's known about hawk migration sites that are vital to understanding what is happening to raptor populations worldwide. This book is not directed to the beginning hawkwatcher, but to those who regularly hawkwatch or individuals who would like to hawkwatch in other states or foreign lands.

The most recent book on hawkwatching is Hawkwatching in the Americas, edited by Keith Bildstein and Daniel Klem Jr. (Kempton, PA: Hawk Migration Association of North America, 2001, 277 pp.). This book consists of peer-reviewed papers presented at the 25th anniversary meeting of the Hawk Migration Association North America (HMANA) in June 2000. Intended primarily for the experienced hawkwatcher, it should be of interest to anyone with an interest in bird migration per se, with major papers on full season hawk watches in coastal Texas, raptor migration through Mesoamerica (Veracruz) , ageing eagles at hawk watches, and using Doppler weather radar to study hawk migration. Raptor Migration in Israel and the Middle East by H. Shirihai, R. Yosef, D. Alon, G.M. Kiwan, and R. Spaar. (Eilat, Israel: International Birding and Research Center, 2000, 191 pp.), documents what can be learned via hawk migration counts. This ground-breaking , well-produced book includes a history of the raptor counting effort in the Middle East, with chapters on migration routes and numbers, monitoring palearctic raptor populations, conservation, flight behavior of migrating raptors in Israel, and more. The core of the book is species accounts of 43 species of palearctic raptors. Since only 5 Golden Eagles have been recorded as migrants in the Middle East, that species account is only a page and half long, with data on the European population. Seven pages are devoted to the much more abundant Steppe Eagle (Aquila nipalensis), which includes peak seasonal counts and locations for autumn and spring, migration phenology at Eilat, population trends, and 51 superb photographs. This book will be of interest primarily to serious students of hawk migration and conservation, or those thinking of traveling to Israel, one of the premier birding spots in the world during migration. The book demonstrates clearly the value of long-term hawk migration counts.

Two books focus on hawk flight in migration. Bill Welch's Hawks at My Wingtip (Thorndike, Maine: North Country Press, 1987 148 pp.), is a non-technical description of innovative work that Welch performed with the New England Hawk Watch, using powered gliders to study hawk migration. The low-key book is loaded with small pearls of information on such topics as the distance at which one can see hawks; the altitude at which hawks migrate throughout New England, and the general speed and direction of their flight. This very inexpensive, unpretentious book is still available through some online booksellers, and may be available through some stores.

For a more thorough, technical analysis of hawk flight in migration, it is essential to turn to Flight Strategies of Migrating Hawks by Paul Kerlinger. (Chicago: University of Chicago Press, 1989, 375 pp.) Not written for the beginning hawk watcher, Flight Strategies is an advanced analysis of specific aspects of migration, supported with formulas, statistics, and graphs. Topics include ecology and geography of hawk migration; methods of studying migrating hawk; structure of the atmosphere, flight mechanics: theory, flight mechanics: empirical research; flight direction, altitude and visibility of migrants, selection of flight speed, and daily flight distance. It is a motherlode of information. I have read this book more times than any other book I've ever owned, and am still gaining new insights into it year after year. Technically out of print, this classic is still available. I would put it in the mandatory category for anyone seriously interested in the migration of hawks or any other birds. (I should mention that I reviewed this manuscript at different stages of development.) At times the book is very dense reading, leaving one to yearn for a "Cliffs Notes" version for the beginning hawk watcher, but it is more than worth the effort at times required of the reader. It is an intellectual artichoke for the hawk watcher, to be peeled piece by piece and carefully savored.

Natural Histories

There are an increasing number of books on specific raptors, one of which is reviewed elsewhere in this issue.. Two broad-based reference works are worthy of special note. Birds of Prey edited by Ian Newton, (New York: Facts on File, 1990, 240 pp.) is an impressive introduction to birds of prey, excluding owls. It includes chapters on "What is a Raptor," "Kinds of Raptors," "How Raptors are Studied," "Habitats and Populations," "Feeding Habits," "Social Behavior," "Reproduction," " Mortality" and an excellent overview of migration and movement by Bill Clark. The book closes with three essays on hawks' relations with humans. Top experts have written each chapter and numerous fascinating sidebars in very readable prose. Laid out like a "coffee-table" book , it is filled with spectacular color photographs and is easy to read. No other book conveys a better understanding or appreciation of hawks for the average person.

A much more detailed natural history of hawks is available in Handbook of North American Birds, Volumes 4 & 5, Diurnal Raptors, Parts 1 & 2, edited by Ralph Palmer (New Haven: Yale University Press, 1988, 433 pp. & 465 pp respectively) If you want to learn more about the life history of a particular species, this is the place to start. These encyclopedic volumes, which include only a few black and white illustrations, provide the best, most complete and most recent "natural histories" or species accounts, of North America's hawks generally available.

The final major source of information on our hawks is The Birds of North America: (Philadelphia, PA and Washington, D.C.: Academy of Natural Sciences and The American Ornithologists' Union, ongoing; typically 20-28 pp. each). This series of individual life history accounts for all North American avian species is not yet complete. Excellent accounts of Broad-winged Hawk, Red-shouldered Hawk, Red-tailed Hawk, Northern Harrier, Cooper's Hawk, and Merlin are currently available, along with some primarily western species. Written to a standard format, the accounts cover: distinguishing characteristics, distribution, systematics, migration, habitat, food habits, sounds, behavior, breeding, demography and populations, conservation and management, appearance, and measurements. These individual species accounts can be ordered through Buteo Books (see Many raptor species accounts are still in development.

With the aid of at least several of these resources, you should be able to add considerable knowledge and enjoyment to your hawk watching, or even 'just" regular birding.

This article appeared in Bird Observer, Vol. 29, No. 4, 2001.

Eastern Massachusetts Hawk Watch, 2008
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