Über die Autorin bzw. den Autor

Jerry Liguori has been studying raptors throughout North America since 1984. He has conducted hawk migration counts at spring and fall migration sites, such as Cape May Point, Sandy Hook, Derby Hill, Braddock Bay, Whitefish Point, and Dinosaur Ridge, and the Goshute, Wasatch, and Sandia mountains. He is the author of Hawks from Every Angle (Princeton).

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"Jerry Liguori's book takes the hawk identification guide to a whole new level. It is hard to imagine the amount of time that went into this book--countless hours on mountaintops and other hawk-watching sites taking the photographs, then selecting and arranging them. The result is simply the best collection of hawk ID photos ever assembled, combined with Liguori's clear and concise identification tips. This book is a gold mine of information for anyone interested in hawk identification."--David Sibley, author of The Sibley Guide to Birds

"Liguori has done it again. Fresh on the heels of his highly acclaimed Hawks from Every Angle, we now have the new Hawks at a Distance. He never missed a beat. Not only did he pick up where he left off, he has taken it to a higher plane. This twenty-first-century offering does for raptors what the seminal Ducks at a Distance did for waterfowl in the mid-twentieth century. It makes a quantum leap in the complex art and science of hawk identification, taming these shape-shifters like never before."--Clay Sutton, coauthor of Hawks in Flight

"Jerry Liguori presents an innovative concept tackling the age-old problem of identifying flying raptors when seen under field-viewing conditions. Optimal grasp of each species and age class is obtained with a multitude of photographs depicting various flight modes and lighting conditions of dorsal, ventral, and head-on views. The concise text is easy to read and very informative. Liguori's field identification prowess is impeccable and is articulated throughout this guide."--Brian K. Wheeler, author of Raptors of Western North America and Raptors of Eastern North America

"Finally a raptor identification guide that depicts hawks the way you are likely to see them--at a distance! Liguori's unique approach to raptor identification will help birders quickly focus on the field marks that matter, to understand broad plumage patterns, and ultimately extend their reach and abilities as hawk-watchers. This guide is an absolute must for anyone interested in raptors, and will become an instant classic among hawk-watching enthusiasts."--Brian Sullivan, eBird project leader, Cornell Lab of Ornithology

"This book is a winner. The spectacular, cutting-edge photos effectively highlight important aspects of raptors in flight and are simply mind-boggling. This is the one guide that almost everyone will take to the field."--Keith Bildstein, Sarkis Acopian Director of Conservation Science, Hawk Mountain Sanctuary

"Clear and concise, I found all the information presented in this book to be accurate and accessible for both neophyte and more experienced hawk-watchers. I congratulate the author for coming up with such wonderfully illustrative photographs."--Tony Leukering, senior ornithologist, Geo-Marine Inc.

"An intriguing concept--take a few hundred of the most distant, silhouetted, weird angle photos and combine them into a field guide. . . . Very useful to raptor enthusiasts and hawk counters!"--Christian Artuso

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HAWKS AT A DISTANCE

IDENTIFICATION OF MIGRANT RAPTORSBy JERRY LIGUORI

PRINCETON UNIVERSITY PRESS

Copyright © 2011 Princeton University Press
All right reserved.
ISBN: 978-0-691-13559-5

Contents

Foreword by Pete Dunne...........................ixPreface..........................................xiiiIntroduction.....................................1Accipiters.......................................14Northern Harrier.................................37Buteos...........................................44Falcons..........................................101Vultures, Osprey, Eagles.........................127Uncommon Migrants and Others.....................157Shapes...........................................171Photo Credits....................................191Bibliography.....................................192Index............................................193

Introduction

Identifying raptors is similar to solving a mystery by piecing together clues. By far, the greatest challenge of raptor identification is naming distant birds. This is because plumage details (and sometimes flight style and structure) can be difficult to judge from afar. Even for the most experienced observers, identifying raptors based on plumage alone can be flawed. With this in mind, imagine how difficult it is to distinguish two species that are practically identical in plumage, like Sharp-shinned and Cooper's Hawks. Even a distinctive plumage trait like the red tail of an adult Red-tailed Hawk can be difficult to view in the field. With practice, it is more accurate to tell similarly plumaged birds apart by shape and flight-style differences than by coloration. I identify most of the distant raptors I see based on shape and flight style, using plumage traits only if clearly visible. Remember, there are exceptions to every rule, so almost no field mark is 100 percent exclusive to one species.

At any hawk-watching site, a close-up bird will draw "oohs" and "aahs" from observers. But because most hawks seen in the field are distant, Hawks at a Distance is a necessary guide. It focuses on distant birds and discusses traits that are truly useful in the field, leaving out certain others that can only be judged at close range. Be aware that some field marks may be difficult to see in the photos in this book. This is done purposely to show how these field marks truly appear in the field. Hawks at a Distance is the first guide that presents birds of unknown identity, pointing out instances when telling age, sex, color morph, or species is impossible, and showing the effect that lighting and molt can have on a bird's appearance. Only migrants that are common across the United States and Canada are covered. Most of the photographs in this book were taken during autumn migration from August 15 to November 30. Birds photographed during spring migration from March to late May or otherwise are noted as such.

I am frequently asked which hawk identification problem I believe is the most difficult. Several come to mind, like telling brown Prairie Merlins from female Kestrels at a distance, ageing Golden Eagles to a specific year, telling a Peregrine Falcon from a Prairie Falcon by silhouette, or telling adult female from juvenile Harriers in spring. However, some aspects of identification are simply impossible due to overlap or similarities in plumages, like telling the race of some Red-tailed Hawks, Merlins, or Peregrine Falcons. Remember, it is enjoyable to simply watch raptors without fussing over their age, sex, or race and that learning hawk identification is an ongoing process.

HOW TO USE THIS BOOK

Hawks at a Distance is designed to show raptors in "real world" settings and help with identification of birds seen with only a quick glimpse. Therefore, the birds throughout these pages are meant to appear distant, unlike most guides that present close-up portraits of birds. Hawks at a Distance presents each species in all light conditions. Each color plate is a composite that includes up to six images and a single caption. They are presented this way so that each color plate is viewed in its entirety as the description is read. Throughout the color plates, birds are shown in poses (i.e., soaring, gliding) in which migrants are normally observed. This is intended to stress the shape features referred to in the captions of certain color plates.

The black-and-white plates portray shape characters for each species pointed out by the accompanying captions. These plates are designed so that the reader's eyes wander around the page and take in the entire page quickly. The text is short so that it is easy to remember and so that the book is uncluttered. Key identification traits are in boldface throughout the text, and memorizing these traits will prove to be useful in the field. For example, the traits in boldface for Golden Eagle are "large, dark bird ... extremely long, somewhat broad wings ... dihedral when soaring, slightly bowed when gliding ... slow moving and steady."

One of the keys to identifying raptors is to learn the basic characteristics of each species well instead of learning the minutiae for each. For example, recognizing the shapes of each raptor, and understanding how they vary under different circumstances, is much more valuable than knowing the eye color of each raptor. Be aware that certain written or spoken descriptions (particularly regarding wing beat and flight style), and even the same field observation between various people, can be interpreted differently. For instance, I once heard the words "stiff," "choppy," "snappy," and "aggressive" used independently by four separate observers to describe the wing beats of a single bird as it flew by.

TERMINOLOGY

Age Terminology

Some age-related terms can be misunderstood or misinterpreted. The terms "juvenile" and "adult" are fairly straightforward and easy to understand (see Glossary), but the terms "immature" and "sub-adult" are sometimes unclear. Even some ornithologists disagree on the exact definitions of these terms. Regardless, the terminology throughout this guide is used in a consistent, practical manner.

The term "immature" describes a bird whose plumage is other than adult. Therefore, an immature bird is either a juvenile or a sub-adult. Some argue the term "immature" relates to a bird's sexual maturity regardless of its plumage. For instance, a breeding accipiter in juvenile plumage (which is sometimes the case with females) could be regarded as an adult because it is producing young. However, age terminology herein defines a plumage as it pertains to field identification, not a yearly age or sexual maturity.

The term "sub-adult" describes a bird whose plumage is a distinct plumage altogether from that of an adult or juvenile. Birds in their first adult plumage (that may have none or several juvenile feathers retained) that are essentially identical or appear identical in the field to successive adult plumages are simply "adults." Most raptors reach adulthood after their first molt cycle starting at about one year old. A few species take about two years, while eagles typically take about five years to reach full adult plumage.

Color Morph Terminology

Throughout this guide, the term "dark" is used to describe buteos that are mostly or completely dark on the underside. This includes birds otherwise known as "intermediate morph" and "dark morph." Intermediate and dark-plumaged birds often appear identical to...