Identifying birds of prey (raptors) has undergone a transformation. The old ‘field mark’ system has been supplemented with a more behavioral approach.

Our ancestors who stayed close to the land and its rhythms could tell species apart at long distances. They used both known field marks and behavior to identify an animal. This approach is more holistic.

The field mark system was pioneered in book form by Roger Tory Peterson. His field guides focused on color, plumage, marking and other easily seen details. This is called the ‘field mark’ approach. This works best when you have a clear and close look at an animal.

But, if the birds is flying a mile overhead, then the field mark system doesn’t work as well.

This is where the behavioral approach comes in handy.

Instead of looking for plumage details or eye color, more emphasis is placed on how a bird behaves.  This behavior approach looks at a number of factors.

• how a bird flies
• the rhythm of the flaps and glides while flying
• does it fly with soaring, rocking motions or long flights or short bursts
• the bird’s overall shape, size and color and silhouette
• the bird’s behavior
• any calls or sounds made

All of these behaviors and clues add up to a good identification. Even still,  it is hard to be accurate all the time.

Birds of prey species often have distinctive ways of flying and holding their wings. If you learn these profiles and behavior you will be able to identify raptors even when they are circling miles above you.

I often see Red-tailed Hawks and Turkey Vultures flying overhead. When they are tiny specks in the sky is not easy to distinct between the two birds. I often check the manner of flight, color pattern of feather and body and whether other birds are in the sky with it.

I focused on identifying a Turkey Vulture. The Turkey Vulture is a dark underneath with a dark body, dark V-shape on the wings and translucent white “fingers” at the end of its wings.  A soaring Turkey Vulture’s silhouette takes on a more pronounced V-shaped than a Red-tailed Hawk. And a Turkey Vulture often looks huge, where a Red-tailed Hawk can look smaller.   I have gotten pretty good at telling a Turkey Vulture from any other bird.

I think the behavioral approach used along with the field marks approach, helps to make a very knowledgeable birder.

There is much to learn on identifying birds of prey. We can’t cover it all here.

Here is a list of some of the best books on identifying birds of prey. The books all focus on day-flying raptors. Owls, being night fliers are not included. These links are Amazon.com affiliate links. I may earn a commission for Amazon purchases using the links. This does not affect the price you pay.

A Field Guide to Hawks of North America (Peterson Field Guides)
A general field guide using field marks and flight silhouettes is William S. Clark’s,  Hawks (A Peterson Field Guide). This guide has very good drawings of birds of prey. It doesn’t include owls but all the other North American raptors are included. It is a good book for learning the “field mark’ system. The book is small enough to carry with you in the field.

Hawks in Flight: Second Edition
A book with an holistic approach is  Hawks in Flight by Pete Dunne, David Sibley and Clay Sutton. The aim is to study the photos before raptor watching. It includes all the diurnal (day-active) raptors. Night-active owls are not included. It focuses on each species distinct characteristics. Including movement, color pattern and body shape. It is too big to carry outdoors.

Hawks at a Distance: Identification of Migrant Raptors and Hawks from Every Angle: How to Identify Raptors In Flight

Both books focus on identifying raptors in flight. Hawks at a Distance has photo of birds when they are just specks in the sky. Hawks from Every Angle focuses on identifying hawks that you can clearly see but from the back, side, or in profile.

The Crossley ID Guide: Raptors (Crossley Id Guides)

I bought this book this spring. The photos are taken from such angles that you wonder how the authors managed to get the photos. For each species there are near and far photos from different angles. There also ‘quiz’ pages.  Photos of several species of raptors, from different angles, are placed on a page. The answer key is in the back of the book. A good book to work with on a chilly winter night.

Of all the books, I like the Peterson field guide and the Crossley Id Guide the best. They fit my skill level. In honing my id skills, I tend to focus on one or two common species that  are abundant in my area. This means I see them often. From there, I can add other species as the need arises.

If you are trying to decide, use the handy links to Amazon.com to weight the merits of each title or browse through them at the library or a bookstore.