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Tips from Pete Dunne for identifying hawks in flight

A beginner's guide to identifying hawks in flight
By Pete Dunne | Published: 5/1/1988

Northern Harrier along the Enchanted Highway in North Dakota by Joshua Galicki.

Northern Harrier along the Enchanted Highway in North Dakota by Joshua Galicki.

For a slow day in September, the north lookout at Hawk Mountain was surprisingly crowded. Strewn across the rocky Pennsylvania promontory was an eclectic assemblage of society’s rank and file, along with a handful of regulars.

In a protective ring of stone, the official counter and his inner circle of advisors discussed cabbages and kings. On the periphery old-timers and newcomers chatted amicably and now and again made desultory scans of the horizon. It was a pleasant Bluebird day and if birds were in short supply, well, that just made more time for conversation.

Sitting directly in front of me was a middle-aged couple, beginning hawkwatchers by all signs but serious beginners nonetheless.

Spread around them, like so many pieces of a complicated puzzle were field guides and pamphlets depicting hawks in flight. Between them they traded a single pair of bargain-basement binoculars. Each in turn would scan the horizon, then surrender the binoculars.

Despite their assorted handicaps, they were doing about as well as everyone else (which is to say, they were seeing virtually nothing). Every passing Turkey Vulture gave cause for heightened interest and scrutiny. An immature Red-tailed Hawk hunting over the valley inspired a furious literature search. After lengthy debate, the couple settled on an identification of Northern Goshawk, which, strictly speaking, wasn’t a bad guess. The bird did bear passing resemblance to several of the not-so-accurate illustrations of the Goshawk in their pictorial arsenal. The couple might even have gotten the identification right if they hadn’t dismissed Red-tailed at the onset. It was obvious the bird didn’t have a red tail, but then, immature birds don’t.

I was a bit younger then, and if not less serious about hawkwatching, certainly more stubborn. Despite the inauspicious conditions, I was determined to find something besides Turkey Vultures. And as often happens when belligerence goes head-to-head with common sense, belligerence won out. I found a bird.

Waaay out there, off the slope, a shimmering phantom appeared — a tiny blur that had just a tad too much substance to be a mirage. “I’ve got a bird.” I shouted, not daring to drop my binoculars or let the concentration that sustained the image falter. “Off the slope of one, half a (binocular) field over the horizon.”

All around me I could feel binoculars brought to bear. From the corner of my eye, I saw the man in front of me bring his glasses up and scan where I seemed to be focused. Unsuccessful, he turned to check his bearings (and to see, perhaps, whether I was serious about something out there or not). A few veteran observers located the bird; many present could not. The bird was a long way off, the kind of bird that only a hawkwatcher could appreciate.

After a minute or so, I felt certain that the apparent upward tilt of the bird’s wings wasn’t a matter of heat wave distortion. The wings really were cocked in a “V” shape, a dihedral, as we say in the trade. That narrowed the possibilities some. The viable options were: Turkey Vulture, Red-tailed Hawk, and Northern Harrier. Rough-legged Hawk and Golden Eagle, because of the conditions, because of the season, and their relative scarcity, were long shots — backup considerations at best.

Turkey Vulture, Bordentown, New Jersey, by Charles Wen.

Turkey Vulture, Bordentown, New Jersey, by Charles Wen.

The bird didn’t seem dark enough to be a vulture or an eagle. Even at the limit of conjecture, these species appear dark. The dihedral seemed too pronounced for the bird to be a Red-tailed Hawk, particularly given the conditions. Red-tails often flatten their wings when winds are light. And was it my imagination, or did I see the bird rock just a bit in flight? A Red-tailed Hawk should be steady as a roof beam on a windless day.

I decided to stick my neck out and put a name to the distant shimmering phantom.

“Marsh Hawk!” I pronounced with more confidence than I really felt. (We called Northern Harriers Marsh Hawks back then, you know.)

At my identifying disclosure, the gentleman in front of me spun around and glowered. Turning back up-ridge he frantically moved his binoculars up and down, back and forth, trying to compensate for poor optics with concentrated effort.

The bird began to move out over the valley. As it came closer, it took on more of the characteristics of a Harrier — the slim Harrier profile, the long narrow wings, and the clincher clue. The bird began flapping its wings, using the lazy, loping wing beats that are as identifiable as a fingerprint from any distance.

As I watched, a stray gust or the edge of a thermal caught the bird. It rolled slightly, showing gleaming white underparts.

“Adult male!” I shouted before anyone else. “It’s an adult male Marsh Hawk.” The bird was, and still is, my favorite raptor.

At this disclosure the frustrated beginner let his binoculars drop, rolled his eyes toward the heavens, raised his hands in a display of mock despair and, turning to his wife, said, “I can’t believe this guy behind us. I can’t even find this bird, and he can see its genitals.”

The identification, of course, was based wholly on the color of the bird’s plumage, not on genitalia. The adult male is white underneath, the adult female, tawny, and the immatures have cinnamon underparts. The beginner hadn’t done his homework.

Now, the point of this anecdotal disclosure is this: The frustration that the neophyte hawkwatcher experienced is absolutely typical. But most of it was avoidable.

No, I’m not going to sell you a fat bill of goods by telling you identifying hawks in flight is so simple even children can do it (even though they can). It is tough. It is challenging, and this is precisely why hawkwatchers love it so much — it never gets dull.

But hawkwatching doesn’t have to be complicated, in fact, quite the contrary! The art of hawk identification is based on the principle of simplification. Identifications can be made by compounding a bunch of field marks — building identifications from scratch. But hawk identifications are usually made by testing the obvious or, as was the case of the Harrier in the story, by default. The bird was a Harrier because nothing else fit.

To become a skilled hawkwatcher takes time and experience, and there is no substitute for this. But beginners can avoid a lot of unnecessary frustration by doing a few simple things and getting properly oriented to a whole new birdwatching arena. Here are some tips for the beginner, offered by another beginner who has simply been at it somewhat longer than most.

Use binoculars that work

Right off the bat, do yourself a big favor. Use a decent pair of binoculars, and make sure there’s a pair for each observer. After years of teaching bird identification, I have come to conclude that it is poor quality or ill-suited optics, not a lack of experience that present the greatest obstacles and sources of frustration for neophytes. Beginners, of course, cannot know this. They simply know they can’t see what everyone else is seeing. They wrongly attribute it to some fault of their own. My guess is the couple on Hawk Mountain were using binoculars that were either desperately out of alignment or stuffed with junk optics.

Get a decent pair of binoculars. Ten power is ideal for hawkwatching, but power is not as important as optical quality. Anything between 7- and 12-power binoculars will work for hawkwatching.

Stay away from zoom binoculars. They are worse than useless. Stay away from optics in the rarified 15- or 20-power class. Not only because most binoculars in these powers are poor quality, but also because the field of view from these turbo-charged optics wouldn’t do justice to the view through a medium-length soda straw. The wider the field, the easier it is to locate a distant bird of prey.

For insight into specific brands and models, find out what experienced hawkwatchers are using. Buying binoculars is like buying a car — expect to hear differences of opinion. What have I used? Bausch and Lomb Discoverer 9×35, Leitz 8×40, Zeiss 10x40B, and they all work fine. Another, quite inexpensive glass that gets high marks from hawkwatchers is the Swift Audubon. Though not popular yet, Swarovski has a 10-power glass that should perform well. The very fine Bausch and Lomb Elite 8×42 should excel in the hawkwatching arena, though many veterans will scoff at the thought of using any power less than 10. Sadly, the Bushnell Custom 10x, perhaps the best hawkwatching binocular ever produced, has been discontinued. If you see one at a garage sale, barter your car for it.

Leave the library at home

If the couple had carried only one field guide with them, they would have been much better off. Surrounding yourself with a confusing array of pictures and descriptions will not make you a decent hawkwatcher. Carry the information you will use in your head, and filter your observations through the mesh of knowledge and growing experience. Even a small storehouse of hawk identification skill locked in your own mind will serve you far better than the discourse of a battery of experts wrapped in a book. Don’t hesitate to bring a guide with you as a reference or a prompt. Don’t use it as a prop.

Here’s another suggestion. Use a field guide specifically geared for the identification of hawks in flight. Hawkwatching is a specialization. General-purpose field guides come up short in hawkwatching because this is not their intended use. I’ve had a hand in the development of two guides to hawk identification: Hawks in Flight, published by Houghton Mifflin, and New Jersey Audubon’s Hawk Watch — A Guide for Beginners. I don’t feel awkward about recommending them… because of the merits of the other authors. I also heartily recommend The Mountain and the Migration, published by the Hawk Mountain Sanctuary Association in Kempton, Pennsylvania, and Houghton Mifflin’s A Field Guide to Hawks, North America.

Use field time to study and bring your knowledge to bear. If my friend on the lookout had done a little prepping before his day on the mountain, he probably wouldn’t have turned a very obvious immature Red-tail into a Goshawk — and would have known that identifying adult male Harriers doesn’t require a degree in avian urology.

Every bird you study increases your knowledge and makes the next bird a little easier to identify. At first even very close birds that are plainly visible will challenge your ability to put them in the right slot. In time your reach will extend to exploring the exciting horizon that lies at the limit of human conjecture — hawkwatching’s frontier.

But, you say, hawks are always so far away, and you can’t see any field characters. Ah, but you can. The field characters used to identify birds are visible at tremendous distances. From a long distance, you won’t be looking for markings like wing bars or plumage patterns. You will look instead at how a whole wing is held; these are the kinds of field identifiers good hawkwatch guides offer. Don’t forget, at most hawkwatching sites, many birds seen at a distance come closer, giving you the chance to test your guess. It is not uncommon for experts to change their initial identification several times as the bird gets closer. It’s all part of the game.

Knowing what to look for

Like any type of bird identification, the flight identification of raptors is predicated on seeing characteristics that distinguish one bird from another. The distance from which most raptors are seen requires field identifiers that are reliably visible at that distance.

General appearance and shape

Raptor identification is very much concerned with shape because at a distance the overall shape of a bird is easier to see than individual parts (like a wing or the tail). The general impression and shape of a distant bird is linked to the interrelationship of tail, wing, and head. For the purposes of simplification, raptors can be lumped into three general categories: large soaring raptors, woodland raptors, and open-country raptors.

Large soaring raptors, the vultures, osprey, eagles, and buteos, are birds with long, broad, plank-like wings and short, broad tails. They are frequently seen soaring for lengthy periods without beating a wing. The general profile is broad and robust.

The woodland raptors — forest kites and accipiters — have shorter, broader, rounder wings and long, narrow tails, which allow great maneuverability in dense woods. Their profiles are long and narrow; their bodies are somewhat tube-like.

The open-country raptors include the kites, harriers, and falcons. These are long, slim birds with tapered wings and long-to-medium-length tails. They are suited for swift and direct aerial pursuit of prey or buoyant, agile flight.

Plumage

Unlike most other bird identifications, plumage takes a back seat to other field marks in the hawkwatching arena, but it is still an important aid to species identification — particularly at close quarters. There are a number of excellent and highly visible plumage-based field marks. For example: the crescent windows at the tip of a Red-shouldered Hawk’s wings; the clean underparts on an immature Cooper’s Hawk. Both of these marks are visible at tremendous distances. And of course as a bird gets closer, more and more detailed plumage marks can be seen.

Manner of flight

This is probably the most useful long-range weapon in the hawkwatcher’s arsenal — but the most subjective and the hardest to convey to a beginner. Its advantage is that movement, the cadence of wings or the rhythm of a bird’s flight, is discernible at distances even beyond the point where its shape and plumage have become virtually indistinguishable.

The lazy, loping wingbeats of a Harrier are diagnostic. The choppy, hurry-up-and-wait wing beat of a Black Vulture easily distinguishes it from a Turkey Vulture or an eagle. Eagles, at a distance, appear to do everything in slow motion.

Behavior

Each species exhibits idiosyncratic behavior that can be used as an aid to identification. On the ridges, Red-shouldered Hawks are often seen flying on the lee, or wind-sheltered, side of the ridge while the bulk of the flight concentrates on the windward side of the ridge. Merlins are highly aggressive toward other raptors. A small falcon harassing other birds is likely a Merlin. Conversely, a small falcon that seems indifferent to other raptors is probably a Kestrel.

Habitat

Habitat is a very useful aid to hawk identification when birds are on territory, though not of much use during migration. A large gray bird sitting out on a snowy, open field might be a Gyrfalcon, but if it flies into heavy woods, the possibility it is a Goshawk should be given more serious consideration. Why? Falcons prefer open areas; accipiters are adept at maneuvering in woodland.

Spatial and temporal distribution

There is no location in North America where an observer has to consider 36 possible species. Many of North America’s resident raptors are extremely localized or are only found in certain places at certain times.

This applies in migration too. Some birds are early migrants, some later. A small buteo with a ruddy chest and banded tail in Ontario in September is probably a Broad-winged, while one in November is almost certainly a Red-shouldered.

Relative abundance

Used with discretion, the relative abundance of hawks can be used as a first step to identification. Needless to say, common species turn up with greater frequency than less common ones. But don’t get cocky. Relative abundance is affected by geography and the calendar. What is common at one place is not necessarily common at another. In the East, Sharp-shinned Hawks usually far outnumber Cooper’s Hawks — from 10 to 20 Sharpies for every Cooper’s. But during the second week in October, when the Cooper’s Hawk migration peaks, the ratio may drop to three to one. And in other parts of the country, Cooper’s Hawks may outnumber Sharp-shinneds.

Revealed at last — the secret, magical formula used by expert hawkwatchers everywhere. Just ask one fundamental question: “What is the bird most likely to be?” Then, before doing anything else, check to see if that is what it is.

Step one: Get rid of extraneous cards in the deck. In most locations you are dealt a hand of no more than 15 or 16 possible raptors. When you plug in the temporal considerations, you drop a few more cards from the deck. Finally, if you can place a distant bird into one of the broad categories (buteo, accipiter, or falcon), you are usually looking at only two or three viable possibilities.

Let’s say you are at New Jersey’s Montclair Quarry, and you see a distant raptor. Well, right away you can eliminate cards like Hook-billed Kite and Harris Hawk because geography has already eliminated them for you.

Let’s say it is November. Because it is late in the migration, you can eliminate early migrants like Broad-winged Hawks and Ospreys from preliminary consideration. Since you are away from the coast, you can give secondary consideration to birds like Peregrine Falcons and Merlins — birds that are relatively uncommon inland and are mid-season, not late season, migrants.

Step two: After letting temporal and geographic considerations whittle down the deck, there are just a few possibilities left. Look at the bird, note observable field marks to see if these match the field marks of any of the most likely raptor candidates. If an identification doesn’t fall easily or neatly into place, then start going through the discarded possibilities.

But, you say, you are a beginner. How do you know what is expected or what is more common?

There is a wealth of information available, much of it compiled in books I’ve already mentioned. Many of the established hawkwatch sites also have literature on hand that presents a seasonal picture of the flight there.

And there is one other way to learn more about the identification of those distant birds, the easiest course of all, but one that beginners are most reluctant to use: Simply ask another hawkwatcher!

Nobody likes to feel inferior or dumb, and many hawkwatches are, unfortunately, clannish places. Hawkwatching is a highly social form of birding. It has its own hierarchy, its own esoteric language. Newcomers are, well, outsiders, and people in this position feel uncomfortable reinforcing their status by touting their lack of knowledge. Here is the key: Shared interest is the coin of the realm. If you are seriously interested in learning how to identify hawks, there is nothing that will win favor more quickly among hawkwatchers.

Ask what that distant puzzling bird is and then ask why.

A word of caution. Soliciting the advice of someone whose experience sounds vast, but whose skills are hardly better than your own, is only going to sow confusion. At most hawkwatches you can be pretty confident of the ability of any person conducting the official count. If duties and a heavy flight preclude private tutorial services from the official counter, solicit the council of those hawkwatchers whose identifications seem to get quick and automatic recognition.

In a very short time you will be the one making identifications and accepting queries from bewildered newcomers. When that day dawns, be a pal, check their field guides and binoculars and share the wealth.

Pete Dunne is vice president for natural history information for the New Jersey Audubon Society, director of the Cape May Bird Observatory, and the author of Prairie Spring: A Journey into the Heart of a Season (2009); Pete Dunne’s Essential Field Guide Companion: A Comprehensive Resource for Identifying North American Birds (2006); Feather Quest: A North American Birder’s Year (1999); and other books about birds and birdwatching.