An immature Cooper’s hawk watches a backyard bird feeder. Credit: Courtesy of Bob Duchesne

Expert hawk-watchers can identify a raptor on the horizon that’s no bigger than a speck of dust. It’s annoying. It makes us mere mortals feel inadequate. The experts can, of course, explain all the tips they are using to make the identification, but that’s not their big secret. Their secret is this: they’ve seen thousands and thousands of hawks. Practice.

Hawk observation is different than most bird identifications, which rely primarily on field marks such as color, breast streaks, tail stripes, etc. Specks on the horizon are not close enough to reveal any of those. The hawk experts focus on the way the raptor flies. How is that possible? It all comes down to that old saying: “You are what you eat.” The shape of a hawk determines how it flies, and how it flies is determined by what it hunts. So let’s review.

In our little corner of the world, there are basically four raptor families we need to consider: falcons, accipiters, buteos and harriers. There are three falcons we are likely to see in Maine: American kestrels, merlins and peregrines. There are three possible accipiters: sharp-shinned hawk, Cooper’s hawk and northern goshawk. There are three likely buteos: broad-winged hawk, red-shouldered hawk and red-tailed hawk. And although there are around 20 harrier type hawks in the world, we have only one in North America: the northern harrier.

Falcons are speedsters. They chase down prey. They are built like jet fighters, with short tails and pointed wings. The smallest — the American kestrel — preys mostly on dragonflies and grasshoppers. Its diet requires it to be nimble in the air, able to twist and turn to snatch a meal. The kestrel is the only falcon that hovers over its hunting grounds, typically open fields. While all falcons tend to fly directly with steady wingbeats, the kestrel’s flight is more bat-like, with aerial jerkiness that helps identify it at a distance.

Merlins are bullet hawks — fast and direct, with the rock-steady wingbeats of a racing scull’s oars. They primarily prey on other birds, chasing them down in level flight. They don’t stoop on prey the way peregrines do. Kestrels are light enough to glide during flight. The heavier merlins don’t.

Peregrines are lightning fast, but their larger size and bigger wings allow them to soar, which is something the other two falcons don’t do. Kestrels and merlins are similar in size, but the peregrine’s bulk makes it easy to distinguish from the other two at a distance.

Accipiters are ambushers. They combine speed and agility to surprise prey. They dine mostly on other birds, flashing through the forest to grab a meal. They require short wings and long tails to be so maneuverable — design characteristics that give them quick acceleration and turning ability — but this creates drag during sustained flight. As a result, they often fly with a flap-flap-flap-glide style that is recognizable from a distance. Sharp-shinned hawks are the most common migrant. As the smallest and lightest of the accipiters, “sharpies” are more buoyant in the air, making them look more fluttery in flight than the slightly larger Cooper’s hawks.

The heftier northern goshawk prefers larger prey, such as woodpeckers, grouse and crows. It also relishes squirrels and snowshoe hares. Some do migrate. Most winter over on their breeding grounds, so goshawks are not often spotted at hawk watches. When seen, its huge size makes it easy to distinguish from the other two. All three accipiters can soar and circle in the sky. Their short wings and long tails give them a T-shape that helps sort them out from other hawks.

Buteos are slower, heavier hawks. They dine mostly on small mammals, reptiles and amphibians. They usually hunt from perches, peering down from a limb, waiting for something to move so they can swoop down and snatch it. They are built for soaring, with short tails and broad wings, making them easy to tell apart from the other hawks at a distance.

Northern harriers are uniquely designed for gliding low and slow over open areas, such as fields and marshes. In fact, they were formerly named marsh hawks. They have long wings and long tails, apparent even at a distance.

So, that’s the secret. The first step is to figure out which family the distant raptor is in. Then, it’s just a matter of figuring out which of the three (or one) family members it is. I mention all this now, because we’re hitting the peak of early hawk migration this week. Practice.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.