A pair of peregrine falcons fly over Cadillac Mountain in Acadia National Park on Sept. 21, during the fall hawk watch. Credit: Bob Duchesne

Hawks are streaming through Maine right now. What are you going to do about it?

Yeah, I know, hawk identification is hard. Except that it isn’t. For 25 years, park rangers and volunteers have been making it look easy on top of Cadillac Mountain in Acadia National Park. Whenever the weather cooperates from now until mid-October, experts are up there, identifying and counting the raptors as they whiz past the summit. They do it for three reasons.

It’s scientifically important. The annual count reveals trends in the hawk population. As the climate changes, the peak dates for hawk migration of each species have been changing. Some are leaving later because they can. It’s warmer. Some are leaving earlier because their food resources are disappearing earlier.

[Read more Good Birding here]

It’s educational. Here’s a chance for nature-lovers to sit with experts, and have the birds come to them. Cadillac is the tallest peak abutting the ocean between here and Brazil. Migrating hawks are drawn to it, knowing that updrafts and thermal air currents will give them a boost. Hundreds of hawks flash by the summit on a good autumn morning.

It’s wicked good fun. Just sit and watch the show. No pressure. If you cannot figure out what a bird is, somebody sitting next to you can. It’s actually fun to be wrong because it always sparks a discussion about how to best recognize the clues.

Let me take some of that mystery away right now. Maine hawks come in various shapes and sizes, grouped into four distinct families.

The most commonly seen hawk in Maine is the broad-winged hawk, a member of the buteo family that also includes red-shouldered and red-tailed hawks. Buteos are characterized by large wings and a short tail. Birds with large wings cannot beat their wings fast, any more than you can paddle a canoe fast with a 20-foot paddle. Buteos soar more and flap less, which is obvious a mile away.

Accipiters are sneaky woodland hawks, characterized by short wings and a long tail. This makes them speedy and maneuverable. They are masters of the surprise attack, both in the woods and in your backyard. When flying by Cadillac, their flight pattern looks “fluttery,” a consequence of having to migrate long distances on short wings. Our most common accipiter is the sharp-shinned hawk, followed by Cooper’s hawks and northern goshawks. They often fly with a flap-flap-glide pattern – the most efficient way to maintain lift on short wings, while reducing drag. This is also obvious a mile away.

Falcons are built like jet fighters. Maine’s three falcons are American kestrel, merlin and peregrine. They are the swiftest birds of prey. Their short, pointed wings are designed for beating fast. Yes, that’s also obvious a mile away. They are capable of gliding and soaring, but on those wings, they really appreciate the help of mountain updrafts.

[Hawk ID is sometimes a matter of elimination]

Northern harriers are the opposite. They are larger than most of the migrant hawks, and have long wings and a long tail. They are built for circling slowly over fields and marshes. They could not fly fast if the devil was chasing them.

So, there are noticeable differences in how each hawk family flies, which the Acadia hawk watch experts would be happy to point out. The next clue is size. Sharp-shinned hawks and American kestrels may be in different families, but they’re both about the size of a blue jay. They’re the two most common migrants in Acadia. It may seem like a daunting task to identify a hawk from among a dozen possibilities, but often, you’re only guessing between two.

Broad-winged hawks are bigger and slower. Northern harriers are even bigger and slower. Bald eagles, turkey vultures and ospreys are much, much bigger, and the IDs usually are not troublesome.

[Just when you think you have hawks figured out, another one shows up]

Did you notice what this discussion didn’t talk about? Color and field marks. Sure, there are differences between the hawks, but by the time the bird is close enough for it to matter, you’ve already figured it out based on size, shape and flight pattern — just three clues to sort out. It turns out, hawk identification is way easier than warblers.

Pick a day when the wind is from the northwest. The hawk watch is just off the summit. Experts are generally present between 9 a.m. and 2 p.m., with the watch usually wrapping up by mid-October. You may feel like a beginner when that first hawk flies by. But by the time you’ve seen your 200th raptor of the morning, you’ll be an expert. Yeah, it’s just that easy.

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.