Outdoors

Hawk ID sometimes a matter of elimination

Posted April 13, 2017, at 2:12 p.m.

They’re back. The influx of spring migrants has added a chorus of bird songs to our backyards. That is, if you want to call the harsh noise made by the eastern phoebe a “song.” It has all the musical quality of nose-blowing.

In this season of changeable weather, it only takes one good night of southerly breezes to bring in a horde of birds. Apparently, one of those nights came last weekend. By Monday morning, phoebes were everywhere. But, alas, that’s not the point of today’s column. Today’s column is about the timing of hawk migration and identification.

As I returned home from a walk on Sunday afternoon, a hawk flashed over. Involuntarily, I went through my mental checklist and identified it within three seconds. I can’t help myself.

Somewhere in the limbic portion of my reptilian brain, I am forced to distinguish every bird.

Within one second, my brain decided it was neither a falcon nor an accipiter. Falcons are streamlined and fast, shaped like a jet fighter. They attack in the open and chase down smaller birds. This hawk was in a hurry, but even his hurried pace wasn’t fast enough to be a falcon.

Accipiters are almost as fast as falcons, but they’re built for maneuverability rather than speed. They have relatively short wings and long tails that allow them to twist and turn smartly through a thick forest. They are masters at stealth and surprise. Sharp-shinned and Cooper’s hawks are the accipiters that most often snatch a bird from your feeder. Northern goshawks are also accipiters, but they are bigger and prefer larger prey, like grouse and hares.

So it took me only one second to declare the hawk a buteo. Buteos have relatively wide wings and short tails, allowing them to soar more easily. Typically they will dive on rodents from a height, and even more often they perch, watch for prey, and pounce.

Because this mystery bird was low and flying away from me, I could make out no field marks. It was too small to be a red-tailed hawk, and I was certain it wasn’t a broad-winged hawk. Why? Because broad-winged hawks hadn’t returned yet. I’ve now cleverly circled back to the actual point of today’s column.

Hawk migration is remarkably true to the calendar. Right on time, turkey vultures began returning to Maine in early March, and peaked late in the month. On March 31, a hawk watch at Bradbury Mountain State Park in Pownal tallied 221 vultures passing the summit. The first ospreys of the season crossed the summit on April 3. More ospreys followed quickly, and within a week most had returned and taken up residence on their nests along Interstate 95. Other hawk species trickled by the peak over the last three weeks, usually just a couple dozen per day.

However, broad-winged hawks arrive all at once. They are due any minute. The first wave crossed the Maine border on Monday, when 33 passed by Bradbury Mountain. You will remember that April 10 was the first really warm day, with a strong southerly wind. These hawks are our champion migrants, riding the wind all the way from South America. In summer, they are Maine’s most commonly seen hawk. On the afternoon of my mystery hawk sighting, the influx of broad-winged hawks had not yet started.

I could rule out other raptors. It certainly wasn’t an eagle, osprey, or vulture. It wasn’t a northern harrier, another family of large hawks that have long wings and tails.

As the second of my three seconds elapsed, my brain was already going over the mental checklist again. Not a falcon, not an accipiter – a buteo, but too small to be a red-tailed hawk, too early to be a broad-winged hawk.

Red-shouldered hawk.

There are remnant populations of red-shouldered hawks in California and Mexico. Otherwise it is exclusively an eastern hawk. It is non-migratory over most of its breeding territory. It is uncommon in Maine where it is at the northern limit of its range. Our residents go south for the winter. I see a few in Maine every summer, including annual sightings around my house. This year, it took me three seconds to figure it out, mostly because it took that long to figure out what it wasn’t.

Because they don’t have far to travel, red-shouldered hawks return early. Because there aren’t many, you might not notice. But you’re about to notice broad-winged hawks. They just arrived, and there are lots of them.

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.

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