Published July 22, 2012, 04:00 AM

ALWAYS IN SEASON: Swallows fill up the mid-summer sky

Swallows have taken over the sky at our place west of Gilby, N.D., and one evening last week, there was an aerial encounter.

By: Mike Jacobs, Grand Forks Herald

Swallows have taken over the sky at our place west of Gilby, N.D., and one evening last week, there was an aerial encounter. A northern harrier drifted across the meadow behind our house, and the swallows attacked.

They were not alone in their aggression. Several blackbirds and an eastern kingbird joined the sortie.

The harrier is a kind of raptor, once known as “marsh hawk.” It’s probably the most common hawk in the open grasslands of Grand Forks County.

The swallows were not the forward attack force. The kingbird took this position, practically riding on the harrier’s neck.

Swallows were by far the most numerous of the flock pursuing the harrier, however. They darted around the hapless harrier, forcing it to bank sharply to one side or the other, an exaggerated version of its usual rocking flight pattern.

Despite the harassment, the harrier was a persistent bird. It had strong reason for its interest in the meadow. There is good hunting there, judging by the number of jumping mice and meadow voles that the cat brings home.

It’s unlikely that the swallows or any of the other birds were in any real danger. Harriers are not aerial hunters. They typically take prey on the ground, by dropping onto it and seizing it in their talons.

There are bird-hunting hawks, however, and the attack on the harrier may have been a survival behavior. But maybe not. Perhaps the swallows simply resented the intrusion and undertook to drive the harrier away.

There were two kinds of swallows in the flock, barn swallows and cliff swallows. The barn swallows are residents at our place. There are three nests, one over a little used door that leads to a corner of the deck, another over the garage and the third under the eaves of the od farmhouse.

The swallows behave quite differently toward us.

Those nesting on the garage ignore us pretty much completely.

Those over the deck are less tolerant, scolding us loudly if we approach too closely too close. By now, I’ve learned precisely the borders of their comfort zone.

The third pair attacks if we get too close. Several times I’ve felt a rush of air from the swallows wings as it zoomed over my head.

Clearly, the swallows on the garage know us and our ways. They’ve seen us use the garage door many times each day. Those on the deck are comfortable as long as we respect their privacy. Those on the other house don’t know us as well. We seldom go there unless we need something we’ve stored there – a book or a canning jar, for example.

The garage-door swallows fledged early last week. There are five young. The nest on the deck has a second clutch of eggs. The birds on the old house appear to have left the nest.

The fledgling swallows return to the garage-door nest each night. It’s comical to see five full-grown birds crowd into a small space. The adults roost on the ledge above the door. The deck nesters are brooding, of course; the male sticks close to the nest, sitting above it an perhaps a yard away.

He does spell the female, covering the eggs when she’s away.

The fledglings from the garage door spend much of their time at the very top of a dead tree near our driveway. Those from the old house roost on the frame of a metal building on our farmstead.

These three groups form a loose colony, and they share the airspace.

Cliff swallows are visitors to this space. They nested here when we first arrived 14 years ago. We took down an outbuilding they’d used, and they haven’t re-established themselves. Every summer, at least some cliff swallows show up. I imagine they are pioneers, looking for appropriate nesting spots.

Or they may be opportunists responding to food supply.

Or they may be socializing.

Swallows are gregarious birds. Cliff swallow colonies sometimes have hundreds of nesting pairs. To my knowledge, the closest cliff swallow colony is more than a mile away, as the swallow flies, so these birds have made a trip once they get to us.

Swallows are strong fliers and great travelers. The swallows of the Red River Valley will migrate to Central and South America.

Jacobs is the publisher of the Herald.