A bald eagle soared along the spine of the river. Ospreys in the tree overhead watched warily, but didn't move from their nest. On the dock, we looked on as well, delighted to be returning to the peaceful rhythms of this wide tidal river. Virtually lost against this majestic backdrop, a handful of much smaller birds coursed about, seemingly oblivious to both the predators and their human observers.

The little birds with long, pointed wings swooped and swirled, executing acrobatic turns with precision and deadly accuracy. They were hawking insects that swarmed above the water, eating buzzing bugs with extraordinary efficiency. These precision flyers were wasting no time watching the eagle glide downriver. A half dozen of them continued to flit about in their pursuit of the endless bounty of the insects.

The barn swallow (Hirundo rustica) is the most widely distributed and abundant swallow in the world.

Along this stretch of the river, we also saw tree and northern rough-winged swallows. Cliff and bank swallows are also found nearby. A farmhouse down the road has a purple martin house that is crammed with occupants.

The world may be full of flying insects, but members of the swallow family do their best to manage the population explosion. Ornithologists have estimated that a single barn swallow can cover 600 miles daily during its constant swirling flight in pursuit of insects. The birds swarming about the dock seemed to be well on their way to that impressive mileage figure.

The sight of swarming swallows is common across the country at this time of year. This stands in stark contrast with the dead of winter, when not a single swallow will be seen. Without the plentiful insects of summer, these birds have nothing to eat. When the weather turns cold, swallows turn south.

The barn swallow breeds throughout the United States except for the Gulf Coast. Its range extends well into Canada. The birds winter in South America. Some barn swallows fly all the way to the tip of Argentina in their endless pursuit of their insect prey.

Barn swallows are relatively easy to identify. They are the only swallows with deeply forked tails. The birds are a dark, iridescent blue on top that transitions to black in the tail and trailing edges of their wings. They have rusty throats with matching forehead patches. The males have a dusky orange underneath while the females show white. Both sexes were displaying their aerial skills near the dock where we stood transfixed.

Barn swallows once built their nests along the rocky edges of streams. As their name suggests, today they are more readily found in barns.

But they are not limited to these rustic structures. The birds circling about us probably roost in the abandoned boat house rusting away next to this aging dock. A short distance downriver, barn swallows have made their nests under a dock, carefully placing them just above the reach of high tides.

Barn swallows' nests are made of wet soil. The birds fill their beaks full of mud and construct a cup that they attach to a cross beam or a man-made shelf. They are monogamous, and both male and female construct the nest. Once it is built, the female lays four to five eggs, which she will incubate for about two weeks. The male may share some of the nesting duties when he is not busy bringing bugs back to the nest for his mate's consumption.

After hatching, the chicks need only three weeks before they are ready to fledge.

That relatively quick breeding period allows the adults in the Chesapeake region to have a second brood most years. In contrast, the barn swallows at the northern extreme of their breeding range in Canada will start their migration south as early as July, cutting short their ability to raise a second brood.

The barn swallows swarming about us had wrested my attention away from the commanding presence of the bald eagle and the wary osprey. Throughout the small drama, the barn swallows mindlessly went about their business of hawking insects.

The barn swallows are content to know their place in the world and take full advantage of it.

Why do we find it so hard to be comfortable fitting into our niche in the world? These barn swallows will soon be sated.

I wish I were as easily satisfied.