Laura Erickson's For the Birds

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(Recording of a Common Nighthawk)

One of the finest riches of autumn is the flight of the nighthawks. Last Sunday the nighthawks flew along the north shore of Lake Superior in a flickering stream at least twenty miles long. One Duluth birder counted fully 6,000 of them– literally a gift from above. I watched them drift along the shore as I rode in the car home from Port Wing, Wisconsin–the line never ended from beyond downtown to the far east side. That day there was also a huge emergence of dragonflies. The nighthawks darted along on wings improbably narrow for their uneven butterfly strokes, sometimes racing, sometimes just cruising, and occasionally swooping at the dragonflies for a quick aerial snack, as they embarked upon their arduous journey to Argentina.

Nighthawks migrate through Minnesota and Wisconsin from mid- August through September, and in late afternoon and early evening occasionally stream over in huge flocks like this. The silent flight is especially wonderful because only a few people ever notice it—it’s like an exotic secret right out in the open yet known only to a select few. The only requirement to enter this exclusive fraternity is the ability to look skyward. The flight occurs over wilderness and sooty cities both. After all, nighthawks are sophisticated, urban birds, nesting above penthouse apartments on the flat roofs of tall buildings, and dining out in the glare of downtown neon lights. A few holdouts still nest in burned over tracts of forests and gravelly pastures, but most of them have followed the example of humans and exchanged their traditional wilderness homes for the comforts of city life.

Nighthawks are uniquely adapted for their aerial lives. They have especially well-developed breast muscles for their long flights, and powerful face muscles for catching flying insects on the wing. Their feet are tiny—not only don’t they spend much time walking on the ground, but larger feet would make them less aerodynamic.

Nighthawks seldom feed at midday except when they have young on the nest—their niche is the evening sky, when moths and mosquitoes are astir. Most daytime sightings are of resting birds, sitting horizontally on a fence, a thick tree branch, or even a deck railing. Sometimes people mistake nighthawks for their close relative, the Whip-poor-will, as they sit, but it’s not hard to distinguish the two species—the nighthawk’s long, pointed wings extend beyond its tail as it rests, while the whip- poor-will’s round wings go only half-way down its tail. Although both species belong to the same family, and once were even classified in the same genus, the differences in their wings, and the nighthawk’s lack of rictal bristles on its face, convinced modern ornithologists to place the two species in different genera.

Like other urban inhabitants, nighthawks can be gluttonous. Ornithologists have counted more than 500 mosquitoes in the stomach of a single one, and 2,175 ants in the stomach of another. That’s a heck of a lot of bugs. Although they can pick up insects on the ground, their feeding technique on the wing is incomparable. They skim through the air on light wings, sweeping effortlessly through clouds of insects, their white wing crescents lighted by sunset and moonlight.

(Recording of a Common Nighthawk)