Watching male common nighthawks perform their aerial courtship displays near my home recently, reminded me of the summers that I conducted my undergraduate and graduate wildlife research work on the Great Plains of North Dakota. I was constantly observing nighthawks throughout the expansive grasslands and prairie pothole landscape.
The acrobatic common nighthawk is perfectly adapted to their mostly aerial way of life. Highly maneuverable and silent on the wing, their erratic flight, though seemingly ungainly looking, is incredibly effective at what they do best — capturing flying insects.
A crepuscular bird, which are birds most active at both dawn and dusk, and sometimes during moonlit nights, nighthawks take flight to begin feeding during peak insect activity. During the daytime these nearly invisible birds remain somewhat sedentary, hiding in thickets on the forest floor, in woodlots, and sometimes in a comfortable roost on a stout branch of a tree.
As the bird sits quietly and blends into its surroundings of leaf litter or the bark of a limb, they truly are almost impossible to see.
The nighthawk’s plumage of mostly brown and black feathers, along with gray and white flecks throughout, is about as cryptic as any bird I know of. Only twice in my life have I enjoyed close encounters with different nighthawks. One bird was nestled within the lower branches of a tree that I stood beside, and didn’t notice until I had been standing there for a while.
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Another time it was a female, which I almost stepped on before I spotted her, sitting in her ground-nest of eggs. She never moved as I stood nearby observing her and taking photographs.
Possessing short legs, small feet, and small bills, nighthawks, which are about 10 inches long with about a two-foot wingspan, make up for these anatomical shortcomings with large heads and enormous mouths.
It is this last feature that equips nighthawks so wonderfully well for the lifestyles they lead (large mouths make it easier for them to capture insects!).
Most of their prey is flying insects such as moths and mosquitoes, so having large and wide mouths enable these acrobatic and graceful flyers to easily capture insects on the wing. Additionally, nighthawks and most other caprimulgiform birds, such as whip-poor-wills, have long bristles that grow around their bills. The bristles assist the birds in catching insects as well as protecting their eyes from ill-timed encounters with insects.
When looking at a field guidebook of birds, nighthawks and its kin look nearly identical. But subtle differences separate the species if you look closer. While the whip-poor-will, for example, has moderately broad and rounded wings, the nighthawk flutters about on long and pointed, white-barred wings.
For sure, the nighthawk’s silhouette, which is very raptor-like, nearly that of a falcon, is often mistaken for a bird-of-prey. As such, its name is really a misnomer; for the nighthawk is neither a true nocturnal bird nor is it, of course, a hawk or raptor.
In the spring of the year, male nighthawks perform aerial flight displays above their breeding grounds that are accompanied by loud “booming” sounds. They accomplish the sounds in a very unusual manner. When the male nighthawk reaches the proper altitude, he enters into an abrupt and very steep dive.
The courtship flight display of male nighthawks, mentioned earlier, is fascinating both visually and audibly. As a diving nighthawk nears the earth from substantial heights to begin with, he bends his wings downward just seconds before coming out of his dive.
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Loud “booms” or “clap-like” sounds are produced as air rushes through the tips of his wings. He performs his aerial acrobatics repeatedly. Indeed, their performances are as remarkable and entertaining avian antics as they come.
We are fortunate to have common nighthawks as summer residents here in northern Minnesota. After the breeding and nesting season is completed, they will depart on their long migrations as far away as the Bahamas and South America.
However, at least for a while yet, common nighthawks, flying in the early morning or late evening skies somewhere near you, are either visible above or invisible below, as we get out and enjoy the great outdoors.
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