Blane Klemek: Common nighthawks are perfectly adapted to their way of life
I spent a fair amount of time in late July-early August picking blueberries. The crop was about as good as I’ve ever seen it. Blueberries were hanging heavy and sometimes in clusters of a dozen or more fat berries. It was outstanding picking.
The hours after work spent methodically picking the tasty berries were relaxing and very enjoyable. After a long day in the office or field, I looked forward to a few hours of doing nothing but picking blueberries and watching wildlife, particularly birds. One such common avian observation was the nightly aerial acrobatics of dozens of common nighthawks.
The birds were constantly darting about and undoubtedly chasing and feeding on a host of flying insects. They also seemed to engage in playful antics with one another, sometimes chasing and dodging each other in aerial games that suggested a sort of avian tag. And often in what I assumed were male nighthawks, they would perform steep dives that would cause air to pass through their wings in such a way to cause a strange rushing sound.
Watching the nighthawks reminded me of a time many years ago when I commented to my young boy while we enjoyed an outdoor evening excursion together and having just seen a lone nighthawk, about how I just didn’t seem to observe many nighthawks anymore. I recounted for him my summers working on the Great Plains and having the occasional opportunity to watch male nighthawks perform their interesting courtship flights above the rolling prairie grasslands.
Indeed, soon after we had observed the single nighthawk, we saw another. Also flying everywhere around us was an abundance of dragonflies. A few moments later we saw even more nighthawks, until, suddenly, everywhere we looked were flying nighthawks. It was remarkable; we were virtually surrounded by tens of dozens of hunting and foraging nighthawks.
I explained to my son that common nighthawks are perfectly adapted to their way of life. Highly maneuverable and silent on the wing, the birds’ erratic flight, though seemingly ungainly looking, is incredibly effective at what they do best — capturing flying insects while they themselves stay aloft, too.
A crepuscular bird, that is, 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.
The nighthawk’s plumage of mostly brown and black feathers, along with gray and white flecks throughout, is about as cryptic of any bird I know of. Twice, again in North Dakota, I had close encounters with different nighthawks on two separate occasions. One bird was nestled in the lower branches of a tree that I stood beside and didn’t notice it until I had been standing there for a while. Another was an incubating female, which I almost stepped on before I saw her.
Possessing short legs, small feet, and small bills, nighthawks, which are about 9½ inches long with about a 22-inch long wingspan, make up for these anatomical shortcomings with large heads and enormous mouths. It is for this last feature that equips nighthawks so wonderfully well for the lifestyles they lead.
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 any other raptor whatsoever.
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.
As the diving nighthawk nears the earth, he bends his wings downward just seconds before coming out of his dive. Loud “booms” or “clap-like” sounds are produced as air rushes through the tips of his wings. He performs his visual and auditory aerial acrobatics over and over again. It’s as fascinating an avian performance as they come.
We are fortunate to have nighthawks as summer residents here in northern Minnesota. After the breeding and nesting season is over, they will depart on their long migrations to as far away as the Bahamas and South America.
But in the meantime, at least for a while yet, common nighthawks, flying in the early morning or late evening summer sky somewhere near you, are fascinating birds to observe as we get out and enjoy the great outdoors.
(Klemek is a DNR Wildlife Manager. You can contact him at firstname.lastname@example.org.)