On the wild side—June, 2012
by Tina Mitchell
Among the last species of breeding birds to arrive from their winter grounds in South America, Common Nighthawks zip and zoom through our dusk and dawn skies starting in late May and early June. They settle primarily in open pinyon/juniper and ponderosa pine woodlands, scrub oak, sagebrush, and shortgrass prairies, although they can be found as high as timberline. A very interesting-looking brown bird, should you ever see it up close, a nighthawk has a big head with large eyes set on each side; its small bill opens to reveal a huge mouth; and it has short legs and weak feet. The precise coloring of nighthawks varies with the predominant color of the region’s soil. For example, they appear grayer or buffier in our area; in the southwest, they look more reddish brown. (The photo on the left was taken on our property in Coaldale.) This cryptic coloring provides amazing camouflage to protect against predators—or even harmless viewing by a human. If you don’t see a nighthawk fly in and land, I dare you to spot one roosting lengthwise on a limb or resting on the bare ground. Males and females look very similar, although in flight, you might notice that the male has a white tail band (which females typically don’t have) and a more distinct white streak at the throat (which is a buffier color in females). Again, though, good luck spotting those differences as the birds flutter and soar hundreds of feet above you in the darkening evening sky.
Indeed, a nighthawk’s bounding, erratic flight and long, pointed wings make it nearly unmistakable in flight. Since it feeds primarily while in flight, it spends a lot of time in the air as evening falls or dawn begins to break the darkness. Although its huge gaping mouth enables it to gobble down large moths mid-flight, it also scoops up just about any insect flying at twilight—even winged stages of ants, small flies, and mosquitoes. (Hurrah for nighthawks!)
Even if you can’t see them, you can often hear a Common Nighthawk’s buzzy “peeent” call in flight. A male Common Nighthawk makes himself known in a second way. From a moderate height, he dives straight toward the ground. As he pulls up from the dive, air rushing through his flight feathers creates a booming “roar” that sounds very non-bird-like. If you’ve been outside on a summer evening as the sun sets, you most likely have heard—and wondered about!—this unusual noise. The first time my husband and I camped on our property in Coaldale, we thought we were hearing a mountain lion. (Yes, we were real city folks…) A couple of weeks later, while I was playing a tape of night sounds in my car, imagine my surprise when this booming roar issued from my car speakers! Mystery solved (and campers relaxed). This dive is part courtship, part territorial defense, part who knows what else.
Once the birds arrive on their breeding grounds, they waste little time getting started with nesting. The “nest” is a nest in function only—a clutch of (typically) 2 eggs rest on the bare ground, almost perfectly blending in with the soil and rocks in the area (as does the incubating female). The eggs hatch after 3 weeks; the young sit quietly near the nest, blending in like chameleons, and are fed by regurgitation by both parents. First flight for the youngsters comes around 21 days after hatching, and the kids can feed themselves independently as early as 25 days after hatching.
The Common Nighthawk’s scientific name is Chordeiles minor. The genus name refers to the nighthawk’s twilight call: khorde (from Greek) refers to a chord or note of a lyre; and deile, evening. Assigned when very few species had been documented, the species name, minor, reflected the fact that this species was smaller than the only other known member of this family at the time, the European nightjar. (Today, a smaller member of the Chordeiles genus can be found in the U.S.—the Lesser Nighthawk. So much for “minor.”) The “common” part of the popular name derives from the fact that it is, indeed, the most common nighthawk in the U.S.; “night,” from its hunting as night falls. “Hawk,” though, is a misnomer, since it is not a hawk at all—but that term may also derive from Anglo-Saxon hafoc, which was the name for this bird in that language.
Greek folklore held that birds in this avian family would come to small groups of goats in the evening and suck milk from them. We now know that these birds flew near the ground to feed on insects stirred up by the goats. This behavior occurs more often among the smaller but similar-looking nightjars (e.g., Common Poorwill, Chuck-will’s-widow), which chase insects by fluttering up from the ground, than among nighthawks, which feed on the wing. Nevertheless, nighthawks and nightjars are sometimes collectively referred to as “goatsuckers.” In fact, the scientific name for this family group is Caprigmulgidae, meaning “goat milker.” Really. You can’t make this stuff up…
You can read more about Common Nighthawks and hear a clip of its calls and the “roar” here.