Nighthawks and Poorwills, birds of the night

From my series on hawks, falcons, and owls, reader “Silvertones” asks: “Could you do one in the future on Poor Wills and Common Nighthawks. They’ve always intrigued me with their falcon like wings and behavior that reminds me of bats. They swoop along the neighborhood streets and above the houses, and sit on the streets at night roused to sudden flight by the lights of the car.”

“Silvertones” made some good observations. Nighthawks, Poorwills, and Nightjars are a group of eight related species of birds that are cryptically colored for camouflage. They hunt insects by moonlight or in the twilight of dawn and dusk. Both Nightjars and Poorwills have large heads relative to body size.

Nighthawk Photo by Arlen Good Arizona-Sonora Desert Museum digital library

Nighthawk
Photo by Arlen Good
Arizona-Sonora Desert Museum digital library

The Common Nighthawk ( not really hawks) occurs all over the U.S. and southern Canada, but is apparently rare in southern Arizona. Instead, we have the Lesser Nighthawk which is found in all Sonoran Desert habitats. The third Nighthawk occurs in the Antilles, in the West Indies. The Arizona-Sonora Desert Museum (ASDM) describes Nighthawks as follows:

“Nighthawks have large eyes, tiny bills, huge gapes, and short legs. They are 8-9 inches in size and are identified in flight by a white wing bar and pointed wings. Nighthawks are insect-eaters. The Nighthawk flies low, silently and gracefully, searching the sky for flying insects, and maneuvering quickly, almost like a bat. These birds are crepuscular, needing some light to hunt by. City lights may extend the activity of the more urban Nighthawk and also attract its prey. Lesser Nighthawks may also be seen until midmorning.”

See more information from the Cornell Lab of Ornithology including sound recordings here.

Common Poorwills, are one of five species of Nightjars. They occur in the western U.S. and are related to the Whip-poor-will which is most abundant east of the Mississippi River. However, the Sibley Guide to Birds shows that Whip-poor-wills also occur in southern Arizona and southern New Mexico. ASDM decribes Poorwills as follows:

“Poorwills have large eyes, tiny bills, huge gapes, and short legs. They have rounded wings (7-8½ inches) and no white bar. Poorwills are insect-eaters. A hunting Poorwill sits on open ground, looking up into the sky for the backlit silhouettes of large moths or beetles. When it spots something, it flutters up, usually no higher than ten feet, and catches the insect in its mouth. These birds are crepuscular, needing some light to hunt by. Poorwills like hunting by moonlight (they’re lunarphilic) and on these nights they take over the niche of the lunar-phobic, insect-eating bat. During the day, Poorwills rest on the ground or horizontally on a branch, well camouflaged by their cryptic coloration. During winter, Poorwills may migrate too. But they may also hibernate, greatly lowering body temperature, respiration, and heart rates for days, even months, at a time. This behavior is very unusual in birds — hummingbirds enter torpor, but only for one night. The first documented hibernating Poorwill was found in the Sonoran Desert, in a hollow in a rocky canyon. Its discoverer tried to find signs of life in this apparently dead bird by catching the condensation of its breath on a mirror, but failed. Ten days later, the bird still hadn’t moved, but when the man touched it, the bird winked at him.”

See more information from the Cornell Lab of Ornithology including sound recordings here.

ASDM calls Nightjars the “birds of mystery.” They are well-camouflaged in shades of brown and gray, sleep usually on the ground during the day, and fly about at night seeking insects.

See also:

Western Screech Owl

Barn Owls

The American Kestrel

Playing with Harris’ Hawks

3 Comments on "Nighthawks and Poorwills, birds of the night"

  1. SilverTones | August 18, 2013 at 7:37 am |

    Aw shucks Jonathan. Thanks for being responsive to a reader’s interest and writing this interesting article. I even learned a new word from this one…”lunarphilic”. I know summer is here when we see the nighthawks swooping around. My neighborhood has lots of poorwills sitting in the roads ast night but the glimpse one gets of them is brief.

  2. Colt Cassidy | August 18, 2013 at 8:04 am |

    I Googled the “Whip Poor Will” call, and I’ve definitely heard it early in the morning just before sunrise. However, nothing beats the call of the Mockingbird! Excellent articles on Arizona’s birds, Jonathan.

  3. The Common Nighthawk was selected by the American Birding Association as its 2013 Bird of the Year. You can read much more about that species and its relatives at http://birdaz.com/blog/category/2013-aba-bird-of-the-year/ .

Comments are closed.