A mystery dispelled: The lesser nighthawk
Named under false pretenses, the nighthawk is actually not a hawk, nor strictly nocturnal in nature, nor "less significant," than any other nighthawk. It is a spectacular aerial acrobat with the distinguishing characteristic of being nearly invisible, even to most naturalists.
The nighthawk is taxonomically found in the family Caprimulgidae, which can be translated from its Latin base to mean "goat milkers." This claim is traced back to ancient times when unknowing goat herders observed nighthawks flying above their goats in the late evening with their large mouths agape and believed the birds were stealing milk. This phenomenon can still be observed in certain areas of the globe, but it is more accurately recognized today as nighthawk foraging behavior: eating aerial insects flushed from the ground by movements of the goat herd.
The lesser nighthawk claims a secretive and enigmatic lifestyle at Site 300. This bird is rarely observed, flying well below the avian radar in stark contrast to more glamorous species, such as the Western bluebird, which is hard to miss with its bright plumage and plentiful numbers. Read on to test your knowledge base of the lesser nighthawk and its unique life history.
Physical description The adult lesser nighthawk averages 20 centimeters in length, has a short bill and is camouflage colored. The upper parts of the body have brown/gray and cream patterning. The bird has dark bars that run across its stomach and chest that break-up its silhouette. The wings also are dark in color with bold stripes near the tip that can only be seen when in flight. The tail has thin grayish–white bars crossing the top. An adult male will usually have a white throat, while the female will have a buff– or tan–colored throat.
Geographic range Lesser nighthawks are found seasonally in a limited portion of the United States. They breed in small numbers in isolated parts of California (e.g., the interior coast ranges) and Nevada; larger populations occur in southern New Mexico, Arizona and Texas. From the Mexican border to the San Joaquin Valley, the bird is scarce. They migrate during the winter to the tropical areas of Brazil, Guatemala and Honduras.
Habitat type Lesser nighthawks prefer open, dry shrubland areas including desert valleys, prairies and sage scrub at lower elevations away from populous towns or cities. The relatively level topography with ephemeral water supplies provides airborne insects in a setting suitable for aerial hunting at night. Lesser nighthawk perching occurs at ground level on a flat scrape or rock. Disturbed birds will usually fly to a tree to perch temporarily. It has been noted that this species may become torpid (hibernate) when food availability drops or when temperatures cool below the average.
Voice A low volume, prolonged, tremolo whirring; very difficult to locate.
Reproduction Lesser nighthawks breed from early spring to mid–summer (May to June), which is typically later than other breeding bird species. An important site quality for a nesting nighthawk is seclusion from human disturbance. The birds rely on their cryptic plumage (which resembles soil, bark or leaves) for protection from predators. Males attract females using a series of calls. During courtship flight display, the male may pursue the female close to the ground, while flashing his white throat patch.
The females usually lay two light gray, speckled eggs in a nest constructed on the ground. The female will incubate the eggs for 18-20 days. Once hatched, the mother brings food to the nestling nighthawks.
Food habits The lesser nighthawk is largely nocturnal, but may be seen at dusk on occasion. It hunts its insect prey by contour flying — flying low above the canopy of trees or the brush and grass of open plains areas. It can range quite far from its roost site during nighttime forays for food. The diet of the lesser nighthawk includes small insects such as winged ants, mosquitoes, beetles, moths and grasshoppers. Studies have documented more than 500 mosquitoes in the stomach of one nighthawk.
Lesser nighthawks can provide invaluable assistance in keeping the local insect population under control. Any or all nighthawks seen goat milking should be meticulously photographed.
