Mexican Whip-poor-will

The Mexican Whip-poor-will (Antrostomus arizonae) is a cryptically patterned nightjar native to the mountainous regions of the southwestern United States and Mexico. Once considered the same species as the Eastern Whip-poor-will, it was recognized as a distinct species in 2010 due to profound differences in vocalizations, genetics, and morphology. Like all nightjars, this species is strictly nocturnal, spending its days roosting on the forest floor or along horizontal tree branches where its highly intricate, leaf-like plumage makes it virtually invisible to predators. At dusk, it emerges to hunt flying insects with remarkable agility.

Identifying a Mexican Whip-poor-will visually is highly challenging due to its nocturnal habits and exceptional camouflage. Key field marks include its mesmerizing, mottled tapestry of gray, brown, black, and buff plumage, adorned with a tawny-to-buff collar on the back of the neck. It features a large, flattened head with huge dark eyes and an extremely small bill that opens into an enormous, cavernous mouth fringed with long, stiff rictal bristles. In flight, males show large white patches on the outer tips of their tail feathers, whereas females show narrower, buffy tips. To distinguish it from the Eastern Whip-poor-will, remember that the Mexican species has a slightly warmer-toned throat bib, a slightly longer tarsus, and is best separated by its rougher voice and distinct southwestern mountain range. To distinguish it from the Common Poorwill, note that the Poorwill is much smaller and lacks the long tail.

The Mexican Whip-poor-will is primarily a breeding resident of mid- to high-elevation montane woodlands. It strongly favors mountainous pine-oak forests, mixed conifer-hardwood forests, and rugged canyons lined with oak, sycamore, and Arizona madrone, typically residing at elevations between 1,200 and 3,000 meters (4,000 to 10,000 feet). Its breeding range extends from southern California, southern Nevada, Utah, Arizona, and New Mexico southward through the highland forests of Mexico into Honduras. While populations in the southwestern United States are migratory, heading south to winter in Mexico and Central America, populations residing in central and southern Mexico are generally year-round residents.

The behavior of the Mexican Whip-poor-will is deeply adapted to the night. Its song is a repetitive, rolling, husky 'whip-poor-will' chant that is lower-pitched, rougher, and more burry than the clean, whistling song of the Eastern Whip-poor-will. It sings continuously on moonlit nights from elevated branches. Foraging occurs during twilight or overnight, utilizing a sallying technique where the bird flies upward from a perch or the ground to snare flying moths and beetles in its wide gape before returning to rest. Breeding occurs on the forest floor with no formal nest structure. The female lays a clutch of two pale, lightly splotched eggs directly on thick leaf litter, typically tucked beneath overhanging brush. Both parents share incubation duties, often timing hatching with the bright nights of the lunar cycle when food is easiest to capture.