- 8.7–10.2 in
- 17.7–18.9 in
- 1.5–2.3 oz
- Smaller than a Chuck-will’s-widow; about the size of a Common Nighthawk.
- Engoulevent bois-pourri (French)
- Tapacamino cuerporruín-norteño (Spanish)
- Eastern Whip-poor-wills lay their eggs in phase with the lunar cycle, so that they hatch on average 10 days before a full moon. When the moon is near full, the adults can forage the entire night and capture large quantities of insects to feed to their nestlings.
- Eastern Whip-poor-will chicks move around as nestlings, making it difficult for predators to rob the nest. The parent may help by shoving a nestling aside with its foot, sometimes sending the young bird tumbling head over heels.
- The male Eastern Whip-poor-will often will investigate intruders near the nest by hovering in place with his body nearly vertical and his tail spread wide, showing off the broad white tips of the tail feathers.
- Eastern and Mexican Whip-poor-wills used to be considered one species, simply called the Whip-poor-will. But in 2011 they were split into two species based on differences in mitochondrial and nuclear DNA. Eastern Whip-poor-wills give faster, higher-pitched whip-poor-will calls and have more colorful eggs than their western counterparts.
- The Eastern Whip-poor-will may locate insects by seeing the bugs’ silhouettes against the sky. Its eyes have a reflective structure behind the retina that is probably an adaptation to low light conditions.
- The oldest recorded Eastern Whip-poor-will was 4 years old.
Eastern Whip-poor-wills breed in dry deciduous or evergreen-deciduous forest with little or no underbrush, close to open areas. The forest types they use include pine-oak with juniper, pine plantations, pine flatwoods, northern hardwood forests, low-elevation white pine, oak, aspen, birch, and scrubby woodlands with pitch pine, scrub oak, and hickory. They seem to avoid large tracts of uninterrupted forest with dense canopy. Their migration habitat is similar to their breeding habitat. In winter, Eastern Whip-poor-wills prefer broadleaf tropical or subtropical forest near open areas.
Eastern Whip-poor-wills feed exclusively on insects, including moths, scarab beetles, click beetles, long-horned grasshoppers, stoneflies, ground beetles, carrion beetles, tiger moths, ants, bees, wasps, fireflies, long-horned beetles, measuringworm moths, owlet moths, weevils, and scavenger beetles. They start foraging 30 minutes after sunset and continue until it gets too dark to see their prey. At first light they resume feeding, stopping about 40 minutes before sunrise. When the moon is bright enough, they may hunt all night long. During cold, rainy weather they will not try to forage. Whip-poor-wills perch in trees (or sometimes on the ground) and make short sallies to snag insects up to 15 feet off the ground, or they may stay out on longer insect-catching flights. Their enormous mouths allow them to swallow insects up to two inches long. They sometimes search rotten logs and leaves for ants, caterpillars, beetles, worms, and other insects.
- Clutch Size
- 2 eggs
- Number of Broods
- 1-2 broods
- Egg Length
- 1.1–1.3 in
- Egg Width
- 0.8–0.9 in
- Incubation Period
- 19–21 days
- Nestling Period
- 3–8 days
- Egg Description
- Cream-colored or grayish white, marbled with lavender-gray, yellowish-brown, or pale brown.
- Condition at Hatching
- Well developed and covered with orange-tan down, but with eyes closed.
Whip-poor-wills build no nest, though the weight of the incubating adult may eventually create a slight hollow in the leaf litter. Despite the absence of nest material, the eggs, nestlings, and adults are all so well camouflaged that they are extremely difficult to see.
The female Eastern Whip-poor-will lays her eggs directly on the leaf litter of the forest floor, usually on the north or northeast side of a small herb, shrub, or seedling that will shade the nest from the hot afternoon sun. Whip-poor-wills occasionally nest on bare ground, sand, or decayed wood. It’s not known whether males or females choose the site.
Eastern Whip-poor-wills are nocturnal birds with loud, distinctive voices. At night they fly slowly and silently, often wheeling around 180 degrees in between wing flaps. When nesting or roosting, whip-poor-wills spend the day sitting motionless, becoming active only at dusk. They can fly nearly vertically when chasing insects. They usually forage in the semidarkness of early morning and early evening, but on moonlit nights they chase moths and beetles all night long. Whip-poor-wills appear to time their nesting so that chicks will hatch about 10 days before the full moon, when the parents have more time (and moonlight) to catch food for them. They regurgitate insects for their nestlings, which may move from the nest site within days of hatching if a predator comes to call. At about eight days old, the young molt into highly camouflaged plumage and the female leaves them in the care of the male, often starting a new clutch of two eggs nearby within the territory. The male establishes and maintains his territory by calling along the perimeter and by chasing off intruders while making aggressive calls and hisses, with raised wings and mouth open. Males and females feign injury to lead predators away from the nest. Whip-poor-wills are generally solitary, forming loose flocks during migration.
Eastern Whip-poor-wills are still fairly common birds, but their numbers are in decline and parts of their range seem to have become unoccupied. Precise numbers for this nocturnal species are difficult to obtain through daytime surveys like the North American Breeding Bird Survey—people can contribute data via the Nightjar Survey Network. Overall numbers appeared stable in 1960–1980, but steep declines were recorded in Illinois, Pennsylvania, Tennessee, and Ontario. Partners in Flight estimates the global breeding population at 2 million with 95 percent living part of the year in the U.S., 5 percent breeding in Canada, and 43 percent wintering in Mexico. They rate a 14 out of 20 on the Continental Concern Score and are listed on the 2012 Watch List. This U.S.-Canada Stewardship species is also listed as a Common Bird in Steep Decline. The main problem Whip-poor-wills face is the loss of open-understory forests. This can come from conversion to crops, pasture, urbanization, or fire suppression leading to dense understories. Some habitat may be being created as abandoned farmland reverts to forest. Because Whip-poor-wills often fly over roads or sit on roadways while foraging, they are also vulnerable to collisions with cars.
Medium-distance migrant. Eastern Whip-poor-wills migrate to Mexico and Central America for the winter, apparently traveling mostly over land to get there. In spring they arrive in breeding grounds between late March and mid-May. Since they are less vocal in autumn we know less about their southward migration routes and timing, but they seem to leave between early September and late November. They may form loose flocks when they migrate.