Common nighthawk
The common nighthawk or bullbat is a medium-sized crepuscular or nocturnal bird of the Americas within the nightjar family, whose presence and identity are best revealed by its vocalization. Typically dark, displaying cryptic colouration and intricate patterns, this bird is difficult to spot with the naked eye during the day. This bird is most conspicuous when in its buoyant and erratic flight. The most remarkable feature of this aerial insectivore is its small beak that belies the massiveness of its mouth. Some claim appearance similarities to owls. With its horizontal stance and short legs, the common nighthawk does not travel frequently on the ground, instead preferring to perch horizontally, parallel to branches, on posts, on the ground or on a roof. The males of this species may roost together but the bird is primarily solitary. The common nighthawk shows variability in territory size.
This caprimulgid has a large, flattened head with large eyes; facially it lacks rictal bristles. The common nighthawk has long slender wings that at rest extend beyond a notched tail. There is noticeable barring on the sides and abdomen, also white wing-patches.
The common nighthawk measures long, displays a wing span of weighs, and has a life span of 4 to 5 years.
Names and etymology
The term "nighthawk", first recorded in the King James Bible version of 1611, was originally a local name in England for the European nightjar. Its use in the Americas referring to members of the genus Chordeiles and related genera was first recorded in 1778.The common nighthawk is sometimes called a "bull-bat", due to its perceived "bat-like" flight, and the "bull-like" boom made by its wings as it pulls from a dive.
They, in addition to other nightjars, are also sometimes called "bugeaters", for their insectivore diet. The common nighthawk is likely the reason that Nebraska's state nickname was once the "Bugeater State", and its people were known as "bugeaters". The Nebraska Cornhuskers college athletic teams were also briefly known the Bugeaters, before adopting their current name, which was also adopted by the state as a whole. A semi-professional soccer team in Nebraska, Nebraska Bugeaters FC, now uses the moniker.
Taxonomy
The common nighthawk was given the binomial name Caprimulgus minor in 1771 by the German naturalist Johann Reinhold Forster based the "whip-poor-will" that was described and illustrated by the English naturalist Mark Catesby in his book The Natural History of Carolina, Florida and the Bahama Islands. The type locality is South Carolina. The common nighthawk is now one of six nighthawks placed in the genus Chordeiles that was introduced by William Swainson in 1832. The genus name Chordeiles is from Ancient Greek khoreia, a dance with music, and deile, "evening". The specific minor is Latin for "smaller".The American Ornithologists' Union treated the smaller Antillean nighthawk as conspecific with the common nighthawk until 1982.
Up until the early 19th century, the common nighthawk and the whip-poor-will were thought to be one species. The latter's call was explained as the nocturnal expression of the common nighthawk. Alexander Wilson, "The Father of American Ornithology", correctly made the differentiation between the two species.
Subspecies
Nine subspecies are recognised:- C. m. minor – : breeds from south east Alaska to Vancouver Island, British Columbia, Canada, and south Canada/northern United States to Virginia, North Carolina, Georgia and Oklahoma. The darkest subspecies.
- C. m. hesperis – Grinnell, 1905: breeds in south west Canada, the western interior of United States. It is darker than sennetti and paler and less cinnamon than henryi.
- C. m. sennetti – Coues, 1888: breeds in the north Great Plains: east Montana, south Saskatchewan, Manitoba, southwards to North Dakota, Minnesota and Iowa. It is the palest of the subspecies.
- C. m. howelli – Oberholser, 1914: breeds in west central United States. It is darker than sennetti and paler and less cinnamon than henryi.
- C. m. henryi – Cassin, 1855: breeds from south east Utah and south west Colorado through mountains of west Texas, Arizona and New Mexico to east Sonora, Chihuahua, and Durango. It is unique with ochraceous to deep cinnamon feather edges on upperparts.
- C. m. aserriensis – Cherrie, 1896: breeds from south central Texas to north Mexico. It is darker than sennetti and paler and less cinnamon than henryi.
- C. m. chapmani – Coues, 1888: breeds from southeast Kansas to east North Carolina and southwards to south east Texas and south Florida. It is the darkest of the subspecies.
- C. m. neotropicalis – Selander & Álvarez del Toro, 1955: breeds in south Mexico and Honduras
- C. m. panamensis – Eisenmann, 1962: breeds on the Pacific slope of Panama and north west Costa Rica. Winters in South America
History
In the late 19th and early 20th centuries, because their name contained the word "hawk", they had habits of diurnal insect hunting, and they travelled in migrating flocks, they were hunted for sport and nourishment and because they were seen as predators.
Description
The common nighthawk is distinguished from other caprimulguids by its forked tail ; its long, unbarred, pointed wings with distinctive white patches; its lack of rictal bristles, and the key identifier – their unmistakable calls. These birds range from in total length and from in wingspan. Body mass can vary from. Among standard measurements, the wing chord is, the tail is, the bill is and the tarsus is.The common nighthawk resembles both the Antillean nighthawk and the lesser nighthawk and occurs at least seasonally in the entire North American range of both of these species. The lesser nighthawk is a smaller bird and displays more buffy on the undertail coverts, where the common nighthawk shows white. Common nighthawks and Antillean nighthawks exhibit entirely dark on the basal portion of the primary feathers, whereas lesser nighthawks have bands of buffy spots. Common and Antillean nighthawks have a longer outermost primary conveying a pointier wing tip than the lesser nighthawk. The common nighthawk forages higher above ground than the lesser nighthawk and has a different call. The only reliable way to distinguish Antillean nighthawk without disturbance is also by the differences in their calls. Visually, they may only be distinguished as different from the common nighthawk once in the hand. Subtle differences are reported to be a challenge in field identification.
Molt
All bodily plumage and rectrices are replaced in the post-juvenile molt. This moult commences in September at the breeding grounds; the majority of the body plumage is replaced but wing-coverts and rectrices are not completed until January–February, once the bird arrives at the wintering grounds. There is no other molt prior to the annual molt of the adult. Common nighthawk adults have a complete molt that occurs mostly or completely on wintering grounds and is not completed until January or February.Distribution and habitat
The common nighthawk may be found in forests, desert, savannahs, beach and desert scrub, cities, and prairies, at elevations of sea level or below to. Nighthawks prefer to nest in edge and early successional habitats, making them one of only a handful of birds which will live and hunt in burned or clearcut patches of forest. The common nighthawk is drawn into urban built-up areas by insects.The common nighthawk is the only nighthawk occurring over the majority of northern North America.
Food availability is likely a key factor in determining which and when areas are suitable for habitation. The common nighthawk is not well adapted to survive in poor conditions, specifically low food availability. Therefore, a constant food supply consistent with warmer temperatures is a driving force for migration and ultimately survival.
It is thought that the bird is not able to enter torpor, although recent evidence suggests it does.
Migration
During migration, common nighthawks may travel. They migrate by day or night in loose flocks, frequently numbering in the thousands; flocks have not been observed with a visible leader. The enormous distance travelled between breeding grounds and wintering range is one of the North America's longer migrations. The northbound journey commences at the end of February and the birds reach destinations as late as mid-June. The southbound migration commences mid-July and reaches a close in early October.While migrating, these birds have been reported travelling through middle America, Florida, the West Indies, Cuba, the Caribbean and Bermuda, finally completing their journey in the wintering grounds of South America, primarily Argentina.
As aerial insectivores, the migrants will feed en route, congregating to hunt in marshes, rivers and on lakeshores. In Manitoba and Ontario, Canada, it is reported that during migration the nighthawks are seen most commonly in the late afternoon, into the evening, with a burst of sunset feeding activities.
Additionally, it has been noted that during migration the birds may fly closer to the ground than normal; possibly foraging for insects. There is speculation that feeding also occurs at higher altitudes.
The common nighthawk winters in southern South America, but distribution in this range is poorly known due to difficulties in distinguishing the bird from the lesser nighthawk and in differentiating between migrants and overwintering birds. In some South and Central American countries, a lack of study has led to restricted and incomplete records of the bird. Records do support wintering in Ecuador, Peru, Bolivia, Brazil, Paraguay, Uruguay and Argentina.