Common nighthawk

Last updated

Common nighthawk
Common Nighthawk (14428313550).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: Strisores
Order: Caprimulgiformes
Family: Caprimulgidae
Genus: Chordeiles
Species:
C. minor
Binomial name
Chordeiles minor
Subspecies

See text

Chordeiles minor map.svg
Synonyms

Caprimulgus minor
Chordeiles virginianus

The common nighthawk or bullbat (Chordeiles minor) is a medium-sized [3] [4] crepuscular or nocturnal bird [3] [5] of the Americas within the nightjar (Caprimulgidae) family, whose presence and identity are best revealed by its vocalization. Typically dark [3] (gray, black and brown), [5] 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 [3] 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. [5] The males of this species may roost together but the bird is primarily solitary. The common nighthawk shows variability in territory size. [4]

Contents

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, [4] also white wing-patches. [3]

The common nighthawk measures 22 to 25 cm (8.7 to 9.8 in) long, [4] displays a wing span of 51 to 61 cm (20 to 24 in) [6] weighs 55 to 98 g (1.9 to 3.5 oz), [4] [6] and has a life span of 4 to 5 years. [4]

Names and etymology

In flight showing characteristic white wing bars Common nighthawk.jpg
In flight showing characteristic white wing bars

The genus name Chordeiles is from Ancient Greek khoreia, a dance with music, and deile, "evening". The specific minor is Latin for "smaller". [7]

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. [8]

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. [6]

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". [9] [10] [11] 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

Within the family Caprimulgidae, the subfamily Chordeilinae (nighthawks) are limited to the New World and are distinguished from the subfamily Caprimulginae, by the lack of rictal bristles.

The American Ornithologists' Union treated the smaller Antillean nighthawk as conspecific with the common nighthawk until 1982. [4]

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

There are 9 currently recognized subspecies: [12]

History

This species is recorded as widespread during the Late Pleistocene, from Virginia to California and from Wyoming to Texas. [4]

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. [6]

Field identification

Common nighthawk in British Columbia Chordeiles minor -British Columbia -Canada-8c.jpg
Common nighthawk in British Columbia

The common nighthawk is distinguished from other caprimulguids by its forked tail (includes a white bar in males); its long, unbarred, pointed wings with distinctive white patches; its lack of rictal bristles, and the key identifier – their unmistakable calls. [13] These birds range from 21 to 25 cm (8.3 to 9.8 in) in total length and from 51 to 61 cm (20 to 24 in) in wingspan. [14] Body mass can vary from 55 to 98 g (1.9 to 3.5 oz). Among standard measurements, the wing chord is 17.2 to 21.3 cm (6.8 to 8.4 in), the tail is 13 to 15.1 cm (5.1 to 5.9 in), the bill is 0.5 to 0.8 cm (0.20 to 0.31 in) and the tarsus is 1.2 to 1.6 cm (0.47 to 0.63 in).

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. [4]

Habitat and distribution

The common nighthawk may be found in forests, desert, savannahs, beach and desert scrub, cities, [3] and prairies, [4] at elevations of sea level or below to 3,000 m (9,800 ft). [3] 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. [15] The common nighthawk is drawn into urban built-up areas by insects. [5]

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.[ citation needed ]

It is thought that the bird is not able to enter torpor, [4] although recent evidence suggests it does. [13]

Migration

During migration, common nighthawks may travel 2,500 to 6,800 kilometres (1,600 to 4,200 mi). They migrate by day or night in loose flocks, frequently numbering in the thousands; [6] 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. [ citation needed ] 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. [4]

Common nighthawk in flight, near Miami, Florida Common Nighthawk2.JPG
Common nighthawk in flight, near Miami, Florida

While migrating, these birds have been reported travelling through middle America, Florida, the West Indies, [6] Cuba, the Caribbean and Bermuda, [4] finally completing their journey in the wintering grounds of South America, [6] [13] primarily Argentina. [13]

As aerial insectivores, the migrants will feed en route, [6] 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, [4] [5] with a burst of sunset feeding activities. [5]

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.[ citation needed ]

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. [4]

Molt

In the common nighthawk, 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. [13]

Behavior

Vocalization

There are no differences between the calls and song of the common nighthawk. The most conspicuous vocalization is a nasal peent or beernt during flight. Peak vocalizations are reported 30 to 45 minutes after sunset. [ citation needed ]

A croaking auk auk auk is vocalized by males while in the presence of a female during courtship. Another courtship sound, thought to be made solely by the males, is the boom, created by air rushing through the primaries after a quick downward flex of the wings during a daytime dive.

In defense of their nests, the females make a rasping sound, and males clap their wings together. [16] Strongly territorial males will perform dives against fledglings, females, and intruders such as humans or raccoons. [4]

Feeding and diet

Frequent flyers, the long-winged common nighthawk hunts on the wing [13] for extended periods at high altitudes or in open areas. [5] Crepuscular, flying insects are its preferred food source. The hunt ends as dusk becomes night, and resumes when night becomes dawn. [13] Nighttime feeding (in complete darkness) is rare, [4] even on evenings with a full moon. [13] The bird displays opportunistic feeding tendencies, although it may be able to fine-tune its meal choice in the moments before capture. Common nighthawks have been shown to prefer eating Coleopterids (beetles) and Hymenopterids (bees, ants, and wasps), seeking these insects out in their habitats. [17] While the most common type of insects in their diets are Lepidopterans (butterflies and moths), they actively avoid eating Dipterids (flies). [17]

Vision is presumed to be the main detection sense; no evidence exists to support the use of echolocation. The birds have been observed to converge on artificial light sources in an effort to forage for insects enticed by the light. [4] The average flight speed of common nighthawks is 23.4 km/h (14.5 mph). [18]

Drinking

The common nighthawk was observed to drink on its winter range by flying extremely low over the surface of the water. [19]

Waste excretion

The common nighthawk is recognized to discharge feces around nest and roosting positions. The bird will sporadically defecate in flight. The defecation is pungent. [4]

Reproduction and nesting

The common nighthawk breeds during the period of mid-March to early October. [6] It most commonly has only one brood per season, however sometimes a second brood is produced. The bird is assumed to breed every year. Reuse of nests by females in subsequent years has been reported. [4] A monogamous habit has also recently been confirmed. [13]

Courting and mate selection occur partially in flight. The male dives and booms (see Vocalization) in an effort to garner female attention; [4] [5] the female may be in flight herself or stationary on the ground.

Copulation occurs when the pair settles on the ground together; the male with his rocking body, widespread tail wagging and bulging throat expresses guttural croaking sounds. This display by the male is performed repeatedly until copulation. [4]

The preferred breeding/nesting habitat is in forested regions with expansive rocky outcrops, in clearings, in burned areas [5] or in small patches of sandy gravel. [4] The eggs are not laid in a nest, but on bare rock, gravel, [5] or sometimes a living substrate such as lichen. [4] Least popular are breeding sites in agricultural settings. [20] As displayed in the latter portion of the 20th century, urban breeding is in decline. [5] If urban breeding sites do occur, they are observed on flat gravel rooftops.

It is a solitary nester, putting great distances between itself and other pairs of the same species, but a nest would more commonly occur in closer proximity to other species of birds.

Females choose the nest site and are the primary incubators of the eggs; males will incubate occasionally. Incubation time varies but is approximately 18 days. The female will leave the nest unattended during the evening in order to feed. The male will roost in a neighbouring tree (the spot he chooses changes daily); he guards the nest by diving, hissing, wing-beating or booming at the sites. In the face of predation, common nighthawks do not abandon the nest easily; instead they likely rely on their cryptic colouration to camouflage themselves. If a departure does occur, the females have been noted to fly away, hissing at the intruder [4] or performing a disturbance display. [13]

Incubation, hatching and young

The eggs are elliptical, strong, and variably coloured with heavy speckling. The common nighthawk lays two 6–7 g (0.21–0.25 oz) eggs per clutch; the eggs are laid over a period of 1 to 2 days. [ citation needed ] The female alone displays a brood patch.

The chicks may be heard peeping in the hours before they hatch. Once the chicks have broken out of the shells, the removal of the debris is necessary in order to avoid predators. The mother may carry the eggshells to another location or consume a portion of them. Once hatched, the nestlings are active and have their eyes fully or half open; additionally they display a sparing cover of soft down feathers. The chicks are semi-precocial. By day 2, the hatchlings' bodily mass will double and they will be able to self-propel towards their mother's call. The young will hiss at an intruder.

The young are fed by regurgitation before sunrise and after sunset. The male parent assists in feeding fledglings and will also feed the female during nesting. No records exist to support a parent's ability to physically carry a chick.

On their 18th day, the young will make their first flight; by days 25–30, they are flying proficiently. The young are last seen with their parents on day 30. Complete development is shown between their 45–50th day. At day 52, the juvenile will join the flock, potentially migrating. Juvenile birds, in both sexes, are lighter in colour and have a smaller white wing-patch than adult common nighthawks. [4]

Predators

Like other members of the caprimulgid clan, the nighthawk's ground nesting habits endanger eggs and nestlings to predation by ground carnivores, such as skunks, raccoons and opossums. [21] Confirmed predation on adults is restricted to domestic cats, golden eagles, and great horned owls. [22] Peregrine falcons have also been confirmed to attack nighthawks as prey, although the one recorded predation attempt was unsuccessful. [23] Other suspected predators are likely to attack them, such as dogs, coyotes, foxes, hawks, American kestrels, [24] owls, crows and ravens, and snakes. [25]

Status and conservation

There has been a general decline in the number of common nighthawks in North America, but some population increases also have occurred [4] in other geographical locations. [13] The bird's large range makes individual risk thresholds in specific regions difficult to establish. [1] In Ontario, the common nighthawk is rated as a species of special concern. [26]

The Common nighthawk's trait of being a ground-nesting bird makes it particularly susceptible to predators, some of which include domestic cats, ravens, snakes, dogs, coyotes, falcons and owls.

Lack of flat roofs, pesticides, [4] increased predation and loss of habitat [13] are noted factors of their decline. Further unstudied potential causes of decline include climate change, disease, road kills, man-made towers (posing aerial hazards), and parasites. [4]

The absence of flat roofs (made with gravel) in urban settings is an important cause of decline. In an effort to provide managed breeding areas, gravel pads have been added in the corners of rubberized roofs; this proves acceptable, as nesting has been observed. [13]

Related Research Articles

<span class="mw-page-title-main">Common swift</span> Species of bird

The common swift is a medium-sized bird, superficially similar to the barn swallow or house martin but somewhat larger, though not stemming from those passerine species, being in the order Apodiformes. The resemblances between the groups are due to convergent evolution, reflecting similar contextual development. The swifts' nearest relatives are the New World hummingbirds and the Southeast Asian treeswifts.

<span class="mw-page-title-main">Red-winged blackbird</span> Species of bird in North and Central America

The red-winged blackbird is a passerine bird of the family Icteridae found in most of North America and much of Central America. It breeds from Alaska and Newfoundland south to Florida, the Gulf of Mexico, Mexico, and Guatemala, with isolated populations in western El Salvador, northwestern Honduras, and northwestern Costa Rica. It may winter as far north as Pennsylvania and British Columbia, but northern populations are generally migratory, moving south to Mexico and the Southern United States. Claims have been made that it is the most abundant living land bird in North America, as bird-counting censuses of wintering red-winged blackbirds sometimes show that loose flocks can number in excess of a million birds per flock and the full number of breeding pairs across North and Central America may exceed 250 million in peak years. It also ranks among the best-studied wild bird species in the world. The red-winged blackbird is sexually dimorphic; the male is all black with a red shoulder and yellow wing bar, while the female is a nondescript dark brown. Seeds and insects make up the bulk of the red-winged blackbird's diet.

<span class="mw-page-title-main">Montagu's harrier</span> Species of bird

Montagu's harrier (Circus pygargus) is a migratory bird of prey of the harrier family. Its common name commemorates the British naturalist George Montagu.

<span class="mw-page-title-main">Nighthawk</span> Subfamily of birds

The nighthawk is a nocturnal bird of the subfamily Chordeilinae, within the nightjar family, Caprimulgidae, native to the western hemisphere. The term "nighthawk", first recorded in the King James Bible of 1611, was originally a local name in England for the European nightjar. Its use in the Americas to refer to members of the genus Chordeiles and related genera was first recorded in 1778.

<span class="mw-page-title-main">Gadwall</span> Species of bird

The gadwall is a common and widespread dabbling duck in the family Anatidae.

<span class="mw-page-title-main">Killdeer</span> Shorebird found in the Americas

The killdeer is a large plover found in the Americas. It gets its name from its shrill, two-syllable call, which is often heard. It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae. Three subspecies are described. Its upperparts are mostly brown with rufous fringes, the head has patches of white and black, and two black bands cross the breast. The belly and the rest of the breast are white. The nominate subspecies breeds from southeastern Alaska and southern Canada to Mexico. It is seen year-round in the southern half of its breeding range; the subspecies C. v. ternominatus is resident in the West Indies, and C. v. peruvianus inhabits Peru and surrounding South American countries throughout the year. North American breeders winter from their resident range south to Central America, the West Indies, and the northernmost portions of South America.

<span class="mw-page-title-main">Rough-legged buzzard</span> Species of bird

The rough-legged buzzard (Europe) or rough-legged hawk is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter. It was traditionally also known as the rough-legged falcon in such works as John James Audubon's The Birds of America.

<span class="mw-page-title-main">Ruby-throated hummingbird</span> Species of bird

The ruby-throated hummingbird is a species of hummingbird that generally spends the winter in Central America, Mexico, and Florida, and migrates to Canada and other parts of Eastern North America for the summer to breed. It is the most common hummingbird in eastern North America, having population estimates of about 35 million in 2021.

<span class="mw-page-title-main">Broad-winged hawk</span> Species of bird

The broad-winged hawk is a medium-sized hawk of the genus Buteo. During the summer, some subspecies are distributed over eastern North America, as far west as British Columbia and Texas; they then migrate south to winter in the Neotropics from Mexico south to southern Brazil. Other subspecies are all-year residents on Caribbean islands. As in most raptors, females are slightly larger than males. Broad-winged hawks' wings are relatively short and broad with a tapered, somewhat pointed appearance. The two types of coloration are a dark morph with fewer white areas and a light morph that is more pale overall. Although the broad-winged hawk's numbers are relatively stable, populations are declining in some parts of its breeding range because of forest fragmentation.

<span class="mw-page-title-main">Wood thrush</span> Species of bird

The wood thrush is a North American passerine bird in the family Turdidae and is the only species placed in the genus Hylocichla. It is closely related to other thrushes such as the American robin and is widely distributed across North America, wintering in Central America and southern Mexico. The wood thrush is the official bird of the District of Columbia.

<span class="mw-page-title-main">Scarlet tanager</span> Species of bird

The scarlet tanager is a medium-sized American songbird. Until recently, it was placed in the tanager family (Thraupidae), but it and other members of its genus are now classified as belonging to the cardinal family (Cardinalidae). The species' plumage and vocalizations are similar to other members of the cardinal family, although the Piranga species lacks the thick conical bill that many cardinals possess. The species resides in thick deciduous woodlands and suburbs.

<span class="mw-page-title-main">Blackpoll warbler</span> Species of bird

The blackpoll warbler is a New World warbler. Breeding males are mostly black and white. They have a prominent black cap, white cheeks, and white wing bars. The blackpoll breeds in forests of northern North America, from Alaska throughout most of Canada, to the Adirondack Mountains of New York as well as New England in the Northeastern United States. They are a common migrant throughout much of North America. In fall, they fly south to the Greater Antilles and the northeastern coasts of South America in a non-stop long-distance migration over open water, averaging 2,500 km (1,600 mi), one of the longest-distance non-stop overwater flights ever recorded for a migratory songbird. Rare vagrants to western Europe, they are one of the more frequent transatlantic passerine wanderers.

<span class="mw-page-title-main">Magnolia warbler</span> Species of bird

The magnolia warbler is a member of the wood warbler family Parulidae.

<span class="mw-page-title-main">Black-and-white warbler</span> Species of New World warbler

The black-and-white warbler is a species of New World warbler, and the only member of its genus, Mniotilta. It breeds in northern and eastern North America and winters in Florida, Central America, and the West Indies down to Peru. This species is a very rare vagrant to western Europe.

<span class="mw-page-title-main">Tennessee warbler</span> Species of bird

The Tennessee warbler is a New World warbler that breeds in eastern North America and winters in southern Central America, the Caribbean, and northern South America. The specific name peregrina is from Latin peregrinus "wanderer".

<span class="mw-page-title-main">Puerto Rican tody</span> Species of bird

The Puerto Rican tody is a bird endemic to Puerto Rico. It is locally known in Spanish as "San Pedrito" and "medio peso".

<span class="mw-page-title-main">Lesser nighthawk</span> Species of bird

The lesser nighthawk is a nightjar found throughout a large part of the Americas. This bird looks similar to the common nighthawk but is slightly smaller, has a slightly less deeply forked tail, and is more buffy in coloration. Their distinctive mouths are very well adapted for capturing insects mid-flight.

<span class="mw-page-title-main">Antillean nighthawk</span> Species of bird

The Antillean nighthawk is a nightjar native to the Caribbean, The Bahamas, and Florida Keys.

<span class="mw-page-title-main">American gray flycatcher</span> Species of bird

The American gray flycatcher, or American grey flycatcher, or just gray flycatcher as it is known in North America, is a small, insectivorous passerine in the tyrant flycatcher family. It is common in the arid regions of western North America, especially the Great Basin. From sagebrush steppes to pinyon-juniper woodlands and ponderosa pine forests, this flycatcher forages for insects from shrubs or low tree branches.

<span class="mw-page-title-main">Hawking (birds)</span> Feeding strategy in birds involving catching flying insects in the air

Hawking is a feeding strategy in birds involving catching flying insects in the air. The term usually refers to a technique of sallying out from a perch to snatch an insect and then returning to the same or a different perch, though it also applies to birds that spend almost their entire lives on the wing. This technique is called "flycatching" and some birds known for it are several families of "flycatchers": Old World flycatchers, monarch flycatchers, and tyrant flycatchers; however, some species known as "flycatchers" use other foraging methods, such as the grey tit-flycatcher. Other birds, such as swifts, swallows, and nightjars, also take insects on the wing in continuous aerial feeding. The term "hawking" comes from the similarity of this behavior to the way hawks take prey in flight, although, whereas raptors may catch prey with their feet, hawking is the behavior of catching insects in the bill. Many birds have a combined strategy of both hawking insects and gleaning them from foliage.

References

  1. 1 2 BirdLife International (2016). "Chordeiles minor". IUCN Red List of Threatened Species . 2016: e.T22689714A93244252. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22689714A93244252.en . Retrieved 12 November 2021.
  2. "Chordeiles minor". Integrated Taxonomic Information System . Retrieved 25 May 2010.
  3. 1 2 3 4 5 6 7 Sibley, David Allen (2001). The Sibley Guide to Bird Life & Behaviour. Chanticleer Press, Inc.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Poulin, R.; Grindal, S.; Brigham, R. (1996). "Common Nighthawk, no. 213". The Birds of North America. The American Ornithologists' Union.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 The Birds of Manitoba . Manitoba Avian Research Committee. Manitoba Naturalists Society. 2003. ISBN   9780969728016.
  6. 1 2 3 4 5 6 7 8 9 Elphick, J., ed. (2007). Atlas of Bird Migration. Firefly Books. ISBN   978-1554079711.
  7. Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 104, 256. ISBN   978-1-4081-2501-4.
  8. "Nighthawk" . Oxford English Dictionary (Online ed.). Oxford University Press.(Subscription or participating institution membership required.)
  9. "NE [Nebraska] introduction". netstate.com.
  10. Capace, Nancy (Jan 1, 1999). Encyclopedia of Nebraska. Somerset Publishers, Inc. pp. 2–3.
  11. U.S. Boston, MA: D. Lothrop Company. 1890. p. 77. An index to the United States of America: Historical, geographical and political. A handbook of reference combining the "curious" in U.S. history.
  12. Gill, F.; Donsker, D., eds. (2014). "IOC World Bird List" (4.4 ed.). doi:10.14344/IOC.ML.4.4 . Retrieved 15 November 2014.
  13. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Holyoak, D.T. (2001). Nightjars and their Allies: the Caprimulgiformes. Oxford University Press. ISBN   0-19-854987-3.
  14. "Common Nighthawk". mountainnature.com. Archived from the original on 14 July 2014. Retrieved 14 August 2013.
  15. Farrell, Claire E.; Wilson, Scott; Mitchell, Greg (2017). "Assessing the relative use of clearcuts, burned stands, and wetlands as breeding habitat for two declining aerial insectivores in the boreal forest". Forest Ecology and Management. 386: 62–70. doi:10.1016/j.foreco.2016.11.026.
  16. "Sounds". allaboutbirds.org. Common Nighthawk. Cornell Laboratory of Ornithology.
  17. 1 2 Todd, L. Danielle; Poulin, Ray G.; Brigham, R. Mark (1998). "Diet of Common Nighthawks (Chordeiles minor: Caprimulgidae) Relative to Prey Abundance". American Midland Naturalist. 139 (1): 20–28. doi:10.1674/0003-0031(1998)139[0020:DOCNCM]2.0.CO;2.
  18. Brigham, R.M.; Fenton, M.B.; Aldridge, H.D.J.N. (1998). "Flight speed of foraging Common Nighthawks (Chordeiles minor): Does the measurement technique matter?". American Midland Naturalist. 139 (2): 325–330. doi:10.1674/0003-0031(1998)139[0325:fsofcn]2.0.co;2. JSTOR   2426689. S2CID   86113224.
  19. Canevari, M.; Canevari, P.; Carrizo, G.; Harris, G.; Mata, J.; Straneck, R. (1991). Nueva guia de las aves Argentinas[New Guide to the Birds of Argentina] (in Spanish). Buenos Aires: Fundacion Acindar. cited in Poulin, Grindal, & Brigham (1996). [4]
  20. Gillette, L. (1991). "Survey of common nighthawks in Minnesota, 1990". The Loon. 62: 141–143. cited in Birds of Manitoba (2003, p. 238). [5] :238
  21. Kantrud, H.A.; Higgins, K.F. (1992). "Nest and nest site characteristics of some groundnesting, nonpasserine birds of northern grasslands". Prairie Naturalist. 24: 67–84.
  22. Olendorff, R.R. (1976). "The food habits of North American golden eagles". American Midland Naturalist. 95 (1): 231–236. doi:10.2307/2424254. JSTOR   2424254.
  23. Bennett, G. (1987). "A vellication of nighthawks". Birdfinding in Canada. 7: 16.
  24. Gross, A.O. (1940). Bent, A.C. (ed.). "Eastern Nighthawk". U.S. Natl. Mus. Bull. Life histories of North American cuckoos, goatsuckers, hummingbirds, and their allies. 176: 206–234.
  25. Marzilli, V. (1989). "Up on the roof". Maine Fish and Wildlife. 31: 25–29.
  26. "Common nighthawk". Government of Ontario. September 10, 2009.