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Phalaenoptilus nuttallii (Audubon, 1844)
Common Poorwill
Family: Caprimulgidae

Species account author: Jamie Fenneman
Introduction to the Birds

Photograph

© Ian Routley     (Photo ID #9548)

Map


Distribution of Phalaenoptilus nuttallii in British Columbia.
(Click on the map to view a larger version.)
Source: Distribution map provided by Jamie Fenneman for E-Fauna BC

Species Information

Adult male
The upperparts (back, scapulars, rump, upperwing coverts) are densely and intricately mottled with grey, grey-brown, and black, with grey dominating on the scapulars and forming pale ‘braces’. The flight feathers are barred with blackish-brown and buff. The tail is relatively short and squared, with rounded corners; the central tail feathers are mottled with grey and grey-brown with narrow black bars, the outer tail feathers are blackish-brown with large white tips (white tip largest on the outermost feather). The underparts are buffy or whitish with narrow dusky-brown barring; barring darkest and most dense on the breast. The crown and nape are greyish and mottled with black, with the black mottling most concentrated along the central crown; remainder of the head and face dark blackish-brown with some paler mottling on the sides of the face. There is a narrow white collar across the lower throat. Some individuals (‘brown morph’) have extensive brownish mottling throughout the plumage. The iris is dark, the very short, pointed bill is blackish, and the legs and feet are brownish or blackish.

Adult female
Very similar to the adult male, but tips of outer tail feathers with smaller and buffier terminal spots.

Juvenile
This plumage is held into the fall of the first year. It is very similar to the plumage of the adult, but the crown is uniformly grey (lacking the concentrated blackish area along the central crown), the collar across the lower throat is buffy (rather than white), and the blackish mottling and barring on the body is less well-defined.
Measurements
Total Length: 19-21 cm
Mass: 35-57 g

Source: Woods et al. (2005); Dittmann and Cardiff (2006)


Biology

Identification

This species is heard far more often than it is seen, and its typical call is highly distinctive and rarely confused with that of any other species. It is also highly distinctive when observed, and the only species that may be confused with the Common Poorwill is the much more widespread Common Nighthawk. The Common Nighthawk is much larger, however, and has long, pointed wings (noticeably extending past the tip of the tail when at rest) with a white band across the primaries that is visible both in flight and at rest. Common Poorwill has shorter, rounded wings that lack the white band across the primaries. In addition, the tail of the Common Nighthawk is shallowly forked and either entirely brownish (females) or with a narrow white subterminal band (males). Common Poorwill, in contrast, has a squared tail with either buffy (female) or white (male) tips to the outer feathers, forming distinctive pale ‘corners’ to the tail. Common Poorwill is almost strictly nocturnal, while Common Nighthawk is both diurnal and crepuscular, and thus any nightjar observed flying during the day will invariably be a Common Nighthawk.
Vocalizations

The dominant vocalization, and the one for which the species receives its common name, is a clear, whistled, far-carrying poor-will or, at close range, poor-will-up (the third syllable is rarely audible at long distances); this call is often repeated continuously for long periods at night. Also gives a low, rough, rising gwep. When disturbed at or near the nest, both sexes often give aggressive hissing or growling calls.

Source: Sibley (2000); Woods et al. (2005)

Bird calls (and videos) from Cornell's Lab of Ornithology
Breeding Ecology

Courtship
Mechanism of pair formation poorly known, but this species appears to be monogamous and most pairs are apparently maintained throughout the breeding season. Pairs appear to form within the month of arrival on the breeding grounds (primarily May in B.C.).

Nest
No nest is built, and the eggs are laid directly on bare ground, rock, or leaf litter, often in a shallow scrape or depression. The nest is usually placed beneath overhanging vegetation, rock, or woody debris, although some nests contain little or no cover.

Eggs
A clutch of 2 eggs is laid in late May or early June and is incubated by both sexes for 20-21 days before hatching. The smooth, slightly glossy eggs are white or creamy-white, sometimes with a few faint, small markings. This species is often double-brooded, and second clutches are laid in July or early August. Eggs are present in B.C. between mid-May and late August.

Young
The young are semi-precocial upon hatching and are entirely covered in dense, buff down (paler on the underparts). They are tended by both parents and remain in and around the nest for several weeks after hatching; the brood is regularly moved by the parents. The young are able to fly at 20-23 days of age. Nestlings are present in B.C. between mid-June and late August (primarily in late June and July).

Source: Campbell et al. (1990b); Baicich and Harrison (1997); Woods et al. (2005)
Foraging Ecology

The Common Poorwill feeds exclusively on night-flying insects, particularly moths and beetles; it typically feeds only on larger insects and avoids the smaller species. All foraging occurs at night, with the first forays generally occurring ~30 minutes after sunset. Foraging occurs throughout much of the night, although it may decrease during the darkest hours when there is no moonlight. It may also forage during the early morning hours, beginning at first light and continuing until ~45 minutes before sunrise. Most insects are captured during brief flights, or ‘sallies’, from a perch on the ground or low perch (tree branch, post, etc.); it sometimes forages in extended flights. The Common Poorwill regularly (sometimes daily) enters periods of torpor, especially during periods of low food availability, during which time it decreases its body temperature and metabolic functions and ceases activity.

Source: Woods et al. (2005)

Habitat


The Common Poorwill is found in a wide diversity of relatively dry, often rocky habitats, ranging from open grassland and arid sagebrush steppe to coniferous forests that are dominated by Ponderosa Pine and/or Douglas-fir. When it occurs in forested environments, it is typically found near forest openings or in parkland habitats. It often roosts on or near gravel roadways at night.

Source: Campbell et al. (1990b)

Distribution

Global Range

Breeds throughout much of the western United States, from Washington, Oregon, and California east to the western Great Plains (North Dakota, Kansas, central Texas), as well as north into southern British Columbia, southeastern Alberta, and southwestern Saskatchewan. It also breeds throughout much of northern Mexico. It winters throughout its Mexican and southwestern U.S. breeding range, north to California, Arizona, New Mexico, and western Texas.
BC Distribution

Breeding
Fairly common in the Okanagan Valley and associated valleys (Similkameen, Kettle) in the south-central interior, north to Vernon. It is also fairly common throughout the Thompson and Nicola basins farther north and west, including the Merritt, Kamloops, and Cache Creek areas; uncommon along the Fraser River from Lytton north to the Chilcotin region. Rare to uncommon along the southern Rocky Mountain Trench north to Golden.

Migration and Vagrancy
The first spring migrants arrive in the south-central interior in mid- to late April (exceptionally early April), but the bulk of the population arrives during May. Peak numbers are present in the south-central interior by mid- to late May. Fall migrants begin to leave the breeding areas in August and continue through early September. Most individuals have left the province by mid-September, although some birds may linger into late September or even early October.

Very rare in spring and summer in southern B.C. between the Kettle River Valley and the southern Rocky Mountain Trench. This species is also a casual fall vagrant (mid-September to late November) on the south coast, including the Lower Mainland, southeastern Vancouver Island, and the Gulf Islands. It is accidental in summer in the Lower Mainland (Hope).

Source: Campbell et al. (1990b)

Conservation

Population and Conservation Status

Breeding populations in British Columbia are relatively large and secure, and the species is often common in the dry valleys of the southern interior. This species is not recognized as a conservation concern either provincially (B.C. Conservation Data Centre [CDC]) or federally (COSEWIC [Committee on the Status of Endangered Wildlife in Canada]).

Taxonomy


Six subspecies are currently recognized (three occurring north of Mexico), but most or all are rather poorly defined; the description of subspecies in this species is complicated by significant individual variation in plumage as well as locally dominant colour morphs (grey or brown). The subspecies occurring in British Columbia is P.n.nuttallii.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
NativeS4?BYellowDD (May 1993)



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