Introduction
The American Black Swift (Cypseloides niger) is a large, dark-plumaged swift of the Americas. It is an aerial insectivore that spends much of its life in flight and is best known for nesting in cool, sheltered sites on steep cliffs, often behind waterfalls. Northern populations are migratory, and much of the species’ breeding biology remains difficult to study because its nesting sites are remote and inaccessible.
Physical Description
The American Black Swift measures approximately 18–18.4 cm in length and weighs about 40–55 g. Its wingspan is roughly 46–51 cm. Both sexes are alike in appearance.
Adults are mostly uniform blackish or sooty charcoal-grey, with long, narrow, curved wings and a slightly notched tail that can appear almost square in flight. Small whitish markings on the sides of the forehead may be visible at close range, but they are difficult to see on a fast-moving bird. The bill is tiny and the feet are very small, adaptations associated with a life spent almost entirely on the wing and clinging to vertical surfaces rather than perching on branches.
Juveniles are generally blackish with pale edging on the body and flight feathers. There is no strong sexual dimorphism.
Range and Habitat
The species breeds across western North America, from Alaska and British Columbia south through the western United States and Mexico. Related breeding populations also occur in parts of Central America and the Caribbean. Northern populations migrate south after the breeding season, and tracking studies have documented winter movements as far as western Brazil. The complete non-breeding distribution remains imperfectly known.
American Black Swifts forage over forests, valleys, open country, mountain slopes and coastal areas, often at considerable height. Breeding sites are usually associated with steep cliffs, deep canyons, caves, sea cliffs or rock faces near waterfalls and running water. The nest is commonly placed on a shaded, damp ledge or in a crevice that is difficult for predators and people to reach. In British Columbia, the species has been recorded from sea level to approximately 2,600 metres, although most observations occur at lower or middle elevations.
Where to See This Species
Johnston Canyon, Banff National Park, Alberta, Canada
Johnston Canyon is one of Alberta’s known Black Swift breeding sites. The shaded, moist canyon contains several waterfalls and steep rock walls that provide suitable nesting habitat. Adults may sometimes be seen leaving the canyon in the early morning or returning near dusk from June to mid-September. Visitors should remain on the official trail and follow all seasonal closures and restrictions because nesting areas are protected.
Nearby accommodation: The town of Banff provides hotels, lodges, guest houses, hostels, cabins and campsites, while accommodation is also available in the Lake Louise and Castle Junction areas.
Marble Canyon, Kootenay National Park, British Columbia, Canada
Marble Canyon supports the largest known Black Swift population among Canada’s mountain national parks. Its steep canyon walls, shaded ledges and nearby waterfalls provide appropriate nesting conditions, and the birds may be observed flying above or into the canyon during the breeding season. The nests themselves are hidden and should not be approached or disturbed.
Nearby accommodation: Radium Hot Springs and the surrounding Columbia Valley provide hotels, motels, lodges, cabins, campsites and self-catering accommodation.
Behaviour and Diet
American Black Swifts feed exclusively while flying. Their diet includes a wide range of airborne insects such as wasps, flies, mayflies, caddisflies, beetles, winged ants and termites. Spiders may also be taken when they become airborne. The birds often forage high above the ground and may travel long distances from their nesting sites in search of concentrated insect activity.
Their flight is fast but comparatively steady for a swift, with long, shallow wingbeats, gliding and wheeling. They may forage alone or in small groups. Birds are often easier to detect on cloudy days, when they may fly lower, or near breeding cliffs in the early morning and around dusk.
Breeding pairs generally raise one nestling each season. The single white egg is incubated by both parents for approximately 24–27 days. Both adults feed the young, which remain in the nest until they are ready to fly, usually after about 45–49 days. Nests are built from moss and other material on damp ledges or in sheltered crevices, often close to spray from a waterfall.
Identification Tips
- Look for a large, blackish swift with long, curved, pointed wings and a slightly notched tail.
- The species is larger and heavier-looking than a Vaux’s Swift, with slower and shallower wingbeats.
- Unlike a White-throated Swift, it lacks a conspicuous white throat and belly.
- It may resemble a Purple Martin at a distance, but the Black Swift has longer, more swept-back wings, a smaller bill and the characteristic flight of a swift.
- Small pale marks on the sides of the forehead may be visible at close range, but they are not reliable at a distance.
- Do not expect to see it perched on a branch. Swifts usually cling to vertical surfaces when resting.
Conservation Status
The American Black Swift is currently assessed as Vulnerable on the IUCN Red List. In Canada, it is listed as Endangered under the Species at Risk Act.
The species is difficult to monitor because colonies are scattered and nests are often hidden behind waterfalls or on inaccessible cliffs. Documented or suspected pressures include long-term declines in aerial insect prey, climate change, drought, altered stream flow, extreme weather and disturbance near nesting sites. Changes in water availability may affect the cool, damp conditions required at some nesting locations.
Important conservation measures include protecting known nesting cliffs and waterfalls, maintaining natural stream flows, restricting climbing and other disturbance near colonies, monitoring breeding sites and improving knowledge of migration and wintering areas. Parks Canada uses visual surveys, thermal cameras and other non-invasive methods to locate and monitor nests in protected areas.
Frequently Asked Questions
What is the scientific name of the American Black Swift?
The scientific name is Cypseloides niger. The species is also commonly called the Black Swift.
Where does the American Black Swift breed?
It breeds mainly in western North America, including western Canada, the western United States and Mexico, with additional breeding populations in parts of Central America and the Caribbean.
Where does the American Black Swift spend the winter?
Northern populations migrate south. Tracking studies have recorded some birds wintering in western Brazil, although the species’ full non-breeding distribution is still not completely known.
What does the American Black Swift eat?
It catches flying insects in the air, including flies, beetles, wasps, mayflies, caddisflies, winged ants and termites. Spiders may also be taken when they are airborne.
Where does the American Black Swift nest?
It nests on steep cliffs, in caves and in shaded crevices, frequently behind or beside waterfalls. Nests are usually placed on damp ledges that are difficult for predators and people to reach.
Is the American Black Swift endangered?
Its global IUCN status is Vulnerable, while the species is listed as Endangered in Canada. Major concerns include declining aerial insects, climate-related changes to water and nesting conditions, and disturbance at breeding sites.
References
- Cornell Lab of Ornithology
- Parks Canada
- IUCN Red List of Threatened Species
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