Merlin

Black Swift Life History

Habitat

Habitat Forests

Black Swifts nest on cliff ledges behind or near waterfalls and sea caves. They forage over forests and open areas. They occur across a wide range of elevations: in British Columbia from sea level to 8,500 feet, in California from sea level to 7,500 feet, and in Oaxaca, Mexico, from 6,800–12,100 feet.

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Food

Food Insects

Black Swifts eat flying insects, especially winged ants in midair. On clear days, they forage at heights where they are often not visible, but on cloudy days they forage lower to the ground. They drink water by flying low over a lake or pond and dipping their bill into it.

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Nesting

Nest Placement

Nest Cliff

Black Swifts nest on cliff ledges and rock ledges behind waterfalls, typically in dark and inaccessible areas. They nest singly or in small colonies depending on the number of available nest sites.

Nest Description

Black Swifts build a cup nest of moss and mud, but unlike other swifts they don't use saliva to hold the materials together. The nest measures 5.5 x 4 inches and is less than 1 inch deep. Pairs often reuse the nest in subsequent breeding seasons.

Nesting Facts
Clutch Size:1 egg
Number of Broods:1 brood
Egg Length:0.9-1.3 in (2.4-3.2 cm)
Egg Width:0.7-0.8 in (1.7-2.1 cm)
Incubation Period:23-30 days
Nestling Period:45-50 days
Egg Description:

White.

Condition at Hatching:

Naked with eyes closed.

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Behavior

Behavior Aerial Forager

Black Swifts are at home in the sky, only touching down at the nest site or roost. They cling to ledges with their tiny feet much like a rock climber holding herself up on the tiniest of ledges. In the air they fly with steady and shallow wingbeats, much less fluttery and erratic than the smaller swifts. Black Swifts are social birds, nesting in loose colonies and migrating in groups often with other swifts and swallows. During aggressive interactions, individuals may grasp each other's feet and tumble a few feet in the air before separating. During courtship male swifts pursue females in high-speed chases. Males and females presumably form monogamous and potentially long-term bonds.

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Conservation

Conservation Declining

Black Swifts are uncommon and their populations declined by 94% between 1970 and 2014, according to Partners in Flight. They are a Yellow Watch List species with a declining population, with a Continental Concern Score of 15 out of 20. The estimated global breeding population is 210,000. Partners in Flight estimates that if current rates of decline continue, Black Swifts will lose another half of their remaining population by 2033. Causes for decline are unknown as so little is known about this swift, including where it spends the winter.

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Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Lowther, Peter E. and Charles T. Collins. (2002). Black Swift (Cypseloides niger), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, USA.

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