The Black Swift nests on rock faces of canyons and waterfalls in British Columbia and western Alberta, and winters in South America. However, all parts of its annual life cycle are relatively poorly known, and its population estimates are also quite uncertain. The best available estimate of global population size is 170,000 individuals, and mapping of relative density based on eBird data suggests that roughly one-third of the total breeds in Canada. The most recent published estimate for the Canadian population suggests a range of 15,000 to 60,000 (average approximately 38,000), which would correspond to 22% of the global population. Despite the uncertainty around abundance, it is very likely that the Canadian population represents a moderate proportion of the global total.

The Canadian population was assessed as Endangered by the Committee on the Status of Endangered Wildlife in Canada in 2015 based on a severe decline over the previous decade (COSEWIC, 2015), and was listed at that level under the Species at Risk Act in 2018. Based on the Breeding Bird Survey, the Canadian population has experienced a large decrease relative to 1970. Although reliability of the Breeding Bird Survey is low because it is poorly suited to detecting this species, confidence is medium because the magnitude of the decline is so large that it is almost certain there has been a decline to some extent. The national population of Black Swift is below its goal range.