Chimney Swift Chaetura pelagica


Justification of Red List Category
This species is classified as Near Threatened as survey data has demonstrated that it has undergone a moderately rapid population decline due to loss of nesting habitat. However, trends for three-generation periods ending in 2006, 2007 and 2009 have reached 32%, 31% and 30% respectively, and should these rates of declines continue, the species may be uplisted to Vulnerable.

Population justification
The North American, and global, population is estimated to number 7,700,000 mature individuals, based on estimates from the North American Breeding Bird Survey (Rosenberg et al. 2016) .

Trend justification
According to figures from the Breeding Birds Survey, trends over a 15 year period (three generations) for the last 20 years have, on average, indicated a 20-29% decline in the global population (J. Sauer in litt. 2010).

Distribution and population

Chaetura pelagica breeds in eastern North America as far north as southern Canada, and occasionally in California and Arizona (USA). It is a migratory species, wintering in eastern Ecuador, Peru, north-west Brazil and northern Chile (del Hoyo et al. 1999). The Canadian population, which occupies one quarter of the breeding range, had been estimated at just 11,820 breeding individuals (COSEWIC 2007), with the global population estimated at 15,000,000 individuals (Rich et al. 2004). The North American, and global, population has subsequently been estimated to number 7,700,000 mature individuals, based on estimates from the North American Breeding Bird Survey (Rosenberg et al. 2016) .

Trends have been recorded through North America between 1966 and 2007, with a decline of 5.5% per year in Canada (total decline of 90%) and 1.8% per year in the USA (total decline of 53%). Overall, during this period the population has declined by 1.9% per year, though this decline has accelerated in recent years, reaching a decline of 2.8% per year between 1980 and 2008 (Dionne et al. 2008) (total decline of 40% over this period) (Sauer et al. 2008).


Behaviour This migratory species is extremely gregarious, and typically nests in chimneys, though other structures such as hollow tree trunks can be used (del Hoyo et al. 1999, COSEWIC 2007). Eggs have been recorded from May to July, though the precise timing varies slightly throughout its range. A clutch of two to seven eggs is laid, and extra-parental co-operation is well established. It is present in North America until September (del Hoyo et al. 1999). Habitat It is readily associated with urban settings, though also forages and breeds over a variety of natural habitats over its wide range. Main habitats include river-edge forest, the edge of tropical lowland evergreen forest and second-growth scrub. It can also be found along the coast in Peru, up to 3,000 m over irrigated farmland in western Andean valleys, and even in central city zones (del Hoyo et al. 1999). Diet Spiders, along with Hymenoptera spp., Diptera spp. and other insects have been recorded (del Hoyo et al. 1999).


The most significant threat to the species appears to be the decreasing number of nesting and roosting sites caused by logging operations, the demolition of old abandoned buildings and, especially, the sharp decline in the number of suitable and accessible traditional chimneys, which are this species's main breeding habitat (COSEWIC 2007, R. Windingstad in litt. 2010). It is projected that very few suitable sites will remain within the next thirty years (COSEWIC 2007). The number of breeding sites in Quebec is limited, and it is estimated that only 60% of breeding-age adults actually reproduce; a trend which is thought to be replicated across Canada (COSEWIC 2007). Hurricanes during the migration period and harsh weather conditions during breeding season have caused a considerable number of deaths (COSEWIC 2007, Dionne et al. 2008). In its South American wintering area, the species is threatened by intensive logging operations and by fires (COSEWIC 2007).

Conservation actions

Conservation Actions Underway
Listed as a Threatened species in Canada (COSEWIC 2007). Populations continue to be monitored as part of the Breeding Birds Survey.

Conservation Actions Proposed
Research potential measures to prevent further population declines. Assess threats in South America.


Text account compilers
Ekstrom, J., Sharpe, C J, Butchart, S., Calvert, R.

Windingstad, R., Wheatley, H.

Recommended citation
BirdLife International (2017) Species factsheet: Chaetura pelagica. Downloaded from http://www.birdlife.org on 25/11/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/11/2017.