Chimney Swift Chaetura pelagica


Justification of Red List Category
This species is classified as Vulnerable as survey data has demonstrated a rapid population decline due to loss of nesting habitat.

Population justification
The global population has been estimated at 15,000,000 individuals in total (Rich et al. 2004) and 7,700,000 mature individuals, based on estimates from the North American Breeding Bird Survey (Rosenberg et al. 2016) .

Trend justification
Its association with chimneys may have historically allowed the population to expand. However, recent trends show strong population declines. The Partners in Flight Landbird Conservation Plan (Rosenberg et al. 2016) suggest that between 1970 and 2014 the species underwent a population reduction of 67%. Partners in Flight also gives the species a half-life of 27 years (Rosenberg et al. 2016). Extrapolating the population reduction based on short term data from the North American Breeding Bird Survey (Sauer et al. 2017) shows that over the last three generations (16 years), the population has been decreasing with a significant, estimated annual decrease of 2.68% (2.38 to 3.00%) (Sauer et al. 2017). This would equate to a reduction of 35.3% (32.1-38.7%) over three generations

Distribution and population

Chaetura pelagica breeds in eastern North America from southern Canada and to the Gulf Coast states of the USA, and occasionally in California and Arizona. It is a migratory species, wintering in eastern Ecuador, Peru, north-west Brazil and northern Chile (del Hoyo et al. 1999).


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, Zanchetta et al. 2014). 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). When breeding, this species is readily associated with urban environments, although it will forage over a range of habitat types. 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). Spiders, along with Hymenoptera spp., Diptera spp. and other insects have been recorded in its diet (del Hoyo et al. 1999).


In recent times, the number of available chimneys has decreased as a result of the demolition of old buildings, the capping of old chimneys and through chimney sweeps removing nests from chimneys (despite the species being protected by federal law) (COSEWIC 2007, R. Windingstad in litt. 2010, Steeves et al. 2014). Even though a scarcity of chimneys may not be limiting the numbers of Chimney Swifts yet (Wake 2016, Stewart et al. 2017), the rate of habitat loss is increasing and possibly developing into a severe threat (C. Artuso in litt. 2018). Logging of old-growth forest may also reduce the number of breeding sites for the species (Steeves et al. 2014). 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). Additionally, the use of DDT in the 1950s to control insect populations may have caused a shift in Chimney Swift diet, although the long term impact on the species is uncertain (Nocera et al. 2012, Steeves et al. 2014). Hurricanes during the migration period and harsh weather conditions during the 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). Overall, the key threat is thought to be the ongoing loss of potential nesting sites (although this may not be the case for all populations; Fitzgerald et al. 2014).

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. Increase public awareness and encourage the preservation of chimneys suitable for nesting. Assess threats in South America.


c. 14 cm. A small, uniformly colored swift with short, rounded tail; plain dark above, plain greyish-brown below; throat, chin and cheeks much paler; distinctive wing shape with hooked outer wing. Voice Quite voal; high-pitched chip notes followed by twittering descending trills.


Text account compilers
Butchart, S., Calvert, R., Hermes, C., Sharpe, C.J., Westrip, J., Ekstrom, J., Wheatley, H.

Windingstad, R., Artuso, C.

Recommended citation
BirdLife International (2022) Species factsheet: Chaetura pelagica. Downloaded from on 22/05/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from on 22/05/2022.