NT
Chuck-will's-widow Antrostomus carolinensis



Justification

Justification of Red List Category
This species is estimated to be undergoing a moderately rapid decline, and as such is listed as Near Threatened.

Population justification
Partners in Flight (2019) estimated the global population of mature individuals at 5,700,000.

Trend justification

Partners in Flight (2019) estimate the population of A. carolinensis to be declining at 2.275% per year, which equates to a ~24% decline over the last three generations (12 years). Similar declining trends are further supported by Rosenberg et al. (2016), the Christmas Bird Count (T. Meehan in litt. 2018) and the North American Breeding Bird Survey (Sauer et al. 2017). As a result, current declines are placed in the range 20-29% over three generations.

Distribution and population

Antrostomus carolinensis is a migratory species that is considered generally common, breeding in eastern U.S.A., locally in southern Canada (extreme southern Ontario), and in the northern Bahamas (see Cleere and Kirwan 2018). It overwinters in southern U.S.A. south through Central America, the Bahamas, Greater Antilles and Virgin Islands, and into northern South America (see Cleere and Kirwan 2018). There is no evidence that this species occurs in Suriname, despite earlier reports (SACC species list, Haverschmidt and Mees 1994, Spaans et al. 2018). The song of the Rufous Nightjar is thought to sound similar to that of the Chuck-wills-widow, therefore this may be the cause of such confusion (O. Ottema in litt. 2020).

Ecology

In both the breeding season and the non-breeding season the species appears to be predominantly associated with woodland habitats, although it does require open areas for foraging, e.g. pastureland or forest gaps (see Straight and Cooper 2012), and it will occur in some other habitat types such as scrubland or even cave entrances (see Straight and Cooper 2012). The species is predominantly insectivorous (Straight and Cooper 2012, Cleere and Kirwan 2018). It breeds generally from mid-April to July, although commencement of breeding varies according to location, with individuals in the south of the breeding range starting even in early March, whereas in the north of the range breeding may not start until mid-May (Cleere and Kirwan 2018). The species is susceptible to disturbance during the nesting stage, and it has been reported that it may even move chicks and eggs in its mouth, although this behaviour has not been witnessed since the 19th Century (see Straight and Cooper 2012).

Threats

The species appears to be threatened by a range of factors. These include habitat degradation due to urban development, and the species’s habit of utilising roads for dust baths etc. at night means it is at risk from collisions with cars (see Straight and Cooper 2012). Forest loss within the species's range is currently estimated at ~8% per three generations (Tracewski et al. 2016). Chuck-will’s-widow is also very sensitive to disturbance (although this may just result in the moving of the nest rather than nest abandonment [see Straight and Cooper 2012]), and could be affected by pesticide use as it is insectivorous, and will feed over pasture (see Straight and Cooper 2012). It has also been suggested that changes in habitat may be bringing the species more into contact with competitors, such as Eastern Whip-poor-will. As the latter’s range alters it may potentially be causing indirect impacts on Chuck-will’s-widow, although there is little direct evidence for this currently (see Straight and Cooper 2012), and Eastern Whip-poor-will itself is thought to be declining moderately rapidly (Rosenberg et al. 2016), so it is highly unclear whether this species is having any impact on Chuck-will's-widow, and as such is not coded as a threat here.

Conservation actions

Conservation Actions Underway
No direct conservation actions are known for this species. It is listed as a common bird in steep decline by Partners in Flight (Rosenberg et al. 2016).

Conservation Actions Proposed
Conduct research to get a better idea of the species's biology, threats, population and trends (Straight and Cooper 2012). In particular research focusing on the foraging behaviour of the species could prove to be valuable, as identifying the most important components of the species's diet - and the trends in these prey species - may help to identify whether this may be a driving factor behind declines (Straight and Cooper 2012).

Acknowledgements

Text account compilers
Everest, J., Elliott, N.

Contributors
Butchart, S., Ekstrom, J., Evans, M., Meehan, T., Ottema, O. & Westrip, J.R.S.


Recommended citation
BirdLife International (2021) Species factsheet: Antrostomus carolinensis. Downloaded from http://www.birdlife.org on 23/04/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/04/2021.