Species

Justification
This poorly known swift qualifies as Vulnerable owing to its very small population. Discovery of new breeding colonies or identification of possible threats would necessitate a reassessment of its threat status.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Identification
17-18 cm. Slim, all-dark swift with scaly underside and deeply forked tail. Tends to have dark throat. Similar spp. Fork-tailed Swift A. pacificus has white rump-band, less sharply forked tail and paler throat. Common Swift A. apus lacks scaling to underparts and has shorter, less deeply forked tail. Voice High-pitched, rapid, quavering tsrr'i'i'i'i and tsrr'i'i'i'i'is'it at nest-sites.

Distribution and population
Apus acuticauda is known from just a few breeding colonies in the Himalayan foothills in Bhutan, and the hills of Meghalaya, Nagaland and Mizoram, north-east India (BirdLife International 2001, Chantler 2005, Ahmed et al. 2007). Its seasonal movements and wintering areas are virtually unknown. There are records throughout the year from India and during the non-breeding season from north-west Thailand and Yunnan, China (J. Hornskov in litt. 2005). There are no confirmed records from Myanmar, but it is likely to occur there. At known breeding colonies, the number of birds ranges from a few to 200 and the total population may not exceed 1,000 individuals.

Population justification
The population is thought to number 250-999 individuals, based on estimates of breeding colony sizes ranging from a few to 200 individuals. This estimate equates to 167-666 mature individuals, rounded here to 150-700 mature individuals.

Trend justification
The population is suspected to be stable in the absence of evidence for any declines or substantial threats.

Ecology
It breeds colonially in the crevices of rocky cliffs and deep gorges, at 200-1,350 m, generally in the vicinity of forest. Breeding is from March to May usually at the same site each year. Birds apparently remain in close proximity to the nesting colonies while breeding, normally disappearing soon afterwards and reappearing the following year. Away from breeding sites, it has been recorded up to at least 1,500 m. It has been suggested that it may only undertake local movements, but this requires further investigation.

Threats
There are no known threats, although its reliance on forest as a feeding habitat should be investigated.

Conservation actions underway
A presumed breeding site is located within the Blue Mountain National Park, Mizoram, north-east India. Strict forest policy and wildlife protection laws in Bhutan suggest that its future there is secure.

Conservation actions proposed
Advocate to include this as a key target species during surveys across north-east India, Bhutan and western and northern Myanmar to establish its breeding range, population status, ecology, seasonal movements, and potential threats. Strict protection should be afforded to all known colonies.

References
BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

Chantler, P. 2005. Dark-rumped Swifts: notes on their breeding plumage and how to see them. BirdingASIA: 39-40.

Ahmed, M. F.; Das, A.; Meyase, V. 2007. Khasi Hills Swift Apus acuticauda: First record from Nagaland and Manipur, north-east India. Journal of the Bombay Natural History Society 104(1): 87-88.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Hear sounds for this species from xeno-canto, the community database of shared bird sounds from around the world.

View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Allinson, T, Bird, J., Davidson, P., Peet, N., Taylor, J., Tobias, J.

Contributors
Ahmed, F, Hornskov, J.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2013) Species factsheet: Apus acuticauda. Downloaded from http://www.birdlife.org on 20/05/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/05/2013.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.