House Swift Apus nipalensis Scientific name definitions

14–15 cm; 20–35 g. Very similar in size and structure to A. affinis, but tail averages longer and has slight, though usually discernible, fork; blacker than A. affinis, notably on head and tail-coverts, with narrower white rump band. Juvenile very similar to adult, but may show paler fringes to flight-feathers. Race subfurcatus even blacker than nominate, especially on upper head; furcatus has deepest tail-fork and browner underparts; kuntzi intermediate between nominate and subfurcatus, with most heavily streaked rump of any subspecies.

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Occurs also in Sulawesi and Lesser Sundas (race unknown, probably subfurcatus or furcatus).

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

In Asia familiar in towns and cities, though scarcer elsewhere. Forages over a wide variety of habitats, including montane and forested land. In E Nepal recorded at c.1525 m in Chainpur area in mid-Jun; highest altitude at which recorded in Nepal was 2100 m.

Some N populations undertake poorly studied winter movements, with records during this season in Indian Subcontinent. Believed to be a winter resident in Luzon. Recorded in N Australia.

Faecal analysis revealed diet consisting of 78% Hymenoptera (19·8% Apocrita, 57·1% Formicoidea, 0·5% Meli­ponidae), 4% Diptera (2% Acalypterates, 1% Muscidae), 10·5% Coleoptera, 5·5% Isoptera and 2·2% others, with mean prey size 6·5 mm. Rarely feeds low, but often seen at great height when foraging far from nest-sites. Gregarious, sometimes with other Apodidae and hirundines. In Malaysia in Feb–Jul forages in high strata (over 30 m), with mean heights of 185 m over forested areas and 114·5 m over open areas; preference for forest during Feb–Mar, reversed in Apr.

Quite vocal. Basically identical to A. affinis. Commonest call is a pleasant twittering descending trill “ti-ti-ti-tititrrrrrr”, repeated at intervals. Around nest, also gives a variety of thin screams and shrieks.

In Myanmar, breeds any time between Feb and early Oct, with most nest-site selection in late Mar, nest-building in Apr, laying in May, hatching in Jun and most nestlings fledged by Jul; in Japan, breeds Apr to late Nov, with hatching peaks late May to early Jun, late Jul to early Aug and late Sept to early Oct; possible prospecting in late Jun, Batangas (Philippines); occupied nests from mid-Dec to mid-Aug, Malay Peninsula; eggs Mar–Apr in Sumatra; nest completed by early Feb with fledging in late Jun, Borneo. Colonial, with breeding synchronized within colony. Typically nests in angle between roof and wall in man-made structure, often in seemingly dangerously accessible sites where human population tolerant; in Yunnan at height above ground of 3·6–15·5 m, average 8·1 m; old nest of Red-rumped Swallow (Cecropis daurica striolata) used on Flores, and in Japan present species is almost entirely dependent on disused swallow nests on multistorey buildings and under bridges for breeding. Large untidy hemispherical nest “bags” in overlapping clusters, constructed of vegetable matter and feathers, sometimes with artefacts such as rags incorporated, agglutinated and adhered with saliva. Clutch 1–5, mean 3·1; incubation 18–26 days, average 21·1; mean of 26 feeding visits per day, range 8–55; fledging period 36–51 days, average 43·6. Typically raises more than one brood per year, with three broods in Japan. Hatching success 89·5%.

Not globally threatened (Least Concern). Abundant over most of range, though level of abundance appears to vary considerably. Common on Sumatra but rather locally distributed. Rare and local in Philippines. Uncommon and very local in Japan, where first recorded in 1965, but range expanding since 1970s and 1980s following arrival of Red-rumped Swallows (Cecropis daurica), in whose old nests it breeds. Recent colonist in Brunei, where three colonies by 1977, but expansion very slow as only one additional colony found since then. Recent colonist also in Wallacea, first recorded with certainty in 1978 on Sulawesi, where scarce and local resident in N & S. Similar story from Lesser Sundas, where recorded on Flores since 1986 and on Timor in 1993, and colony of 50 birds on Sumba in Jun 1994. In the Moluccas, several birds and a possibly abandoned nest recorded in May 2012 in city of Ternate, North Maluku (2 van Balen, B., Trainor, C. and Noske, R. (2014). Around the Archipelago. Kukila. 17(2): 74–97. Close ), and several birds and a colony of at least six nests on Buru I in 2014 Ornithological Note .