Common Swift Apus apus Scientific name definitions

16–18 cm; 31–52 g; wingspan 42–48 cm. Large rakish swift with long, deeply forked tail and sharply pointed wings ; black-brown mantle, outer wing, lesser coverts, tail, crown and underparts beneath small off-white throat patch; slightly paler inner wing, greater coverts of underwing , forehead and rump; contrast between paler and darker tracts varies individually and temporally, fresh feathers being blacker with narrow white fringes. Juvenile very black, with little contrast between tracts; white fringes most apparent on forehead, which can show as small white patch, and larger, more defined white throat-patch. Race pekinensis has paler forehead and shows greater contrast in wing.

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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.

Wide range of habitats from arid steppe and desert on S & E boundaries, temperate and Mediterranean zones N into boreal zone; also over all sub-Saharan habitats. Recorded from sea-level to high altitudes. Abundance in Britain and Ireland seemingly correlates with climate: commonest in relatively warm and dry S & E, becoming scarcer to N & W, where cooler, wetter and windier weather reduces insect abundance. In Israel primarily in Mediterranean climatic zone, with only small numbers in semi-desert areas. Race pekinensis occurs in Himalayas at 1500–3300 m, foraging to 4000 m, and recorded migrating at 5700 m in Ladakh.

Long-distance migrant. Present at SW Palearctic sites from mid Mar, arriving later further N; main arrival N Europe early May, with migration persisting to early Jun. Main spring and autumn passage in Egypt late Mar to mid-May and mid-Aug to mid-Oct; records in late Jan to early Feb could indicate local wintering or early migration. Spring migration of nominate race through Israel mid Jan to mid Jun, peaking Apr–May; passage S throughout country mid-May to mid-Nov; in spring pekinensis moves mainly in Mar–Apr, occurring primarily in E in autumn. Leaves N Europe from late Jul, mainly Aug, very rare from Nov. Autumn movement over W Turkish migration watchpoints peaks mid–late Aug. Present on African wintering grounds from Sept. Broad-front autumn migration from Europe on SSW bearing, returning by generally more E route. Race pekinensis departs South Africa by early Mar, nominate race leaving somewhat earlier, late Jan to early Feb. Winters in small numbers N of Sahara, e.g. Cape Verde Is, with records Aug–Jun, possibly in Egypt among flocks of A. pallidus along Nile, in Israel and Arabian Gulf states (where presence recently documented photographically in United Arab Emirates (2 Roberts, H. and Campbell, O. (2015). Proving the occurrence of Common Swift Apus apus pekinensis in the United Arab Emirates. Sandgrouse. 37(1): 79–86. Close ), and all records in Oman are either thought or presumed to be this race) (3 Eriksen, J., and R. Victor (2013). Oman Bird List: the Official List of the Birds of the Sultanate of Oman. Seventh edition. Sultan Qaboos University, Muscat, Oman. Close ). Vagrant to many oceanic archipelagos, including Prince Edward Is in S Indian Ocean. Also three records for North America (one of them a specimen of pekinensis), all of them offshore (Jun 1950 and two in Jun 1986) (4 Howell, S. N. G., I. Lewington, and W. Russell (2014). Rare Birds of North America. Princeton University Press, Princeton, New Jersey & Oxford. Close ), and one at sea off Suriname, in mid-Jul 2012 (5 de Boer, M.N., Saulino, J.T. and Williams, A.C. (2014). First documented record of Common Swift Apus apus for Surinam and South America. Cotinga. 36: 107–109. Close ). During the ten-month non-breeding period five birds equipped with data loggers in Sweden, overwintering in W or C Africa, were airborne for over 99% of the time and some of them never settled (6 Hedenström, A., Norevik, G., Warfvinge, K., Andersson, A., Bäckman, J. and Åkesson, S. (2016). Annual 173-month aerial life phase in the Common Swift Apus apus. Current Biol.. 26: 3066–3070. Close ).

Prey up to 12 mm taken, with stinging insects avoided. Over 500 prey species noted in European diet. German study analysed 11,384 insects and 17 spiders: 53% were Hemiptera, 26% Coleoptera, 10% Diptera and 3% Lepidoptera and Neuroptera.

Most common call is a shrill, piercing, wheezy or reedy scream “srreeeeerrr”, overslurred with top frequency around 6–7 kHz. In groups, typically several birds call together, resulting in a continuous high-pitched reeling, which is a common summer sound over many towns and cities. The typical screaming calls include a scream followed by a trill (7 Bretagnolle, V. (1993). Call types of the Common Swift Apus apus: adults calls given at the nest. Avocetta. 17(2): 141–146. Close ), the trill part being a reliable indicator of a bird’s sex: females show an average time lapse between the trills of ≥ 25 milliseconds, whereas that of males is ≤ 20 milliseconds; the modulation frequency at the end of the screaming call of females is ≤ 4 kHz, whereas that of males is ≥ 5 kHz (8 Ansorge, K. (2016). Sexual dimorphism of acoustic signals in the Common Swift. British Birds 109(5):293–297. Close ).

Season: Mar–Jun, Israel; probably May–Jun, Pakistan and Kashmir; mid-May to late Jul Britain and Ireland, and a week earlier and later in Switzerland and Fennoscandia respectively; in Turkmenistan, nest-building at Kopet-Dag in Apr, completed nest Kyzylcha-kala in early May, clutches completed in Ashkhabad from late Apr; laying NW Africa in May, and Russia early–mid Jun. Colonial, though solitary nests not infrequent; separate nests, typically over 1 m apart. Site prospected and chosen by male; initially female greeted with hostile display, though allopreening occurs when she submits by lifting head to expose throat patch; copulation on wing and at nest. Nests mainly in buildings, but in remote parts of range also in tree hollows and rock crevices. Nest cup constructed of small pieces of vegetable matter and feathers, agglutinated with saliva, measuring 125 mm × 110 mm, internal diameter 45 mm. Clutch 1–4 eggs, averaging two in N Africa but typically more in Europe; both sexes share nesting duties equally; incubation, initiated by laying of last egg, occurs in equal periods of c. 2 hours, more intensive when weather poor; period 19·5 days; brooding continuous in first week, discontinuous from second, with young unattended during inclement weather; down that grows from day 13 is extensive by day 17, being fully replaced by day 30; feeding rate depends on weather, average ten food balls daily in Gibraltar; two young share food ball until large enough to swallow one whole by day 14; nestlings restless from 2–3 weeks, with wing exercises and allopreening; average fledging period 42·5 days (wide range of 37–56 days due to weather conditions), self-initiated fledging after sunset or prior to 08:00 h. Average breeding success 58–65%, with mean 1·3–1·7 young fledging per breeding effort.

Not globally threatened (Least Concern). Declines apparent in some areas of Europe at least, where breeding population recently reported to have decreased in 12 countries. Modern building techniques and materials appear to reduce the number of available nesting sites, so that installing nest-boxes is likely to be an appropriate measure to compensate for nest-sites lost during building renovations (9 Schaub, T., Meffert, P.J. and Kerth, G. (2016). Nest-boxes for Common Swifts Apus apus as compensatory measures in the context of building renovation: efficacy and predictors of occupancy. Bird Conservation International. 26(2): 164–176. Close ). In Britain and Ireland, census work during 1968–1972 revealed an estimated 100,000 pairs; between then and 1989–1990 there is no evidence of significant population change, and it is believed that if previous figure is correct there are c. 80,000 and c. 20,000 pairs in Britain and Ireland respectively. Population estimates (breeding pairs) in 1997: Europe 3,973,943–4,872,619, Russia 1,000,000–5,000,000 and Turkey 50,000–500,000. Has recently colonized Canary Is, breeding on Gran Canaria and probably Tenerife.