Malagasy Swift Apus balstoni Scientific name definitions

Previously treated as a subspecies of African Swift (Apus barbatus), there are two races of Malagasy Swift; the nominate subspecies is endemic to the island of the same name, where it occurs widely including over urban areas from sea level to almost 2,500 m, whereas race mayottensis occurs on all four main islands of the Comoros, where it too has a very broad elevational range but is generally rather scarce. Split from A. barbatus is based on the strong molecular differentiation between them, as well as the present species’ smaller size, blacker head and body, and its smaller pale throat patch. Within Madagascar, local movements apparently occur involving comparatively large numbers of individuals, sometimes even thousands of birds, which probably are much influenced by weather conditions, e.g., the species seemingly vacates eastern regions and moves westward in face of cyclones and thunderstorms, but often appears following local rainfall which stimulates the emergence of winged insects such as termites. Like many tropical Apodidae, the breeding of this species is poorly known, with few known nest sites in Madagascar, the largest being in limestone cliffs in the far north of the island, and none on the Comoros.

Large, bulky swift, with broad blunt-tipped wings, short, well-forked tail and heavy body.

The largest regularly occurring swift in Magagascar and the Comoros; Alpine Swift (Tachymarptis melba) is larger, but only a vagrant, and has a white throat and belly, divided by a broad brown breast-band. Another vagrant to the region, Common Swift (Apus apus) is similarly sized; in comparison, the present species is mostly blackish, darkest on the mantle, with a clear white throat, and paler secondaries and inner primaries forming a clearly contrasting patch on both wing surfaces. All other Malagasy swifts are smaller; African Palm-swift (Cypsiurus parvus) is much slimmer-bodied, paler, longer-tailed, and has notably different wing shape, while both Madagascar Spinetail (Zoonavena grandidieri) and Little Swift (Apus affinis) have short, square-ended tails, and have obviously pale rump patches.

Juvenile

Like adult, but remiges have fine whitish fringes.

Adult

Forehead dark greyish brown, becoming sooty black on crown, with nape to mantle and scapulars black, back to uppertail-coverts sooty black, tail black, lores, and ear-coverts dark grayish brown, center of chin and throat grayish white with short dark streaks, rest of underparts sooty black with narrow grayish-white fringes, primaries black, secondaries slightly paler, and wing-coverts generally a fraction paler still, while underwing-coverts are darkest area of underside, secondaries palest, but overall contrast not significant.

No information.

Bill

Black (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

Iris

Dark brown (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

Legs and Feet

No information.

Linear Measurements

Overall length 16 cm.

Linear measurements (in mm, sexes combined, sample sizes in parentheses, all data from Safford and Hawkins 1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close and Benson (2 Benson, C. W. (1960). The birds of the Comoro Islands: results of the British Ornithologists’ Union Centenary Expedition 1958. Ibis 103B(1):5–106. Close ):

Mass

Male (n = 2) 49.5–51.0 g, female (n = 2) 38–46 g (3 Benson, C. W., J. F. R. Colebrook-Robjent, and A. Williams (1976). Contribution à l’ornithologie de Madagascar. Suite. Oiseau et Revue Française d'Ornithologie 46:367–386. Close ).

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Commonly treated as conspecific with African Swift (Apus barbatus), but “differs in appearance from the other races of A. barbatus by at least as much as do the other members of the superspecies [Bradfield’s Swift A. bradfieldi, A. sladeniae, Forbes-Watson’s Swift A. berliozi]” (4 Snow, D. W., Editor (1978). An Atlas of Speciation in African Non-passerine Birds. Trustees of the British Museum (Natural History), London, UK. Close ), being (compared with barbatus) “smaller…, with blacker head and body, and smaller pale throat-patch with distinct dark streaks” (5 Safford, R.J. and Hawkins, A.F.A. eds. (2013). The Birds of Africa. Vol. 8: The Malagasy Region. Christopher Helm, London. Close ); scoring not attempted but “strong molecular differentiation… against… A. barbatus” (6 Päckert, M., J. Martens, M. Wink, A. Feigl, and D. T. Tietze (2012). Molecular phylogeny of Old World swifts (Aves: Apodiformes, Apodidae, Apus and Tachymarptis) based on mitochondrial and nuclear markers. Molecular Phylogenetics and Evolution 63(3):606–616. Close ) adds evidence to support split.

Expressed by minor differences in size and plumage between the two island groups on which the species occurs.

Two subspecies recognized.

A. b. mayottensis (Nicoll, 1906)—Comoro Islands (on all four major islands, also Pamandzi, off Mayotte, and islets south of Mohéli). Has forehead paler, malar area slightly grayer, and pale patch on chin and upper throat more restricted, sometimes obscure, while size is overall smaller, see Measurements (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

A. b. balstoni (E. Bartlett, 1880)—Madagascar.

See Systematics History.

Madagascar (throughout) and the Comoros (Grande Comore, Anjouan, Mohéli, Mayotte and Pamandzi, and islets south of Mohéli).

None known.

Recorded over all manner of habitats throughout range, including urban areas, especially wet regions, e.g. rice fields, ponds and marshes, and large commercial cotton fields; breeds in cliffs and caves (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Observed from sea level to 2,450 m on Madagascar, and to 2,361 m (Mt Karthala, the highest point) on the Comoros (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

Generally presumed to be resident and sedentary, but highly mobile with fluctuations in numbers observed in several areas of Madagascar, for example around Mangoky, species is present year-round, but scarce April–June (early dry season) (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ), and on central plateau, reported at Ivato only in August–April (7 Rand, A. L. (1936). The distribution and habits of Madagascar birds. Bulletin of the American Museum of Natural History 72:143–499. Close ,8 Salvan, J. (1970). Remarques sur l’évolution de l’avifaune malgache depuis 1945. Alauda 38(3):191–203. Close ), while in nearby Antananarivo present mostly October–March, with passage observed at all times of year, but with no obvious direction to such movements (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ,9 Boedts, B. (2014). Observations ornithologiques aux environs d’Antananarivo, Madagascar. Bulletin of the African Bird Club 21(1):72–81. Close ). Behaviour and movements (sometimes with other species) are apparently strongly influenced by weather, especially thunderstorms, although these are probably only local (10 Appert, O. (1972). Die Segler (Apodidae) und Schwalben (Hirundinidae) des Mangokygebietes in Südwest-Madagaskar. Ornithologische Beobachter 69:275–286. Close ,1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Large flocks of swifts arriving off sea in Mozambique have been suggested to be this species, rather than African Swift Apus barbatus, but this remains unproven and hypothetical (11 Fry, C. H., S. Keith, and E. K. Urban (Editors) (1988). The Birds of Africa. Volume 3. Parrots to Woodpeckers. Academic Press, London & San Diego. Close ).

Diet recorded as airborne insects, mostly small flies (Diptera), and beetles (2 Benson, C. W. (1960). The birds of the Comoro Islands: results of the British Ornithologists’ Union Centenary Expedition 1958. Ibis 103B(1):5–106. Close ). Also appears at large emergences of winged termites (Isoptera). Hunts over open grassland and water, as well as forests (usually high, although it descends over clearings), and mixes with other swifts (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ), namely Alpine Swift Apus melba, Little Swift Apus affinis (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ), African Palm Swift Cypsiurus parvus and Madagascar Spinetail Zoonavena grandidieri (especially the first two), as well as Mascarene Martin Phedina borbonica (12 Goodman, S. M., M. Pidgeon, A. F. A. Hawkins, and T. S. Schulenberg (1997). The birds of southeastern Madagascar. Fieldiana: Zoology (New Series) 87. Close ). Regularly in small flocks of 5–10 individuals, but occasionally hundreds in both Madagascar and Comoros (13 Louette, M. (2004). Oiseaux. In La Faune Terrestre de l’Archipel des Comores. Studies in Afrotropical Zoology 293 (M. Louette, D. Meirte, and R. Jocque, editors). Musée Royal de l’Afrique Centrale and Commission de l’Océan Indien, Tervuren, Belgium. Pp. 89–196 (In French.). Close ,1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

A high screaming trill is typical, rendered zzzzziiieeewwww, which falls at the end and lasts 1–2 seconds; often given in chorus. Slightly lower than Common Swift Apus apus, and perhaps closest to Forbes-Watson’s Swift A. berliozi (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

Season at least September–November on Madagascar (late dry to early wet season) (10 Appert, O. (1972). Die Segler (Apodidae) und Schwalben (Hirundinidae) des Mangokygebietes in Südwest-Madagaskar. Ornithologische Beobachter 69:275–286. Close ,1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ); possibly September in Comoros (2 Benson, C. W. (1960). The birds of the Comoro Islands: results of the British Ornithologists’ Union Centenary Expedition 1958. Ibis 103B(1):5–106. Close ). Strong synchronicity within colonies. Breeds on ledges and in holes in limestone cliffs and caves, including on offshore islets, as well as on ledges under buildings, typically 50–400 mm from cavity entrance (c. 70 mm wide), in some cases c. 3 m above mean water level in cave; nest constructed of blades/stems of vegetation, small feathers, tiny leaves and many plant and seed hairs (e.g. Cryptostegia madagascariensis, Asclepiadaceae), sealed with saliva, and c. 100 mm in diameter (10 Appert, O. (1972). Die Segler (Apodidae) und Schwalben (Hirundinidae) des Mangokygebietes in Südwest-Madagaskar. Ornithologische Beobachter 69:275–286. Close ,1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Presumably 1–2 white eggs, like African Swift Apus barbatus, but not known with certainty, all nests examined had two chicks (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). No further information, e.g., on incubation or fledging periods, breeding success, etc.

Nothing known.

Not globally threatened (Least Concern). Fairly common in northwest Madagascar (14 Delacour, J. (1932). Les oiseaux de la mission zoologique Franco-Anglo-Américaine à Madagascar. L'Oiseau et la Revue Francaise d'Ornithologie 2:1–96. Close ), with apparent breeding colonies involving hundreds of pairs in at least five areas of western and southern Madagascar. The total breeding population has not been assessed, but is suggested to number tens of thousands of pairs (1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Race mayottensis on Comoros is apparently scarce, apparently never being recorded in large numbers, with groups of 20–100 birds, e.g., on Grand Comoro (Ngazidja) in early Aug 1981, and has been observed on all four islands of the archipelago (15 Stevens, J., M. Herremans, and M. Louette (1992). Conserving the endemic birds on the Comoro Islands, II: population fluctuations on Ngazidja. Bird Conservation International 2(1):81–91. Close ,16 Stevens, J., and M. Louette (1999). Land bird abundance and the conservation of biodiversity on the island of Mayotte (Indian Ocean). Alauda 67(2):123–139. Close ,13 Louette, M. (2004). Oiseaux. In La Faune Terrestre de l’Archipel des Comores. Studies in Afrotropical Zoology 293 (M. Louette, D. Meirte, and R. Jocque, editors). Musée Royal de l’Afrique Centrale and Commission de l’Océan Indien, Tervuren, Belgium. Pp. 89–196 (In French.). Close ,1 Safford, R., and F. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).