Hirundo atrocaerulea (Blue swallow) 

Blouswael [Afrikaans]; Sisampamema (generic term for swallows, martins, swifts and spinetails) [Kwangali]; Blauwe zwaluw [Dutch]; Hirondelle bleue [French]; Stahlschwalbe [German]; Andorinha-azul [Portuguese]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Tetrapoda (four-legged vertebrates) > Reptiliomorpha > Amniota > Reptilia (reptiles) > Romeriida > Diapsida > Archosauromorpha > Archosauria > Dinosauria (dinosaurs) > Saurischia > Theropoda (bipedal predatory dinosaurs) > Coelurosauria > Maniraptora > Aves (birds) > Order: Passeriformes  > Family: Hirundinidae

Blue swallow, near Nelspruit, South Africa. [photo Chris Morgan ©]	Blue swallows, Roselands, near Richmond, KwaZulu-Natal, South Africa. [photo Alan Manson ©]

For information about this species, see www.birdforum.net/opus/Hirundo_atrocaerulea

Distribution and habitat

Rare and localised, it has disjunct populations in Uganda and north-eastern DRC, southern Tanzania, southern Malawi and southern Africa. Here it has small breeding populations in Zimbabwe's eastern highlands and the eastern Escarpment in South Africa and Swaziland, with a separate population in the mistbelt veld just east of Lesotho in KZN. It occurs in montane grassland with high rainfall and streams forming shallow valleys, dongas and potholes. It can also be seen in montane sourveld in many parts of its South African range.

Movements and migrations

Intra-African breeding migrant, it is present in Zimbabwe from late August to mid April and in South Africa from October to April. It migrates in flocks of about 40 birds to east Africa in the non-breeding season.

Food 

It eats flying insects, usually foraging in flocks of 4-5, catching prey near the ground.

Breeding

• Monogamous, strongly territorial solitary nester; breeding pairs vigorously chasing other swallows away from their territory. It often produces two broods per breeding season.
• Nest construction starts around October, with both sexes collecting mud while simultaneously mixing it with grass. This mixture is then evenly applied to form a half-bowl, which once completed is lined with dry grass, fine roots and white feathers (possibly to help them find the nest in the dark). It is usually placed in the sloping wall of a pothole, donga, riverbank or Aardvark (Orycteropus) burrow. In some areas (especially Mpumalanga) most nests are placed in old mine workings. There are also a few records of nests in road culverts and buildings.

Blue swallow at its nest, Kaapschehoop, South Africa. [photo Warwick Tarboton ©]

• Egg-laying season is from October-March, peaking in South Africa during December-January.
• It lays 2-3, rarely 4 eggs, which are incubated solely by the female for 14-17 days.
• The chicks are fed by both adults, leaving the nest after approximately 20-26 days.

Threats

Globally Vulnerable, in South Africa classified as Critically endangered, making it South Africa's most threatened bird. It has an estimated world population of just 4000 birds, with about 300 pairs in Zimbabwe, 100 pairs in Mozambique, 15 pairs in Swaziland and 81 definite and possibly 39 more pairs in South Africa. The main cause of is the destruction of sour grassland habitat for commercial forestry or agriculture. It is uncertain whether nest site availability is cause for concern, due to the abundance of mine shafts to nest in.

References

• Hockey PAR, Dean WRJ and Ryan PG 2005. Roberts - Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.