Blue swallow  (Hirundo atrocaerulea)

The blue swallow is classified globally as Vulnerable (VU) on the IUCN Red List 2007 (1), although this classification is currently under review, and as Critically Endangered in South Africa (5). It is also listed on Appendices I and II of the Convention on Migratory Species (CMS or Bonn Convention) (6).

The magnificent blue swallow is a relatively easily identifiable species as the adult birds have a highly lustrous dark metallic steel-blue appearance with long tail streamers, which are particularly noticeable in males. White feathers are visible on the rump and flanks when the birds are preening and especially during courtship. In poor light, blue swallows appear almost black and therefore can be mistaken for black sawwing swallows (Psalidoprogne holomelas) which occur throughout the breeding range of the blue swallow (5) (7). Young blue swallows start life a brownish-grey, acquiring their blue colour as they mature (5). This species has a musical ‘bee-bee-bee-bee’ call when in flight (7).

The blue swallow migrates seasonally within the African continent, breeding in South Africa, west Swaziland, Zimbabwe, Malawi, northeast Zambia, southwestern Tanzania, west Mozambique and southeast Democratic Republic of Congo, and wintering in northeast Democratic Republic of Congo, south Uganda and west Kenya (7). In 2002 there were estimated to be around 1,500 pairs remaining (8).

In the breeding range, the blue swallow inhabits areas of rolling montane grasslands where rainfall is high (7). In the non-breeding range, this species prefers open grassland with very large wetlands (5) (7).

The blue swallow arrives on the breeding range at the end of September and constructs cup-shaped nests from mud and grass on the inside of sinkholes cavities, aardvark burrows and old mine shafts. The breeding system of the blue swallow is not well understood although co-operative breeding has been widely recorded in this species. The nests are lined with fine grass, animal hair and white feathers. Normally, three white eggs are laid. They are incubated by the female for 14 days, and the chicks are fed for approximately 22 days until they fledge. Once fledged, the young spend the next couple of days around the nest site before disappearing. Most blue swallows will nest for a second time before returning to the over-wintering grounds in April (2).

Blue swallows feed on small, soft-bodied flies and other arthropods, catching them on the wing (2).

The grassland habitat of the blue swallow is being diminished at an unprecedented rate. The main causes of this habitat loss are afforestation, human settlement, agricultural expansion, over-grazing by livestock, and the invasion of alien plants. In the South African province of KwaZulu-Natal, the grassland habitat of the blue swallow declined by 46 per cent between 1981 and 2000 (3).

The blue swallow breeds within national parks in Malawi, Zimbabwe, Kenya and Swaziland (7), and an international species conservation action plan is in place (8). However, without the official intervention of government agencies and the expansion of the network of formal protected areas, the future of this species hangs in the balance (5).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the blue swallow see:

• Endangered Wildlife Trust:
  https://www.ewt.org.za/WHATWEDO/OurProgrammes/ThreatenedGrasslandSpeciesProgramme/OurProjects.aspx#BlueSwallow
• IUCN Red List:
  www.iucnredlist.org

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org