In Briefly: Man-made nests a success


The blue swallow Hirundo atrocaerulea is an intra-African migratory species threatened by destruction of upland grassland. It nests in montane grassland interspersed with drainage gullies and valleys at scattered localities in southeast Africa. In 1998 the global breeding population was estimated to be 2,000 pairs. In South Africa and Swaziland it breeds only within north-eastern Mountain Sourveld and Natal Mist Belt Grassland. The nest is usually attached to the roof or side of a hole in the ground, often in sinkholes or old aardvark Orycteropus afer burrows. Birds are very site faithful, returning to the same nest-hole for up to 30 years. Its grassland habitat is being degraded or lost to afforestation, human settlement and farming, grass-burning and mining. It is now close to extinction in Swaziland and South Africa where between 81 and 120 breeding pairs remain. In an attempt to provide nest sites for blue swallows, some artificial nest burrows were excavated.

Nest hole excavation: In 1995, three nest holes were excavated in an area of upland mistbelt grassland in eastern South Africa. The area was known to be frequented by foraging blue swallows Hirundo atrocaerulea but lacked suitable nesting holes. the nest holes were at least 250 m apart; pairs are territorial and a distance of 250 m is the closest that two nesting pairs has been recorded. 

The year after excavation, two of the three holes were used by blue swallows for nesting. Even though successful, provision of nest sites through the excavation of nest holes is only regarded as a temporary stop-gap measure until natural hole-creation process are reinstated, and hopefully some areas of mistbelt grassland are restored.

Note: If using or referring to this published study, please read and quote the original paper.

[Original source: Johnson, D.N., Morford, J.S. and Croft, M. Digging for the Blue Swallow - does it work? Is it ethical?  Lammergeyer 44 September 1996, 46-49.]

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