Barn swallow roosting at an oil gathering station

Abstract

Barn swallow (Hirundo rustica) is a migratory aerial-insectivorous bird and has been known to winter in Indonesia. Normally roost on trees, there was a report that thousands of them roosted on human-made building. The objective of this paper was to document the barn swallows that use an oil gathering station (GS) as their roosting site, examined their roosting habitat, and seek the reasons on why the GS was selected as the roosting habitat for the barn swallows. Observation was conducted in Petapahan GS, Riau, in May 2023. Swallow abundance was estimated in the evening (6:30-8:00pm), perching spots were observed. The land-use of surrounded area was observed. There were 4,000 barn swallows roosted at night in the GS. There were many big tanks, small-large pipes, handrails, valves, processing buildings that can be used for roosting. At night, the GS was bright and warm in most parts. The surrounding was a vast area of oil-palm plantation, mixed with mosaic microhabitats (agricultural area, open area, housing). Some possible reasons why swallows used GS were: (1) located at the migration route, (2) the abundance of perch sites, (3) warm temperatures, (4) sufficient lighting at night, (5) abundant insect food at the surrounding oil-palm.