Roosting of Savanna Nightjar
Posted by BESG on 18 September 09, Friday
Contributed by Chris Lee
On the morning of 22nd August 2009, Chris Lee a.k.a. chrisle023 came across about 20 Savanna Nightjars (Caprimulgus affinis) roosting on the ground of a scrub area in Singapore. Unfortunately the area has now been developed into a race track and the birds need to seek out a new roosting site.
Nightjars roost and breed on the ground. The site must be able to provide camouflage to allow their plumage to blend in with the surroundings. At the same time the roosting birds must have a good view of any approaching danger.
The birds normally arrive at the roosting site before dawn and leave at or during the twilight period of dusk. When the weather is dull and overcast, they may roost slightly earlier. During the period of roosting, they may wake up for short periods to preen, stretch their wings or gape widely. They may even move if they are in direct sunlight or are too long in the sun. They may shift their position to face the sun so as to reduce tell-tale shadows or even move from cooler and shadier place to sunbathe.
They leave their roosting site at or during the twilight period of dusk, slightly earlier when the weather is dull or the sky is overcast. Such site is often used and reused unless the birds are disturbed.
The birds roost alone or in pairs. However, during the non-breeding season, nightjars may roost semi-colonially, as seen here.
Image by Chris Lee.
Reference:
Cleere, N., 1999. Family Caprimulgidae (Nightjars). In: del Hoyo, J., Elliott, A. & Sargatal, J. (eds.), Handbook of the birds of the world. Vol. 5. Barn-owls to hummingbirds. Lynx Editions, Barcelona. Pp. 302-386.
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Categories: Roosting
Comment by Subaraj
Made Friday, 18 of September , 2009 at 4:44 am
Actually, based on my observations of roosting Savanna Nightjars over the years, they normally do not roost colonially or semi-colonially, breeding or non-breeding periods.
This colonial roost seem to only occur after a heavy downpour floods much of the scrubland or grassland, and the birds congregate on grounds that are slightly higher and drier.
Most of the time, such habitats are much drier and these nightjars spread out to roost in any suitable areas. moving to shady or semi-shady areas during the heat of the day.
