The Savanna Nightjar (Caprimulgus affinis) is a species of nightjar found in South and South-east Asia. Its preferred habitat are scrub, open country and particularly grassland with open stony patches.
Unknown to most, it is actually a recent resident species of Singapore. It is believed to have colonised Singapore through the Riau Archipelago in Indonesia, and spread to Singapore and Malaysia subsequently from the 1980s onwards. What is surprising about this fact is that the species is not known to be a strong flier nor is it a migratory one. So perhaps what one can say about birds in strange places is that one should not jump to conclusion about their origin!
The bird is largely nocturnal and hunts for insects at night, usually solitary but sometimes in a small group. They are very vocal in flight, and that one of the way to find them.