Habitats and Microhabitats.—Edible-nest Swiftlets were more active in forested areas,
whereas Glossy Swiftlets were more active in open paddy lands. The Edible-nest Swiftlet’s activity is in concordance with previous studies (Medway 1962, Harrison 1972, Hails and Amirrudin 1981, Waugh and Hails 1983, Charles 1987, Lim and Cranbrook 2002, Nguyen et al. 2002).
The Glossy Swiftlet is the only swiftlet species known to occur in all habitats. The diet of the Glossy Swiftlet in Malaysia (Laurie and Tompkins 2000) shows elasticity in food and foraging habitat selection unlike the Edible-nest Swiftlet. Further validity is given the concept of greater elasticity by Collins (2000) for Glossy Swiftlets
on Palawan where it has resource partitioning caused by the presence of Pygmy Swiftlet
(Collocalia troglodytes). In this situation, it was restricted in most of its feeding to ,2 m above ground; a zone more likely to increase vulnerability
to land-based predators. That this species flies so low when ‘‘forced’’ into ecological partitioning was reported from New Guinea by Schoddle and Hitchcock (1968), where it was sharing habitat with the Uniform Swiftlet (Aerodramus vanikorensis). It has been shown on that
same island, but at greater altitudes, to share space with the Mountain Swiftlet (A. hirundinaceus) in a similar way (Diamond 1972).