Wetland, Forest, and Open Paddy Land Are the Key Foraging Habitats for Germain’s Swiftlet ( Aerodramus inexpectatus germani ) in Southern Thailand

摘要

Germain’s swiftlets (Aerodramus inexpectatus germani) are farmed regularly in Southeast Asia and produce highly valuable nests for which there is an increasing demand. Some populations of this species are thought to be decreasing, but little is known about the habitat used by swiftlets for foraging. Here, we focused on this swiftlet’s foraging habitat selection and describe their daily and seasonal variations in habitat use. We predict that the prey capture attempts would be highest during twilight periods of each day, but that overall capture rates would vary with season and habitat type. Prey capture attempts at different times of the day and seasons in five different habitats were investigated and compared to flying insect availability (estimate as biomass). For each habitat, insects were trapped immediately 5–10?m above vegetation levels (i.e., tree canopy and open paddies) and 0–5?m above water surfaces in water body habitat. The highest foraging intensity occurred over water bodies, forest, and open paddy land; all of which contained high numbers of major prey insects (Hymenoptera, Diptera, and Hemiptera). Foraging during the wet season was at a greater intensity than during the dry season which was associated with increased insect availability. This suggested that food supply in each habitat type, time of day, and season influenced the bird’s foraging habitat use. To conserve populations of this swiftlet, it is therefore important to protect wetlands, forest areas, and open paddy land to support natural insect prey within the foraging range of local swiftlets.