Gomanton caves
E. Banks’s short note describes the Gomanton caves in Sabah, documenting their swiftlet colonies, bat populations, and associated raptor and seabird communities.
Summary
Banks provides a physical description of the cave system, which comprises a lower gallery (Simud Hitam) and an upper gallery (Simud Putih) connected by a vertical funnel, with a further narrow funnel (Bun Bulat) leading to the hilltop (p. 177). He records the collection of 80–100 piculs of “black” nests (Collocalia lowi) and up to 20 piculs of “white” nests (C. vestita) per harvest, estimating minimum populations of one million and 150,000 birds respectively. He also discusses the “mossy” nest swiftlet (C. esculenta) and a similar species in the Simud Putih that he assigns as a subspecies of C. whiteheadi from Palawan and the Philippines (pp. 177–178).
The note’s most vivid passage describes the evening bat exodus: a conga-like column a mile or more long, two yards wide, emerging in a whirling spiral from the vertical tunnel. Banks identifies the mouse-eared bat as the dominant species, with horseshoe bats forming dense clusters that break away from the column. He contrasts this spectacle with the less dramatic bat issue at Niah caves in Sarawak (p. 178). The note closes with observations on fish-trap bird communities at Beluran and Semporna, where Brahminy Kites, Adjutant Storks, and various terns exploit the tugau stake nets (pp. 178–179).