Black-billed Koel

The black-billed koel is an island cuckoo whose dark bill separates it from every other member of the common-koel complex, all of which have a pale bill. Its voice includes the familiar rising koel call and short sequences of rising and falling woo notes. The species is endemic to forest and woodland on Sulawesi, Sula, Banggai, the Togian Islands and other nearby Indonesian islands (Wikipedia general and taxonomic account).

Taxonomic treatment of this bird remains unsettled. It has often been included within the common or eastern koel, while the International Ornithologists’ Union recognises Eudynamys melanorhynchus as a distinct species. General koel sources describe fruit eating and brood parasitism, but the opened species account did not verify a particular diet or host for the black-billed koel itself. Those ecological and breeding details are therefore omitted rather than transferred from a related form (IOC treatment reported in Wikipedia; Australian Museum comparison account).