Male  Indian Cuckoos Cuculus micropterus  can be heard calling all day long in the forest around the Ulu Ulu Resort and the Belalong Canopy Walkway but are rarely seen. The Indian Cuckoo in Borneo is a nest parasite on Black and Yellow Broadbills. The male cuckoo calls  to attract a female cuckoo to mate  and presumably announces to her that he has discovered a Black and Yellow Broadbill nest into which she can deposit an egg. A pair of Black & Yellow Broadbills are resident  next to he Belalong Canopy Walkway so it is hardly surprising  to encounter an Indian Cuckoo calling nearby !
Hans unspecified.jpg
A female Black &  Yellow Broadbill photographed next to the Belalong Canopy Walkway by Hans Hazebroek.