This page gives some indication of the variety of calls of the Chestnut-breasted Cuckoo. Samples 1 and 2 are both from the same bird at Cape York (Lockerbie Scrub), sample 3 a "fee-ooo" call taken at the same place may have been a different individual (a female?) The repeated chop-chop-chop in the background is some sort of rainforest sound I can't identify, certainly not a nightjar! Sample 4 was again at Lockerbie Scrub but in this sample there are at least two, or even three birds calling - there are two birds trilling and maybe another giving the two or three note soft whistle in between( the HANZAB 3 note call), unfortunately overlaid on other rainforest calls. The final sample is of a Fan-tailed Cuckoo from near Malanda on the Atherton tableland - the main difference is that the rate of modulation in the Fan-tail is faster - about 12 elements in each call compared with only 9 in the Chestnut-breasted. I suspect that the very long final call in sample 4 is part of some sort of confrontation between Chestnut-breasteds but I did not see this at the time.