Horsfield's Bronze-Cuckoo is the real soprano of the Bronze-Cuckoos - its slow, downslurred whistle is several notes higher in pitch than its nearest "rival", the Shining Bronze-Cuckoo. Samples 145-540, 042-250 and 031-150 are all examples of the main advertising song, the first two from Round Hill in NSW and the last from Western Australia. The individual songs do vary but not by very much. 031-150 is an example of how cuckoos can be harassed by other small birds but the bird in 042-250 has solved that problem - he is singing at night! a strategy common to cuckoos the world over. Sample 145-520 is what is generally known as the 'chirrup' call - it sounds a bit like a pipit. The function of this call is not known but it doesn't carry a long way like the advertising song which is audible from several hundred metres away.