Noisy Nocternal Calls (1 Viewer)

Can anyone help with a strage call during darkness ,my son is currently working in SOuth Korea .....Jujeon-dong ,Ulsan,he is staying in a rural sounding area and this Possible bird starts calling from darkness till dawn,it sounds like three loud clunks one after the other ,like something hitting wood ........far reaching but he cant find anything that sounds like it in internet ...any ideas appreciated...

Is there any way you could post a recording of the sound?

I will try and post the recording once he gets home tomorrow......no idea how yet but i will try .....