Lena Chow recorded a video clip of a White-breasted Waterhen (Amaurornis phoenicurus ) in March 2011 “…making its usual loud, repetitive croaky call to another bird (or two) in the low bushes this evening. The ruak-ruak calls taper off at the end into a seldom heard (at least to me) coo-ing, and I can’t seem to find any description of dove-like coo-ing in a quick check of online literature. Perhaps this has something to do with calling out the other bird in hiding?”
Lee Chiu San
I have a pair of waterhens resident in my garden. They come for food every morning, and I can confirm that they do have a wider range of vocalisations than the ruak-ruak recorded in the literature. The ruak-ruak call seems to be triggered by aggression. When they are calling to each other, the notes are more varied, and include the cooing sound.
The Chinese name of the White-breasted Waterhen is 苦恶鸟 (kǔ-è bird). I think the 苦恶 (kǔ-è) part reflects the cooing sound. If you listen to the cooing, it sounds like coo-er coo-er.
Sun Chong Hong
The word 恶 is also pronounced as wu4 (in Han Yu Pin Yin). Whether it sounded like “ku-e” or “ku-wu” depended on how one heard the call. One Chinese web-site described the sound as “ku-u” (http://www.newsmth.net/bbsanc.php?path=%2Fgroups%2Fsci.faq%2FWildLife%2Fflx%2Fbird1%2FM.1101807323.V0) while another one had it as “kue” (http://www.cngba.com/thread-17110653-1-1.html).
I have listened to all the sound samples of white-breasted waterhen in http://www.xeno-canto.org/asia but didn’t hear any ku-e or ku-wu, I only heard 苦哇 (ku-wa). By the way this bird is called 苦哇鸟 by the Northern Chinese.