6. Guard calls
Generally, K-RC display much more GC than J-RC do. Moreover, many GC of K-RC sound completely different. Whereas the J-RC GC is more like we know GC from other crane species, the K-RC can display both the "normal" GC as also a "chatter", sounding more like a flight call.
It might be of interest that I have not succeeded in provoquing a unison call (or even a guard call) from a K-RC using J-RC unison calls (which I have on CD and replayed via megaphone). Not a single reaction based on this. GC were only displayed towards us when we were seen and in their view too close to the pair.
Several features of the calls, like
show basic differences between Japan and China / Korea.
This supports the hypothesis that the Japanese population was separated from the mainland since sufficiently long time to allow the development of at least a "dialect", if not a completely different "language". My impression is, that the differences are as strong as between RC and Whooper Cranes.