Even an Expert Can’t Tell

This is a Pond-Heron.  There are two types of Pond-Herons mostly seen; Chinese and Javan.  Even our expert guide could not tell which of those two species this one, and many other ones, were.  In their non-breeding plumage they are identical, however when we traveled north, the difference was more apparent (in breeding season there).  I randomly assigned this as a Chinese Pond-Heron, even though it is impossible to know if that is right, or if it is a Javan.