Which hawk-eagle?

One species that I find most confusing in the field is the Changeable hawk-eagle (Nisaetus cirrhatus). The least confusing aspect is that there are two morphs. The one you see in these photos is called the light morph. The dark morph does not have the streaked white chest, and is much darker uniformly. But more than that, the field identification is rendered more confusing because of controversies about subspecies and cryptic species. This has left a legacy of birders looking at multiple characteristics and distinguishing between features which could perhaps be widely variable without distinguishing species or subspecies. I will not enter that controversy (you can read a condensed version in its Wikipedia article) but will go with the Linnaean wisdom: if two things have the same binomial, they are one species.

It’s a common enough bird, easily spotted across India, south of Jammu, below the Tibetan plateau, and eastward across Asia right up to Banda Sea, in central and South Vietnam and the Philippines. What was uncommon about this sighting in Kanha NP was that I found it in a little muddy pool drinking water in great gulps. It looked up as we stopped, but after that it didn’t pay us much attention. It is the apex predator in its own niche, after all. I’d never seen it drinking water before, so I didn’t know whether it was extra thirsty because of the heat or what looked like an orgy of drinking was normal. But then, just a week before, I’d seen a small but feisty Jungle owlet (Glaucidium radiatum) drive one away by flying directly at it. I wouldn’t have thought that was normal either, except that a much more experienced birder said that he’d seen smaller raptors shooing away bigger ones before. The longer you watch birds, the more interesting behaviour you see. I suppose all that it means is that, within their physical limits, creatures have more autonomy and adaptability than they were once supposed to have. Hawk-eagle, thy name is change.