What's so changeable about this forest eagle, you may ask. The answer has more than one context.
I cannot talk about the Changeable Hawk Eagle with laypersons without encountering that most pedestrian and wearying of questions: "What hawk eagle?" For your benefit, I say again: Changeable. One that is capable of change. It implies that the species is extremely variable in appearance. Adult birds may be dark or pale, and juveniles may be quite confusing. It used to be called the Crested Hawk Eagle earlier, and I wish they had stuck to that name. But to add to our confusion, some races, particularly those found in Southeast Asia, lack the crest. In Latin, it is Spizaetus cirrhatus cirrhatus or Spizaetus cirrhatus limnaetus, depending on the subspecies you are staring at. And if Pam Rasmussen must have her way, both subspecies are now separate species. A curious case of (S D) Ripley's Believe it or Not. Or some such. My first memorable encounter with this species (I usually exclude early childhood sightings because imagination overpowers memory and tends to fictionalise fact) was at the BRT Wildlife Sanctuary in March this year. A few turns before the K Gudi forest gate, Sandy (who took a record photograph then), spotted the raptor perched on a vantage bough overlooking the valley. On a more recent trip to BR Hills early this month, we saw two individuals who illustrated beyond doubt the predicament of baffled ornithologists (or taxonomists) who christened it. Both we saw up close. The first was a dark individual (above), and the second (below) had a plume of a crest and was paler. Probably a juvenile. 
The Changeable Hawk Eagle, like most forest eagles, is extremely agile. The second individual we saw shot off from its perch at great speed through a maze of forest trees and with immense power in its takeoff. Two weeks ago, I chanced upon this hunter at work. Driving back from Meghamalai, my car reached a bend in the road where forest shared an indistinct boundary with tea plantation. In a glade, I saw a hare cleaning its whiskers. Overhead, a shape darted out of the trees. The hare, startled by the sound of our engine, bolted. The eagle missed and, shrieking, cut a jagged path across the tea garden, then disappeared into the thicket. Did it strike or did it miss? I couldn't stay to find out. Photographs: © Sandeep Somashekaran. All rights reserved