I was walking through the beautiful evergreen forests of Agumbe (see photos) in south India. It was late morning and raptors were flying over the forest in search of prey. As I walked into a forest clearing I saw a crested serpent eagle soaring high above the forest. It was soon joined by a crested goshawk and both birds circled above.
I have a habit of whistling a species’ call when I see a bird. This helps me remember bird calls/songs. As I watched the serpent eagle through my binoculars, I whistled the crested serpent eagle’s plaintive whistling call which sounds something like kuk-kuk sceeeeeew- sceew sceew a few times. Suddenly I heard a response!
I had never heard a crested serpent eagle respond to a whistle! Startled I whistled loudly again, and again there was a response. The response came from somewhere close in the forest. I suspected that there was an individual sitting on a tree responding to my calls. I scanned the trees in the direction of the call but couldn’t see an eagle. I continued to whistle and continued to get a reply. After about 3 minutes of searching I realized that the bird responding to my playback was actually a greater racket-tailed drongo sitting in a tree hidden by foliage, responding to my whistles!! It was mimicking the eagle’s call perfectly!!
Several species of drongos are excellent mimics of bird and even some mammal calls. Racket tailed drongos are known to mimic several species in their environment. They are known to use mimetic calls to deceive other birds. For example, when in a mixed species flock, if a racket tailed drongo finds something big and juicy it doesn’t want to share, it will mimic a raptor like a serpent eagle to scare other members of the flock away!!
Fooled by the drongo I walked back to the field station for some hot idlis!