Last Thursday, my brief siesta was disturbed by the loud, raucous screeching of the parakeets from the tamarind tree outside the house. Initially I ignored this but when it persisted, I decided to investigate. These incessant alarm calls normally indicate the presence of a predator, usually a snake.
I could notice half a dozen parakeets fluttering and excitedly flying about a particular branch and there were also a couple of palm squirrels moving around the same spot, their tails raised in alarm. A few minutes of patient waiting revealed the cause of their concern – a 4-foot long rat snake, moving slowly along the thick branch, thirty feet above the ground. The noise attracted the attention of a crow that briefly joined the parakeets. The drama persisted for well over 45 minutes during which the snake moved from branch to branch, the birds in hot pursuit. There were some intervals of silence, during which the snake was concealed in one of the numerous cavities of this ancient tree or amidst the foliage of the pipal tree that has taken root on the main trunk of the tamarind. I had to warn the girls who were going for lunch or coming back from lunch to Red House (completely oblivious to the racket made by the parakeets!) since the snake has a tendency to drop off from the tree to escape the harassment of the birds. Close to 2.00 pm, a couple of students reported seeing a large snake crossing the road and by then the parakeets fell silent.
Communal mobbing of snakes is a fairly common sight in Rishi Valley and I have come across this on several occasions. On some instances, I have seen a host of bird species participating in this activity and the list includes sunbirds, flowerpeckers, tailorbirds, Magpie-robins, common iora, bulbuls, occasionally drongoes, parakeets, mynas and crows. Rat snakes regularly climb trees where there are bird nests, especially those of parakeets and mynas. The smaller birds named above usually mob the green vine snake which is an arboreal species. While mobbing, birds give sharp alarm calls and move excitedly and often very close to their adversary. Birds like crows even nip the reptile’s tail and harass it. Once a few years ago, I had seen a vine snake with an ashy drongo, dead, in its mouth, being mobbed by crows.
Dr Santharam