Recently, I stumbled upon a very interesting paper that offered insight into, of all things, how birds react to overenthusiastic birdwatchers trying to attract their attention by playing back recorded bird calls. Published last month, the study by Berton Harris and David Haskell in Ecuador came up with the expected and the surprising.
Though dubious, playback remains a widespread practice. While the amateur uses it to boost his or her “life count” of birds, many professionals employ the trick to test hypotheses about the evolution of behaviour etc. Closely watching, nay listening to, their subjects, Harris and Haskell found that the plain-tailed wren (Thryothorus euophrys) “sang more duets” in reply to playback, while the Rufous Antpitta (Grallaria rufula) “made more vocalisations of all types, except for trills”.
The duo went on to conclude that increased vocalisations (bird noises) could be interpreted as a negative effect of playback if birds expend energy in response, become stressed and divert time from other activities. Worse still, they warned, scientists might compromise research if they did not carefully select research sites to ensure their subjects’ behaviour was not already altered by birdwatchers’ playback.
Expectedly, this set many conservationists and bird lovers aflutter. Some demonised “competitive birdwatchers for causing stress and affecting natural birdlife”. They were not entirely off the mark. Like most vocations, birdwatching too has become a rather elaborate affair, trappings included. Thoughtfully enough, even smartphones now offer a birding app that allows one to identify different bird calls through playback. Given most birders belong to the smarter variety of their species, chances are many a bird is hearing mechanised calls to mating or competition.
I am not a great bird (or animal, for that matter) enthusiast and prefer any exploration in moderation. But birdwatchers (who watch less and photograph more these days) are guilty of far graver crimes than playing back bird calls. Some even go to the extent of destroying nests after clicking lest others get a chance too. And anyway, playback cannot ruin a bird’s life. During the study, Harris and Haskell found that birds are smarter than we think.
In repeated playback experiments, notes the paper, responses from wrens were strong at first, but hardly detectable by day 12. One group built a nest, apparently unperturbed, near a playback site. This means even the smaller bird species can figure out the playback fraud pretty soon. And confusion over a week or two cannot really throw the bird off kilter. Also, in popular birding areas where birds are likely to be accustomed to playback, birders may altogether stop bothering about it. Unless, they get lucky simulating a female to draw the males of the species.
I don’t know how birds will react to that; here’s a pointer to mammals. A few years ago, Rajasthan’s forest officials were struggling to bring back two ‘straying’ tigers of Ranthambhore. After repeated tracking attempts failed, they decided to “call” the animals in.
The female had settled down in a degraded forest patch by a state highway outside the national park. Sharpshooters and tranquiliser guns in place, the hopeful staff played the male roar on loudspeaker. Soon enough, the tigress appeared at the edge of the forest but did not approach the staff’s vehicles immediately. After observing the collective ruckus of several jeeps and chattering foresters for half an hour, she went back into the forest. The roar was played over and over again, but the tigress had heard enough.
Clearly, she could make out the faux roar and was too disgusted to respond a second time. Not so her male counterpart. Every time, he emerged to check out the female voice even if the feline itself was not in evidence. It is unlikely that he was any less intelligent than the tigress. Perhaps, testosterone was getting in the way. He came off as desperate but the foresters were empathetic.
A male couldn’t take a chance with a female, they said. I agreed.