Appearances are deceptive, and unbelievably so for the tiny Tawny lark: the dull brown-coloured bird that is small enough to fit in your palm can imitate calls of 34 other birds found in its habitat, and even shepherds’ whistles.
Many birds mimic the calls of other birds to impress females during territorial displays, to discourage competing species from using the area and to teach their young to associate the calls of other birds with danger. The diminutive crested Tawny lark – found only in the arid grasslands and scrub lands of central and west-central India including Gujarat, Uttar Pradesh and Maharashtra – belongs to a family of larks well-known for their mimicking abilities.
A team of scientists from Cornell University and the Bombay Natural History Society studied the flight songs of these birds in Gujarat and analysed the acoustics of their calls. They found that male Tawny larks imitate the calls of 34 other bird species, including babblers and lapwings, with varied accuracy.
Interestingly, they even mimicked a squirrel and whistles of local shepherds – indicating that the birds learn from their surroundings. “So larks in other parts of India are likely to mimic other species too,” one of the authors, Sahas Barve who took a Ph.D from Cornell University told The Hindu in an e-mail.
“Not only are the males listening to other species [in their environment] but if it is a signal of male quality then it means that the females know all the calls well too and are choosing males that can either mimic the most number of species or can mimic the most species really accurately or both. We don’t know yet,” writes Dr. Barve.
Birds often learn to mimic other birds and sounds they hear, like Australia’s Superb lyrebird which can imitate chainsaws and car alarms. Though mimicry is poorly-studied and its functions highly debated, it is thought to influence the behaviour of birds (of the same species and others) that are listening.
Disappearing habitat
Also a songbird, the Tawny lark is one of India’s 22 lark species. It is endemic to the Deccan region, locally common in its range and not yet threatened, says Dr. Barve. However, the habitat it lives in – grasslands and scrub lands – are one of the fastest disappearing in the country, he adds. Rapid urbanisation and conversion of grassland and scrub habitats into farms endanger these master mimics. The researcher says common birds need to remain common, and others saved.
Published - October 21, 2017 08:23 pm IST
