Environment

How birds' mating calls have become more audible thanks to lower noise pollution

Ashy Prinia

Ashy Prinia   | Photo Credit: Special Arrangement

It is a familiar, unmistakable melody. Starting with a softer ku..oo ku..oo… it rises gradually to a crescendo. This is the Asian male koel, serenading the female which responds with a shriller kik… keek... keek. Love is in the air for koels and the COVID-19 lockdown is helping fuel the romance.

“During the breeding season, koels sing lustily, at midnight, 2 am, 3 am...,” says Bengaluru-based Ashvin Vishwanathan, Research Associate at Nature Conservation Foundation. “When there is less noise, the mating songs the male koel sings reaches female koels farther away.”

Asian Koel ( female)

Asian Koel ( female)   | Photo Credit: Special Arrangement

 

With far less ambient pollution, and human interference, their mating calls are louder and clearer than ever before. AM Aravind says now he knows why the Yellow-billed Babblers are called silamban in Tamil. “I noticed how their call sounds just like the silambam: kala kala kala during silambattam or stick fighting, a form of martial arts,” says the birding enthusiast from Madipakkam. Aravind says he has been noticing different species of birds around his house engaged in courtship. “They flap their wings and perform a mating dance. I watched two male babblers fighting over a female. After a few days, I saw the courting couple collect twigs to build the nest.”

He adds that he was lucky enough to spot the male Grey-breasted Prinia perform acrobatics in the sky to attract females, as well as watch the White-throated Kingfisher build the nest inside a well. “ They were super nosy chasing away crows, mynahs or shikras. I saw them carrying fish to the nest for the juveniles.”

Baya weaver

Baya weaver   | Photo Credit: Special Arrangement

 

Aravind has uploaded eight episodes on his YouTube channel Neengalum Aagalaam Birdwatcher, which documents the behaviour and calls of nearly 20 species including sunbirds, flowerpeckers, owls, mynahs, parakeets, and Rufous treepie. “I started this channel during the lockdown as I had time to observe birds closely. I wanted people to appreciate the birds in their neighbourhood.”

Neha Arte is convinced she is hearing a lot more birds since the lockdown began.“ It’s a mix of alarm calls and songs, as they are moving towards urban spaces. I saw the Golden Oriole for the first time,” says the environmental architect from Mumbai.

Common Kingfisher

Common Kingfisher   | Photo Credit: Special Arrangement

 

A video of a pair of India grey hornbills perched on the balcony of a home in South Mumbai left many thrilled. “It is rarely spotted in the city but has made an appearance during the lock down,” adds Neha.

Suhel Quader, senior scientist at NCF in Bengaluru, says the mating calls often have multiple notes, strung together into a melody. Then there are birds like the Baya Weaver, which likes to do things differently. Its song, which sounds more like a long screech to human ears, is presumably music to the female bird’s ears.

The Jerdon’s Bushlark, a pale brown bird, lets out high-pitched whistles repeatedly as it performs a ‘parachuting’ display, and the Oriental Magpie-robin, a black-and-white bird, has a wide repertoire, that varies between a whistle, long song and short notes. The song of the Oriental Skylark, can go on for 10 to 15 minutes.

How birds' mating calls have become more audible thanks to lower noise pollution
 

What about the crow? For Christy Bharath, an independent birder in Chennai who has been observing and documenting birds for over seven years in South India, the common crow is the most romantic of them all. “It rubs the beak of the female bird and speaks to her in hushed whispers,” he says.

When birds can hear each other better they can procreate more successfully, says Christy. “We can’t undo the decades-old damage to the habitat. But, we can learn lessons about being more responsible about creating less of a din with our vehicles and their horns. If reduced noise level is helping in species expansion, then why not follow the same even after the lockdown?”

Ravindran Kamatchi, conservationist, agrees that the birds are singing more. “House sparrows, tailorbirds, sunbirds are building nests. During my morning walk, I hear bright green tailorbirds, calling out with a mild kee kee. Zitting Cisticolas circle, uttering a high-pitched call. The lockdown coinciding with the mating season could lead to not just more, but also healthier hatchlings.”

Asian Koel (male)

Asian Koel (male)   | Photo Credit: Special Arrangement

 

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Printable version | Aug 14, 2020 1:28:39 AM | https://www.thehindu.com/sci-tech/energy-and-environment/music-to-the-ears/article31968868.ece

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