Some bird lovers in the city find that crows are using metal wires along with twigs to build their homes. They tell Akila Kannadasan that urbanisation and tree-felling could be leading to these architectural changes

The crow’s nest looks quite ordinary. One might think it’s just a bunch of twigs of varying sizes heaped together. But did you know that beneath each of those twigs is several weeks of hard work put in by a crow-couple? They start gathering twigs a month before they breed. Each twig is selected with utmost care — the stronger ones for the base in order to secure the nest between the branches of a tree; the softer ones at the centre to form a bed for the eggs.

As you read this, crows in our neighbourhood are building their nests — their breeding season falls on the months of March and April. Look a little closer and you may spot them as they fly past with a twig between their beaks.

Joseph Reginald, a PhD student at the Sálim Ali Centre for Ornithology and Natural History, Vinny Peter, a research student at Bharathiyar University, and school student Ashok, have collected 45 such meticulously constructed nests. The team is from Animal Rescuers, a welfare organisation made of students that rescues and rehabilitates birds with help from the forest department.

Nests for sale

It all began in September 2012. Trees were being felled on Thadagam Road. As dead branches fell to the ground, the nests they held fell too, along with their new-born inhabitants. Some of them died from the impact. Vinny and her friends were surprised to see the contract-labourers on the job burn some crow’s nests. “The nests had a lot of metal wires in them. They told us that they were going to sell them,” says Vinny. Intrigued, they bought two nests for Rs.40. They also brought some chicks home and nursed them till they were fit to fend for themselves.

With support from the contract-labourers, the team collected more nests from the area and from Kuniyamuthur. Each nest gave them an insight into the world of crows. “Some nests were made completely of wire. Aluminium, iron, nylon and brass wires, plastic threads…one even had a tongue cleaner,” says Joseph. A nest weighed as much as two kilos, and one had an iron wire that measured two feet!

“Crows do not roost and nest in the same place,” says Joseph. They might hang out as a group but when it comes to nesting, a couple prefers some privacy. “But a tree close to Thadagam Road had about ten nests,” he says.

Have changing environmental conditions driven crows to alter their nesting material? Joseph, Vinny and Ashok are looking for answers inside the nests. They weigh the nests, measure them and look into their architecture. Their subject being a species that is deemed as ‘vermin’ in The Wildlife (Protection) Act, 1972, Vinny says reference material is scarce.

The team is working with Manchi Shirish, a scientist at SACON. Shirish says that nesting materials they found are a grim reflection of the effects of urbanisation on birdlife. “The study gives us an opportunity to look into the lives of birds that live in cities. We want to convey the science behind the issue as well as the problems. We can strongly say that the nesting materials of birds are changing… 20 years ago, crows would have found more twigs than wires. You never know, in the future, a crow’s nest could be made completely of wire.”

Bird expert R. Ratnam says that he has seen crows using wires as nesting material in Mumbai, some 30 years ago. He feels that industrialisation could have driven the birds to do the same here. “Since trees are being cut, they might find it easier to find wires than small twigs,” he says.

Though not as intricate as that of a weaver bird’s, the crow’s nest is more elaborate than the sparrow’s, adds Ratnam. The birds are sticklers for cleanliness. Joseph says that none of the nests they observed had droppings in them. Crows instinctively keep their houses spic and span.

Animal Rescuers feels that when trees are cut, the welfare of their inhabitants should be taken into consideration. “It will be nice if trees are not felled during the breeding season. Before chopping a tree, a local birder or the forest department should be consulted. This will spare the lives of a lot of birds.”