Flying the nest: With Ludhiana becoming a concrete jungle, avians flock to greener pastures

: Rapid urbanisation, decreased green cover, and change in land-use pattern has adversely affected the avian diversity of the city, a study carried out by Punjab Agricultural University ornithologists has found.

The team of ornithologists studied the interaction of avian species with the vegetation in select areas – Rajguru Nagar, Aggar Nagar, Dugri Estate and the PAU campus – using remote sensing, and geospatial (satellite) technology. Data from the Punjab Remote Sensing Centre (PRSC) was also collated for the study.

Principal ornithologist Tejdeep Kaur Kler said, “Each site was classified into built-up area, vegetation, parks, fallow land and road cover. To understand location-wise bird diversity, a comparison of species along with their feeding guilds was carried out. The study revealed that bird distribution, composition and structure had been affected by urbanisation in Ludhiana city.”

Claiming that city was exhibiting signs of a biodiversity crisis, she said, “Increased urbanisation has led to an increase in urban generalist species (birds that thrive in urban areas) in the city, which has led to biotic homogenisation.”

Kler and her team spotted 46 species of birds during the study, which was carried out early in the morning and in the evening. As many as 32 bird species were spotted on the PAU campus alone.

“The crow, common myna, rock pigeon, red-vented bulbul, which have adapted to the urban habitat, were most commonly spotted,” said Kler, who carried out the study with master of science (MSc) student Hasneet Kaur.

Woodpeckers were only found on the PAU campus, which is has ficus (fig) tree species, which are ideal nesting sites for the bird. “Birds who thrive on fruit (frugivores) are thriving on the PAU campus, which is rich in flora. In urbanised areas, granivores (grain eaters) and omnivores are more abundant as they are able to build nests on multistorey buildings and outside windows,” the principal ornithologist said.

On the reasons for the decrease in avian diversity in the city, Kler said, “There are two types of birds – excavator species and cavity nesters. Excavator birds are those who dig their nests, while cavity nesters build their nests in holes or other safe spaces. Unfortunately, ideal nesting sites for both types of species are decreasing in cities. Besides, concrete structures release more heat due to which certain species have migrated to greener areas.”

“Another reason is decrease in indigenous plant varieties. Most people prefer planting exotic plants rather than indigenous plants, which is why birds are migrating to suitable habitats,” said Kler.

“Urban locations with balanced built-up areas and vegetation might help in sustaining a rich avian biodiversity ,” concluded Kler.

House sparrow rendered homeless

Ornithologists say the rapid decline of house sparrows from urban areas is a classic example of how changes in urban structures have led to the migration of bird species.

“To protect its offspring from predators such as cats and kites, and to teach them how to fly, the sparrow needs a bushy tree with thorns. The modern urban setup lacks both, which has led to the migration of sparrows to safer locations,” says Kler.

Indigenous trees could turn the tables

With as many as 22 bird species preferring to build nests on four indigenous trees – Peepal (Ficus religiosa), pilkhan (Ficus virens), banyan (Ficus benghalensis)and common fig (Ficus carica), Kler says the introduction of these trees could be a game changer for the avian population of the city.