New Delhi, Jan 17 (IANS) The declining number of migratory birds in Delhi and the National Capital Region (NCR) has been perturbing bird watching circles who blame it on loss of habitat due to human encroachment.

Every winter, a large number of migratory birds from frigid northern and central Asia visit the cold yet comparatively warmer parts of the Indian subcontinent. Though the number of species has remained constant over the years, it’s the declining populations per specie that is perturbing enthusiasts.

According to experts, the chief reason for this decline is rapid urbanisation, leading to loss of bird habitat. They also add that the threat is larger to birds inhabiting swampy wetlands.

“Rapid urbanisation and encroachment of habitat is the single biggest reason for the decline in bird populations, especially migratory birds,” environment activist Mehran Zaidi told IANS.

Surya Prakash, ornithologist and professor of zoology at the Jawaharlal Nehru University (JNU), agrees: “The numbers per species of migratory birds have drastically gone down because of habitat loss, specially wetlands and aquatic ecosystems, due to commercial use of land and other anthropogenic factors.”

Riverbeds, wetlands and other waterbird habitats have degraded heavily. Bhalaswa lake, for instance, was a very popular birding site, but now a low income housing colony stands on almost half of the lake area.

The once famous Najafgarh Jheel has also dried up. The waterbody, now called Najafgarh drain, was a major nesting ground for waterbirds and waders.

According to Prakash, non-aquatic birds like black redstarts, blue throats, red throated flycatchers and wagtails which inhabit forests are faring much better due to the green cover in Delhi and the national capital region remaining the same - as opposed to those in the wetlands.

“Earlier, we used to have a large number of greater flamingoes in the Bassai wetlands of Haryana during the winters, but this season we’ve hardly had any sightings. Common cranes have not been sighted in Delhi at all this year,” he said.

Leapfrog migration, where the birds decide to shift from one flocking location to another because of more favourable conditions, is said to be another reason for the declining numbers.

In the wake of fast dwindling habitats, the experts and enthusiasts are urging greater attention to manmade sanctuaries. However, the government’s inaction is compounding the problem.

At the Okhla Pakshi Vihar in south Delhi, the birds brave filthy waters, a thin tree cover and high voltage cables overhead. Visitors feel the government should develop the sanctuary properly.

Lamenting the lack of general maintenance of the park, Jeetendra Parashar, an amateur photographer, said: “One of the trails to the watchtowers is broken. If the authorities can’t maintain them, what’s the use of constructing watchtowers?”

He claimed that the state of most of the other bird sanctuaries in the region is similar, except for the Sultanpur Bird Sanctuary in Gurgaon, where the birds have flocked in substantial numbers this winter.

Agrees Prakash, “The authorities need to pay more attention to proper maintenance of manmade reserves.”

(Nikhil Walia can be contacted at nikhilwalia87@gmail.com)