In late October the winter migratory season for birds begins in India. In and around Delhi the lightly forested Ridge and the Yamuna and various water bodies attract birds from Europe and northern Asia. They come to escape the winters of the northern latitudes. Here they find food, a mild climate, and dedicated birdwatchers. Some flocks stay till March.
Or at least, they used to. New birdwatchers who visit Okhla, Surajpur and Wazirpur along the Yamuna may be thrilled by the migratory birds they see, from several species of duck to cranes, skimmers and raptors (birds of prey). But long-time birders have a dismal tale to tell.
Nikhil Devasar, of the Delhi Bird group, is curt. "I would say the number is down by about 30 per cent from last year," he says. "From 10 years back to today, I would say we are down to 10 per cent. Ten years back you could not see water [at some sites], just ducks. Ten years down the line there will be probably no [migratory birds]."
There are no data, however, to quantify the decline. No bird census is done in the Delhi region, or indeed in most of India.
"The number of birds, resident or migratory, depends on the quality of the habitat," says Kanwar B Singh, an ex-Navy officer and long-time birder. Winter migrants are mostly water birds, he points out, so the availability and cleanness of water is important. "The marshes at Coronation Park," for example, "are not there any more." In Najafgarh, where there used to be a historic jheel, or lake, "water bodies have been reclaimed as agricultural land, or drained or polluted." Consequently, "There is a significant decline, year on year, in the total number and in the variety" of visiting birds.
Birds like the ferruginous pochard, a duck, are sensitive to changes in water quality. In Singh's terms, they occupy a "narrow" ecological niche and are more vulnerable.
It’s not dirty water and habitat loss alone that deter migratory flocks — it could also be sound. In the Okhla Bird Sanctuary, the wetland along the Kalindi Kunj bridge is devoid of birds because the traffic makes too much noise. The sanctuary is also squeezed on both sides by developments like the vast nw memorial parks of Noida and Delhi colonies like Abul Fazal Enclave.
The counter-example is Sultanpur, a small national park in Haryana near Delhi. Its lake almost dried up recently and drastic action had to be taken. "The idea is not to create an island" of green, says Singh, describing another useful step at Sultanpur. "It needs a buffer zone around, contiguous areas that are developed in an eco-sensitive manner." Conservation biologist Lima Rosalind agrees, "There are more birds in Sultanpur as compared to 2010," she says. The park authorities "have cleaned up, created bunds, there is less disturbance."
According to Devasar, however, the key factor in decline is global warming. Because the birds’ cold homelands no longer freeze over, the plants and insects upon which they feed are available in winter. "They leave later, or stay there," says Devasar.
Take the Siberian cranes, that used to be, as author Ranjit Lal says, "the stars of the show". Since 2002, they have not come. The flock that wintered in Bharatpur lost its halting places to development. Hunters in Central Asia took care of the rest.
Lal goes walking on the forested Ridge. Birds that migrate here, like warblers, are small and harder to spot than waterbirds. Monkeys might deter birds from nesting. The crested serpent eagle and the paradise flycatcher he has not seen for years.
"In spite of all these things," says Singh, "Delhi has a good, diverse bird population. In half a day I can count 150-160 species,” including residents. This means that an event like the annual Big Bird Day, usually held in late February near the end of the season, in which amateurs from children to senior citizens go out to watch and count birds, can be a success and help create new birdwatchers — even as the migrant flocks slowly stop coming.