On a misty Sunday morning at the Okhla Bird Sanctuary, thousands of avian migrants waded along with resident water birds.
The Northern Shovelers and Common Coot have flown down in large numbers and so have the Greylag Geese and Tufted Pochards. Volunteers out in field for the annual Asian Waterbird Census (AWC) — a two-week-long exercise that ended on Sunday — discovered that the Eurasian Wigeon and the Gadwal are fewer in number, compared to last year.
The sanctuary, spread over four sq kms on the Yamuna river, is one of the International Bird areas listed by Bird Live International, a non-government organisation that works for promotion and conservation of world habitat.
"The Northern Shoveler was spotted in large numbers compared to 484 last year. The other species that were seen in more numbers are Common Teal (184) and Eurasian Wigeon (18). Northern Pintails were seen much lesser than last year's 172," said Tarun K Roy, Delhi state coordinator for AWC.
However, there were several species that were not spotted this year. Comb Duck and Garganey have not been spotted in the last five years, while Mallard has not been seen for the last three years.
Delhi had registered more than 40 species of water birds in the earlier census. Among them were Bar-headed Geese, Grey Lag Geese and Minimum Ferrugenous Poacherd.
Nikhil Devasar, founder of the Delhi Birds' Club, said, "The activity (annual census) is important to know the impact of global warming/climate change on the migration pattern of birds."
Roy adds, "Around 10 years ago, we spotted about 10,000 or more migratory birds. Now, it is just about 3,000-4,000 birds. Several factors affect migration. There is more human thoroughfare here and pollution in the Yamuna has increased.”