Usually by November, the lakes and wetlands of the national capital and the NCR area witness the arrival of migratory birds.

However, this year the data from three major wetlands suggests lesser diversity and number of migratory birds till November.

A survey was done by a team of volunteers headed by Ecologist T K Roy on three wetlands – Okhla Bird Sanctuary (OBS), Surajpur Wetland, and NajafgarhJheel – two days ago.

As per latest status, out of a total of 26 species of winter migratory water birds observed, around 1,500 birds of 20 species at OBS, Noida, 3,000 birds of 21 species at Surajpur Lake, Greater Noida and 2,500 birds of 21 species at NajafgarhJheel, Delhi have been recorded this week which is much lesser than previous years.

These birds, identified as Graylag Gees, Bar-headed Geese, Rudy Shelduck, NorhernShoveler, Gadwal, Common Pochard, Ruff, Eurasian Spoonbill, among others have arrived from Central Asia, North Asia, Temperate Asia, East-South Asia, Central and South Asia, Western Europe, West Asia, North Asia, Central Asia and Tundra, South and East Asia, etc.

“The winter season has already started but the climate of Delhi remains unchanged and we are still experiencing warm days. To add to it are the extreme pollution levels which have delayed the arrival. We are expecting arrival of more number and species in some more time,” said Roy.

Out of 26 species only two species (Common Pochard and Black-tailed Godwit) are under ‘Vulnerable’ and ‘Near-Threatened’ category of IUCN Red-listed Threatened Bird species.

Roy also suggests that local disturbance like construction activities in the eco-sensitive zone at OBS also result in dwindling number of birds over the years.

Only three wetlands were chosen for the survey as many others like Delhi Zoo, HauzKhas Lake, and Sultanpur are closed after the death of many resident water birds due to bird flu recently.