The population of local and migratory birds has gone down substantially in the Delhi-National Capital
Region due to unfavourable breeding conditions that are being attributed to an unusually warm winter and lack of adequate rainfall during the monsoon season.
While the short winter has seen a decline in the number of migratory birds that flock to sanctuaries in and around the national Capital from November on to breed, the problem is compounded by the fact that many wetlands in the area usually favoured by migratory as well as local birds have very little water now.
As a result, the habitat of birds in and around wetlands has been disturbed to a large extent and a lesser number of migratory and local water birds are setting up nests for breeding, leading to a fall in their population.
According to the latest report of the Asian Waterbird Census (AWC) on the water birds in Asia and Australia, inadequate rainfall and global warming have affected the population of migratory and resident birds in India.
Ornithologist, TK Roy and the Delhi State Coordinator of AWC said that rising temperatures and lack of rain has had a major impact on the population of birds. “Water bodies in Delhi-NCR are under threat as the water level in wetlands is going down and these wetlands that used to house thousands of migratory and resident water birds are on the verge of extinction,” said Roy.
A poor monsoon last year has reduced the Najafgarh lake into a drying marshland. This lake used to host wader species like Black-tailed Godwit and Ruff even though it was unsuitable for duck and geese. However, these waders who used to flock here in large numbers earlier have given this water body a miss this year.
The usual sight of birds walking through the marshland is missing too and bird watchers are dismayed as lack of vegetation and food has forced the migratory and residents birds to skip this lake.
“A good amount of rainfall is necessary for macrophytic vegetation to grown in a wetland as birds need such a habitat for breeding. If birds don’t have a suitable breeding environment and habitat, they can divert themselves from the conventional habitat,” Roy said.
Out of the 1,481 birds spotted at Najafgarh lake, AWC recorded a total of 38 water bird species. Out of these, 17 were that of resident water birds and 21 species were of winter migratory water birds, including four that are on the on the verge of extinction and are on the International Union for Conservation of Nature’s red list.
In the category of resident birds, there were 99 Black-Winged Stilt this year as compared to 326 last year. Only 11 Grey Herons were sighted this year as compared to 145 in 2015, while the population of Ruff was recorded at 24 this year in comparison to 73 last year.
Among the winter migratory birds, 221 Bar-Headed Geese were recorded this year, while the population of Common Teal, the migratory birds from Central Asia stood at 633, Black-Tailed Godwit the migrants from North Asia were at 160. The popular Greater Flamingo population also came down to mere 52 this year.
Another bird identified as One Flock also skipped Okhla Bird Sanctuary habitat because of pollutants in the water body. This is being cited as another reason for the migratory birds giving this habitat a miss this year, experts said.