Delay in migratory birds visiting Delhi last year has many worriedhttps://indianexpress.com/article/cities/delhi/delay-in-migratory-birds-visiting-delhi-last-year-has-many-worried-5542113/

Delay in migratory birds visiting Delhi last year has many worried

“Birds follow the central flyway route, and Delhi-NCR falls in that... due to climate change, their departure is delayed... Due to the crop-burning, they have trouble seeing because of the smoke. It is impacting their pattern," an expert says.

Delay in migratory birds visiting Delhi last year has many worried
Flocks of Common Pochard and Tufted Duck (Photos by T K Roy)

The common pochard, a medium-sized duck that migrates to India from central Asia October onwards was only spotted at two wetlands in Delhi-NCR till December 15 last year, instead of four where it migrated to till 2017.

According to ecologist TK Roy, the bird was spotted at the Okhla Bird Sanctuary and at Surajpur wetlands in Greater Noida. “In the last two months (of last year), I observed that it did not stop by at Najafgarh jheel and the Yamuna,” said Roy.

As per the International Union for Conservation of Nature (IUCN), the common pochard falls in the “vulnerable” category, and its number is declining globally. As winged visitors make their annual pit-stop in Delhi-NCR, birders and ecologists are seeing a worrying trend of fluctuating number of species and delayed arrivals.

“In 2017, both the mallard (duck) and common shelduck were spotted… Last year, no mallard has been seen. Only a pair of the common shelduck was recorded at Okhla Bird Sanctuary in November, but hasn’t been seen since. The shelduck has not arrived at the Najafgarh jheel at all,” said Roy.

Similarly, the long-legged, long-billed black-tail godwit, which migrates from the north and east Asia, only arrived at Najafgarh jheel in 2017. “It’s not been seen at Surajpur wetland because the water levels there have been low, and some work has also been going on,” said Roy.

Delay in migratory birds visiting Delhi last year has many worried
The Bar-headed Geese (Photos by T K Roy)

Likewise, around 20 Ferruginous ducks, which according to IUCN falls in the “near-threatened” category, were only recorded at Okhla bird sanctuary.

In December, at least 12 teams of birders conducted bird counting in Delhi-NCR in areas such as Basai, Mangar, Najafgarh, Yamuna river, Surajpur, and Okhla Bird sanctuary, among others.  “There are at least 22 species that we did not spot last year, but saw in 2017… such as Asian brown flycatcher, Black Bittern, Little Tern and Water pipit, among others. Species such as booted warbler, dunlin and the Spanish sparrow which we didn’t spot in 2017, were seen last year.”

Due to a better monsoon in 2018, the Najafgarh jheel has become quite the attraction for migratory birds, with a good flock of the Northern Shoveler, from central Asia, arriving there.

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Roy said the delay in the arrival of several migratory birds, however, has been attributed to crop-burning in November:  “Birds follow the central flyway route, and Delhi-NCR falls in that… due to climate change, their departure is delayed… Due to the crop-burning, they have trouble seeing because of the smoke. It is impacting their pattern,” he said.