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Experts call for testing of Okhla waters as birds die at Sambhar lake

By Kushagra Dixit
UPDATED ON NOV 26, 2019 09:09 PM IST

Noida: Reports of over 18,000 migratory birds dying at Rajasthan’s Sambhar lake since November 10, owing to a bacteria favoured by poor water health, have prompted birders to demand that the forest department test the waters of Okhla Bird Sanctuary (OBS), an exercise which they feel is imperative given that winter is the time when migratory birds arrive at the park.

Birders said it is high time that the district forest department tests the water quality, which has not been done since February 2016.

According to experts, while it’s still early to come to a definite conclusion, the district forest department should take a cue from the death of 18,445 birds (as reported by Rajasthan government on Thursday) at Sambhar lake and assess the water health of major bird habitats — Okhla, Dhanauri and Surajpur.

The cause of death, according to the report by Indian Veterinary Research Institute (IVRI), is avian botulism, a neuromuscular illness caused by bacterium Clostridium botulinum that produces toxins in low oxygen conditions. This disease does not spread from bird to bird, rather from maggots to birds. The report, released Thursday, said carcasses were infested with maggots and the birds that fed on the carcasses have also succumbed to botulism.

Birders point out that certain bird species — northern shovelers, Kentish plovers, common teals, common sandpipers, ruff, pied avocets, whistling ducks and coots — that are either omnivorous or insectivorous which visit Sambhar lake during winter also reach Noida and adjoining regions. Citing the conditions (as mentioned in IVRI report), birders said the conditions are ideal in wetlands of Gautam Budh Nagar for the bacteria to grow.

“This is a wake-up call for foresters to at least prepare the health card of their respective sanctuaries or wetland. The report has pointed out that the water of Sambhar lake was not in good health,” Delhi-based birder Bikram Grewal said.

The forest department got samples of the surface water at Okhla last tested in February 2016 on a total of 37 factors, including presence of metal, pH, hardness, coliforms, oil & grease, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), and alkalinity, among others. Some of the elements DO and BOD were not up to the mark even back then.

The IVRI report said high COD and low DO were among the factors that favoured growth of Clostridium botulinum.

The waters of Surajpur in Greater Noida have not been tested in the past five years, officials said. There have been no tests at Dhanauri since the wetland — one of the largest sarus crane habitat in the region and home to 50,000 birds of 211 species (migratory and resident) — is yet to be notified as one.

The forest department said it be getting the Okhla water tested soon. “We have ordered that the water be tested in the next 15 days,” Pramod Kumar Srivastava, divisional forest officer, Gautam Budh Nagar, said.

Noida-based eminent birder Anand Arya said a number of birds are giving Okhla’s polluted waters a miss over the years.

“For example, songbirds such as the pied bushchat and the whitetail stonechat were in abundance at Okhla at one time, but their numbers have dropped from thousands to just a few hundreds now,” Arya said.

He said the forest department must provide the required protection to wetlands, especially Dhanauri.

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