Is Sambhar Lake Responsible for Mass Death of Birds? Perplexed Officers Hunt for Answers
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New Delhi: Two separate incidents of multiple birds dying in Rajasthan, the second of which near Jodhpur’s Sambhal Lake saw nearly 2,000 birds dead, the country’s largest inland saltwater lake, has left officials flummoxed.
The first incident took place last week, on Thursday, with demoiselle cranes found dead in Jodhpur’s Khinchan area. On Monday, thousands of migratory birds, of at least 10 separate species, were found lying dead at Sambhar Lake. Officials said that nearly 2,000 birds died, including 1,690 northern shovelers.
In both cases, officials said that the viscera of the birds had been sent for a post-mortem analysis and that results were awaited. Neither water contamination, nor avian flu has been ruled out. Recent research has pointed out that food sources for migratory birds could greatly decline with low water levels and high salt content in salt water lakes.
“We are looking at all different possibilities. A team from Jaipur has come and collected water samples and a few of the carcasses to analyze and understand what happened. But we are flummoxed,” said an official of the forest department.
Officials added that initial investigations suggesting probability of avian flu was relatively unlikely. A doctor explained that prima facie the birds didn’t display any secretions. Infected birds shed flu viruses through their saliva, nasal secretions and feces. “Birds that are susceptible get infected when they come in contact with contaminated excretions, or surfaces that are contaminated. It hasn’t been ruled out yet, but initial investigations didn’t show any sign of such secretions,” said the official.
Another possibility, which officials haven’t ruled out, is an increase in the salinity of the water at the lake. “An increase in salinity would impact the birds by increasing the salt levels in their blood. This would impact internal organs,” the official added.
Chief Minister Ashok Gehlot, meanwhile, termed the deaths as “worrying” and said that the government was taking "immediate steps to prevent deaths during this migratory season." He said, “Protecting flora and fauna remains one of our top priorities. Chief Conservator of Forest (CCF) and several teams of the Animal Husbandry Department are at Sambhar Lake. Chief Wildlife Warden (CWLW) and CCF are monitoring the situation.”
He added that the carcasses were being sent to Bhopal to test for bird flu and that toxicologists had also been called from WWI and SARCON, Coimbatore. "Once investigations are complete, we will do everything possible so that no more birds lose lives," he said.
A 2018 study from researchers at the University of Montana, National Audubon Society, Oregon State University and East Cascades Audubon that looked at data gathered for more than 25 years Lake Abert in Oregon – a key stop for migratory waterbirds — found that as surface water levels decline, salinity increases and affects the availability of brine shrimp and other invertebrates — a key food source for waterbirds.
The study had found that Lake Abert had reduced greatly in size since the two decades and the water levels had also decreased due to water diversions, drought and climate change. The periods of low water and high salinity had a direct impact on bird populations.