Paralysed, unable to fly or even waddle, a shoveller sits helpless in the sand at the edge of Rajasthan’s Sambhar lake. At some distance another bird — a black-winged stilt — sips water, its leg awkwardly placed and incapable of motion.

These birds appear to be affected by a kind of paralysis, clear symptoms of avian botulism which has sent alarm bells ringing at the famous Sambhar salt lake of Rajasthan 

“On October 26, unusual mortality in birds was reported,” said Dr Bhawani Singh Rathore, director of animal husbandry.

“In 2019, there had been cases of avian botulism that acquired epidemic proportions. Area teams rushed to Sambhar lake and with the help of NGOs and other teams from different departments, wildlife and the district administration. We are working on disposing the carcasses. More than 160 birds have been found dead, 20 are sick and we have also set up a nursery to treat sick birds,” he said.

In 2019, thousands of birds (a government report said 18,000) had died due to avian botulism at Sambhar lake. 

The season for the migratory birds is yet to begin. As of now, the deaths of birds have been reported among species like the shovler, cootes, and the black-winged stilts. 

Sambhar is a wetland that attracts hundreds of migratory birds, among them the famous flamingos who are now in danger of being infected. 

Avian botulism is a neuromuscular illness that leaves birds paralysed and unable to fly. The disease is caused by a bacteria thrives in water where there is less oxygen. When birds ingest the bacteria, they are affected by the disease. When other birds feed on their carcasses, the disease spreads further. This is why it is imperative to burn bird carcasses, say wildlife experts. 

Migratory birds also often feed on these bird carcasses and are in danger of being infected. Wildlife teams are working overtime at the lake site to prevent what can be another disaster of epidemic proportions among both migratory and local birds in the area. 

Wildlife experts say the bacteria are found more at the edge of the lake, where water is less. So this affects birds that stay on the fringes of the lake like shovellers and stilts. 

Bountiful rains in Rajasthan this year also caused the lake waters to spread and that is one reason why the toxic bacteria have also spread outside, towards the edges of the lake shore.

Sambhar lake being spread over 60 square kilometres, it is difficult to man the area and see where bird deaths are happening. Local NGOs have been called in to help.

Migratory birds will begin to come to the famous wetlands from the third week of November. More than 35 species, including the famous flamingos, come here each year to escape harsh winters elsewhere.

Officials are hopeful that by then, this outbreak would have been contained.