In mysterious circumstances, hundreds of birds die at the Sambhar lake, which is a famous breeding ground for migratory birds…
Sambhar lake, located 80 km southwest of Jaipur city in the state of Rajasthan record the mysterious phenomenon that birds were just falling dead from the sky. The officials were in action to ascertain the cause of sudden death of these flighted animals. They were foxed by the investigations as it was the Avian Botulism – a paralytic and frequently fatal disease caused by the ingestion of toxins that led to the death of hundreds of migratory birds… About Sambhar lake The lake receives water from five rivers – Medtha, Samaod, Mantha, Rupangarh, Khari and Khandela.
The lake is an extensive saline wetland with water depth fluctuating from as few as 60 centimetres during the dry season to about 3 meters (10 feet) at the end of the monsoon season. It occupies an area of 190 to 230 square kilometers based on the season. The lake is elliptically shaped with a length of approximately 35.5 km and a breadth varying between 3 km and 11 km. The circumference of the lake is 96 km, and it is surrounded by the by the Aravali hills on all sides
Birds that were found dead
Every year, thousands of migratory birds flock to the Sambhar lake. According to official records, more than 83 species of water birds are found nesting in this enchanting lake. Among these, the most common ones are little grebe, great crested grebe, great white pelican, little cormorant, black stork, and darter, apart from various species of plovers, egrets, herons, and geese.
Out of the total, about 25-30 species of birds have been found dead. It all began when tourists found a large number of dead birds on November 10, 2019. The trend continued over the next few days, until the Rajasthan government swung into action and buried almost 18,422 bird carcasses to prevent the spread of infection. The officials also rescued about 748 birds, of which around 400 were up and flying.
The cause of death
Finally, it was confirmed by the Indian Veterinary Research Institute (IVRI) of Bareilly that Avian botulism (bacteria which is commonly found in the soil, rivers, and seawater when consumed by birds affects their nervous system, leading to paralysis in their legs and wings) was the cause. The avian botulism that caused the mass die-off at Sambhar was caused by the climate.
Heavy rains reduced the salinity of the lake. However, when the water evaporated, it increased the salinity around the edges of the lake bed. The low-levels of warm, saline water in the lake is further estimated by ecologists to have provided an ideal location for the manifestation of botulism.
Why is it a cause for concern?
Mass deaths among migratory birds are not uncommon and it is definitely a grave matter as each bird is a contributor to maintain the ecological balance. In the US, thousands of blackbirds were found dead on roads. In Gujarat, hundreds of migratory seagulls turned up dead in Jamnagar in 2005. In the case of the Sambhar Lake, it is the high mortality rate that has sparked concern. It ranks on par with the death of an estimated 750,000 migrating
Lapland Longspurs in Worthington, Minnesota, US in 1904.
The Need of the Hour
While the IVRI, Wildlife Institute of India (WII) in Dehradun, Salim Ali Centre for Ornithology and Natural History (SACON) in Coimbatore and Bombay Natural History Society (BNHS) in Mumbai assessed the situation to understand and contain the outbreak. There is need for a long-term, sustainable solution that needs to be arrived at to safeguard not only avian but also human health.
In the era of climate change it is more important to preserve and prevent the loss of avian wealth
Manoj Mahanta
Team ScienceNow
