Drone pesticide spraying raises concerns at Vedanthangal Sanctuary

The winged visitors at the Vedanthangal Bird Sanctuary in Chengalpattu are now facing a new threat in the form of whirring drones.

The use of drones by farmers to spray pesticides over the farmlands opposite the sanctuary has raised significant concerns among bird enthusiasts. The sanctuary is situated amidst agricultural lands, and recently, naturalist and avid bird watcher Yuvan Aves observed drones at work in the area. He noticed that pond herons and glossy ibises were frightened and flew away as the drones passed by. 

“Using drones to spray pesticides increases the drift area compared to traditional spraying. Drones move at a certain speed, and wind can carry the pesticide over a larger area. The sanctuary extends 5 km from the lake, and pesticides being spread within the sanctuary can drift to the bund, possibly contaminating the water,” he explained.

Mr. Yuvan also pointed out that drones disturb nesting birds within a certain radius. The birds perceive drones as a predator threat, causing them to abandon their nests and avoid foraging areas. “In some cases, birds may even attempt to attack the drones, disrupting their natural behavior,” he said, adding that pesticide spraying within the sanctuary, where birds and chicks are actively feeding, poses a significant risk to their health. These areas, essential for bird foraging, should be designated as no-pesticide zones to protect the wildlife, he suggested.

The sanctuary hosts several species including common sandpiper, garganey, blue-winged teal, darters, spot-billed duck, large egrets, little egrets, painted storks, shovellers, grey pelicans, cormorants. 

S. Balachandran, a retired scientist from the Bombay Natural History Society, noted that certain studies suggest pesticides can cause eggshell thinning. Further, some birds consume worms from agricultural fields, allowing pesticides to enter their food chain. While the effects may not be immediate, they can have a gradual impact over time, he said.

In response, Manish Meena, the Wildlife Warden of Chennai, said steps are being taken to address the issue. “We are persuading farmers to adopt manual pesticide applications. We have raised awareness among farmers and their families, and we have also informed the Agriculture Department and District Collector,” he stated.