Snake catchers visited the old air traffic control (ATC) building at Calcutta airport on Tuesday after snakes were spotted inside the nine-storey structure on several occasions in recent months.
A team of three snake catchers from the North 24-Parganas forest division visited the building.
The team came from the Barasat range office, a forest official said.
“Armed with tongs, they searched the building for over an hour but could not find any snake. The airport authorities have been asked to alert us the next time they spot one,” he said.
The airport authorities had sent the forest department photographs of a snake.
“The picture was of a common krait, known locally as kalach. It is venomous and is one of the ‘Big Four’ most venomous snakes found in India,” the official said.
Airport officials said the snake catchers had placed traps to catch rats inside the building.
“They said snakes often enter the building in search of rats,” an airport official said, adding that employees were frightened by the frequent sightings.
Metro had earlier reported that snakes had been appearing with unusual frequency inside the ATC building, next to the old domestic terminal. They have been spotted on four occasions over the past few months.
One snake was spotted as high as the second floor. On September 30, an airport employee spotted another on the landing between the seventh and eighth floors.
The ATC tower, from where aircraft takeoffs and landings are controlled, is on the eighth floor. The seventh floor houses the anti-hijacking coordination room.
According to experts, many snakes are surprisingly adept climbers. Unlike lizards and insects, however, they cannot cling to smooth surfaces such as glass and need a physical grip, texture, or friction to climb.
Common bronzebacks, common wolf snakes and Oriental flying snakes are among the species found in the area that can climb trees and rough surfaces such as walls and pipes. They are also often found on overhead utility cables and can sometimes be electrocuted, experts said.
Venomous snakes found in the airport area include the monocled cobra, Russell’s viper and common krait.
An airport official spotted a snake on the second floor of the ATC building at around 3.30am on August 2, sources said.
The building was constructed in 1971, while the new ATC building is to start functioning.