The crash of Air India flight A1171 moments after take off on June 12 has magnified the hazard ratio of any external factor that could potentially imperil an aircraft, including birds. Since the reason for the crash is still unknown, a flock of birds moving silently through the sky is not a poet's delight but a nightmare. 

The topography around Trivandrum International Airport makes the space above the runway a kind of bird town. All around the airport are areas where birds flock.

To the airport's south-east is the Valiyathura beach where fishermen pull in their catches. To its north is Kumarichantha, a milling market where fish, meat and vegetable leftovers are never in short supply. Right behind the runway threshold, separated only by the airport perimeter wall and a narrow road, are butcheries full of animal waste that attract birds.

In 2021, when the airport was taken over by the Adani Group, the bird strike rate (BSR) of the airport was 11.11. BSR is the number of bird hits per 10,000 aircraft movements (take offs and landings). The safety performance target fixed by the National Aviation Safety Plan is 4.26. By December 2024, the BSR of the Thiruvananthapuram airport came down to 3.52. 

The reduction is the outcome of the teamwork of the Corporation, the airport administration and small-time butchers.

Butchers’ distress
Meat vendors, at least 15 of them, are lined up along the 200 metres between the Ponnara Bridge and Bangladesh junction. In this stretch there are at least 15 meat shops, most of them house-cum-shops. Meat is chopped and sold in the converted sitouts of cramped dark one-room shacks. In the revenue land behind the shacks, animals are slaughtered.

When meat vendors in the area were told of the bird menace, they sought help for waste disposal. The Corporation identified an agency to collect waste from them daily. A meat seller pays ₹3 for every kilogram of animal waste picked from his place. A shop along the Ponnara-Bangladesh stretch, on an average, hands over 80 kg waste every day to the collection agency. A larger portion of the waste collection cost is met by the Adani Group, which spends over ₹6 lakh a month.

"After September when we started collecting the animal waste, things improved. The traders cooperated," Thiruvananthapuram Corporation secretary S Jahangir said. 

WhatsApp surveillance
The secretary has formed a WhatsApp group with members of the airport security, health inspectors and representatives of traders. "We will post a picture of the areas under surveillance twice everyday. The Police have been instructed to register an FIR if there are violations," the secretary said. In the last nine months there were just two violations.

Nonetheless, animal slaughter will be soon shifted to the modern abattoir that is near complete at Kunnukuzhi, some seven kilometres away from the airport. The Corporation secretary said that the new slaughter house and waste treatment plant will be commissioned on July 5. 

The meat vendors will then have to shift all their slaughter activities to Kunnukuzhi. "They can however sell meat from their old shops till we shift them to a new housing complex," Jahangir said. The residential complex will come up right across their shacks, at the Bangladesh junction.

The Corporation has also widened its waste management drive to include 10 wards that fall within a four-kilometre radius of the airport. "We have ensured a 97 per cent coverage of Haritha Karma Senas in these 10 wards," Jahangir said.

Guns, mice and grass 
A top wildlife expert working for the airport was satisfied with the efforts of the Corporation to reduce bird strikes. "There is definitely some respite," the expert said.

According to him, the birds that usually collide with aircraft are black kites (chakki parunthu), brahminy kites (krishnaparunthu), barn owls (vellimoonga)and rock pigeons (reared in houses surrounding the airport for racing competitions). 

The kites are lured by the fish catch in nearby Valiyathura. They are kept away by detonating earth bombs or firing scare guns before a plane lands or takes off. The airport now employs 22 'bird scarers', skilled explosive technicians.

Barn owls are brought to the runway by the Food Corporation of India warehouse barely two kilometres away in Valiyathura. It is the food chain that is activated here. Rodents arrive in numbers to feed on the grains spilled when rice sacks are unloaded at the warehouse. Barn owls descend on the warehouse grounds to feast on these rats. The post-meal drowsiness takes them to the airport.

"After the rodent meal, they become heavy and intoxicated. The airport runway nearby is the best place where they can rest without fearing predators," the expert said. The cleaning up of the warehouse has reduced the rodent population, taking away the reason that causes owls to disrupt air traffic. 

It is the panic that rock pigeons feel when alone that the airport administrators have exploited to neutralise their threat. Pigeons frequent the runway not for food but for a material that will help digest food. 

"The households that nurture them keep them well fed. But they need grit (loose stone particles or sand) to grind the food that reach their stomach. It is in search of grit that they flock to runways," the wildlife expert said.

However, pigeons are confident only in flocks. This trait prompted authorities to raise the height of grass near the runway. The grass, which was 10 cms high, has now been grown to 30 cms. "When pigeons land on the runway, the high grass hides their mates. This induces nervousness in them. Next time, they will avoid the place," the airport expert said.

The grass used is 'stylo grass'. "It does not grow wild like the other grass species and is therefore easy to maintain. It won't grow beyond 50 cms," he said. Spear grass is the second variety used, Its leaves are hard, thorny and leathery. Insects that birds feed on are not attracted to spear grass. This will further keep birds away from the runway.