Thanatip Chaiyos, a volunteer photographer, was part of a mission to move the five-year-old Asian black bear back to forest, which ended tragically on February 11, sparking criticism from wildlife activists.

The bear had been found wandering into villagers’ houses and eating their crops on November 30 last year.

A team of vets, park officials and Thanatip then captured the bear near Wangmuang waterfall in Nakhon Nayok’s Pakplee district.

Over the following weeks, the animal was cared for and received regular medical check-ups in preparation for its return to forest. It was also fitted with a collar and tag for enable further monitoring.

The authorities involved decided to transfer the bear back to the deep forest to prevent it from wandering out again so a helicopter was the most suitable choice of transport, Thanatip said.

He said that as the route could take them hundreds of kilometres deep into the forest, if a car was used, there would be the danger that the tranquillised bear would wake up along the way. “This was not the first time that we had transported animals by helicopter,” he said.

On the day of the accident, the sedated bear was put in a net suspended from a hook under the helicopter.

Thanatip said that the incident took place as the helicopter flew to a place near Nangrong waterfall when it hit air turbulence, causing it to swing back and forth.

The weight of the bear worsened the swinging of the aircraft, making it more difficult for the pilot to control it. “The chopper swung for a while and I saw something falling down. The pilot landed and found that the net with the bear inside had disappeared. Examining the hook, they also found that it come loose. Maybe that is how the bear fell,” he said.

Thanatip said no one could have predicted the sudden change in weather and that the bear’s death was a tragic accident.

He added that the operation had been well-prepared and planned carefully. “No one wants an incident like this to happen,” Thanatip said.

Earlier, Thongchai Saengprathum, secretary of the Khao Yai Foundation, strongly criticised park officials for allowing the bear to fall to its death, adding that people concerned should face legal action for negligence.

Reports had claimed that the bear woke up in mid-air while it was being flown into the national park in Prachin Buri, and that as the helicopter flew over forestland, the animal panicked and fell to its death.

Thongchai said the accident could have been avoided as Khao Yai National Park had been a role model for other parks in its handling of rescued wild animals.

Meanwhile, the National Parks and Wildlife Department has set up a panel to investigate the accident leading to the bear’s death.