JAKARTA (REUTERS) - A Bornean orang utan found on an Indonesian palm plantation has been rescued and returned to the forest, a conservation group said on Wednesday (Aug 19), the latest example of how habitat loss is piling pressure on the critically endangered animal in the wild.

The male orang utan, named Boncel and estimated to be 30 to 40 years old, was found in a plantation in the Indonesian portion of Borneo island with four other orang utans in early August, International Animal Rescue (IAR) said in a statement.

"We found five orang utans (in the area) and we managed to relocate four of them back into the wild, except this male orang utan that still remained in the plantation," said Mr Andiri Nurillah, a veterinarian working for the Indonesian arm of IAR.

The great ape was darted with a tranquiliser at the plantation in Ketapang, West Kalimantan province, before being put in a cage and taken by motor boat on a river to a safer area in the forest.

Boncel was in good condition when found, apart from a fractured finger and other minor injuries, said Mr Nurillah, adding that his move had gone smoothly.

The release came soon after two other Bornean orang utans were rescued from captivity on Java island and sent to a rehabilitation centre on Borneo to assess whether they can be released back into the wild.

Only around 100,000 Bornean orang utans are estimated to be left in the wild, according to the World Wildlife Fund, with the population crashing by more than 50 per cent over the past 60 years.

The animals have suffered from illegal poaching, as well as destruction of habitat due to large-scale logging and replacement of forests with cash crops such as oil palm.