Inter-Agency Collaboration Enables the Release of Three Orangutans in Bukit Baka Bukit Raya National Park, West Kalimantan (Borneo), Indonesia

16 January 2026 — The West Kalimantan Natural Resources Conservation Agency (BKSDA West Kalimantan), the Bukit Baka Bukit Raya National Park Authority (BTNBBBR), and Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI) have successfully released three Bornean orangutans (Pongo pygmaeus) into the Bukit Baka Bukit Raya National Park (TNBBBR), within the Mentatai Resort management area, Menukung Subdistrict, Melawi Regency, West Kalimantan.

Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI) is a strategic partner of International Animal Rescue (IAR). Over the past 17 years IAR and YIARI have collaborated to develop holistic programmes to protect wildlife and habitats, and deliver a positive impact for communities, ecosystems and the environment.

Bukit Baka Bukit Raya National Park (TNBBBR) was selected as the release site because it still has good forest cover, abundant food resources, and relatively low human pressure. In addition, the area is considered safe for orangutans as it is a conservation area subject to routine monitoring through BTNBBBR patrols. As seed dispersers and forest gap creators, orangutans play an essential role in maintaining forest health. The addition of rehabilitated orangutans to this area is expected to strengthen the long-term population of Bornean orangutans while helping to preserve the forests of TNBBBR.

To reach the release point within TNBBBR, the team had to travel by land and river and conduct forest trekking, with a total journey time of approximately three days from YIARI’s Orangutan Rehabilitation Centre. The release was also supported by residents of villages surrounding TNBBBR, who were involved as cage porters. Their involvement not only facilitated the operation but also created space for community participation and fostered a sense of ownership toward orangutans and the surrounding forests.

The three orangutans released were Badul, Korwas, and Asoka. They are orangutans entrusted by BKSDA West Kalimantan to YIARI’s Orangutan Rescue and Rehabilitation Centre in Sungai Awan Kiri Village, Ketapang. The rehabilitation process aims to restore natural behaviours necessary for survival in the wild, including foraging, ranging, and nest-building skills, as well as rebuilding wild behaviour and maintaining distance from humans.

In the wild, infant orangutans should learn life skills from their mothers until the age of 6–8 years. However, when orangutans are separated from their mothers due to illegal keeping, wildlife trade, or habitat pressure, they lose these learning opportunities and require a lengthy rehabilitation process before being ready to return to their natural habitat.

Badul is a male orangutan whose life journey was closely intertwined with humans. Before being transferred to YIARI on 25 November 2017, he was previously kept at Sinka Island Park in Singkawang, where his enclosure was adjacent to other animals such as porcupines and birds. Living conditions far removed from a forest environment meant that his “forest life” had to be relearned when he began rehabilitation at YIARI’s Ketapang Rehabilitation Centre.

Over eight years, YIARI’s medical team and animal caretakers accompanied Badul as he grew into an individual capable of long-distance ranging, proficient in finding natural forest food, and skilled at building his own nests. With nearly a fourfold increase in body weight since his arrival and excellent health examination results, Badul has now been assessed as having graduated from “forest school” and is ready to return to life in the forests of TNBBBR.

Korwas is a female orangutan whose story began with illegal wildlife trade through social media. She was confiscated by the Forest Police Rapid Response Unit (SPORC) and transferred to YIARI’s Orangutan Rehabilitation Centre on 23 August 2017. Upon arrival, Korwas bore the “scars” of her past: she suffered from a fungal skin infection (dermatophytosis) that caused dry, ring-shaped lesions on her body. After undergoing antifungal therapy, her condition improved, and Korwas began joining other orangutans in forest school.

Gradually, Korwas displayed increasingly wild behaviours required for survival in the forest: extensive ranging, effective foraging, and a tendency to avoid humans, including medical staff and caretakers. Now, having been declared healthy in her latest examination, Korwas is ready to conclude her rehabilitation period and return to life as a wild orangutan in the heart of TNBBBR.

Asoka is a male orangutan rescued from residents in Sungai Besar. When found, he was still an infant, estimated to be around five months old at the time he was kept. According to residents, Asoka was discovered while they were fishing in the river, then taken home and fed sweetened condensed milk daily. This inappropriate care and diet resulted in Asoka arriving at YIARI on 27 July 2015 in a vulnerable condition requiring intensive care.

With support from YIARI’s medical team and animal caretakers, Asoka learned to climb, forage for forest foods, select leaves and fruits, and build nests. Ten years after his arrival, Asoka is now actively ranging long distances, independently foraging, and demonstrating good social behaviour with other orangutans. His latest health examinations indicate stable and healthy conditions. From an infant once kept in a household, Asoka is now ready to return to his true home: the forests of TNBBBR.

YIARI’s Animal Management Manager, drh. Andini Nurillah, explained that health considerations form the primary foundation before release decisions are made. “Every orangutan we release has undergone strict and routine health examinations throughout the rehabilitation period. Badul, Korwas, and Asoka have demonstrated good physical condition, stable health, and behaviours that support successful survival in the wild,” she explained.

Prior to release, all three individuals underwent pre-release medical procedures, including physical examinations, supporting diagnostic tests, routine body weight monitoring, and identity verification through microchips. After release, a joint YIARI–BTNBBBR team will conduct monitoring to ensure the adaptation process proceeds well. Monitoring focuses on foraging ability, nest-building, and the maintenance of wild behaviour in the new environment.

YIARI Chairman Silverius Oscar Unggul expressed appreciation for the synergy among all parties involved. “Every orangutan successfully returned to the forest is the result of a long process: rescue, rehabilitation, and routine care by dedicated teams. The release of these three orangutans is not only good news for YIARI but also for the future of Indonesia’s biodiversity. We deeply appreciate the support of BKSDA West Kalimantan, TNBBBR, and the surrounding communities who help ensure that forests remain safe homes for orangutans,” he stated.

International Animal Rescue’s CEO, Gavin Bruce, stated, “The release of these three orangutans is the culmination of years of dedication from the team at YIARI. Without this intervention, their story would have been very different, and they would have been lost to the population. I am extremely proud of IAR’s long-standing collaboration with YIARI, which has delivered such a positive impact for wildlife and precious habitats. The strong relationship between YIARI, the Indonesian Ministry of Forestry, the BKSDA, and the National Park Authority drives this successful outcome for Indonesia’s biodiversity. YIARI will now monitor these newly reintroduced orangutans to ensure they thrive in the wild and help rebuild the population.”

Head of BKSDA West Kalimantan, Murlan Dameria Pane, stated: “The release of rehabilitated orangutans by Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI) from Ketapang into Bukit Baka Bukit Raya National Park is not merely about moving orangutans from a rehabilitation centre back into their habitat, but represents a collective commitment to biodiversity conservation, particularly orangutan conservation. This release gives Badul, Korwas, and Asoka the opportunity to live and thrive in the wild. May they live well and reproduce, contributing to the growth of the Bornean orangutan population.”

Head of Bukit Baka Bukit Raya National Park, Persada Agussetia Sitepu, stated that the release of these three orangutans forms part of efforts to strengthen TNBBBR’s function as a safe and sustainable natural habitat for wildlife.

“The release of three Bornean orangutans in Bukit Baka Bukit Raya National Park is the result of a carefully planned process based on habitat suitability assessments, carrying capacity, and the readiness of rehabilitated animals. The Mentatai Resort area was chosen because it has good forest cover, adequate availability of natural food, and relatively low levels of human disturbance.”

He further explained that the TNBBBR Authority bears responsibility for ensuring that released orangutans can adapt and survive in their natural habitat. “Post-release, together with partners, we will conduct regular monitoring to observe movement patterns, foraging behaviour, nest-building, and interactions with the surrounding environment, to ensure the adaptation process runs optimally.”

He also emphasized the importance of involving surrounding communities. “The support and participation of buffer-zone village communities, who were directly involved in this activity, are a crucial part of efforts to keep the area safe. This aligns with our commitment to strengthening collaborative conservation and fostering a sense of ownership toward wildlife and forests.”

Concluding his remarks, Persada Agussetia Sitepu stated that the release has impacts not only on saving individual orangutans but also on forest ecosystem sustainability. “Orangutans play an important ecological role as seed dispersers. Their presence in TNBBBR is expected to strengthen forest ecosystem balance while supporting long-term conservation efforts in Bukit Baka Bukit Raya National Park.”