Releasing orangutan is a continuous work. It does not stop with the orangutans returning to the wild. A series of monitoring activities have to be conducted to oversee their ability to survive in their new home.
According to Dr. Sri Suci Utami, a well-known primatologist in Indonesia, a Post-Release Monitoring (PRM) Team must conduct nest-to-nest observation for a minimum of one year. Orangutans, like the great apes who live in Africa (chimpanzees, gorillas and bonobos), make nests to rest or sleep everyday. Their nests are relatively firm and big enough to support their body size. Because orangutans roam a very large area, they actively move from sunrise to sunset. The observers will find it easier to monitor their activities if monitoring is initiated from their first nest in the morning to their new nest in the evening. Therefore, this method is called nest-to-nest observation.
Why should we observe them for one year? Because during that time we can see how they adapt to their new home, including in non-fruiting season. The results from this study will be evaluated to decide whether the monitoring activity should be extended or not. Nest-to-nest observation is conducted for six consecutive days for two months. After that, they should be continuously monitored by radio telemetry. If the radar detects the orangutans, respective recording and observation for two hours should be conducted to check their behavior and health. On the other hand, if the radar does not detect them within one month, the team must conduct a search (including outside the designated transect area). If the ‘lost’ orangutan is found, then a new nest-to-nest mission must be conducted to study his/her condition.
One good example is when Hamzah disappeared from radar detection some time ago. He was just recently found again and thus the RHOI PRM Team must go back to the nest-to-nest method to trace his doing in the wild.
The team started their mission at 4 am. They went into the forest, venturing two kilometers from Camp 103, and they found Hamzah still sleeping on the nest he made the day before in the Croton argyratus tree or locally known as Balek Puteh. This tree usually grows to a height of 20-27 meters, physically identifiable with its silvery-golden branches. That’s why it is also called the Silver Croton.
Hamzah was up at 5:08 am. His tiny but muscular body began to appear in front of us. It’s time to adventure with Hamzah.
All through the day, the team had to keep up with Hamzah who is known for his speed and agility. Some of the trees he visited, particularly for his meals, include the Artocarpus elasticus tree (a type of jackfruit tree), Calamus sp. (rattan), Koordersiodendron pinnatum (a relative of the cashew tree, Ficus aurata (figs with yellow-orange fruits), Macaranga sp. (also known as the parasol leaf tree), Piper aduncum or sometimes called a “rat tail”, among many more. Hamzah definitely gave us a good work out, up and down the hills, circling all the hills, charging off deep into the forest, back again and off again. All day!
By the time the sun started to set, Hamzah settled in and made a new comfortable nest in a Macaranga sp. tree located near the Gonda River. At 6:58 pm, Hamzah was fast asleep. The nest-to-nest adventure with Hamzah concluded successfully. The team returned to camp feeling tired but happy at the same time as Hamzah is obviously in a healthy and vibrant condition.
Warm greetings from the Kehje Sewen Forest!
Photos by: Putri Wulansari