Nest-to-Nest with Hamzah

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


A Surprise Jump from Lesan!

Photo taken by: Wulan

Lesan is one of six orangutans reintroduced to Kehje Sewen forest in April this year. There are three words associated with her: naughty, funny and agile.

That morning we started the routine with unsteady steps as we were still very sleepy. Indeed, it is very hard when we had to climb up and down the hill, looking for Lesan’s nest. At 5:35 am we finally found it, Lesan was still there in her nest. We were relieved because we found her before she woke up.

Lesan woke up in the Banyan tree (Ficus sp.). She then moved to Mahang tree (Macaranga sp.). She ate a lot of its fruits enthusiastically, maybe she felt hungry because she ate less yesterday due to heavy rain. The Mahang fruit is also her favorite. Lucky for her, it is fruiting season now in the forest.

Slowly but surely our spirits began to rise. Apart from Lesan’s very adorable face, she is also very funny. She ate the Mahang fruit in a hurry as she observed the surrounding as though there were others who would seize her food. Lesan moved from one tree to another and just kept eating – fruits, leaves, young stems, ginger, cambium, and even young leaves of thorny plants. Even so, her favorite is still Mahang fruit. Insatiable indeed, but she made us smile.

In the afternoon, Lesan was still moving, climbing, jumping, hanging and sitting on the top of the tallest trees on a hill. Luckily we brought binoculars, so we could still see her activities. Lesan’s agility made ​​us feel a little overwhelmed. We had to climb up and down the hill, walked continuously and sometimes we had to run as Lesan moved very quickly. But that’s art of the monitoring activity. It’s very challenging and fun at the same time.

In the evening, the Tonggeret began to sing. Tonggeret is an insect that produces a loud noise in the dusk and dawn. However Lesan was still actively jumping between trees before finally returning to one of the Banyan trees. She climbed up to the highest end and then looked around as if looking for something. We thought that Lesan would make a nest in that tree. But she instead squared off and jumped into the Jabon (Anthocephalus sp.) tree located across the river. She jumped from a height of 20 meters above the ground to the Jabon tree that is only 7 meters in height, flying over a river that’s 3-meter wide!

We instinctively screamed in shock and in fear that she would fall. But when Lesan managed to reach a branch of the Jabon tree, we smiled in relief. After settling down in the tree, finally Lesan started to make her nest.

Today’s monitoring activity was completed. We headed back to camp. Sleep tight, Lesan. See you tomorrow. We cannot wait to get another surprise from you.