Friendship Between Casey and Lesan and Other News from KJ7  


During several patrols by the Team, Upi seems to presently be concentrating her time around transect Ariyo at the 440 m point. Jackfruit appears to be one of her favourite foods, but she also eats liana fruit and young leaves, wild cherries, Macaranga and many more different food types. Based on direct observations, Upi is looking very healthy. She is eating well and generally remains in the trees. Once in a while she would descend to the ground briefly, but then immediately climbed back up to continue eating.

2014.07.26_4 IMG-20140726-WA0007_Upi_Bowo


The Team had not encountered Leke for almost two weeks, but a few days ago Leke finally showed up. The Team found her eating in a tree more than 20 meters above ground and were very happy to see her looking well.

2014.08.01_7 IMG-20140801-WA0012_Leke_Moris


2014.08.04_4 IMG-20140804-WA0005_YS_Bowo

Mother-child pair Yayang and Sayang were observed 770 meters along transect Ariyo and the Team recorded data on the pair for two hours. Yayang spent more time in the trees eating fruits and once in a while she stopped to groom her young daughter and also used her body as a bridge so Sayang was able to move in between the trees safely.

2014.08.04_5 IMG-20140804-WA0006_Sayang_Bowo AGUS
The Team also found Agus near the Camp 103 water supply track eating Macaranga. He spent his time playing in the trees, eating liana fruits and also jackfruit.

2014.08.04_18 IMG-20140804-WA0019_Agus_Bani


When Berlian saw the Team she tried to approach them. She repeatedly tried to follow the team and ignored their efforts to shoo her away. They finally decided to rapidly retreat leaving her behind, but Berlian persisted and ran after them stopping only when the Team crossed the river.

2014.08.07_4 IMG-20140807-WA0017_Berlian_Wibowo


Lesan’s signal has not been detected since February. But unexpectedly a few days ago along transect Ariyo, the Team picked Lesan’s signal. Apparently she had joined up with Casey in a tree. It seems like their friendship is still going strong!

2014.08.08_2 IMG-20140808-WA0119_Lesan_Yosi

Upon seeing the Team, Lesan seemed annoyed. She kiss-squeaked and threw tree branches towards the Team. She continued to do so while moving from one tree to another.

Lesan was also seen feeding well. During the observation, the Team recorded Lesan eating jackfruit, liana fruits and leaves and other wild species. She looked physically healthy and her hair had grown longer. We are delighted that her radio transmitter is still working fine after more than 2 years and we are still able to track her and once again confirm her successful reintroduction.

2014.08.04_22 IMG-20140804-WA0023_Casey_Bani

During the observation, Casey was also still around. She and Lesan played together and moved towards transect Martin in the direction of the contiguous conservation forest. They also groomed each other and Casey seemed to copy whatever Lesan did including eating different kinds of food.

After more than three hours the Team left them to quietly go about their activities. We hope their friendship will always be strong and they both will continue to be happy and healthy exploring more of the Kehje Sewen forest.

Great results team!

Text by: Bani, PRM Technician. 

Our critical monitoring work is only possible due to your generous support. Please donate today and help us continue to watch over our orangutans!


Challenging Months in the Forest

The success of our orangutan reintroduction programs, which recommenced in February 2012, has been an amazing journey for all of us to be part of and such a joy to share our stories and lessons learned. The large majority of our orangutans have adapted well, though we have had experienced disappointments. We are continually learning so we can improve all of our processes from pre-release, release and post-release. This is the first time that orangutan reintroductions in Borneo have been so thoroughly prepared for and monitored post-release. We aim for high rates of success, and our post-release monitoring enables intervention if and when needed, but we have to be realistic in accepting that it is impossible to achieve a 100% success rate.

Natural mortality rates for wild orangutans are estimated to vary from 2-8% depending on age, with higher mortality rates occurring their first year, after independence from their mother, and after maturation for adult males. This means for every 100 orangutans we release, we would expect between 2 to 8 orangutans to die every year from natural causes. Obviously a reintroduction program should expect higher rates of mortality because of the historical backgrounds of our orangutans. The survival rate for rehabilitated orangutans released during their juvenile-adolescence years has been reportedly varied between 20-80% (Russon et al, 2009); significantly different to what we would expect within wild populations.

A rehabilitant orangutan in release site.

A rehabilitant orangutan in release site.

Following 28 months of reintroductions in Kalimantan and the release of 162 orangutans, we have recently experienced two losses in East Kalimantan, which have been difficult for all of our team members as we know each individual orangutan so well. Unfortunately these took place within a short time-frame. However, we remain committed to our task of reintroduction and post-release monitoring to reestablish new genetically viable populations of orangutans to bolster conservation of the species in the wild in the long-term.

The Departure and Return of our Orangutans

Maduri was released in Kehje Sewen Forest on March 20, 2014. Despite her best efforts to adapt in her new environment, trying several natural food and learning to live in the trees, she had faced difficulties since the beginning of her release. So the Post Release Monitoring (PRM) Team focused their efforts on closely monitoring her development daily. But on May 6, 2014 at 8.30 am, the PRM Team and the vet on duty found Maduri lying on the ground, lethargic and weak with a wound to her neck. At the time, the team was also intensively treating and caring for Kent, another orangutan who was also found with some serious injuries. So their concentration and focus were divided in two.



Our vet checked her condition and decided to evacuate Maduri to Camp 103. She immediately received intensive care including intravenous liquids and was encouraged to eat. Unfortunately, all attempts failed. Maduri sadly passed away at Camp 103 on May 7, 2014.

As the same time Kent, who was released on March 22, 2014, was found with open wounds to the nape of his neck, chest and left arm on April 30, 2014, which we believed were probably a result of conflict with another male. The PRM Team had previously witnessed a fight between Kent and Bajuri, another released male orangutan, on March 24, 2014 but no injuries had been observed.



It doesn’t take long for infections to establish in a wild setting, and in line with our procedures the vet and PRM Team decided to evacuate Kent to the acclimatization enclosure and provided intensive care. Our vet cleaned and treated his wounds daily and provided forest fruits as supplement.

His condition began to improve, he started to eat well and was very active. However, because Kehje Sewen was in fruiting season, it was swarming with bees. There were several bee hives around the enclosure and Kent’s condition worsened again due to bee stings. The bees did not just sting Kent but also stung our vet who was on site treating him. Annoyed and in pain from sting bites, Kent couldn’t help but scratch his body, which aggravated and worsened his wounds. The team tried to remove the bees through various methods but to no avail.

PRM Team decided to evacuate Kent to the acclimatization enclosure.

PRM Team decided to evacuate Kent to the acclimatization enclosure.

Just like Kent, Maduri was also suspected to have received injuries to her neck from a fight with another orangutan. Although her injuries were not as bad as Kent’s, the fight would likely have caused her significant stress, which influenced her eating patterns and left her unsure of her range.The fight could have been triggered by many things including a dispute over territory or food resources.

After the passing of Maduri, the team concentrated on Kent’s health. His wounds had significantly worsened and unfortunately the facility at camp is not adequate to support the type of intensive care he required, so for the first time in 28 months we made the decision to evacuate Kent and return him to Samboja Lestari on May 23, 2014.

6 2014.05

Our vet checked her condition and decided to evacuate Maduri to Camp 103.


Following the death of Maduri and then Kent’s evacuation to Samboja Lestari, we received another blow when the team found the remains of Wani in the Gunung Belah area on June 12, 2014. Large teeth marks indicated that Wani might have been attacked, or at least scavenged upon, by another large mammal. Clouded leopards (Neofelis diardi borneensis) occur in Kehje Sewen, although they are not known to generally attack lone adult female orangutans. However there are reports of clouded leopards attempting to take orangutan infants, for example in the Ketambe Forest in Aceh, seven rehabilitated juvenile orangutans died after attacks by clouded leopards (Rijksen, 1978). Possibly it is more than likely that Wani had died and her remains were scavenged by Bornean bearded pigs (Sus barbatus). There have been cases of this species killing (but did not prey on) several young rehabilitated orangutans in Gunung Beratus Conservation Forest, East Kalimantan, and also in Tanjung Puting National Park, Central Kalimantan.



Wani could have also have died from sickness and then nature does the rest. Likely we’ll never know. Only one fact remains, which is that Wani is very sadly no longer with us. In her efforts to adapt in her new home in Kehje Sewen, Wani showed remarkable improvement in her survival skills. She identified natural food and was feeding well, despite her reluctance to build arboreal nests. However in the last few weeks of her life, Wani had started to build her nests in the trees and we were very encouraged. The last PRM note on June 5 indicated that her behavior was improving with healthy feeding behavior and good quality nests. The team decided to leave Wani alone without our constant presence, which would have naturally changed her behavior, while the team focused on other orangutans. Sadly, we had to face her death a week later.

Wani showed remarkable improvement in her survival skills.

Wani showed remarkable improvement in her survival skills.

Working for the Best

Inevitably, the last two months have been tough for the BOS Foundation. The team is doing all they can to ensure the well-being of all of our orangutans through PRM activities but of course we cannot observe everything that happens in the wild. Orangutans often simply don’t want to be followed, which is something we expect and would be demonstrated in wild orangutans. After the death of Maduri and Wani, we are now hoping the best for Kent’s recovery. The latest report from Samboja Lestari confirmed that Kent underwent surgery on May 27 to suture his wounds and he is now receiving intensive care. He is now recovering thanks to the loving care and adequate medical facilities.

We continue to work intensively on Kent’s recovery.

We continue to work intensively on Kent’s recovery.

Maduri and Wani will always be in our hearts, and we continue to work intensively on Kent’s recovery and for the continuation of a successful reintroduction program. The teams at Samboja Lestari and in Kehje Sewen Forest have been amazing in ensuring the welfare of our orangutans! We can’t thank you enough. Last but not least we thank all of you for your ongoing support for the BOS Foundation as we work towards ensuring the long-term success of our programs.

Text: Nur Hariyanto, Syahik Nurbani, Monica Devi Krisnasari, Media R. Clemm, Paulina Wijanarko, Meirini Sucahyo, Fransiska Sulistyo, Agus Irwanto, Aldrianto Priadjati, Sri Suci Utami Atmoko, Jacqui Sunderland-Groves, Simon Husson

Photos: Agus Purniawan, Awal Choirianto, Syahik Nur Bani, Suwardy



Singleton, I., Wich, S.A., Stephens, S., Utami Atmoko, S.S., Leighton, M., Rosen, N., Traylor-Holzer, K., Lacy, R., and Byers, O (eds.). 2004: Orangutan Population and Habitat Viability Assessment: Final Report. IUCN/SSC Conservation Breeding Specialist Group, Apple Valley, MN.

Marshall, A.J., Lacy, R., Ancrenaz, M., Byers, O., Husson, S.J., Leighton, M., Meijaard, E., Rosen, N., Singleton, I., Stephens, S., Traylor-Holzer, K., Utami Atmoko, S.S., van Schaik, C.P., Wich, S.A. 2009. Orangutan population biology, life history, and conservation. In Serge A. Wich, S. Suci Utami Atmoko, Tatang Mitra Setia and Carel P. van Schaik, eds. Orangutans: Geographic Variation in Behavioral Ecology and Conservation, pp. 311-326. Oxford University Press, New York.

Russon, A.E. 2009. Orangutan rehabilitation and reintroduction: Success, failures, and role in conservation. In Serge A. Wich, S. Suci Utami Atmoko, Tatang Mitra Setia and Carel P. van Schaik, eds. Orangutans: Geographic Variation in Behavioral Ecology and Conservation, pp. 327-350. Oxford University Press, New York.




Updates from Kehje Sewen: The Friendship between Upi, Casey and Noel and the Search for Leo

Upi, Casey and Noel Meet Up

Upi has made a full recovery, regained her appetite and is spending most of her time once again foraging for food.

2014.06.29_9 IMG-20140629-WA0013_Upi_Kenang


More than half of her day is spent foraging and she is eating various forest fruits, lianas, shoots and Scleria (commonly known as nutrushes). She usually wakes up at around 7.30 in the morning, climbs out of her nest and begins her search for food. She has occasionally been seen to prefer to eat inside her nest and some mornings will reach out, grab a liana to eat and start munching away whilst still comfortably in her nest. Generally though she tends to roam far throughout the forest to find her preferred foods. At the end of a day spent foraging, Upi either returns to her old nest or build a new one nearby.

2014.06.29_2 IMG-20140629-WA0004_Upi_Kenang

Upi and Noel are having party.

Upi, Noel and Casey were recently observed together. They ate together, but avoided any physical contact amongst themselves. When it started raining Upi made a cover for her head, while Casey chose to build a nest and Noel sheltered under the leaves. Sitting in the rain is pretty miserable and during other observations Upi has been seen to idle the time away in her nest until the rain ceases and she can again commence her activities.

2014.06.27_10 IMG-20140627-WA0022_Casey

Casey, drinking water from the river.

The three of them ate well and played together and while Casey and Upi sometimes fight over food, it seems to be half-hearted. On the whole Upi and Casey’s relationship has improved tremendously after their initial conflict.

Leke was found by the team on a rainy day along phenology transect 1081. Upon noticing the team Leke approached them briefly before leaving to continue looking for food. She must have been hungry that day as she ate for two hours without a break!

2014.07.02_5 IMG-20140702-WA0005_Leke_Agus

The next day however, she behaved differently and tried to avoid the team. She kept moving from one tree to another and chose not to come down to the ground which is a good sign. Her appetite was as healthy as before though and she ate fruits, bark, Etlingera shoots (a herb from the ginger family), ficus leaves and termites.

2014.07.06_5 IMG-20140706-WA0053_Leke_Kenang


It was lovely to see Leke and Upi interacting as well; they were observed eating together very harmoniously.

Looking for Leo

Leo was too fast for the team to observe and it took them a while to finally catch up with him along the phenology transects. He was absorbed eating figs and though he seemed to notice the observers around, he chose to continue eating after just a glance. Not that far away the team also spotted Jumiten and Mona having fun in each other’s company and it was great to see them interact so well together.

The next day, the team detected both Leo’s and Mail’s signals along phenology transect Lembu River 1000. Unfortunately, inspite of a long pursuit neither of them could be tracked and observed.

2014.06.05_12 IMG-20140605-WA0014 Mona_Fajar


Juminten and Mona’s signals meanwhile, showed that they were still around and together and the team decided not to observe them as daylight was fading and it was time to call it a day.

The team is already planning an overnight stay in the Lembu phenology area to search for Leo and we are sure that we will be able to find him soon!

Look forward to our next update!

Text by: Bani, PRM Technician.

Quick Updates from Kehje Sewen!


The team has been busy in the forest as always, following the daily lives of our orangutans.  During five days of nest-to-nest monitoring on Casey, the Post Release Monitoring Team recorded Casey eating a good, varied diet including many different food items; fruit, leaves, young shoots and termites. During monitoring she usually woke up at around 6 am, climbed out of her nest, descended the tree and onto the ground to look for food. Orangutans are generally supposed to forage arboreally rather than terrestrially, but Casey still often searches for food on the ground. That said, she also travels and nests in the trees and the team reported that her nest making skills have continued to improve. Having been up and about for 12 hours, Casey normally settled down in her new nest for the night at around 6 pm. 2014.06.12_19 IMG-20140612-WA0032 Casey_Masino Released in April 2012, Casey has now lived in the forest for over 2 years. She has adapted well despite the disability inflicted on her hand before she first came into our care. We are so thrilled that Casey is thriving in Kehje Sewen. 2014.06.15_1 IMG-20140615-WA0012_Casey_Kenang UPI

Upi was only released recently and two weeks ago we received concerning news from the field that she seemed lethargic, had lost weight and was eating a lot less than normal. In response to the change in Upi’s behavior the Team focused on intensively monitoring her through nest-to-nest follows and data collection for 14 days straight. 2014.06.16_8 IMG-20140616-WA0010_Upi_Guswan During the following days she regained her appetite and strength. She started eating more natural foods such as lianas, rattan shoots, termites, and figs. The Team could visually see her grow stronger and gain weight. Maybe she had eaten something that didn’t agree with her, as we have seen happen in other rehabilitated orangutans we have reintroduced or she was still struggling to find a range suitable for her. Whatever the reason, she seems to have overcome this and has improved daily. Upi was active and often moved between the trees though she, like some of our other orangutans, still also travels on the ground. Sometimes when the Team were close by, she would climb down and try to follow the observers. Having been fed and cared for by humans for many years before her reintroduction, she still likes human company. This is something we will have to overcome with Upi. 2014.06.19_5 IMG-20140619-WA0010 Upi_Awal On one occasion Upi was seen with Agus. Agus tried to approach her and copulate, but she refused his attempts. Soon after, Agus gave up and left her alone.


The Team found Agus along phenology trail 1000. As always, he doesn’t like seeing the Team and he threw branches and kiss-squeaked at them. Based on their observations, the Team reported that Agus was eating well and overall looked very healthy and well. Good job guys and we look forward to posting more news on our orangutans. 2014.06.13_6 IMG-20140613-WA0005 Agus_Masino

2014.06.17_7 -WA0007 Agus_Awal  

Text by: Bani, PRM Technician.

Orangutan Progress in Kehje Sewen!

Independent Leke

Grup Leke 2014.05.26_11 IMG-20140526-WA0007 Leke_Arif

We recently received information on how Leke is progressing and were interested to hear whether she was still spending time with Agus. Well apparently she is not. This week, Leke was seen exploring the forest by herself. In the morning she generally woke up at around 7 am and immediately started to look for food. She has been eating many kinds of foods such as rattanand liana shoots, fruit, cambium, termites and so on.  Despite being seen alone most of the time, the Monitoring Team once observed her and Agus copulate before they went their own ways again. Noel was also observed attempting to engage Leke in copulation and after several attempts, he finally succeeded.

2014.05.29_4 IMG-20140529-WA0007 Leke_Noel_Bani

Leke and Noel.

Leke holds a respected place amongst the orangutans in Kehje Sewen. When Casey and Yayang tried to aggravate her, Leke stood her ground and the duo retreated. Maybe that was the reason why Leke no longer joined Yayang and Sayang during fruit feeding sessions.

Leke seems to be getting to know Kehje Sewen more each day. She is skillful in foraging for food and building nests.

Mother and Daughter Yayang-Sayang

Meanwhile, how are Yayang and Sayang?  Based on our observations, they both look healthy and have adapted well to Kehje Sewen. Usually when Yayang wakes up in the morning, she doesn’t leave her nest right away. Patiently she waits for Sayang to wake up so they can forage together. Yayang often helps Sayang in looking for and selecting foods. She has also been seen helping her daughter bridge gaps between the trees so Sayang can move freely. Yayang always gives Sayang a chance to walk ahead with her following closely behind. Based on our observations, Yayang and Sayang are consuming several forest foods such as termites, lianas, rattan shoots, Baccaurea sp., figs etc.

2014.05.29_5 IMG-20140529-WA0017 YS_Handoko

The lovely mother-daughter.

Sayang still sleeps and shares a nest with her mother. Sometimes if she wakes up earlier than her mother, she will nurse for a while before playing by herself in the trees. If she sees the Monitoring Team, she will generally throw branches at them.

2014.05.28_1 IMG-20140528-WA0018 Yayang_Arif


Sayang seems to be becoming more and more independent. Several times, the team recorded Sayang looking for her own food, even though Yayang was always watching. Despite this budding independence, Yayang will still carry Sayang around while looking for food. Sayang having just turned 5 years old in April, is still being guided by her mother and learning the refined skills she needs to become independent.

2014.05.27_19 IMG-20140527-WA0069 Sayang_Agus

The 5 yo Sayang.

Agus and Friends

Agus seems to have no shortage of friends. He and Leke were seen mating and then made their nests in a same tree. The next day, Leke moved away from Agus and Agus also moved on and continued  feeding alone. As a matter of fact, he ate a lot. He tried many kinds of fruit, shoots and young leaves and travelled continuously through the trees.

2014.06.08_16 IMG-20140608-WA0008 Agus_Agus


At one point Casey approached Agus who for some reason stayed away from her. Casey, who looked healthy, then continued her own journey.

2014.06.03_3 IMG-20140603-WA0007 Casey_Agus


In addition to Agus and Casey, the Monitoring Team also observed Upi. Upi was found feeding on liana fruits and shoots of different species.

In the Gunung Belah area where Upi was located, the Team recorded signals from Acong and Mayang’s transmitters, but couldn’t pinpoint them. Oneng and Nila’s signals were also recorded. The Team will continue to monitor these orangutans and obtain direct observations so we can review their health and progress.

2014.06.04_14 IMG-20140604-WA0017 Upi_Arif


Siwi who was observed in the Kali Tengah area also looked healthy.  She was found at around 11 in the morning whilst feeding. These orangutans are doing well in their new home Kehje Sewen.  We’ll watch and report on their progress and hope they will continue to explore even further!

2014.06.07_11 IMG-20140607-WA0007 Siwie_Lung


Text by: Bani, PRM Technician.

Quick Updates!

Agus and Leke, Love is Blossoming.

Since being released into the Kehje Sewen forest in October 2013, Agus has adapted really well to his new environment. He has been recorded ranging through the forest while trying many new kinds of wild foods available. Based on data collected by the Post-release Monitoring Team, Agus has tried Ficus, Macaranga, Algae, various lianas, mangos and termites.



In the past few days Agus has often been observed approaching Leke. Leke who has usually been actively exploring and trying forest foods was found inactive and lethargic. Agus seems to have boosted her spirit once again.



When the Monitoring Team was on their way to observe Leke, they found her together with Agus. Leke didn’t seem to object to Agus’s company and they were observed foraging for food together.

Agus and Leke.

Agus and Leke.


The next day, the two orangutans were once again together. When Casey arrived, Agus approached Casey, but not for long and he soon returned to the company of Leke. At 14.44, Agus was seen moving away from Leke. She didn’t seem to mind though and continued feeding before finally making her nest in a tall tree.

Agus and Leke.

Agus and Leke.

Oneng and Wani, the Food Lovers.

If there’s a good way to describe Oneng and Wani, it is probably that these two are true food lovers because they are constantly eating.

Wani's fav food, Arthocarpus.

Wani’s fav food, Artocarpus.

The Monitring Team has recorded many kinds of forest food which they have tried, including Ficus, rattan (Calamus) shoots, wild ginger (Etlingera) shoots, Baccaurea fruit, cambium, Artocarpus fruits, and many more.



Oneng and Wani currently spend their time feeding and playing in the trees, followed by more feeding. During one observation the Team recorded Wani foraging for food despite the heavy rain pouring down on her.



Oneng and Wani both look healthy and active. At the end of each day, they generally start collecting the branches and leaves needed to build their nests. Hope you will continue to enjoy your life in Kehje Sewen, Wani and Oneng!

Text by: Bani, PRM Technician.

News from the Forest

Nest-to-nest monitoring by our team in Camp 103 is a long-term program to enable us to observe the newly released orangutans in the Kehje Sewen Forest and monitor their adaptation. There is always so much going on in the daily lives of both the orangutans and our PRM team and we are delighted to give you an update on some of their news.


5 IMG-20140502-WA0009 Noel -by Dani

Early morning when the Team had just started activities for the day, they detected Noel’s signal just nearby. Apparently Noel was on the hill adjacent to Camp 103.  Observations commenced at 08.40 and Noel was seen moving from one tree to another, feeding as he went.

2 IMG-20140502-WA0006 Noel -by Dani

After a while, he stopped for a rest and napped until 14.05.  Upon waking, he started feeding once again then moved to the riverbank behind camp. Unfortunately, the Team couldn’t follow him because he moved too fast deep into the forest. See you next time, Noel!


8 IMG-20140503-WA0010 Siwie -by Agus

The Monitoring Team also observed Siwie eating macaranga.  She looked active and moved from one tree to another. This was the third day in a row the Team recorded her eating macaranga, so we guess now we know one of her favourite foods!


2014.05.09_8 IMG-20140509-WA0014 Agus -by Agus

Agus was found along one of our  monitoring transects. He caused the team some concern as he stayed in his nest all day.

2014.05.09_5 IMG-20140509-WA0011 Agus -by Agus

The next day however, he was located on the hill nearby the acclimatisation enclosure. Upon seeing the Team, Agus made kiss-squeak vocalisations, prompting the Team to retreat a little and give him some space. During the day of monitoring, Agus was recorded eating forest fruits and moving through the trees. We are relieved that he is active again. Perhaps he ate something that disagreed with him, which has happened to a couple of orangutans in our Central Kalimantan release program.  We will keep a close eye on him over the coming weeks.


5 IMG-20140507-WA0014 Nila -Agus

The Monitoring team met Nila at around 15.02. Nila was seen relaxing in a tree while feeding on forest fruits. The Team observed her for almost two hours and left her at sunset when she was still eating.

2014.05.11_21 IMG-20140511-WA0027 Nila di sarang -Agus

NIla’s nest.


2014.05.11_16 IMG-20140511-WA0032 Oneng -Agus

Oneng was also seen briefly and is one agile orangutan! In the afternoon when the Team reached her location, she was hanging on a tree. She moved around in the trees, sometimes stopping for a quick bite to eat. But quickly moved off into the forest leaving our PRM Team behind.

2014.05.11_18 IMG-20140511-WA0030 Oneng- Agus

Text by: Bani, PRM Technician.

Kehje Sewen This Week

Miss Popular Wani


Since being released on March 22, Wani who immediately climbed a tree as soon as her travel cage door was opened has been moving around with great agility. She moves from one tree to another trying many different natural wild foods she finds.

Wani has befriended many orangutans and based on our teams observations, Wani has been seen together with Kent, Leke, Berlian, Mona, Noel, and Maduri. Out of these six orangutans, Wani seems to be closer to Berlian and doesn’t appear to enjoy the company of Mona and Kent as much. One time, Hamzah continuously approached her in an attempt to copulate, but she steadfastly refused. Hamzah continued to try several times until night fell, but his efforts were to no avail.

Apart from her courageous efforts in trying new foods, Wani is also starting to feed and travel in taller trees, even those higher than 15 m, and she is also improving her nest building skills.


Kent who Loves to Play in High Trees


Kent usually wakes up at 6 in the morning. Getting out from his nest, he will then move to a nearby tree and start looking for food. So far, he has tried several foods such as various lianas, Diospyrus and ficus shoots. He also loves spending time in high trees. Once, he was seen in a ficus tree higher than 30 meters.


During our latest observations, his radio signal indicated that Kent was nearby a main road by the Soh River. He was indeed sitting in a tree with many lianas intertwined. After waiting for a few hours, the team could no longer see him. Hopefully he will be able to be observed for a longer period next time.

Nila the Wanderer


On a drizzly morning, the Monitoring Team walked towards the Lesik River where Nila was recorded previously. It was already 10.28 but Nila was still in her nest. She climbed out of her nest at 10.32 and it seemed that the cold weather had boosted her appetite. She plucked some nearby fruit and started to eat. Nila has been recorded feeding high up in the trees, and has  only come down to the ground to move to another tree. As the days have gone by, her ranging area is getting larger. According to her radio signal, her range now covers deep into the protected forest and often at times includes the steeper hill areas.


Leke and Bajuri, Stay Together?


Leke was found at 15.05 that particular day, never too far away from that area. She spent the day eating liana fruits she found.  The Monitoring Team also found Bajuri’s signal so maybe they are still hanging out together, as we have reported previously. But since Bajuri’s signal was weak and it was late in the day, the Team decided to observe only Leke. Hopefully they can meet Bajuri during the next observations.

Text by: Bani, PRM Technician. 

Updates from Kehje Sewen: Love Quadrilateral?

Nest-to-nest monitoring is a mandatory activity after orangutans are released. The purpose of this activity is to monitor the progress of the orangutans in their new habitat. From this activity, it can be observed whether our rehabilitation program is successful and which areas may need improvement or adjustment.

So, how are they?


5 IMG-20140403-WA0076 Upi -by Ruben

After more than 2 weeks living in Kehje Sewen, Upi has started to adapt very well with her new home. She started to try new forest food found in her surroundings. According to the Monitoring Team, Upi has tried various kinds of leaves, liana fruit, ficus and syzgium, among others.

3 IMG-20140403-WA0074 pakan Upi -by Bani

Upi’s fav food!

She is also active, moving from one tree to another. After days of nesting on the forest floor, finally the Monitoring Team saw Upi building her first proper nest in a tree in Kehje Sewen. Although seemed slow, Upi is progressing. We are so happy.

8 IMG-20140403-WA0035 Upi -by Bani


During her first days living in Kehje Sewen, Oneng seemed confused. She was still trying to adapt with her new home. But it only lasted a few days. Soon enough, Oneng was seen actively exploring Kehje Sewen. She has also started eating natural food such as various kinds of fruits and ficus leaves. Oneng’s ability to build a nest for her to sleep at night is also improving considerably.

4 IMG-20140403-WA0036 Oneng -by Vio

Oneng loves playing in high trees. She enjoys eating delicious aglaia fruit, ficus, rattan, bark, and termites. She tries more types of food as the days go by. She is also skilled in searching water sources. Oneng will run to the nearest stream and drink the water using her hands.

10 IMG-20140403-WA0100 Oneng -by drh Jati


Just like Oneng and Upi, Nila seemed to have enjoyed her new home. Slowly but surely, Nila has adapted well in Kehje Sewen. According to the Monitoring Team, her diet includes fruits and leaves of liana, ficus, rattan and bark. Nila has also successfully built her own nest every night.

14 IMG-20140406-WA0015 Nila -by Fajar

After the first few days of getting to know her new home, Nila has now started to explore more of Kehje Sewen. She now plays high in the trees, swinging from one tree to another. We are very happy about her progress and delighted to see that Nila is also happy in her new home.

8 IMG-20140408-WA0009 Nila -by Fajar


It has been a little bit difficult observing Indo. Indo dislikes the presence of the Monitoring Team. However, the Team has now learned that Indo simply needs his space.

1 IMG-20140411-WA0021 Indo -by Agus

As long as he is observed from a safe distance, not too close for comfort, he is actually fine with the team’s presence. Indo has tried many kinds of fruits such as Pterospermum and liana leaves. He is adapting and settling well in his new home.

6 IMG-20140412-WA0012 Indo -by Nur 


Maduri is very close to Leke and Kent. The Monitoring Team has seen them playing together on several occasions. Maduri loves the leaves of liana and Farella johorensis. And she seems to be enjoying her new freedom.

12 IMG-20140411-WA0012 Maduri -by Fajar


The team has also witnessed love blossoming between Kent and Maduri. One afternoon, the two were seen mating. But Leke seemed unhappy when she saw this. Leke got angry! Are you jealous, Leke?

Once, Leke tried to reunite with her old friends Berlian and Mona. But Berlian and Mona did not like the idea very much. They chased Leke away and finally Leke decided to split.

13 IMG-20140403-WA0048 Leke-Bajuri -by Sam Edri

Leke and Bajuri.

10 IMG-20140403-WA0037 Bajuri -by Nur


Both Leke and Maduri were also seen mating with Bajuri. Kent of course did not like this at all! He immediately challenged Bajuri in a fight. Bajuri, happy to have mated with the two girls, finally ran away.

Love quadrilateral?


While conducting nest-to-nest monitoring on the newly released orangutans, the team also ran into some of the orangutans who have been living in the forest for quiet some times, such as Hamzah, Berlian and Mona.

3 IMG-20140404-WA0018 Berlian -by Sam Edri


Hamzah, who was found when the team was observing Oneng, looked very healthy. He kiss-squeaked at the team, showing his disapproval of them being there. Berlian and Mona were also found nearby and are very healthy. Hamzah, Berlian and Mona clearly feel at home now in Kehje Sewen and have developed into truly wild orangutans!

11 IMG-20140409-WA0024 Hamzah-Berlian -by Wagino


Text by: Bani, PRM Technician.

10 Orangutans from Samboja Lestari are Going Home! (Part 3)

March 22, 2014 | Orangutan Release Day 3

The first eight orangutans were returned to their true home in the Kehje Sewen Forest on March 20, 2014. But due to bad weather conditions, Kent and Wani had to stay overnight in Muara Wahau. Today, after a full assessment, the weather was deemed safe for the B3 helicopter to finally fly the two orangutans back to their true home.

The Final Two Return Home!

Leaving for the airport at 6.30 am this morning, the Orangutan Release Team in Muara Wahau was in high spirits. The town was still covered in a thick morning fog, but unlike the previous morning, the birds were singing songs of hope. We were going to send Kent and Wani home to the Kehje Sewen Forest, after the unfortunate delay yesterday due to bad weather.

Foggy Morning

The team arrived at PT. Swakarsa Sinar Sentosa’s airport at 7 am. Vet Agnes and the five technicians who had stayed with the orangutans last night, were already busy checking and feeding Kent and Wani. Wani was getting a bit impatient and who could blame her!  She banged her travel cage and shook it from side to side, but stopped as soon as vet Agnes brought her some milk. Kent and Wani were both in good health. Vet Agnes said that they were mostly calm and slept soundly all through the night.

Vet Agnes checking orangutans’ condition.

Reports and photos from Kehje Sewen indicated that the forest too, was still foggy. But it didn’t rain this morning, so we hoped that was a good sign. We took our time, had breakfast and cheered up each other up by telling jokes. We had all day. As soon as the fog cleared up, we would send these two orangutans back to where they belong – the forest.

Have a Safe Trip, Kent & Wani!

Warm rays of the sun finally pierced through the fog at 11 am, chasing it away. At Camp 103 in Kehje Sewen, the sky had reportedly cleared also. We immediately got ready. After final checks on the orangutans by vet Agnes, the technicians took the travel cages and loaded them into the sling load net. Then the Helicopter Landing Officer (HLO) secured and checked the sling load thoroughly and soon after the pilot started the helicopter’s engines.

Securing the sling load.

At 11.11 am, Kent and Wani were finally lifted up into the sky once again, heading to their new home in the Kehje Sewen Forest. We waved goodbye and prayed for their safe journey home. Then we returned to the small hut (waiting area at the airport) and waited for good news from our team in the forest.

Kent and Wani finally on their way home.

The helicopter returned safely to Muara Wahau at 12.48 pm, bringing empty travel cages from the previous release trip two days ago. Shortly after, the helicopter flew back to Balikpapan with four of our team members on board. The rest of the team happily drove back to town to have a good rest while waiting for exciting release stories of Kent and Wani from our team in Kehje Sewen Forest.

Orangutan Release Team in Muara Wahau thanks all of you for your support!

They Who Finally Returned Home

At 10:55 precisely, the B3 helicopter carrying Kent and Wani in their travel cages landed safely on the helipad in Camp 103, guided by Masino, our HLO from Samboja Lestari.

Helicopter that brings Kent and Wani landed in Kehje Sewen.

Their arrival was greeted by rain in Kehje Sewen. Immediately, they were taken to their release points, 1.8 km from Camp 103 towards the Lembu River. The release points were specially designated by Dr. Sri Suci Utami Atmoko, orangutan expert who is also a supporting expert consultant for the BOS Foundation and who was attending the release event in Kehje Sewen.

Kent and Wani were brought to the release point.

Wani’s travel cage was opened first at 12.30. Released by Sam Edri, Samboja Lestari’s technician, the female orangutan dashed out of the cage and climbed a tree. Wani who had been impatient and kept banging on her travel cage door, kept climbing and climbing while observing her surroundings from the tree.


Fifteen minutes later, it was Kent’s turn for freedom. He was released 200 meters away from Wani by Wondo, a driver from Pelangsiran (a small transit community of agarwood and bird’s nest collectors located on the border of Kehje Sewen) who had driven the orangutans to their release points. Kent climbed a tree almost immediately after the door was opened, and just like Wani, took the chance to observe his new surroundings from the tree.

Kent’s cage was opened by Wondo.


Kent and Wani were very lucky to have been included within this release event. DNA tests are costly and take time. The BOS Foundation received their DNA test results at the very last minute, during the transport of the first eight orangutans on March 20. Once we found out the results did indeed confirm that Kent and Wani are East Kalimantan orangutans, it was decided that they retained their candidacy and would go home following the first eight. Adding to the gut wrenching drama was the delay of their release yesterday, due to the weather conditions. But now, they’re safe. Wani and Kent have finally been returned to the forest. Welcome to Kehje Sewen and we’ll be watching over you!


Your Immediate Support is Needed

While the unforeseen delay is beyond our control, it has hampered us with additional costs, including the cost of helicopter rental. We desperately need your immediate support. Click and donate to give your support for our successful reintroduction event from Samboja Lestari.


Text by: Rini Sucahyo and Monica Devi Krisnasari.