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Ideally reintroduction projects should be able to accept all of the Guidelines for Reintroduction, IUCN/SSC Reintroduction Specialist Group, any International Guidelines or International Reintroduction Standards. 
 
In reality though, each organization is different and situations, resources, and limitations vary. For this reason we need to work together and accept that those organizations with less resources are doing what they can.

We currently have 15 gibbons in the reintroduction site (November, 2008) that have been released using soft release method (gibbon held in enclosures at the reintroduction site prior to release, to assist them in adjusting to their new environment). Release stock types are captive and captive-born gibbons.
 
It is estimated that once we have chosen a family group, it takes approximately 1 year to complete the release. With this in mind our goal is to release at least one gibbon group every year. Khao Phra Theaw non-hunting area can support at least 60 groups of gibbons, so we can carry on this work for many years to come. It also allows area for the reintroduced gibbons to breed and create a wild population.

Stopping the supplemental feeding

After we have released a group of gibbons it is necessary to provide them with a small amount of supplementary food, which is gradually reduced until it is no longer needed. Since 19th February 2004, we decided that the first group had been in the wild for a sufficient time (since October 2002) to learn how to forage alone.  The small amount of food we were providing them with was increasingly being ignored in favour of food they found themselves, particularly once the rainy season began and more food was naturally available.  We stopped feeding them, but continue with regular observations. If all goes well, we will consider them fully rehabilitated and focus our efforts on releasing a new family.

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(1) Feeding Basket for Released Gibbons
(2) Released Gibbons feeding from tree tops

Follow-up and Data Collection

Radio telemetry is recommended by some researchers. This method proved to be successful for monitoring released primates, like in the case of the golden lion tamarins released in a reserve in Brazil. Unfortunately, due to its high cost, this technique is unable to be used at GRP.
We are able to use only follow-up observations to evaluate the success of the release. The study groups were watched every day during the first month and after that several days each month, the amount varying depending on the number of observers available.  Follow-up studies may be required for many years after the release. Observations include general behavior, grooming behaviors, duetting, general appearance and vigor, monitoring of range, height reached in the canopy, distances between group members, identification of types of natural food eaten.
The free animals were also discouraged from following and interacting with humans. To prevent attacks on the observers, the adults were kept at a distance of at least 5 meters using a sling shot which sometimes contained harmless beans and other time contained nothing at all (just the noise of it scared them off).

Human Aggression

Aggression towards humans included the following behaviors: jaw-snapping, loud vocalization, vigorous locomotion, legs and arms spread (to show a large surface and consequently to increase the body size), touching, grabbing, and biting..

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(3-6) Observation and data collection

Current Released Gibbons

First group – Hope Group

We released the first group of gibbons (Adult male=Joe, Adult female=Kip and Juvenile male offspring=Thong, born at Rehabilitation Site) on the 27th of September 2002, and the female, Kip, gave birth to a male baby, who we named Hope on the 21st October 2002. On 26th October 2006, during the observation hour, our staff found that Kip had given birth to her third baby. We can give an educated estimate of the date of birth as the 21st of October and we have not yet determined the sex of the new baby, who we named "Toffee".

This group has continued to be observed in the forest on a regular basis. Supplementary feeding of this group ceased early 2004 as they now forage and function as a wild family of gibbons.

Hope is now 6 years old and thriving. Toffee is almost 2 and is starting to display some independence from his mother, often venturing out of her arms for short periods but under her watchful eye. Thong, the eldest child, at 8 years old has now reached sexual maturity and has been observed spending more and more time away from the family unit to be with Dao (8 y.o. female of Arun group). This new coupling have been spending time together away from their respective families, playing and copulating. This new development is very promising and is demonstrating that newly wild ex-captive gibbons released by the GRP are capable of forming monogamous relationships just as their wild-born counterparts do. It also illustrates that further releases should provide sufficient variation in order to make a long-term wild population viable.

Group members:

(Joe) (Kip)

(Thong) (Hope)

New born, Toffee

Second group – Arun Group

The second group (Adult Male=Bo, Adult female=Lek, Juvenile female offspring=Dao and Male offspring= Arun, both born at the Rehabilitation Site) was released on 15th of August 2003. This group appeared easier to observe than the first group and was much friendlier towards humans. The adult male, Bo, particularly liked to approach observers. Observers used to shoot at him with the air gun, but he was less scared of it than the gibbons of the first group. Sometimes we did not see him creep up on us and were wary of shouting at him in this kind of situation (in case it would excite him and he’d bite us). Then he would embrace us. In March 2004 Bo bit an observer at feeding time and the observer had to beat him off with a stick. After that exchange, Bo’s aggressive behaviour seemed to decrease. Unfortunately, Bo repeatedly returned to the rehabilitation site. After several attempts to reintroduce him back to his family in the forest we decided that he would remain at the rehabilitation site for the foreseeable future. This left Lek alone with the two offspring, but under observation all three seemed to be doing very well in the wild on their own.  

After some time, the three were joined by two other gibbons that belonged to a subsequent release that had failed (Yoge group), Yoge and Sabai. Yoge and Sabai are the offspring of Bird and Pompam who were released on the 10th December 2004. In the beginning this group was doing well in the forest; the family tended to stay together and move around the forest looking for trees bearing food. Bird, the adult male, showed signs of aggressive behaviour.  He attacked one of our volunteers and came very close to at least two others.  He was afraid of the Thai staff and tended only to be interested in attacking females.  We started to take sling shots into the forest, using kidney beans as ammunition, but often just the sight of the sling shot was enough to send Bird away.  The rest of the family has little to no interest in us aside from feeding time.

On the 18th of December 2004 Bird went missing, and although he was seen again on the 21st December, on the 21st February 2005 he disappeared again and has not been seen since.
After Bird went missing, the rest of the family seemed to be doing well, until the mother, Pompam also went missing on the 1st December 2005. We concluded that Pompam must be dead and much to our dismay our worries were confirmed when we discovered her skull and some other bones and fur in the forest lying next to some gun cartridges on 17th March 2006. She had been poached. We were obviously concerned for the safety of the two offspring, Yoge and Sabai, but allowed them to remain in the forest for the time being under observation.

On the 7th February 2006 we released two juvenile males, Khan Ngean and Bank, who had been living at a resort in Khao Lak. Sabai and Yoge were seen playing with these two while they were still in the acclimatisation cage and it was hoped they would stay together. Sadly Khan Ngean became ill soon after the release and had to be bought back to the clinic for treatment, however he died several days later due to intestinal complications. We suspected that Yoge and Bank had joined with the Arun group after staff observed them playing with Dao on the 11th February. We can happily confirm that Bank has formed a breeding pair with Lek and on the 20th November 2007 we discovered that she had given birth to a baby. Unfortunately, though, the baby did not survive, as we discovered four days later that Lek was no longer carrying the infant, and concluded that it had died of three possible causes: either it had been taken by a predator, such as a python or a bird, had been dropped by Lek – which is possible as her previous offspring were born in cages, where they would not be harmed if dropped – or that the baby was simply too weak to survive.

On the 17th of February 2006 we were unable to find Sabai. She was finally traced on the 18th March in a different part of the forest. Staff brought her back to the acclimitisation cage in Arun territory. However during the night, the females from the Arun group, Lek and Dao fought with Sabai through the cage and left her with serious wounds on her arms and hands. We had to bring Sabai back to the clinic for veterinary treatment. As the other females had rejected her, we made the decision to keep Sabai at our Rehabilitation site rather than leave her in the forest alone. Attempts were made, unsuccessfully, to pair Sabai with a mate. Shortly after her return to the Rehabilitation Site, Sabai tragically died of Pneumonia.

Third group (Fifth Released) – Payu Group

This group (adult male = Khao, adult female = Nuan, male offspring = Payu, infant female = Namthip, both born at the Rehabilitation Site) were first released on 7th June 2007 in commemoration of the King Thailand who celebrated his 80th birthday in the same year. However it soon became apparent that the Arun group were clashing over territory with the Payu group, as they fought shortly after we opened the door of the acclimatisation cage, which resulted in Nuan dropping the baby, Namthip. This meant that we had to find a new territory for the group, much further away. The move to the new site took place on 7th July 2007 and we opened the door for the second time on 26th September. Staff and volunteers continue to observe this group every day and, as mentioned above, we have recently decreased the amount of supplementary feeding, as they appear to be foraging more and more for naturally occurring forest food. At the moment their territory is still very small (50m2) and we have recently attempted to increase their range by creating a second feeding site, further away. Although it is still early days we are very hopeful about this group’s survival in the wild and hope that they will produce more offspring. The group have recently been observed vocalising with members of the Hope group. Recent observations of this group (carried out during their daily supplementary feeding) reveal that they are flourishing in the forest environment and we have high hopes that this group will completely adapt to life as wild gibbons.

Other releases – Unsuccessful

Yoge Group- Third Released

As detailed above, under description of second group (Arun).

Group Members of Yoge Group

(Bird)(Pompam)

(Sabai)(Yoge)          

Nat group- Forth Released

On the 10th March 2006 we released a group of three gibbons (adult male=Bozo, adult female=Kushta, infant male offspring=Nat, born at the Rehabilitation Centre). Unfortunately this release was unsuccessful as Bozo went missing just two days after the initial release, and despite our best efforts, was never found again and is presumed dead. It was decided to bring Kushta and Nat back to our rehabilitation site on the 12th of April 2006. Nat remains with his mother and is a very healthy infant, larger than some gibbons at the Rehabilitation site who are twice his age. This is due to his being raised naturally by his mother and thus having received the necessary care and nutrition that those gibbons taken from the wild whilst still suckling sadly lack. Nat is approaching an age when he can be separated from his mother and we then hope to pair Kushta with another male so that she can have a second chance to be released. Nat was separated from his mother earlier this year and is now living with playmates Muki, Jorn and Cop (Nov, 2008) at the rehabilitation site. Kushta was introduced to one of the adult males, Mai, and they have formed a successful pairing- confirmed by Kushta's recent pregmancy.

Group Members of Nat Group

(Bozo)(Kushta and Nat)

Public relations, conservation education

Before and after the release, local residents were educated about the project and the release program. Flyers were distributed in the villages, especially in schools and to hunters, near the release site and people were asked to support the project not disturbing the animals once they were in the forest. Signs were placed around the release site indicating that a research was going on in the area.

Information on wildlife conservation has been distributed for ten years by GRP/WARF. At the east entry of the forest boards are installed indicating the goals of the project, the procedures and news about ongoing releases. At the same place local people and tourists are educated about conservation in general and funds are collected, mainly from foreign tourists. Film crews are allowed to go to the release site and document the re-introduction. Small groups of very interested people can also visit the animals in the forest.

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Latest Update on 24-nov-08