Latest update Bili Chimp Project.
- Bili-Aketi Field Project Research Update, June 2008

Bili Chimp Project.
On-line presentation with pictures and video.

Bili field season 2004 - 2005		Bili field season 2006 - 2007

Bili Chimps Research Project
- IBED information
- Bili Date Summary - Winter 2004
- Report on Chimpanzee Nest Survey

Contact: Prof.dr. Steph Menken
Telephone number: +31 20 525 6297
E-mail menken@science.uva.nl

Early 2004 through its director (prof.dr. Jan Sevink) IBED (Institute for Biodiversity and Ecosystems Dynamics, University of Amsterdam, the Netherlands) established contacts with the Wasmoeth Wildlife Foundation and became involved in its activities in the Bili area and the protection of its wild life including apes. Though this involvement pertains particularly to the genetics and ecology of the chimps in the area, the scope of IBED’s research in the Bili area is wider, reflecting the broad scientific mission of IBED and complexity of wild life conservation. Currently, the following topics can be distinguished:

1. Genetics, ecology and behaviour of the chimps
   
   From mid 2004 onwards Thurston Cleveland Hicks started a 4-years PhD study at the University of Amsterdam under supervision of prof.dr. Steph Menken and dr Hans Breeuwer (evolutionary biology) and prof.dr. Jan van Hooff (primatologist/ethologist, formerly at University of Utrecht). Cleve Hicks holds a MSc in Experimental Psychology from the Central Washington University, USA. He worked on “Chimpanzee Tool Use in the Ngotto Forest, Central African Republic”. Based on this expertise and background he was accepted by the University of Amsterdam as PhD-student on a project entitled ‘Genetics, ecology and behaviour of the Bili chimps’.
   
   IBED and its associated Zoological Museum Amsterdam have a long standing tradition in evolutionary and taxonomic animal studies, including primates (e.g. Southeast Asian Orang-Utangs). It furthermore has up-to-date facilities and expertise in molecular biological (DNA) studies. It is the intention to extensively sample the various chimp groups in the Bili area in order to assess both their phylogenetic relationships and evolutionary status.
   
   Jan van Hooff is an internationally recognized expert in primate ethology and evolution of behaviour. He recently retired from his chair in Ethology at the University of Utrecht, the Netherlands, but still is highly active in research on primate behaviour.
   
   The first phase of Hick’s PhD-study comprises an extended, but preliminary field study in the Bili area, focusing on:
• basic observations on behaviour and occurrence of chimps, including such aspects as group composition, feeding habits, habitat use, etc. At this moment (October 2004) Cleve Hicks already holds extensive information on these aspects, based on systematic transect observations and frequent encounters (see appendix).
• collection of materials (hair, excrements, etc.) that allow for genetic fingerprinting studies of the individuals concerned. A first set of excrement samples collected by Steve Hicks is currently being analysed.

Research by Cleve Hicks encompasses an in-depth study of the genetics, ecology and behaviour of the chimps and a general characterization of the Bili region (vegetation, climate, etc.) in order to assess their habitat use and preferences. The exact contents, however, will depend on the outcome of the preliminary research. Facilities on site and logistics are provided by Mr. Karl Ammann and the Wasmoeth Wildlife Foundation and research is being carried out in consultation with Mr. Karl Ammann and Mr. Hans Wasmoeth.

2. The (paleo)environment and Quaternary evolution of the Bili region
   
   Main topics in primate studies are the reconstruction of the phylogenetics and phylogeography of the taxa involved, the dating of speciation events and identification of factors that drove differentiation and speciation.  As to the latter, focus is generally on changes in vegetation and habitat that is related to climate changes at the scale of the Quaternary and Late Pliocene.
   
   Within IBED internationally recognized expertise exists in paleo-ecological studies of tropical areas, notably Latin-America and Africa. Major specialists are prof.dr. Henry Hooghiemstra (Quaternary of Latin-America and Africa) and dr. Bas van Geel (Holocene climatic changes). Studies of suited sediment sequences will be executed to obtain detailed reconstructions of former habitats and fluctuations in these and results will be linked to differentiation/speciation events. This will be achieved through regular MSc research projects and most probably in cooperation with sister groups in paleo-ecology from the United Kingdom active in central Africa, closely collaborating with Hooghiemstra’s group.
   
   For proper interpretation of paleo-records (pollen data mostly) insight into the current vegetation is needed, which will be acquired through systematic vegetation studies and surveys using a.o. remote sensing/satellite images (see also 3).

3. Vegetation studies and non-timber forest products
   
   Conservation of the existing wild life including the chimps requires that alternative sources of income for the local population can be found and developed, NTFP being such potential source. To that purpose, vegetation studies will be carried out and types will be characterized for their potential non-timber forest products (NTFP).  Identification of these NTFP will be based on a participative approach. IBED will search for funding of such project by submitting a proposal to its national science foundation (WOTRO), supported by the Wasmoeth Wildlife Foundation.

BILI DATA SUMMARY, FALL 2004 FIELD SEASON

First day at Camp Louis: August 18, 2004
First day collecting field data: August 21, 2004
First break in data collection, return to Bili Village: Oct. 1-6, 2004
Total of 40 days of data collection.

RESULTS:

CONTACTS WITH CHIMPANZEES:

We have had 12 contacts with the chimpanzees in the study area, a contact being defined as a period of time where the chimpanzees and the observers are aware of one another. Visual and auditory observations of chimpanzees are not included here if there is insufficient evidence to know whether or not the apes were aware of the observers.

TOTAL CONTACT TIME: 308.6 minutes
AVERAGE CONTACT TIME PER CONTACT: 25.7 minutes
MINIMUM: .1 minutes
MAXIMUM: 88 minutes

For 7 of these 12 contacts Cleve Hicks was present (254.6 minutes, averaging 36.4 minutes). The other 5 were conducted by the Bili trackers and Camp Manager Makassi. Many of these contacts were recorded on film, and for several of the latter contacts approximations of the contact duration had to be made based on this and information provided by the trackers and Camp Manager. In these cases the most conservative estimate was made.

In general the younger juveniles and sub adults were least afraid of the observers, often peering at the camera with apparent curiosity and sometimes even approaching arboreally to get a better look. Females showed moderate fear but were often filmed in the trees and remained for up to 45 minutes observing (and often screaming at) the observers. On every occasion adults males were encountered in the trees (at least 3 times) they immediately leaped from the tree to the ground and fled. When they were encountered on the ground they would flee immediately as well.

7 of the 12 contacts occurred in the Dikpai/Nambala region in the NW of the study area, 2 were at the Dikpito River to the W Center, and 2 were to the direct N or S of Camp Louis. Visiting the Dikpai/Nambala Region almost guarantees a contact or auditory observation of chimps on non-rain days.

The adult males do appear to my eye to be larger than the average chimpanzee male, although I doubt nearly as large as gorilla males. I have obtained one film of an adult male moving on the ground towards the camera, and he seems quite a bit bigger than the other individual (probably an adult female) in the frame with him. However, because the males are so timid it has been difficult to get a good look at them. The 3 footprints we have measured have been 25, 27.7 and 28 cm in length.

NEST SITES

Nest sites were searched for unsystematically, usually in the process of searching for the chimps themselves. Unlike Karl Ammann, we have not so far focused on river beds to look for nests. The trackers say that during the dry season we will find more nests in that habitat. 

We have found 203 individual nests in 64 nest sites (a nest site is considered all nests appearing to date from the same age within an area not separated by more than 25 m). The average height of the 166 of these nests for which height was recorded (estimated by Cleve Hicks, who has considerable experience doing this, but should nevertheless be reliability-tested), when ground nests are not included,  is 7.4 m, considerably lower than that of chimps at many other sites. 20 of the 203 individual nests were ground nests, approx. 10%. Including these the average nest height is 6.63 m. Only 6 nests were over 15 m elev.

It seems likely that ground nests decay more rapidly than tree nests. When looking only at the 56 fresh or recent nests (nests which are still green and have not started to decay), 12 of these were ground nests (21.43%). All but one of these nests was found with other tree nests around. With only 2 exceptions, they appeared to have been solidly constructed. Out of the 18 fresh or recent nests sites, 8 (44%) had at least one ground nest present, while 10 sites had none. The average number of ground nests per site. For fresh or recent nest sites, there was an average of 2.9 nests per site total: this includes 0.6 ground nests per site. When only including sites with ground nests present, there were 1.3 ground nests per site. Of the 12 fresh or recent ground nests found, 1 was in open dry-ground forest, 2 were in river-bed forests, 3 were in medium dry-ground forest, and 6 (50%) were in dense dry-ground forest.

Looking at ALL ground nests found, fresh and old,  out of 19 for which forest-type were recorded, 7 (37%) were in dense dry-ground forest, 4 (21.5%) in open dry-ground forest, 3 (16%) in medium dense dry-ground forest, and 5 (26%) in river-bed forest. Considering the low surface-area covered by river-bed forest compared to the other forest types, it would appear that the chimps have a preference for nesting there. We are expecting to see the chimps nest more in the riverbeds during the dry season.

Materials: Of the 20 ground nests found, 7 used Megaphrynium stems in their construction, 1 used Afromomum, and all but 6 of the nests (6 of the Megaphrynium ones) used some small trees (not yet identified) in their construction. The ground nests in the riverbeds used almost exclusively Megaphrynium, and once Afromomum.

Five apparent chimp tools were found at 3 tool sites. They were all apparently used to dip or probe for Dorylus driver ants (although no ants were seen). Two were found projecting from holes, and 3 were lying on and beside an ant mound. All were made of branches with the exception of one made from a Megaphrynium stem (the leaf found ripped off and discarded to the side). They were stripped of bark on at least one end, and had been broken off from trees within 5 m of the hole. 

The average length of the tools was 83.92 cm (min: 67.5 cm, max: 122 cm) and had an average prox. circumference of 3.44 cm, and a distal circumference of 2.76 cm (midpoint average: 3.24).

Photos are available of all tools and many of the nest sites, ground nests, and contacts with chimps.