PSGB Winter Meeting 2001

5th December 2001

The Winter Meeting of the Primate Society of Great Britain will be on the Primates of the forests of Western Uganda, and will take place in the Meeting Rooms of the Zoological Society of London (London Zoo) from 0900 - 18:30. This will be a unique opportunity to hear about current exciting research on primates in this area of high biodiversity. Registration at the door (PSGB members and students £15 non-members £20 The meeting is organised by Prof. Vernon Reynolds (vernon.reynolds@bioanthropology.oxford.ac.uk), who can be contacted for further information.

Programme

8.00 - 9.00 REGISTRATION

Morning - first session. Chair: V. Reynolds

9.15 - 9.30 a.m. The Budongo chimpanzee population - V. Reynolds (Institute of Biological Anthropology, University of Oxford)

9.30 - 9.55 a.m. Ecology of the Budongo Forest Redtail: patterns of habitat use and population density in primary and regenerating forest sites - D. Sheppard & J. Paterson (Department of Anthropology, University of Calgary)

9.55 - 10.20 a.m. Coping with injury: feeding skills and adaptations of the chimpanzees of Budongo Forest, Uganda. E. Stokes & R. Byrne (Scottish Primate Research Group, University of St Andrews)

10.20 - 10.45 a.m. Feeding habits of chimpanzees (Pan troglodytes schweinfurthii), red tailed monkeys (Cercopithecus ascanius schmidti) and blue monkeys (Cercopithecus mitis stuhlmanni) on figs in Budongo Forest Reserve, Uganda - M. Tweheyo (Department of Forestry, Makerere University)

10.45 - 11.10 a.m. Crop raiding by primates in Uganda; the cost to farmers and implications for conservation policy and practice - K. Hill (Department of Anthropology, Oxford Brookes University)

11.10 - 11.30 a.m. COFFEE

Morning - second session. Chair: N. Newton-Fisher

11.30 - 11.55 a.m. The nature of female chimpanzee social relationships in Budongo Forest, Uganda - K. Fawcett (Institute of Cell, Animal and Population Biology, University of Edinburgh)

11.55 - 12.20 p.m. Reproduction and sexual behaviour of the chiimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest. J. Wallis (Department of Psychiatry and Behavioral Sciences, University of Oklahoma Health Sciences Center)

12.20 - 12.45 p.m. The feeding ecology of mountain gorillas in Bwindi Impenetrable National Park, Uganda - J. Bosco Nkurununji (Institute of Environment and Natural Resources, Makerere University)

12.45 P.M. PRIMATE SOCIETY OF GREAT BRITAIN ANNUAL GENERAL MEETING

LUNCH

Afternoon - first session. Chair H. Buchanan-Smith

2.00 - 2.25 p.m. Factors influencing chimpanzee party size in the Kalinzu Forest - C. Hashimoto, T. Furuichi and Y. Tashiro (Primate Research Institute, Kyoto University and Laboratory of Biology, Meiji-Gakuin University)

2.25 - 2.50 p.m. Socioecology of mountain gorillas in Bwindi Impenetrable National Park, Uganda - M. Robbins (Max Planck Institute for Evolutionary Anthropology, Leipzig)

2.50 - 3.15 p.m. A non-invasive genetic assessment of the social structure and male reproductive success of mountain gorillas in Bwindi Impenetrable National Park, Uganda - A. N. Nsubuga, M. Robbins, L. Vigilant and C. Boesch (Dept. of Zoology, Makerere University, Uganda and Max Planck Institute for Evolutionary Anthropology, Leipzig)

3.15 - 3.40 p.m. Genetic structure and paternity in a wild East African chimpanzee community (Pan troglodytes schweinfurthii) - L. Vigilant, U.-D. Immel and V. Reynolds (Max Planck Institute for Evolutionary Anthropology, Leipzig and Institute of Biological Anthropology, Oxford University)

3.40 - 4.05 p.m. Leaf-sponging by chimpanzees of the Sonso community - D. Quiatt (Department of Anthropology, University of Colorado, Denver)

4.05 - 4.25 P.M. TEA

Afternoon - final session. Chair P. Lee

4.25 - 4.50 p.m. Ecological Factors influencing the behavioural diversity of leaf-swallowing and other health maintenance aspects of the diet in chimpanzees of the Budongo and Mahale - M.A. Huffman, P. Pebsworth, C. Bakuneeta, S. Gotoh, C. Obbo, Z. Kiwede, J. Karamaji, and G. Muhumuza (Primate Research Institute, Kyoto University, University of Colorado-Denver, Makerere University, Kampala and Budongo Forest Project, Uganda)

4.50 - 5.15 p.m. Behavioral ecology of chimpanzees in Bwindi Impenetrable National Park; preliminary evidence - C. B. Stanford (Department of Anthropology, University of S. California, Los Angeles)

5.15 - 5.40 p.m.The structure, meaning and function of chimpanzee pant hoots from the Budongo Forest, Uganda - H. Notman (Department of Anthropology, University of Calgary, Canada)

5.40 - 6.05 p.m. Post-conflict Behaviour of Wild Chimpanzees of the Budongo Forest, Uganda - K. Arnold and A. Whiten (School of Psychology, University of St. Andrews)

6.05 - 6.30 p.m. Hunting and carnivory by Budongo Forest chimpanzees - N. Newton-Fisher (Budongo Forest Project, Masindi, Uganda)

6.30 P.M. CONCLUDING REMARKS - P. LEE

6.30 - 7.15 P.M. WINE RECEPTION SPONSORED BY WISE PRESS

7.30 P.M. DINNER SPONSORED BY THE BUDONGO FOREST PROJECT

POSTER PRESENTATIONS

Terrestrial nest-building in chimpanzees (Pan troglodytes schweinfurthii) in Bwindi Impenetrable National Park, Uganda, East Africa. J. Maughan and C. Stanford (Dept of Psychology, University of Stirling and Department of Anthropology, University of S. California)T

The reproductive ecology and stress physiology of male chimpanzees (Pan troglodytes schweinfurthii) free-ranging in Budongo Forest, Uganda - S. Seraphin, P. Whitten and V. Reynolds (Department of Anthropology, Emory University and Institute of Biological Anthropology, Oxford University)

Chemical composition of the foods eaten by mountain gorillas in Bwindi Impenetrable National Park, Uganda: preliminary results - J. Rothman, A.N. Pell, E.S. Dierenfeld and El Rodriguez (Department of Animal Science, Cornell University, Ithaca, Nutrition Department. Wildlife Conservation Society, New York, and Department of Plant Sciences, Cornell University, Ithaca)

Evaluation of factors affecting chimpanzees' choice of sleeping sites - T. Furuichi and C. Hashimoto (Laboratory of Biology, Meiji-Gakuin University and Primate Research Institute, Kyoto University)

Ecotourism and the mountain gorillas in Bwindi Impenetrable National Park, Uganda - M.L. Goldsmith (Tufts Center for Conservation Medicine, Dept of Environmental and Population Health, Tufts University School of Veterinary Medicine, N. Grafton)

Ecology of Budongo Forest blue monkeys (Cercopithecus mitis stuhlmanni) - C. Fairgrieve (Budongo Forest Project, Uganda)

ABSTRACTS OF ORAL PRESENTATIONS

Introduction: the Budongo chimpanzee population

V. Reynolds

University of Oxford and Budongo Forest Project

A recent survey of Budongo Forest (Plumptre et al., unpublished) found the mean population size of chimpanzees in Budongo Forest to be 584 individuals (95%confidence limits 356-723) thus confirming the earlier estimate of 570 (95% confidence limits 425-711) (Plumptre and Reynolds 1996). Kibale Forest by contrast was found in the recent survey by Plumptre et al. to have a mean population of 1,298 (95% confidence limits 817-1,615). Hunting of wildlife (duikers and pigs) has increased dramatically in recent years in Budongo, with a high proportion (up to a third) of chimpanzees suffering from snare injuries. Mortality from snares is not known but may be high. Hunting at Kibale is on a smaller scale. Has the Budongo Forest chimpanzee population declined as a result of hunting?

Ecology of the Budongo Forest Redtail: patterns of habitat use and population density in primary and regenerating forest sites

D.J. Sheppard and J.D. Paterson

Department of Anthropology, University of Calgary, Calgary, Alberta, Canada, T2N 1N4

Selective timber harvesting in tropical rain forests is one solution to maintaining conservation objectives while at the same time providing forest resources. Quantitative studies aimed at understanding the effects of selective logging on forest ecosystems can contribute to sustainable management designs and minimise the negative impacts of habitat alteration on wildlife. Estimation of changes in primate density and patterns of habitat use in human modified habitats are useful indicators of impact. Using the comparative model, ecological and behavioral correlates of two groups of redtail monkeys (Cercopithecus ascanius schmidti) inhabiting primary and regenerating forest sites in the Budongo Forest Reserve, Uganda were conducted. Observational data were collected on two groups of redtail monkeys over a six month period based on 135 hours of scan sampling data. One group was ranging within an unlogged primary forest and the second group in a mixed forest selectively harvested in 1947 and 1952. Results revealed that redtail group densities were three times higher in the selectively logged habitat. Significant differences in habitat use patterns, as indicated by differences in plant diet, ranging patterns, canopy use and group spread, were observed between the two study groups. Factors which best explain these differences include the higher densities of preferred redtail food trees and the increase in tree species diversity in the regenerating forest. This situation, advantageous to redtails, developed in the logged forest due to the relatively low intensity of selective logging there and the trend towards Cynometra monodominance in the primary forest.

Feeding habits of Chimpanzees (Pan troglodytes schweinfurthii) red tailed monkeys (Cercopithecus ascanius schmidti) and blue monkeys (Cercopithecus mitis stuhlmanni) on figs in Budongo Forest Reserve, Uganda.

M. Tweheyo

Faculty of Forestry and Nature Conservation, Makerere University.

The importance of figs to primates was studied in Budongo Forest Reserve from September 1997 to March 1998. The aim of the study was to examine the spatial and temporal foraging habits of chimpanzees, red tailed monkeys and blue monkeys on figs in the forest reserve. Both scan and focal sampling methods were used to assess the foraging habits of the primates. It was found that primates fed on emerging leaves of Ficus mucuso Ficalho, F. varifolia Warb. and F. exasperata Vahl. Primates also preferred ripe fruits to emerging, young and unripe fruits. Chimpanzee dung had more than 95% proportion of fig seeds during each month of the study period. Fig trees with ripe fruits attracted larger numbers of primate groups. It is concluded that information on the feeding habits of chimpanzees and monkeys is needed in order to have a clear understanding of the social behaviour and patterns of movement of the primates and to assist in predicting the likely impact of poor forest management, forest degradation and loss of food resources on their populations.

Crop raiding by primates in Uganda; the costs to farmers and implications for conservation policy and practice

Catherine M Hill

Dept. of Anthropology, Oxford Brookes University.

In this paper I use data collected during a study carried out in villages around the southern edge of the Buduongo Forest Reserve, Uganda, to examine:

1. the nature, and extent, of crop damage experienced by subsistence farmers that is attributable to primates,

2. people-s attitudes towards wildlife, and primates in particular, and the extent to which people-s attitudes reflect their experience of primates as crop raiders, and

3. the likely impact of previous policy and practice on people-s concerns and expectations regarding crop raiding by wild animals.

The results of these analyses are then discussed within the broader context of crop raiding by wildlife and potential implications for future conservation policy and implementation.

The Nature of Female Chimpanzee Social Relationships in Budongo Forest, Uganda.

Katie Fawcett

Institute of Cell, Animal and Population Biology, Edinburgh University, West Mains Road, Edinburgh EH9 3JT, Scotland

The extent of behavioural diversity between chimpanzee communities is becoming increasingly apparent. Compared to our understanding of male social relationships our knowledge of female chimpanzee relationships is scant and inconsistent. Socioecological theory predicts that variation in female social relationships may be the result of differences in habitat. One habituated community of chimpanzees was studied for two years in order to investigate the nature of female social relationships in a forest environment.

Analysis of ranging patterns provided evidence of a mixed sex community with a distinct boundary area. Non-cycling females occupied significantly smaller core areas than cycling females. Females could be classified as peripheral or central. Core area sizes were similar to those found in Gombe but showed a higher degree of overlap. Dyadic association patterns showed that in general male chimpanzees were more closely associated than females. However, there was great variation in the association strength between individual female dyads with some dyads as closely bonded as males. All association indices were greater when food availability was high. In contrast to the consistent choice of male chimpanzees to associate with each other, female associate choice varied with food availability. Female alliances were not observed. The importance of female competition is illustrated through dominance interactions and the emergence of a clear alpha female.

This study emphasises similarities and differences of the behavioural ecology of the Budongo chimpanzees with other habituated communities in East and West Africa.

The feeding ecology of mountain gorillas in Bwindi Impenetrable National Park, Uganda

Bosco J. Nkurunungi

Makerere University Institute of Environment and Natural Resources P.O. Box 7062, Kampala, Uganda

Bwindi mountain gorillas live at a lower elevation (below 2607m) than their relatives in the Virungas (above 2600m) who are only approximately 50 km away. As a result there are ecological differences between their respective habitats and probably much variation in their behavioral ecology which is influenced by the distribution and abundance of foods. This study documented the diet of one group of mountain gorillas around Mubwindi swamp (2,100m) to study how spatial and temporal availability of food influences the way they use their habitat. Preliminary results indicate that this group consumes at least 98 food plant species. Analysis of fecal samples show that they eat non-fruit herbaceous vegetation most of the time, and consume fruit from 14 tree species with 47.2% of fecal samples containing fruit remains. Wood eating and geophagia have also been observed. Over three years of data show that the gorillas have a home range of approximately 25 km2 and travelled a mean daily journey length of approximately 841.2m. Day journey length increased during fruit eating months compared to low or non-fruit eating months. Monthly fruit consumption was positively correlated with availability of fruit although there was variation in fruiting patterns for individual fruit trees. The number of non-herbaceous food species consumed every month was lower when more fruit species and large amounts of fruit were consumed. Results of this study show that Bwindi mountain gorillas exhibit large differences in their feeding ecology compared to Virunga mountain gorillas.

Factors influencing chimpanzee party size in the Kalinzu Forest

Chie Hashimoto (1), Takeshi Furuichi (2) and Yasuko Tashiro (3)

(1) Primate Research Institute, Kyoto University

(2) Laboratory of Biology, Meiji-Gakuin University

(3) Primate Research Institute, Kyoto University

Intensive ecological studies of chimpanzees have been carried out in the Kalinzu Forest, Uganda, since 1997. Nest count survey revealed the chimpanzees- adaptation to seasonal changes in fruit production and combinations of various vegetation types in this area. This study, based on direct observation, examines the factors influencing chimpanzee party size. Several factors have been pointed out to influence party size, including predation pressure, fruit abundance, number of oestrous females, and demographic factors, of which fruit abundance and number of oestrous females were examined as factors influencing party size in Kalinzu, using quantitative data for both factors. We found that the number of individuals observed in a party increased with the observation time. Therefore, we employed two methods to reduce this bias: (1) we evaluated party size using the mean number of individuals observed in each 1-hour period during the observation of a party (1-hour party size), and (2) we used the number of all individuals observed in a party (1-day party size) and performed an analysis of covariance with observation time of the party as the covariant. There was no relationship between fruit abundance and party size, probably because constant availability of fruits of Musanga leo-errerae and Ficus spp., did not require a change in party size. On the other hand, party size showed a positive correlation with the number of oestrous females. Multi-regression analysis also showed that the number of oestrous females had a much greater influence on party size than the fruit abundance.

Socioecology of mountain gorillas in Bwindi Impenetrable National Park, Uganda

Martha M. Robbins

Max Planck Institute for Evolutionary Anthropology, Leipzig

Socioecological theory predicts that two major variables influencing the social system of a species are the distribution of food resources and access to reproductive opportunities. Despite the broad distribution of gorillas across Africa, the majority of our knowledge of the social system of gorillas comes from the well-studied mountain gorillas of the Virunga Volcanoes; currently relatively little is known about variation in the gorilla social system in differing environments. Therefore, to study the impact of feeding competition and reproductive strategies on the social system of another population of gorillas, since 1998 I have been studying one group of habituated gorillas in Bwindi Impenetrable National Park, Uganda. Ecologically, Bwindi gorillas incorporate more fruit into their diet and have a larger home range than Virunga gorillas. Behaviourally, feeding competition is greater when the gorillas feed on fruit than when eating herbaceous vegetation. Females have weak dominance and weak affiliative relationships with each other. Strategies used by males to gain access to mates and develop relationships with females are based on both aggressive and affiliative behaviours. Male-male competition has increased dramatically as the subordinate silverback has been challenging the dominant male-s status in a manner not yet observed in the Virungas. Despite some ecological and behavioural differences, social relationships among females and between males and females are largely similar to those observed in Virunga mountain gorillas. Results of this study emphasize the need to study the relationship between the ecology and behaviour of gorillas in a wide variety of habitats to better understand the evolution of their social system.

A non-invasive genetic assessment of the social structure and male reproductive success of mountain gorillas in Bwindi Impenetrable National Park, Uganda.

Anthony M. Nsubuga (1,2), Martha M. Robbins (2), Linda Vigilant (2) and Christophe Boesch (2)

(1) Department of Zoology, Makerere University, P.O. Box 7062 Kampala, Uganda.

(2) Max Planck Institute for Evolutionary Anthropology, Inselstrasse 22, D-04103 Leipzig, Germany.

The mountain gorilla (Gorilla beringei beringei) has been described as having a one-male mating system, with the silverback male expected to father all of the offspring in the group. However, almost 50 % of mountain gorilla groups in Bwindi Impenetrable National Park, Uganda, contain more than one adult male. Given subordinate males have been observed mating with adult females, paternity assignment must depend on more than behavioural observations. Additionally, it is also unknown if extragroup paternities by lone males or males from neighbouring groups occur in mountain gorillas. We are using genetic analysis to determine the paternity of mountain gorilla offspring and thus determine the relative reproductive success of males in relation to their dominance rank and group status. Using DNA extracted from faecal samples, we are employing 11 highly variable microsatellite markers to construct individually distinctive genetic profiles. We will discuss results from our analysis of a habituated research group and compare the genetic attributes of paternity with predictions of mating success using behavioural data.

Genetic structure and paternity in a wild East African chimpanzee commmunity (Pan troglodytes schweinfurthii)

L. Vigilant (1), U.-D. Immel (1), V. Reynolds (2), and C. Boesch (1)

(1) Max Planck Institute for Evolutionary Anthropology, Inselstrasse 22, 04103 Leipzig, Germany

(2) Institute of Biological Anthropology, University of Oxford, Oxford, OX2 6QS, U.K.

Studies of multiple wild chimpanzee populations are needed to determine whether extra-group paternity plays a significant role in influencing the genetic structure of chimpanzee communities. In this study, 53 individuals (Pan troglodytes schweinfurthii) comprising the Sonso study community in the Budongo Forest Reserve, Uganda, as well as additional males from neighboring communities, were genotyped at nine highly variable microsatellite markers using DNA extracted from noninvasive samples. The paternity of some 23 offspring was analysed. Results were analysed in conjunction with data on male dominance rank at the time of conception. Importantly, the markers used in this study are the same as those employed in a major re-analysis of paternity in three adjacent communities of west African chimpanzees (P. t. verus). Thus, not only can levels of extra-group paternity be compared, but also relative levels of genetic diversity and genetic distances between the subspecies can be calculated.

Leaf-sponging by chimpanzees of the Sonso community

Duane Quiatt

Department of Anthropology, University of Colorado at Denver, Denver, CO 80217-3364

108 instances of leaf-sponging or leaf-assisted drinking (LAD) were recorded for chimpanzees of the Budongo Forest (Sonso community) over a period of three years(Oct. 1996 - Nov. 1999). 72% of the leaves selected by Sonso chimpanzees for LAD were drawn from species of Alafia, a common climber that is widely distributed across the study area. The great majority of leaves in the sample were described by contributors of data as hairy or furry (= densely tomentellous on the underside), and most of these were identified as Alafia spp. The temporal and geographic distribution of leaf-sponging by Sonso chimpanzees is compared with that of 18 observations of unassisted drinking (UAD) made over the same period of study; the behaviour itself is compared with other chimpanzee behaviours commonly represented as 'cultural' in character. Whether leaf-sponging is simply or primarily a means of managing water intake, where access to water is problematic (as is commonly assumed), or serves other needs, physiological or behavioural, remains to be examined.

Ecological factors influencing the behavioural diversity of leaf-swallowing and other health maintenance aspects of the diet in chimpanzees of Budongo and Mahale

Michael A. Huffman (1), Paula Pebsworth (2), Chris Bakuneeta (3), Shunji Gotoh (1), Chris Obbo (3), Zephyr Kiwedi (4), Joseph Kalamagi (4), Gershom Muhumuza (4)

(1) Primate Research Institute, Kyoto University, Japan

(2) University of Colorado-Denver, USA

(3) Makerere University, Kampala, Uganda

(4) Budongo Forest Project, Masindi, Uganda

Where physiological adaptation is insufficient, hosts have developed behavioural responses to avoid or limit contact with parasites. One such proposed behaviour, leaf swallowing, occurs widely among the African great apes in at least 13 sites across the continent. A new study reported here on the Budongo Forest chimpanzees of Sonso links leaf swallowing with contemporaneous outbreaks of tapeworm infection. Rainfall patterns and their effect on parasite reproductive strategies is hypothesized to be responsible for regional and seasonal differences in these different target parasites thought to elicit leaf swallowing behaviour. The details of leaf-swallowing behaviour obtained from these sites are reviewed with available information from other sites where leaf swallowing is known to occur. Inter-regional similarities and intra-regional differences in the plant species selected for use suggest behavioural traditions in plant selection.

Behavioural ecology of chimpanzees in Bwindi Impenetrable National Park; preliminary evidence.

C.B.Stanford

Dept of Anthropology, University of S. California, Los Angeles

This paper presents data from a field study of chimpanzees in Bwindi Impenetrable National Park, Uganda. Bwindi chimpanzees are sympatric with gorillas, and our research seeks to understand the ecological relationship between the two species. The Ruhija chimpanzee community occupies roughly the same home range as several gorilla group, including one habituated group. The Ruhija chimpanzee community consists of at least 20 individuals, including at least 6 adult and adolescent males. Diet is composed of about 75% fruit; mammalian meat or bones have been found in 8 % of dung samples to date. A high degree of arboreal bipedalism has been observed. Honey-probing tools are used and consist of two non-overlapping size classes, which are used for foraging in the nests of two different bee species. There is extensive seasonal overlap in chimpanzee and gorilla diet. Bwindi chimpanzees and gorillas have been observed feeding together only once thus far, at a distance as near as 3 meters, without inter-specific aggression.

Post-conflict behaviour of wild chimpanzees of the Budongo Forest, Uganda

Kate Arnold and Andrew Whiten

School of Psychology, Univ. St Andrews, UK

Since de Waal & van Roosmalen (1979) first documented the occurrence of reconciliation between former opponents in captive chimpanzees, the study of primate post-conflict behaviour has provided valuable information about the details of primate social organisation. The vast majority of these studies have been carried out on captive subjects and it has been assumed that findings are representative of wild primates. We set out to investigate whether this was true for the Sonso community of wild chimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest, Uganda, using procedures comparable with those used in captive studies. We found that these chimpanzees were much less likely to reconcile than their captive counterparts. Only one dimension of relationship quality had an effect on the likelihood of reconciliation. Individuals which were highly compatible, in terms of time spent affiliating and in close proximity, reconciled conflicts more often than those with weak relationships. Captive chimpanzees have also been shown to 'console' one another. Consolation is said to occur when uninvolved third parties initiate affiliative contact with victims of aggression. So far, chimpanzees have been found to be unique among primates in this respect. This study did not confirm that consolatory behaviour was characteristic of wild chimpanzee post-conflict behaviour. Nor did these chimpanzees use explicit gestures during post-conflict interactions as they did at Arnhem (de Waal & van Roosmalen, 1979). We conclude that the post-conflict behaviour of chimpanzees is more variable than has previously been thought and is likely to be dependent on the prevailing social environment.

The structure, meaning and function of chimpanzee pant hoots from the Budongo Forest, Uganda

H. Notman

Dept of Anthropology, University of Calgary, Calgary, Alberta, Canada, T2N 1N4

Pant hoots are the species-typical, long-distance calls produced by chimpanzees in a variety of behavioural contexts. As such, these calls are typically produced in the absence of any visual or olfactory cues that may be indicative of context, and thus all communicatively relevant information must be contained within the acoustic channel. This study examines variations in the acoustic structure of pant hoots that correlate with specific social, behavioural and ecological contexts of call production. That is, do chimpanzee distance calls convey specific behavioural and/or ecological information to receivers, and if so, how is this information encoded within the acoustic structure of the call? Identifying and matching reliable acoustic variants with their associated contexts is critical for discerning the specific function of different pant hoot types. Moreover, the existence of such acoustic variants in this call category suggests at least a rudimentary capacity for referential signalling within the species.

Hunting and carnivory by Budongo Forest chimpanzees.

N.E. Newton-Fisher

Budongo Forest Project, PO Box 362, Masindi, Uganda

Observations of hunting, carnivory, and meat sharing over a six-year period (1995-2000) suggest that chimpanzees of the Sonso community from the Budongo Forest are infrequent predators. In other respects their hunting behaviour appears similar to that of other East African chimpanzee populations. Males are the primary hunters and consumers of mammalian prey, which includes other primate species and forest ungulates. The single most common prey are black and white colobus (Colobus guereza), and these chimpanzees may preferentially target infants and juveniles. It seems likely that the absence from Budongo of red colobus monkeys (Procolobus badius), the most common prey at other sites, precludes more frequent hunting. Kills are often shared, and begging appears to be a successful strategy with which to acquire meat. These observations suggest that current theories concerning the evolved function of hunting, in which hunting is seen as intimately linked with male chimpanzee relationships, need refining: the low levels of hunting in Budongo do not appear to compromise male relationships, which follow similar patterns to those in other populations.

Coping with injury: feeding skills and adaptations of the chimpanzees of

Budongo Forest, Uganda

Emma Stokes and Richard Byrne,

Scottish Primate Research Group, University of St Andrews, Fife KY16 9JU

Although gorillas and orang-utans have been shown to display considerable manual skill in order to obtain some plant foods, this has only been described for chimpanzees in the restricted context of tool use. Furthermore, in the Sonso community of chimpanzees at Budongo Forest in Uganda, over 20% of individuals suffer from some form of upper or lower limb injury as a result of snares. This paper investigates the feeding skills of a non-tool using community of chimpanzees and the strategies used by injured individuals in compensating for injury. Chimpanzees were found to employ a broad range of skills in feeding, reflecting variation in their environment and in their diet. Three food types were examined, each illustrating a particular aspect of feeding skill. In processing leaves of Broussonettia papyrifera, chimpanzees use complex multi-stage feeding techniques, employing bimanual co-ordination at several stages. Able-bodied individuals show considerable standardisation in their feeding with a preference for two techniques. In contrast, when feeding on figs, chimpanzees rely upon simple processing techniques but at the same time employ strategies that serve to minimise the effects of feeding competition, either by co-ordinating several handfuls of food simultaneously between limbs (Ficus mucuso) or by displaying a range of dynamic feeding postures and positions in order to access food patches and increase relative food availability (Ficus sur). Even the most severe of injuries does not result in a decline in feeding efficiency. Injured individuals were found not to invent novel solutions to familiar tasks, but instead to modify their existing repertoire in order to work around their injuries, thus sharing the program-level organisation observed in able-bodied individuals and compensating at the level of individual actions. However, the physical limitations imposed by the injured limb considerably reduce bimanual co-ordination and manoeuvrability in the tree, which may have long-term negative implications.

Reproduction and sexual behaviour of the chimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest

Janette Wallis, Ph.D. - Department of Psychiatry & Behavioral Sciences,

University of Oklahoma Health Sciences Center, Oklahoma, P.O. Box 26901, Oklahoma City, OK 73190

This presentation will provide the reproductive profile of the Sonso Chimpanzee Community, living in the Budongo Forest Reserve, Uganda. Review of records collected 1993 to 2001, indicates that the presence of oestrous females and frequency of copulation occurred in a non-random annual distribution. For example, whereas sexual activity shows a slight seasonal trend at most field sites the pattern at Budongo is much more dramatic. Approximately half of the observed copulation occurred during the months of October and November, whereas mating was rarely seen in May through August. Conception and parturition patterns show a seasonal trend, as does the resumption of reproductive cycles postpartum. The average number of both males and females in travel parties varied throughout the year and, as in other chimpanzee communities, the number of adult males was positively correlated with the number of oestrous females in parties. Preliminary analysis of some foods at Budongo suggest the possible role of phytochemicals, such as isoflavonoids and phenolic acids, in producing these patterns; as dietary content varies throughout the year, the resulting influence on female hormones may vary throughout the year. These data confirm an important seasonal influence at Budongo and suggest additional involvement of complex biological, ecological, and diurnal factors working together to influence socio-sexual behaviour of the chimpanzees.

ABSTRACTS OF POSTER PRESENTATIONS

Evaluation of factors affecting chimpanzees- choice of sleeping sites

Takeshi Furuichi (1) and Chie Hashimoto (2)

(1) Laboratory of Biology, Meiji-Gakuin University

(2) Primate Research Institute, Kyoto University

In a previous study, we examined seasonal changes in the use of vegetation types by chimpanzees in the Kalinzu Forest, Uganda, by using a marked nest count method. Such a study, however, poses a question whether the distribution of nests reflects the habitat use during the daytime: if chimpanzees chose the sleeping site by factors other than the distribution of foods, the distribution of nests may not reflect the use of each vegetation type for foraging. To elucidate this point, we analyzed influences of vegetation type, topography, tree species, and fruit availability on the choice of sleeping sites. Chimpanzees significantly preferred to sleep in 2 of 4 vegetation types in Kalinzu. They preferred to sleep on ridges or on shoulders of tablelands. They made more than 90% of nests in trees of 15 species, and only 9 of these species were significantly preferred as compared to the expected number of nests. Chimpanzees frequently used non-preferred common trees where they could not find the preferred tree species. Chimpanzees preferred to sleep at sites where they could find fruit food nearby. The relative analysis using a generalized linear model showed that the distribution of fruits had a much greater influence on the choice of sleeping sites than the other factors. These results suggest that we can use the nest count for the study of habitat use for foraging, and that preference of sleeping sites does not greatly affect the ranging pattern of chimpanzees in Kalinzu.

Ecotourism and the mountain gorillas in Bwindi Impenetrable National Park, Uganda

Michele L. Goldsmith

Tufts Center for Conservation Medicine, Department of Environmental and Population Health, Tufts University School of Veterinary Medicine, N. Grafton, MA 01536 michele.goldsmith@ tufts.edu

Ecotourism, developed to protect fragile habitats and species, is one of the fastest growing global industries. There is concern, however, over how tourism affects small, fragmented, endangered populations such as the mountain gorilla. One concern centers on habituation, a necessary prerequisite for tourism, which extinguishes a primate-s natural fear of humans. An effect of gorilla habituation in Bwindi Impenetrable National Park, Uganda has been an increase in the use of agricultural land and other human inhabited areas. This study is a preliminary examination as to how habituation influences habitat use and behavioral ecology of Bwindi-s tourist gorilla groups. Data on diet, foraging and grouping patterns were collected and habitat use was mapped using Geographic Information Systems (GIS). Results demonstrate that groups spent a majority of their time outside the park boundary (e.g., one group nested within the park once in 36 consecutive days). When outside the park, Bwindi gorillas 1) increased their consumption of non-forest foods, especially wild and domestic banana plants, 2) traveled shorter daily distances, and 3) nested more cohesively often reusing specific sleeping areas over consecutive nights. These preliminary findings suggest that gorillas increase their use of human areas, which influences aspects of their behavior. This also results in increased contact with humans, which intensifies the potential of disease transmission, such as the many scabies outbreaks that have plagued Bwindi-s gorillas. Further investigation on what attracts gorillas outside of the park is needed to reduce risks and increase gorilla wellbeing while striving to conserve this highly endangered subspecies.

Terrestrial Nest Building in Chimpanzees (Pan troglodytes schweinfurthii) in Bwindi Impenetrable National Park, Uganda, East Africa.

Johanna Maughan (1) and Craig Stanford (2, 3)

(1) Dept of Psychology, University of Stirling, Stirling, Scotland, UK E-mail: johannamaughan@hotmail.com

(2) Department of Anthropology, University of Southern California, Los Angeles, CA.

(3) Bwindi Impenetrable Great Ape Project, Kabale, Uganda. E-mail: stanford@rcf.usc.edu

The construction and distribution of chimpanzee nests provide important clues about the behavioral ecology of early hominids. A small percentage of chimpanzee nests in BINP are found on the ground, a rare occurrence in wild chimpanzees. Ground nesting was first documented in BINP by Bolwig (1959), who found 5 ground nests. Ground nesting was recently confirmed by McNeilage et al. (1997) during a census of gorillas and chimpanzees in the park. In the southern portion of BINP, where over 2,000 nests have been documented (Stanford, unpublished), only one has been found on the ground. In a study of approximately 1,000 nests in the northern portion of the park, 5.5% were found to be terrestrial. Two regions of the northern sector were sampled to examine the frequency of ground nests. Ground nests occurred in all areas sampled. The greatest percentage of ground nests (15%) occurred in one area of 3 sq.km. Terrestrial nests were found in clusters of 3 to 5. The majority of ground nests closely resembled arboreal night nests. They were composed of bracken ferns (Pteridium equilium) and sapling trees, and typically used fallen trees as supports for the side of the nest that faced downslope. While it is unknown whether these are night or day nests, the systematic construction of Bwindi ground nests suggests that they are night nests. This unique nesting culture may be due to the absence of predators and other large mammals, including elephants and gorillas, in the northern sector of BINP.

Chemical composition of the foods eaten by mountain gorillas in Bwindi Impenetrable National Park, Uganda: Preliminary Results

Jessica M. Rothman (1), Alice N. Pell (1), Ellen S. Dierenfeld (2) and Eloy Rodriguez (3)

(1) Department of Animal Science, Cornell University, Ithaca NY 14850 USA

(2) Nutrition Department, Wildlife Conservation Society, Bronx, NY 10460 USA

(3) Department of Plant Science, Cornell University, Ithaca NY 14850 USA

Plants and fungi eaten by highly endangered mountain gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda were collected, processed, and analysed for their chemical composition. Plant parts and fungi were identified as food items when gorillas were observed feeding on them or by their trail remains. Foods were collected within the home range of the gorilla group observed and were dried, packaged, and transported to Cornell University's animal nutrition laboratories in New York, USA and the nutrition laboratory at the Wildlife Conservation Society, New York, USA. Moisture content was recorded and foods were analysed for acid and neutral detergent fiber, lignin, crude protein, soluble carbohydrates, condensed tannins, and total phenolics using standard methods. Preliminary results indicate that Bwindi mountain gorillas eat protein rich leaves (4% to 26% crude protein) compared with their overall diet (2% to 14% crude protein). Neutral detergent fiber ranged from 22% to 78% and acid detergent fiber ranged from 9% to 42% dry matter in food parts. Preliminary results reveal that lignin values in foods were moderate (2% to 22%). Compared with Virunga gorillas, Bwindi gorillas eat more foods containing condensed tannins. The chemical analysis of common forest plants that are not consumed is in progress to assess the importance of chemistry in food selection. We plan to analyze foods collected in other seasons and conduct observations of food intake so that an estimate of the frequency of consumption of each food item is recorded. The combination of chemical analyses and observations of food intake will provide an accurate profile of the nutrient intake of the Bwindi gorillas. Understanding the feeding ecology and nutritional needs of Bwindi gorillas is essential to their management and conservation.

The reproductive ecology and stress physiology of male chimpanzees (Pan troglodytes schweinfurthii) free-ranging in Budongo Forest, Uganda

S. Seraphin (1, 2, 3); P. Whitten (1) and V. Reynolds (2,3)

(1) Emory University, Department of Anthropology, 1557 Pierce Drive, Atlanta, GA, 30322, USA

(2) Institute of Biological Anthropology, Oxford University, Oxford 0X2 6QS, UK.

(3) Budongo Forest Project, P.O. Box 362, Masindi, Uganda.

In this first behavioural endocrinology study of a primate from Uganda-s Budongo Forest, the effects of social dominance, age, injury, illness, and one seasonal factor (i.e.: forest temperature) upon androgen (testosterone & dehydroepiandrosterone-sulphate) and glucocorticoid (corticosterone & cortisol) production were examined in 15 male chimpanzees of adult (N=9), subadult (N=3), and juvenile (3) age status. Over a 17 week period at the Budongo Forest Project research site (BFP), daily information on forest temperature, female oestrus-status, and male health-status were compiled. In addition, 109 faecal-hormone samples were non-invasively collected, oven-dried at BFP, and then analysed by solid phase extraction and radioimmunoassay for hormones in the Reproductive Ecology Laboratory of Emory University. While both male dominance and the presence of an oestrus female within the community influenced hormone production by males, glucocorticoid and androgen levels were equally modulated by chimpanzee age, chimpanzee health-status, and forest temperature. Since these variables potentially confound tests of hormone-behaviour interaction, we conclude that primatologists should continually monitor seasonal factors while noting age and morbidity in their research subjects. Our investigation was partially funded by the L.S.B. Leakey Trust, NORAD, Conservation International, and the National Geographic Society.

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