Claudia Wilke is a PhD candidate at the University of York in the United Kingdom. She was awarded a Leakey Foundation research grant during our fall 2013 cycle for her project entitled “Are cooperative chimpanzees more communicative (Kibale Forest, Uganda)?” Here she gives us an update on her field season and how her research is progressing.
My time at Kibale Chimpanzee Project (KCP) went surprisingly quickly, and luckily I encountered no major difficulties. As I was already familiar with the chimps, the field assistants and the forest from my pilot season, this made it much easier to get back into the field routine. The overall aim of the project was still to establish how communicative and cooperative each focal animal was, in order then to explore the relationship between these variables and establish whether those that are more communicative are also more cooperative – as a coevolution of these two cognitive capacities has often been proposed. I wanted to adopt a multimodal approach to establishing how communicative an individual was; therefore, as part of the project, I have also collected a valuable and rich data set on multimodal communication in wild chimpanzees. As little is known about multimodal communication in wild chimpanzees, I aim to capitalise on this data set, and as soon as the data are extracted, prepare a paper for publication detailing aspects of both production and reception of multimodal signals compared to their unimodal constituent signals (vocalisations, gesture and facial expression).
On each day in the forest, once I had found a party of chimps (either by listening for long distance calls or going to the location where chimps had been seen to nest the night before), I identified the individuals for which I had the least focal filming time and then made these chimps the priority to film – altogether I had 26 individuals which I collected data for. I kept a notebook with the number of minutes I already had for each individual, in each behavioural context (rest, feed, groom, travel, play), and focused on trying to keep the times in these contexts equal for each individual and between individuals. This worked well, though it was still much trickier to get certain individuals in certain contexts than others. For instance, some of the older males do not spend as much time playing as the mothers do with their offspring, and some of the females are much harder to follow when traveling than the males are. As I only filmed each individual once per day for one 15 minute focal sample period, this meant it was best to find large parties, with many individuals. Of course not all individuals could be found on every day, and on the days when we only had a small party, once I had finished with the available individuals, I could go back to camp and do some video coding.
During August 2014 almost the entire community went to the very north of their territory, leaving behind only a few females, and as the field assistants do not follow the chimps when they are so far away and ‘off-grid’ (away from the maintained path system), I had quite a few weeks of following the same females every day. Although this was frustrating in some ways, it enabled me to make good progress with my video coding, and I finished my field season with roughly a quarter of my videos coded, making the coding job on my return to the UK a bit less daunting. Another pleasant surprise in this otherwise quiet period was that several of the females I collected data on gave birth – this was very exciting, and the four babies are still doing well today.
For the cooperation aspect of the data collection, this was slightly less fruitful, as this community of chimps engages in behaviours such as hunting, boundary patrolling and intercommunity encounters quite rarely. However, I have details of all the hunts and intercommunity encounters that did take place during the data collection period (there were no boundary patrols) and managed to collect plenty of data on grooming interactions and reciprocation. To supplement my own rather sparse data on some aspects of cooperative behaviour, I have also been given permission to use the long term data from the project on these behaviours, which if examined over a longer time period will give a better estimate of cooperative tendencies than my data alone. One of the big differences in this field season compared to my pilot period was having a research assistant to aid filming communicative signal production and reception in more detail. This was only possible because of your funding and the difference to the quality of the data collected was considerable.
Generally, one person would focus closely on the focal animal, whilst the other zoomed out to capture responses from the potential recipients surrounding the focal animal. This worked best when all the individuals were together on the ground, sitting on a path, or when there were only two individuals in the party and each person could film one chimp. The extra person and camera also came in useful when the focal individual frequently moved or turned and it was difficult for the primary filmer to move. In this case one camera could only capture all the signals produced for some of the time – and if the other person could walk around to the other side of the tree, or other side of the group of chimps, they could capture the focal signal production from this side – thus having almost a 360 degree view of the focal animal at all times and making sure the face and hands were almost always visible so we could capture visual signals effectively.
During this field period I managed to collect almost 800 focal videos. This was my realistic aim, as I had assumed that the rains would make data collection difficult or impossible for at least one or two months – although in the end the rains did not have as much of an impact as the month when most of the community was away in the North. Of these videos I have already coded half and am working on the rest. As it takes between one and four hours to code each video (usually around two/three hours), I may not have time to code all videos – however again I am making sure I code an equal amount of time for all individuals and am focusing on the best-quality videos first.
Once this video coding is finished I will be able to report the frequency and types of unimodal and multimodal communication produced – I will also be able to look at the effects of age, sex, rank, party composition and behavioural context. Furthermore, I will investigate the frequency and types of responses these signals elicit from the recipients/audience and how this is influenced by different factors. This has not previously been reported for a wild chimp community and will hopefully shed more light on the complexity of their communication system. These data will also form the basis for the calculation of a ‘communicative’ index to compare to the cooperative index I will calculate from both my observations and the long term data on cooperative behaviours. Additionally, whilst in the field I became interested in some of the more commonly produced gestural signals (big loud scratch and hand clasp grooming), and I aim to use my detailed video data to explore the functions of these signals.