I don’t think I could have asked for a better last day in the forest. There were relaxing feeding events in Kakombe Valley, two different bouts of food-callling, a rigorous hike to the top of the ridge and even an altercation with red colobus monkeys…

Following Apollo on my last day

My focal target was Apollo, a somewhat quirky adult male who is always exciting to follow. We discovered him early in the day feeding on Mabungo Makubwa in the general vicinity of Titan, another adult male. Though he was high above us, we had a great view of him, which is good because he didn’t come down for several hours. Apollo and Titan gradually inched closer to one another as they fed independently in the vine masses above, while my field assistant and I lounged below with binoculars. After feeding independently and silently for over two hours, the two eventually arrived at the same patch of vines and belted out a dramatic pant-hoot chorus. Unexpectedly, it was answered by the distinctively squeaky pant-hoot of Tom, an adolescent male who must have also been feeding nearby. After answering this pant-hoot with one more of their own, Apollo and Titan began a long series of loud rough-grunts (listen here!) and proceeded to feed together intensively for two more hours, eventually being joined by Tom. Finally, four hours after the start of my focal follow, the pitter patter of falling fruit began to slow and the chimps came down from the trees for the first time. After a short bout of grooming, Apollo and Tom left Titan in Kakombe and took off for the land above the waterfalls where Apollo spends most of his time. Continue reading →

One night while working in the office on my day off, a boisterous panthoot chorus erupted directly behind me. I was startled by the commotion, as it was already dark and the chimps should have been asleep deep in the forest. After asking around I found out that a large party had nested right on the periphery of the forest, basically in our back yard. This was during the time of Mabungo Makubwa when large parties of chimpanzees were coming together to feed. Needless to say it was extremely easy to unnest the following morning, as I quickly found my focal target, Sampson, with minimal effort.

The timid Sampson

Being pretty low ranking, Sampson is very skittish around other males. He makes rapid detours around menacing-looking elders and bolts up trees whenever the group starts into a pant-hoot chorus. That morning the large nesting party dissipated shortly after sunrise as different subgroups went off to feed in various choice locations. Sampson had gone off alone to feed in a palm tree and was contentedly consuming palm nuts until the pant-hoots began. Ferdinand and others had come across a large patch of Mabungo Makubwa a short distance away and were carrying on with typical chimpanzee fervor. Sampson climbed down and tentatively made his way towards the others. Upon approaching, Ferdinand made it very clear that he would not tolerate Sampson in close proximity to himself while feeding on the precious Mabungo. Without making much of a fuss, Sampson resigned to an adjacent tree containing a scattering of likely-inferior Mabungo fruits woven among the branches. This pattern continued throughout the day with parties dispersing for awhile and then fervently coming back together again after a new and abundant resource had been discovered. Continue reading →

 

A party of chimpanzees grooming in the trail after a nice bout of feeding on Mabungo Makubwa

Earlier this field season I talked a lot about how the chimps were moving far and fast as they searched for meager fruits scattered around the park. However, a few weeks ago, thing began to change. The chimps were hanging out all day in Kakombe Valley and in large, boisterous parties. As I am studying their vocalizations, this was good news for my research. It all started with the arrival of Mtobogoro fruits in trees growing along Kakombe Stream (read about an exciting event involving these trees here). However, as only a few trees were fruiting, I figured I would be back following lone chimps through the forest within a week or so. However, then came Mabungo Makubwa.

Continue reading →

The adult males groom one another while the adolescent, Tarzan, rests

So my focal target has gotten out of his nest and I am now following him through the forest. Now, what do I write down? This can depend on whether I am focusing on behavioral states or events.  In general, states are behaviors that last for awhile, like resting and feeding, while events are behaviors that happen quickly, such as producing a vocalization or mating.

For events, you simply need to document the time that they occurred. For instance I could write “Sampson screamed at 9:47:35” (hour:minute:second). However, for states, obtaining information on duration is also important. So, one way to record data on these behaviors is to write down the start and end time of each behavioral state (called “Focal-Animal Sampling”). For instance I would write “From 10:55:43 to 11:03:07 Frodo was feeding ”. In this way I know how long each behavior lasted and when it occurred. Also, for both states and events, it is usually important to include additional information, such as why Sampson was screaming or what Frodo was eating. Continue reading →

As I described in my last blog, I am conducting 8 hour focal follows on my target male chimpanzees. Since they are usually awake for 11-12 hours a day, I stagger my follows so that half of the time I am with them right when they wake up and half of the time with them up until they go to sleep. With transport time to and from, this usually means I am in the forest for 10-12 hours a day and go out 5-6 days a week.

Packing my waistpack the night before

The chimps normally wake up between 6:30 and 7:00am. However, they often nest far from camp and we always have to travel uphill to get to them. This means that on the days that I unnest, I have to leave the house between 5:00 and 5:30am. The night before, I pack my bag with the things I will need for the day. These are many of the supplies I showed you in my suitcase. I have my recorder and microphone, binoculars, camera, notepad and pens, and datasheets. I also carry a bottle of water, some water purification tablets (in case I need to refill my bottle from a forest stream), a basic first aid kit, and a poncho for the frequent rain storms this time of year. I stuff all of these things into a waistpack- the biggest thing we can get by carrying in the dense forest. Its a tight fit so I rarely carry any food with me, but when I do, I bring a small bag of peanuts and raisens or a piece of a power bar. The forest is dense and almost everything gets caught up in the vine tangles, so I try to travel as lightly as possible. Continue reading →

My field assistant and I following our focal target

Its 8:05 am and Ferdinand is crashing through the forest shaking branches, pounding on tree trunks and making a big display of his dominance to approaching group members. Meanwhile, in a nearby area, Titan is up in a tree feeding, Gremlin is playing with her infant below, and Freud and Faustino are grooming one another in the tall grass. With all of this going on, how do you get the data you need to answer a research question? In these situations, a person’s natural reaction is to focus on the most exciting event: Ferdinand’s display. It is loud, eye-catching, and, at times, outright alarming (particularly if he’s coming your way!).  That is why, if you approach observational research in an unsystematic manner, your data will be biased towards these exciting events and will overlook more subtle behaviors, like the quiet grooming of Freud and Faustino. It would kind of be like studying a group of students but only taking data on the class clown or bully. Obviously, these data would not represent the behavior of the class as a whole. This is why many scientists studying animal behavior conduct something called “focal individual follows”. Continue reading →