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Chimpanzee and Chimpanzee Habitat Surveys across the GME

GME survey, 2023-2024

View from Mahale Mountains National Park (Credit: A. Chitayat/GMERC).jpg

GMERC has been leading survey work to prioritise chimpanzee habitat and extra-park populations since 2011. Our data have informed conservation planners and government policies and contributed to a 10 year conservation action plan, which can be found here.

In 2023, we received support from the Arcus Foundation and Frankfurt Zoological Society to continue these survey efforts, building on findings that described monkey and chimpanzee abundance, habitat connectivity, and gene flow (see Publications for more).

**********GME survey, 2023-2024 **********

Survey Leaders

Devon Thurston


My name is Devon and I’m from Massachusetts, USA. I’ve always been an avid animal-lover, with a special soft spot for non-human primates (NHP). My mother raised me to love and respect our planet, with many of our days spent volunteering at farm sanctuaries or at local trash clean-ups. These two passions, for NHPs and for the conservation of our Earth, naturally led me to complete my MSc in Primate Conservation at Oxford Brookes University. Last year I performed a population survey on a subspecies of blue monkeys, Cercopithecus mitis ssp. manyaraensis, in Lake Manyara National Park, Tanzania. I loved spending long days out in the field collecting data, especially in this beautiful country. This year I’m extremely grateful to be surveying chimpanzee abundance and densities in the Greater Mahale Ecosystem, and to determine crucial wildlife corridors in the area. It’s a dream come true to lead a team through this sort of work, and to contribute to the conservation of eastern chimpanzees in Tanzania.

Hi, I’m a recent graduate of the Primate Conservation MSc at Oxford Brookes University and unsurprisingly have long held a deep interest in both primates….and conservation. While my initial passion for the protection of primates is rooted deep in my past, my career with them began interning at a wildlife rehabilitation centre where I cared for howler, spider and capuchin monkeys. After a stint performing a population survey of blue monkeys in Lake Manyara National Park in 2022 I found myself drawn back to the stunning and welcoming country on Tanzania. So once the opportunity to study the awe-inspiring chimpanzee of the GME came along, I seized it. As an amateur mycologist/mushroom enthusiast, conducting a study in such a fungal hotspot such as Issa Valley means I could not be happier with my decision.


James Parsons

Site 1: Kajeje

As a pilot survey site, the team went east from Issa towards Kajeje valley and assessed an area that hosts potentially a neighbouring chimpanzee community. The team found evidence of chimpanzees, but also human disturbance including logging and bushmeat consumption. Below, photos (by D. Thurston) capture (clockwise) packing up to return to Issa, Kajeje habitat, and @Huruma Mwasomola deploying a motion triggered camera. The video captures the early start to the fire season! 

Sunlight breaks through (photo: D. Thurston/GMERC)
Kajeje mambo woodland (photo: D. Thurston/GMERC).jpeg

Site 2: Ntakata Plateau Forest
(blog from James Parsons & Devon Thurston)

Ntakata Blog (Hakuna Matata Ntakata)


It’s a far leap from learning about primates in lectures and watching YouTube videos about their behaviour in class to conducting a population survey of chimpanzees in Western Tanzania. For one thing there are far more metaphorical mountains to climb during a university semester than literal ones. We (myself & co-survey leader, Devon) had unfortunately missed the first two weeks of surveys conducted in the first of two camps in Ntakata due to Devon suffering from malaria. We were thoroughly jealous of the environments that our team had the privilege to explore before our arrival. We weren’t jealous for long, however, as the trek to our second camp took us through some strikingly beautiful scenery. 

     We were walking just as the annual fires in the area were beginning and the unburned areas were covered in long grasses, shades of golds and yellows that swayed with the wind. We walked along lightly trodden and uneven paths with loose stones strewn along it ready to wobble underfoot the moment you tried to take in the view. While we walked along the top of mountain plateaus, land stretched out on either side, allowing us to see for miles. Valleys were filled with patches of green riparian forests, where we could tell rivers flowed through the landscape as the greens darkened. I regularly hummed the Lord of the Rings soundtrack.

     We had traversed the mountains of Ntakata from the first camp, approximately 15 kilometres to the second camp with tents, food, camera traps and research equipment in tow. Our ‘mpishi’ (cook in Kiswahili) prepared us a hearty meal of beans and ugali (a local dish described as ‘stiff porridge’) to fill our tummies and replenish our strength. The only thing left to do was get some sleep. What followed were two weeks of clambering up extremely steep slopes, looking for chimp nests, and the satisfaction of sitting around a campfire with friends after overcoming the physical challenges of a day. 

      Some particular highlights included heading out each day to conduct transects in the coolness of the morning and watching the sunrise over the landscape, and Devon and I seeing our first red colobus monkeys, discovering the joys of their squeaky (almost sci-fi-esque) vocalisations. One particularly special moment was standing halfway up a hill, and hearing chimps in the valley below calling and hooting away. 

      Each night we would sit and teach one another new words in either Kiswahili or in English. My British & alien pronunciation of Swahili words caused great amusement and the team were always encouraging in helping with my vocal articulations. Apparently the British accent speaking Swahili sounds like it’s ’restricted’ and ‘tight’. I imagine something like somebody trying to talk through a kazoo but I hope I’m wrong. My new favourite Swahili words are ‘kuanguka’ (to fall), ‘birika’ (kettle…a essential term for any Brit looking for a cuppa tea) and ‘kupiga chafya’ (to sneeze). 

      After dinner, we would retire to our tents exhausted and each evening we would doze off to the sounds of two owls (African wood owls, I hesitantly suggest) hooting at each other. It was thought that they were singing a ‘wimbo wa upendo’ or in English a ‘song of love’. 

Asante sana Ntakata, you were amazing. Next stop Kashagulu…let’s see what challenges and wonders you have in store.
























Not long after we filled our water bottles from the Lugonesi river, the cows arrived to take a drink, too. These cows were ‘Ankole’ cattle. They sport particularly long horns and are common throughout much of the area around the southern coast of Lake Tangynika. Often belonging to the largest tribe in Tanzania, the Sukuma, these impressively horned bovines are also a common sight throughout much of Western Tanzania, but represent a potential threat to especially wildlife habitat. 

      Our first day at each survey site tends to be the same but never disappointing. We split into groups, each carrying heavy rucksacks with equipment and set out to find the best location for camera traps and audio sensors. We thoroughly enjoy these remote devices as they allow a glimpse into the lives of animals that we would rarely observe. Once the devices are deployed, it’s a waiting game to learn what they’ve detected in our absence!

We spent the following weeks navigating the steady and intense hills of Kashagulu forest. Once we crossed, trudged and sweated our way over the peaks we were treated to spectacular views of the lake and savored the breeze that rolled off its waters. Lake T is the second oldest and deepest as well as second largest (by volume) lake in the world. Throughout the forests that overlook its water, we regularly heard the calls of southern ground hornbills. These large birds are a pleasure to both eyes and ears. They trundle along the ground with black and white plumage and bright red faces embellished with throat wattles. Their calls are low and serve the function of defending territory or attracting a mate and sound like a deep panpipe. These brilliant birds will also inflate their throat sacs to scare off predators with load calls. 

     We also regularly encountered bushbuck (or in KiSwahili: pongo). Typically, encounters are fleeting and from 40-50m, from which they detect our presence early. However, on the last day when a field assistant (George) and I were collecting camera traps, we heard a harsh, raspy bark reverberate across the hills. We stopped to listen further when a commotion in the bushes in front of us grabbed our attention. A rustling sound was coming closer and closer until we realised it was the hooved footfall of a bushbuck frantically running...towards us! Suddenly a female bushbuck burst through the foliage, her path intersected with where we were standing, all of us paralyzed in shock! Two male bushbucks in pursuit erupted in a shower of leaves from the same bushes frm where she had emerged. Upon seeing us, they immediately bolted to avoid us – a relief to everyone undoubtedly!

Ultimately, our cameras detected other bushbucks, mongooses, and even a leopard (in Kiswahili: chui), which spent most of her time investigating the scent of either the camera or more likely, my sweaty hands fiddling with the controls and straps when I deployed it. 

     Ultimately, we packed up our small camp, said goodbye to the red colobus monkeys that had slept in the tree behind our tent (squeaking throughout the night) and the soft hums of the crowned hornbills. 

     Photos (from the authors) below of (from left, clockwise) base camp near the Lugonesi River, crossing the Lugonesi, uninvited visitors to camp, Kalya village, a crowned hornbill).


(Left) Devon heads off to begin a transect (left), (centre) a red colobus monkey that (arboreally) joined the survey team's camp and (right) Magloire and Georgie contemplate a swim!

Site 3: Kashagulu

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