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Counting mountain gorillas in Bwindi Forest

Since mountain gorillas are critically endangered and their numbers are small, it’s important to know just how many there are and how well their populations are doing. For that reason, every few years conservation groups and park authorities working in mountain gorilla habitat conduct a census – or count – of the population, to learn how they are faring. The information gained helps us understand whether the population is growing or shrinking and other important trends that may be occurring. Currently we can also obtain genetic information as well, through the fecal samples that are collected.

Collecting gorilla fecal samples

Mountain gorillas live in two separate populations – the Virunga mountains that span Rwanda, Uganda and the Democratic Republic of Congo, and the separate Bwindi Impenetrable Forest/Sarambwe Reserve area, in Uganda and the Democratic Republic of Congo. In the Virunga mountains, gorilla census work started in the 1970s, when Dian Fossey worked there. In Bwindi, the first full census was conducted in 1997.

This month, Dian Fossey Gorilla Fund staff are participating in a new census of the Bwindi/Sarambwe gorillas, which is being conducted by the park authorities of Congo and Uganda and organized by the International Gorilla Conservation Program. The Fossey Fund has played a critical role in the censuses conducted in the Virunga region since their initiation and now we are adding to the expertise and personnel needed to conduct the new census of the Bwindi/Sarambwe population. The last census of these gorillas, conducted in 2012, showed at least 400 gorillas, which was up from 302 counted in the previous census in 2006.

A census of the Virunga mountain gorilla population, where the Fossey Fund operates daily protection patrols, was undertaken in 2015-2016, and those results will be available shortly. Due to intensive protection, this population has also shown increases in past counts, making the mountain gorilla the only wild ape whose numbers are known to be increasing. Nevertheless, given the overall tiny numbers (only about 880 total in both areas) and other potential dangers, the mountain gorilla is still classified as critically endangered.

How the Bwindi census will be done

The Bwindi census will take place in two sweeps during the year, with the first one beginning this month and the second sweep in September. Participants will be divided into 12 teams, with six in the forest at a time, divided into three camps. In each of these sweeps, the goal is to systematically cover the entire habitat and record all evidence of gorillas by looking for trails, signs, and nest sites. The teams will also collect fecal samples for genetic analysis. The training period is now underway, with personnel from Uganda, Rwanda, and Congo, including five staff from the Fossey Fund.

GPS training for the Bwindi census

The Fossey Fund’s Rwanda research manager Dr. Winnie Eckardt will play a critical role serving as a co-instructor in the training for this census. She will be located at Bwindi for the next three weeks, conducting the initial training and then working in the field to ensure that the data are being accurately collected and entered.  Also working in the census will be Fossey Fund trackers Prosper Kaberabose, Clement Tuyishime Kagaba, Olivier Hodari and Phocas Nkunzingoma.

Fossey Fund trackers Clement Tuyishime Kagaba and Phocas Nkunzingoma

Once the census is underway, teams will camp in the forest for two weeks at a time, and walk along pre-planned recces each day to search for signs of gorillas, especially nest sites, collecting fecal samples from each nest for DNA analysis to ensure accurate gorilla identification.  They will also record signs of other large mammals as well as any illegal activities in the forest.

“I am really looking forward to getting more familiar with the Bwindi mountain gorilla population and their habitat,” says Dr. Eckardt. “It is wonderful to be part of this important transboundary conservation initiative, which brings people from three countries with different experience and skill sets in gorilla conservation together, targeting one mission. We will learn a lot from each other,” she adds.

“We are very pleased to be able to help support this census by lending the expertise and time of our staff,” says Fossey Fund President and CEO/Chief Scientific Officer Dr. Tara Stoinski.

“With both the Bwindi and Virunga mountain gorilla populations being so small, continual monitoring of population trends is essential and we are glad to support our national park colleagues and conservation partners in doing this work,” adds Dr. Stoinski.

The 2018 Bwindi-Sarambwe population surveys of mountain gorillas, large mammals, and illegal activities are being conducted by the Protected Area Authorities in Uganda and the Democratic Republic of Congo (Uganda Wildlife Authority and l’Institut Congolais pour la Conservation de la Nature) under the transboundary framework of the Greater Virunga Transboundary Collaboration. The census is supported by the Rwanda Development Board, International Gorilla Conservation Programme (a coalition of Fauna & Flora International and WWF), Max Planck Institute for Evolutionary Anthropology, the Dian Fossey Gorilla Fund, Institute of Tropical Forest Conservation, Gorilla Doctors, Conservation Through Public Health, Wildlife Conservation Society Uganda Country Office, WWF Uganda Country Office, and Bwindi Mgahinga Conservation Trust. The census was funded by Fauna & Flora International, WWF, and Partners in Conservation at the Columbus Zoo & Aquarium.