Mountain gorillas are still hanging tough in Uganda’s Bwindi Impenetrable National Park, one of only two places in the world where these endangered great apes live. A recent census in the park found that the population has increased by 6 percent since the last census in 2002, up from 320 to 340 individual gorillas. Staff from Uganda Wildlife Authority, Wildlife Conservation Society (WCS), Max Planck Institute of Anthropology, and other groups conducted the latest survey between April and June 2006.

“This is great news for all of the organizations that have worked to protect Bwindi and its gorilla population,” said WCS researcher Dr. Alastair McNeilage, who also directs the Institute of Tropical Forest Conservation in Bwindi. “There are very few cases in this world where a small population of a endangered primates is actually increasing.”

The researchers surveyed the distribution, size, and makeup of the Bwindi population, and gauged human impacts on the gorillas. Because the gorillas inhabit a relatively small area—Bwindi Impenetrable National Park covers only 127 square miles—the team was able to count every family group in the forest. In addition to tallying trails and nests, they used genetic samples from fecal specimens to identify and distinguish individual gorillas. This survey marked the first time the DNA analysis technique had been employed successfully.

Since the first count in 1997 of 300 gorillas, the population has grown annually by 1 percent. The current population shows a healthy distribution of ages, including adults, juveniles, and infants. The researchers also found that the gorillas are not using the eastern side of the park, possibly as a result of human disturbances there. Particularly encouraging, however, was their discovery that one group is using the northern sector for the first time in living memory.

Bwindi is also home to a thriving gorilla ecotourism program, which generates much needed revenue for Uganda. Four of the 30 family groups have been habituated to the tourists’ presence, and tolerate them for short periods.

In Virunga National Park on the borders of Uganda, Rwanda, and the Democratic Republic of Congo, another mountain gorilla population is hanging on, thanks to the efforts of conservationists and park guards. A 2003 census of the Virunga population counted 380 gorillas, up from 324 in 1989. The combined total of mountain gorillas at the two locations brings the worldwide population to approximately 720 animals.