Colobus chorus
Recorded by Daan Hendricks.
"We visited the rainforests of Mabira, Kibale, Kalinzu, Bwindi and Mgahinga, each sporting their own blend of vegetation and wildlife. Monkeys such as black and white colobus, mangabey, red tailed monkey and olive baboon were ubiquitous; the great apes, chimpanzee and mountain gorilla, of course less so. We did hear both types of ape occasionally in the distance."
Part of the Sounding Nature project - for more information, see http://www.citiesandmemory.com/sounding-nature