Status and conservation of the only population of the Vulnerable owl-faced monkey Cercopithecus hamlyni in Rwanda

Nyungwe National Park in Rwanda hosts the sole known population of the Vulnerable owl-faced monkey (Cercopithecus hamlyni), confined to a 32 km² bamboo and forest mosaic. This study provides the first empirical data on its abundance, revealing an encounter rate of 0.081 groups per km (n=15) with mean group sizes of 3.6 individuals. Camera traps captured eight independent images over 182 days, confirming cohabitation with four other primate species. Threats from illegal bamboo harvesting and trapping, driven by neighboring Burundi, endanger the habitat. Urgent conservation measures are needed to protect this critically isolated population and its unique ecosystem.

Easton, J., Chao, N., Mulindahabi, F., Ntare, N., Rugyerinyange, L., & Ndikubwimana, I. (2011). Status and conservation of the only population of the Vulnerable owl-faced monkey Cercopithecus hamlyni in Rwanda. Oryx, 45(3), 435–438. https://doi.org/10.1017/s0030605310001468