Short Communications

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

Julian Eastona1 c1, Nerissa Chaoa1, Felix Mulindahabia1, Nicolas Ntarea1, Louis Rugyerinyangea2 and Innocent Ndikubwimanaa2

a1 Wildlife Conservation Society–Rwanda, P.O. Box 1699, Kigali, Rwanda.

a2 Rwanda Development Board, Nyungwe National Park, Rwanda


The elusive, Vulnerable owl-faced monkey Cercopithecus hamlyni is a rare and little studied species and one of the least known of the African Cercopithecidae. This study describes the distribution and relative abundance of the only known population in East Africa, in Nyungwe National Park, Rwanda. This species is restricted to a small (32 km2) area of bamboo and bamboo–forest mix in the southern sector of the Park, close to the international border with Burundi. We present the first empirical data of its abundance in the bamboo forests of Nyungwe. A total length of 185 km of transect were surveyed to estimate relative abundance of diurnal primates. Encounter rates with the owl-faced monkey were 0.081 groups km-1 (n = 15). Mean group size was 3.6 individuals. Eight independent photographs of C. hamlyni were obtained from five camera traps during 182 camera-days. Four other species of primates occur in the bamboo forest: eastern chimpanzee Pan troglodytes schweinfurthii, Angola colobus Colobus angolensis, L’Hoest’s monkey Cercopithecus l’hoesti and blue monkey Cercopithecus mitis. The main threats to the bamboo forest are from the illegal harvesting of bamboo, trapping and tree-cutting. These threats originate from both Rwanda and Burundi. There is an urgent need for conservation action to halt the destruction and degradation of the bamboo forest and to ensure the long-term survival of the owl-faced monkey in Rwanda.

(Received March 12 2010)

(Reviewed July 02 2010)

(Accepted August 24 2010)

(Online publication June 07 2011)


c1 Wildlife Conservation Society–Rwanda, P.O. Box 1699, Kigali, Rwanda. E-mail juleseaston@yahoo.co.uk

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