Re-introduction of mona monkeys to supplement a depleted population in community forest in southeast Nigeria

Summary

Mona monkeys (Cercopithecus mona) had been hunted to near-extirpation in Iko Esai community rainforest in Cross River State, southeast Nigeria, with only three sightings of solitary individuals recorded during an eight-month survey. CERCOPAN spent seven years building a relationship with the Iko Esai community before establishing a 400 hectare protected release zone in 2000, patrolled by former hunters, adjacent to a co-managed 3,000 hectare buffer, under a 99-year memorandum of understanding that ultimately set aside more than 12,000 hectares from logging and farming. A community-wide ban on primate hunting followed in 2006. On 1 November 2007, one group of three rehabilitated monkeys, an adult male, adult female, and sub-adult female, was released; all were micro-chipped and the adults radio-collared. Daily high-energy food supplementation was quickly reduced as the group began successfully foraging on wild fruits, insects, and leaves, establishing a roughly 2 hectare core home range and a routine resembling wild Cercopithecus groups. Major difficulties included funding-related release delays, initial community mistrust, and a nutritional-deficiency health condition in the captive population that was diagnosed and resolved before release. The project rated itself Partially Successful, noting it is still too early to judge survival or population recovery, while community support, forest protection, and reduced hunting violations are already showing clear success.