I determined the degree of ecological partitioning among 3 species of guenons (Cercopithecus campbelli, C. petaurista, and C. diana) in the Taï Forest, Côte d'Ivoire and used the partitioning data to understand competitive relationships among them. Over a 13-mo period, I measured ecological partitioning in terms of food and canopy stratum use for 2 habituated groups of each guenon species and also collected data on food availability. I found that the study species diverged primarily in food items consumed and vertical strata occupied. Cercopithecus petaurista ate much more foliage than the other species did and used mostly the middle strata (5-20 m). Cercopithecus diana ate primarily fruit and used mostly the upper strata (>20 m). Cercopithecus campbelli ate mostly fruit together with large amounts of animal matter and primarily occupied the ground and low strata (<5 m). Of the specific pairs, the diets of Cercopithecus campbelli/C. diana overlapped the most overall and decreased during the season of low fruit availability. Cercopithecus campbelli and C. diana age/sex classes also overlapped more than the age/sex classes of other species pairs. The results suggest that the potential for competition was more intense for Cercopithecus campbelli/C.diana relations than it is for other species pairs. I compare my results from Taï with those from other primate and guenon communities and demonstrate that 530 Buzzard dietary overlaps and seasonal dietary divergence are lower in Taï than in most other guenon communities.

Polyspecific associations (PSA) are common in many African primate communities, including the diurnal primates at Taï Forest, Côte d'Ivoire. In this paper I use data on the PSA of two forest guenons, Campbell's (Cercopithecus campbelli) and lesser spot-nosed monkeys (C. petaurista), with Diana monkeys (C. diana) and other primates to clarify interspecific relationships during 17 months including a 3-month low-fruit period. I analyzed association in relation to fruit availability and measured forest strata use for C. campbelli and C. petaurista when alone and in associations with and without C. diana. I also measured predator risk and reactions to potential predators. C. campbelli and C. petaurista had high association rates with C. diana monkeys, and fruit availability did not influence association rates. C. campbelli and C. petaurista used higher strata when in association with C. diana than when alone, but they used even higher strata when associated with other primates without C. diana. This suggested that C. diana competitively exclude C. campbelli and C. petaurista from higher strata. There were relatively large numbers of potential predators, and C. diana were usually the first callers to threatening stimuli, suggesting that antipredator benefits of association with C. diana outweighed the competitive costs. C. campbelli spent more time in association with C. diana than C. petaurista did and appeared to be more reliant on C. diana for antipredator benefits. C. petaurista were less reliant on C. diana because of a cryptic strategy and may have associated less in some months because of high chimpanzee (Pan troglodytes) presence.

My objective is to better understand the influences of seasonality and frugivory on ranging patterns for 3 guenon species of the Taï Forest: Cercopithecus campbelli, C. petaurista, and C. diana). Over a 17-mo period, I gathered data on the daily path length, home range size, and home range use for 2 habituated groups of each species. The ranging patterns of the 3 species were very similar to each other and across seasons. Further, the ranging patterns were not closely related to fruit abundance or consumption. Each species had a long-ranging strategy with long daily ranges relative to home range size and little repeated use of areas on successive days, which may relate to territory and boundary patrols, especially for Cercopithecus diana. I compare them with other guenon communities and demonstrate that the ranging patterns of the 3 species are more similar than the ranging patterns of sympatric guenons in other communities. I discuss the results in relation to the association of Cercopithecus campbelli and C. petaurista with C. diana for antipredator benefits.