Blue monkeys’ utilization of five tree species in relation to abundance of each tree species : Diospyros abyssinica, Euclea divinorum, Turraea robusta, Warburgia ugandensis and Ficus lutea

Abstract: This study was carried out in the Sabaringo forest outside the Masai Mara National Reserve in Kenya in order to obtain knowledge about the dietary preferences of the blue monkey Cercopithecus mitis stuhlmanni. Previous studies of foraging behaviour of lactating and non-lactating females in this forest have investigated the monkeys’ preferences of tree species to foraging of and being positioned in. To relate the monkeys’ preferences of each tree species to the abundance of the tree species we made a total inventory of the trees in the forest. This was done by identifying species and size of each tree, as well as GPS position in order to create maps of the area. For the ten most popular tree species displayed in the previous study, comparisons were then made between the monkeys’ use of the species and the abundance of these species (measured by number of trees, number of branches and stem area). The observations displayed in this thesis are based on the analysis of five of the ten most popular tree species; Diospyros abyssinica (Giant Diospyros), Euclea divinorum (Diamond-leaved Euclea), Turraea robusta (Honeysuckle tree), Warburgia ugandensis (East African Greenheart) and Ficus lutea (Giant-leaved Fig). The remaining five tree species are analysed in a corresponding thesis by Ahlbäck. F. lutea was despite of its low frequency in the area the clearly most popular tree species, mainly for foraging of but also for being positioned in. It was used 28 times its abundance for foraging and 10.2 times its abundance for positioning, concerning its number of trees. Both lactating and non-lactating females showed this preference, even though the trend was stronger among the latter. The second most popular tree species for foraging was W. Ugandensis and D. Abyssinica. Both E. divinorum and T. robusta were utilized for foraging with same or less frequency than their abundance. When looking at the tree species used for positioning, the most popular species after F. lutea was W. Ugandensis, E. divinorum and D. abyssinica. The least popular species was T. robusta.