Report on a short study of the dry season feeding ecology and habitat preferences of the golden-backed uacari or bicó, Cacajao melanocephalus ouakary (Cebidae: Pitheciinae), on the lower Rio Jaú, Amazonas, Brazil

Golden-backed uacaris Cacajao melanocephalus ouakary were studied in the forests of Jaú National Park, Amazônas, Brazil, for 17 days in late October/early November 2000, the mid-dry season. Studies complimented our previous studies in the wet season of 1999 (Barnett et al., 2000). Eight uacari groups were seen and seven more were heard. Group sizes ranged from 1-100+. Uacaris were recorded in igapó, campina and terra firme forest types. Information was obtained from local informants on seasonal use of these forest types and of other, smaller, more spatially patchy habitat types, with high temporal patchyness in fruit availability (e.g. buritzal). Foods were recorded directly for animals in igapó and terra firme, and indirectly for all three forest types. A total of 64 food plant species were recorded. These included hard fruits, soft fruits and leaves. The physical dimensions and hardness of fruits was recorded for 34 of these species. Together, young leaves of three tree species (Buchenavia oxicarpa Combretaceae, Eschweilera tenuifolia Lecythidaceae and Mabea taquari Euphorbiaceae) appeared to form a substantial dietary component. This is the first record of substantial folivory for this primate. Quantitative transects showed fruit and flower availability to be low in all habitats. Leaves may thus be a refuge food. At Jaú there appears to be considerable overlap in the uacari’s diet with that of Cebus spp. and Saimiri, but only for soft fruits. Alouatta was not seen eating the leaves consumed by the uacari. Evidence was obtained that some key wet-season diet components (e.g. Eschweilera seeds) were also consumed by macaws and parrots. For golden-backed uacaris the seasonal use patterns for habitats and the food resources within them may be more complex than previously realized.