Diet choice among red colobus (Colobus badius rufomitratus) on the Tana River, Kenya

The feeding behaviour of a group of red colobus was observed in gallery forest beside the Tana River, Kenya, between October 1973 and December 1974. Food availability was quantified from tree enumeration data and a monthly sample of phenology, 22 species contributed to the annual diet but there was great variation in selection among them. Young leaves were not only the most important items in the diet, but also the most consistently selected in relation to their availability. Compared to red colobus studied at rain-forest sites in Uganda and Tanzania, those at the Tana have a much less diverse diet and eat more fruit but less mature leaf. The hypothesis is discussed that more use can be made of mature leaves in rain forest, because there are more species from which to choose.