On several flights and safaris in the lower Omo River valley the authors and others recorded the numbers of larger mammals they saw. The results showed no regular general migration pattern, although certain species showed trends, notably eland, zebra, elephant and Lelwel–s hartebeest which moved into the area after the rains and out again when the grass died. Dr Urban is working in the Department of Biology in the Haile Sellassie I University in Addis Ababa. Leslie Brown, well known Kenya naturalist, is a UNESCO wildlife consultant.