The focus was on the Rift Valley in the southern and central sector of the park. A total of 184 500 hectares was fully covered by means of a helicopter. Systematic, parallel strips that were 500 m wide were assessed. All large mammals observed were counted. All data, including geographical positions, were directly entered into a custom-made census programme. In addition to this count block, a distance of respectively 100 and 125 km of transect lines were flown on the western and eastern side of the core count area. This represents an additional coverage of 11 250 ha. Total coverage through the central counting block and these additional transect lines is 51.6% of the Park.