Mortality of wildlife in Nairobi National Park, during the drought of 1973–1974

Abstract

(1) The mortality of wildlife in Nairobi National Park during the drought period of 1973/74 was monitored by monthly ground counts. (2) Highest mortality rate was recorded for kongoni at 27%, followed by wildebeest at 10% and zebra at 7% of the live populations present in the Park. (3) The dry period was marked by a massive influx into the Park of the three species most affected. Eland also moved in, and sub sequently left the Athi-Kapiti ecosystem entirely, while populations of the other species in the Park remained relatively static. (4) Proportionally the highest mortality was recorded in the driest part of the Park and in the forest. (5) Immature and female animals died earliest, but the overall sex and age ratios reflected those reported for live populations, except that a greater proportion of female wildebeest died than expected. (6) Mortality was suspected to result from poor physical condition and lowered disease resistance caused by malnutrition. This occurred during the latter half of 16 consecutive months of below-average rainfall, which considerably reduced vegetation growth. (7) The results are discussed in relation to those found elsewhere in this ecosystem, and in relation to domestic stock, human development and the future of Nairobi National Park.