Numbers and age and sex structures of the defassa waterbuck population in the Nazinga Classified Forest and Game Ranch in Burkina Faso

Abstract

The population size of Kobus ellipsiprymnus defassa is decreasing. The present study was carried out in 2021 and 2022. It aimed to provide updated data on the population structure of Kobus ellipsiprymnus defassa in the Nazinga Classified Forest and Game Ranch. The numbers, age and sex structures of the defassa waterbuck population were estimated by the direct census method along online transects in 2021 and 2022 between the month of April and the first week of the month of may. The average population’size of the population of Kobus ellipsiprymnus defassa in 2021 and 2022 was 797 and 942, respectively. Age structure in percentage was in favor of adults (62.74% in 2021 and 54.19% in 2022) followed by subadults (33.96% in 2021 and 36.12% in 2022), finally juveniles (3.30% in 2021 and 9.69% in 2022). The data showed higher numbers of females in 2021 and 2022 (173 and 176) compared to those of males (36 and 22). According to the results, Kobus ellipsiprymnus defassa population is aging with a very high sex ratio in favor of females.