Does illegal hunting affect density and behaviour of African grassland birds? A case study on ostrich (Struthio camelus)
Widespread bushmeat hunting represents one of the major threats to many mammals and birds in Africa. We studied the influence of illegal bushmeat hunting on large grassland birds in the Serengeti National Park (SNP) and adjoining protected areas, by using the ostrich (Struthio camelus) as a case study. First, we documented illegal hunting of both small and large birds by using a questionnaire in the villages on the western and eastern side of the SNP. Second, we studied the effect of illegal hunting on density by driving 4,659 km of transects inside SNP and on the adjacent protected areas, where the data were analysed by DISTANCE sampling. Last, we used flight initiation distance (FID, i.e. the distance between an approaching predator (human) and prey when flight is started), to assess possible impacts on behaviour from illegal hunting. We found that people from the western side of the SNP admitted to hunting both small and large grassland birds, and collect ostrich feathers and eggs. Although the Maasai also hunted small birds, only ostrich feathers and eggs of the large grassland birds were used. Surprisingly, we found no significant differences in densities between the SNP and adjoining partially protected areas, but ostriches had longer FID to an approaching human outside the SNP. Currently illegal hunting does not appear to affect the ostrich population, but given the extensive use of birds for consumption more awareness educational programs accompanied by provision of agricultural incentives within the protected areas are needed.