Red-billed oxpecker which feed on backs of large animals.......

Red-billed oxpeckers take a ride on a greater kudu. Oxpeckers graze exclusively on the bodies of large mammals. Certain species are seemingly preferred, whereas others, like the Lichtenstein's hartebeest or Topi are generally avoided. Smaller antelope such as lechwe, duikers, and reedbuck are also avoided; the smallest regularly used species is the Impala, probably because of the heavy tick load and social nature of that species. In many parts of their range they now feed on cattle but avoid camels. They feed on ectoparasites, particularly ticks, as well as insects infecting wounds and the flesh and blood of some wounds as well. They are sometimes classified as parasites because they open wounds on the animals' backs.