The "Big 5" refers to the African Cape buffalo, lion, rhino, leopard and elephant. The origin of the Big Five is at the beginning of the twentieth century. The white settlers went on hunting safaris. The Big Five refers to the five most difficult animals in Africa to hunt on foot! The members of the Big Five were chosen for the difficulty in hunting them and the degree of danger involved.
Critically endangered birds, the Taita Falcon. Part of a set of 5 stamps, issued 2014.