The Uaso Nyiro is famous for its big crocodiles. The arid bush country of northern Kenya supports an amazing variety of birds. The presence of water and riverine woodlands in the three Reserves increase this diversity. Almost 400 species have been recorded in these areas. The Ostrich is readily seen, the males having bluish necks and legs, unlike the southern race which has a pink neck and legs.
Birds of prey are abundant, from the martial eagle to the tiny, shrike like pygmy falcon.
Bateleur eagles soar on warm air currents, and perform acrobatic mating displays. It can be distinguished from the Augur buzzard by its black underparts and very short tail, the buzzard having a red fan-shaped tail and broader wings. The pale chanting goshawk, a grey long legged hawk with a white rump, is commonly encountered sitting high in thorn trees. Along the rivers and in the swamps and springs, one sees a great diversity of waterbirds such as Egyptian geese, pied kingfishers, and wading plovers and sandpipers. A morning spent sitting quietly under the Acacia elatior trees will reveal many small sunbirds, warblers, flycatchers and doves.