Samburu and Buffalo Springs host basically two different environments for wildlife observation. The first one holds all the arid plains, far off the water sources. Relatively few animals inhabit these lands on a permanent basis, outstanding the oryx, Guenther's dik-dik (in addition to the more widely extended Kirk's), gerenuk, eland and impala. These species are little water-dependent and may be found in the scrublands during the day, sheltered beneath a tree shade. Conversely, the rest of herbivores, including zebra, giraffe, elephant, buffalo, warthog, waterbuck, Grant's gazelle and bushbuck seek the fresh and shaded riverbanks during daylight, leaving them at dusk. The great advantage for the watcher in Samburu and Buffalo Springs is that driving along the river gives the chance to see a huge lot of animals close at hand. Waters welcome their permanent dwellers, hippos and crocodiles, while up its big trees and doum palms roam the vervet monkeys and baboons.

The three reserves are also the haunt for a rich avifauna, with more than 300 species recorded. This is the place for the Somali ostrich, with its bluish neck and thighs, and for the Kori bustard, standing a meter high. The scrublands are home for some game birds, like crested francolins, yellow-necked spurfowls and the Guineafowls, both vulturine and helmeted that actually belong to different genuses and that flock to drink down at the river banks. Red-billed hornbills, marabou storks and superb starlings are a permanent presence. Prey birds include eagles, owls, kites, goshawks and sparrowhawks. Woodpeckers nest in the riverine trees. The Ewaso Nyiro waters attract a great deal of water birds, like pelicans, herons, hamerkops and kingfishers.