18. Aves

The study of the entire fossil bird collection from Laetoli, including the specimens collected by Mary Leakey (1974–1981) and the recent ones collected by the Eyasi Plateau Paleontological Expedition (1998–2005), is presented here. The 247 bird fossils allow the identification of 21 different taxa in 11 families (and eight orders). One fossil is from the Lower Laetolil Beds, 229 from the Upper Laetolil Beds, and 17 from the Upper Ndolanya Beds. The large majority of the fossils belong to francolins (Phasianidae) and guineafowl (Numididae), followed in decreasing order of abundance by Columbidae, Accipitridae, Strigidae, Passeriformes, Coliidae, and – one fossil each – Ardeidae, Falconidae, Scolopacidae and Tytonidae. Some genera or species constitute the earliest known representatives of modern lineages, among which are the falcon Falco cf. eleonorae, the Vulturine Guineafowl Acryllium vulturinum, a dove Streptopelia sp. and the eagle-owl Bubo cf. lacteus. Acryllium vulturinum, from the Upper Laetolil Beds, indicates semi-open or open country habitats in the paleoenvironment. A heron, Ardea sp. (Upper Ndolanya Beds) and a calidrine wader (Upper Laetolil Beds) imply aquatic settings. Most other birds, including most Galliformes, the Columbidae and the Coliidae (mousebirds) indicate a minimal cover of at least scattered trees or bushes. The fossil birds yield additional information regarding biogeo-graphy, differences between stratigraphic units, environment, new perspectives on the study of bird prints and eggs from diverse localities at Laetoli, and finally some clues about the probable status of some birds (i.e., breeding, passage or wintering migrant).