Fossil birds from Cooper's D aid in reconstructing the Early Pleistocene paleoenvironment in the Cradle of Humankind (Gauteng, South Africa)

Several large-bodied hominin and nonhuman primates have coexisted in the Cradle of Humankind inSouth Africa during the Early Pleistocene. Previous paleoenvironmental studies regarding the Plio-Pleistocene of South Africa have focused heavily on mammal assemblages. Here, we conducted acomprehensive taxonomic analysis of the fossil bird remains from Cooper's D, the most fossiliferouslocality of the hominin-bearing Cooper's Cave complex in South Africa. Our taxonomic evaluation of 505remains reveals the presence of 23 bird taxa, two of which are extinct and already reported from thenearby fossil locality of Kromdraai. The taxonomically diverse bird assemblage is dominated by Francolinussp. and other species associated with open grassland habitats, followed by rock-dwelling species,including Tyto cf. alba and the extinct Corvus bragai, and by woodland species such as Agapornis sp.,Accipiter melanoleucos, and the extinct Glaucidium ireneae. The occurrence of these taxa and theirrespective proportions in the assemblage, in terms of both numbers of bones and individuals, point to thepresence of extensive open grassland and/or savannah with rocky outcrops and woodland. These findingscorroborate previous analyses of mammals from Cooper's D, with the exception of aquatic species,which are rare in the bird assemblage. Comparison with older deposits from Kromdraai confirms thedefinitive establishment of open habitats in the Cradle of Humankind during the Early Pleistocenefollowing a transition from woodier habitats during the Late Pliocene. This study constitutes a furtherstep in investigating the fossil bird diversity in the Cradle of Humankind during the Plio-Pleistocene. Ourresults add to the larger body of work using avian fossils for paleoenvironmental reconstructions inAfrica and support the utility of birds as paleoenvironmental proxies. Similar future studies will refineour understanding of the paleoenvironments and landscape transformation during the Plio-Pleistocene,a critical timeframe for hominin evolution in southern Africa.