Avian remains from Venta Micena (Baza Basin, Granada Geopark) shed light on the Early Pleistocene wetland environments and trophic dynamics of the Southern Iberian Peninsula

The fossil site of Venta Micena (Baza Basin, southeastern Iberian Peninsula), dated to the Early Pleistocene (1.6–1.5 Ma), is renowned for its huge assemblage of skeletal remains of large mammals, most of which were unburied from two roughly coeval excavation quarries, VM3 and VM4. These bone accumulations resulted from the scavenging habits of giant hyaenas ( Pachycrocuta brevirostris ), which transported ungulate carcasses to their maternity dens to consume them. The fossils have enabled detailed reconstructions of Western European faunal communities during the Early Pleistocene, but the remains of small vertebrates, particularly birds, are rare and still poorly understood. Here we describe the first avian remains from Venta Micena and assess their palaeoenvironmental and ecological significance. Three taxa were identified: (i) the Common Shelduck Tadorna tadorna ; (ii) the Pleistocene Giant Crane Grus cf. primigenia ; and (iii) the Pleistocene subspecies of Common Raven, Corvus corax antecorax . The presence of T. tadorna and G. cf. primigenia suggests the existence of a wetland environment characterized by oligohaline waters surrounded by brackish pools in the vicinity of the site. The presence of C. corax antecorax is consistent with the abundance of remains of ungulate carcasses exploited by P. brevirostris , indicating rich scavenging opportunities. Palaeosynecological modeling suggests that meat consumption by ravens approached those of each of the large carnivores, thus significantly reducing the available carrion for other secondary consumers. Moreover, digestive corrosion and tooth marks on bird bones evidence the consumption of avian remains by carnivores, probably juvenile hyaenas. Altogether, these findings reveal a more complex structure of the faunal community that inhabited Venta Micena than previously recognized. First avian remains from Venta Micena are described, including a shelduck, Tadorna tadorna , and the oldest records of the large crane Grus cf. primigenia and raven Corvus corax antecorax . Grus and Tadorna support the presence of a mild, oligohaline to brackish wetland environment in the Baza Basin. The scavenging habits of Corvus add complexity to the trophic interactions in the ecosystem surrounding the Baza palaeolake.