Resumen
Paleogene records of birds in the Eastern margin of the Pacific Ocean have increased in recent years, being almost exclusively restricted to fossil Sphenisciformes (penguins). New avian remains (Ornithurae, Neornithes)from Middle-to-Late Eocene levels of the Estratos de Algarrobo unit, in Algarrobo, central Chile, are disclosed in the present work. These new finds are significant in representing the first non-spheniscid bird remains of Middle to Late Eocene age, recovered in mid-latitudes of the eastern Pacific and probably belonging to a procelarid. It complements the regional record of Eocene birds, previously known only at high-latitudes such as Seymour Island (Antarctica) and Magallanes (Chile), and low-latitude locations in Peru.