 Nest sites are typically in relatively secure places, such as the crook of a large tree or an ample cliff ledge, and can vary in elevation from the flat ground of prairies or steppe to near the peaks of the tallest mountains such as the Himalayas.Accipitrids will readily return to use a nest site repeatedly, which has resulted in several of the largest bird's nests known, as a single nest may see decades of use, with more material added each breeding season.The single largest known tree nest known for any animal, belong to a bald eagle ("Haliaeetus leucocephalus"), was found to be deep, across, and to weigh .