Unlike mammals, birds have no external ears. The outer ears of mammals play an important function in that they help the animal identify sounds coming from different elevations. But birds are also able to perceive whether the source of a sound is above them, below them, or at the same level. Now a research team from Technische Universität München (TUM) has discovered how birds are able to localize these sounds, namely by utilizing their entire head. Their findings were published recently in the PLOS ONE journal.