part of part of in taxon Aves head surface structure beak The term beak is also used to refer to a similar mouthpart in some Ornithischian dinosaurs, monotremes, cephalopods, cetaceans, pufferfishes, turtles, Anuran tadpoles and sirens bill MESH:D001502 The avian beak is an external anatomical structure, in the head region, that is adapted for feeding self and young, catching prey, probing, etc. It encompasses, but is not restricted to, the maxilla, mandible, maxillary ramaphotheca, mandibular ramaphotheca, nostril, nasal fossa, nasal bones, egg tooth and rictus[GO]. The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, probing for food, courtship and feeding young. Wikipedia:Beak TODO - add superclass rostrum avian beak UBERON:0005094