Birds are a group of warm-blooded vertebrates constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
copied from Wikipedia
This tag implicates avian (learn more).
The following tags implicate this tag: gull, hawk, owl, picid, and pigeon (learn more).