File:Corvus frugilegus (rook).jpg

English: Corvus frugilegus Linnaeus, 1758 - rook (Field Museum of Natural History, Chicago, Illinois, USA).

Jays, crows, and ravens (Family Corvidae) have the largest body sizes of any passerine bird group in the world. Corvid passerine birds are omnivorous, aggressive, usually gregarious, have harsh calls, powerful beaks, and limited to no sexual dimorphism. These birds typically have bristles covering the nostrils along the upper proximal portions of the beak.

Classification: Animalia, Chordata, Vertebrata, Aves, Passeriformes, Corvidae

---

Birds are small to large, warm-blooded, egg-laying, feathered, bipedal vertebrates capable of powered flight (although some are secondarily flightless). Many scientists characterize birds as dinosaurs, but this is consequence of the physical structure of evolutionary diagrams. Birds aren’t dinosaurs. They’re birds. The logic & rationale that some use to justify statements such as “birds are dinosaurs” is the same logic & rationale that results in saying “vertebrates are echinoderms”. Well, no one says the latter. No one should say the former, either.

However, birds are evolutionarily derived from theropod dinosaurs. Birds first appeared in the Triassic or Jurassic, depending on which avian paleontologist you ask. They inhabit a wide variety of terrestrial and surface marine environments, and exhibit considerable variation in behaviors and diets.