See studies by B. Heinrich (repr. 1991; 1999).
Any of several species (genus Corvus, crow family Corvidae) of heavy-billed, usually solitary, songbirds, once abundant throughout the Northern Hemisphere but now restricted to undisturbed areas. The common raven (C. corax), the biggest passerine, grows to 26 in. (66 cm) long and has a wingspan of more than 4 ft (1.3 m). The dark, iridescent plumage is shaggy, especially around the throat. Ravens eat rodents, insects, grain, birds' eggs, and, in winter, carrion and refuse. Captive nestlings may learn to mimic a few words. The large nest, a crude structure of sticks, is built high on a cliff or treetop.
Learn more about raven with a free trial on Britannica.com.
An obsolete collective noun for a group of ravens (or at least the Common Raven) is an "unkindness or a "conspiracy