What is the meaning of a raven bird?
A raven is, in many cultures, a bad omen. Primarily one of death or bodily harm.
The raven is also known to be wise (not as wise as owls) and to convey messages (most often dire). In Norse mythology there were two raven that brought Odin all the (hidden) news from around the world and under-worlds.

In the poem "The Raven" Edgar Allen Poe uses the Raven as a herald from hell to let the narrator know his is condemned to reside there 'ever-more'.
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.