Corvus corax; Print; The common raven (Corvus corax); also known as the northern raven; is a large all-black passerine bird. Found across the Northern Hemisphere; it is the most widely distributed of all corvids. There are at least eight subspecies with little variation in appearance; although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids; alongside the thick-billed raven; and is possibly the heaviest passerine bird; at maturity; the common raven averages 63 centimetres (25 inches) in length and 1.2 kilograms (2.6 pounds) in mass. Common ravens can live up to 21 years in the wild; a lifespan surpassed among passerines by only a few Australasian species such as the satin bowerbird and probably the lyrebirds. Young birds may travel in flocks but later mate for life; with each mated pair defending a territory.; 1700-1880