Age is a critical factor in many avian social interactions, often making it crucial in studies of social biology. Plumage, iris color, and bill color are well-known characteristics that can be used to determine age in many species ofbirds. In many corvids, all three characteristics change with age during the first two years of life, but then remain constant (Skutch 1935, Brown 1963, Ligon and White 1974, Rowley 1970, Dorn 1972). In numerous studies on the Common Raven, Corvus corax, age of birds has been assigned to juvenile, immature or yearling, subadult (2-3 years) and adult (3 plus years of age). These determinations all rely primarily on one criterion: mouth and tongue color (Mahringer 1970, Dorn 1972, Kerttu 1973, Stiehl 1978, Huber 1988, Heinrich 1988). The mouth color of juveniles is pink, that of is blue-black, and that of those in between is assumed to vary in a gradual progression that is strictly a function of age. In no instance, however, has the assumption of a gradual color change with age been tested. We have raised 17 ravens from fledglings and here show that mouth color is a function of age only in very young and possibly old birds. Some birds retain pink mouths long into adulthood and mouth color may be related more to social status than to age. Young ravens were taken from nests in Vermont and Maine and reared by hand in outdoor aviaries. All were fed the same diet consisting primarily of road-killed animals, meat scraps, and occasional kitchen scraps. All the birds fledged in May. They were kept in family groups (3-6 individuals) until fall, at which time some were kept in company of up to 20 others. We assessed dominance among these birds as described previously (Heinrich and Marzluff 1991) and recorded mouth color at approximately monthly intervals. In a total of 17 birds fledged in May, none had black mouth linings by the first fall (November). However, four of the 17 already had mottled mouth linings (corresponding to presumed 1-2 year-old birds) at that time (six months post-fledging). These four birds were highly dominant individuals. All of the 13 pinkmouthed birds were subordinate individuals. By January (eight months after fledging) four birds already had fully black mouth linings like adults (i.e., 3 plus years old), two had mottled mouths, and 11 still had pink mouths. The six black or mottled-mouthed individuals were still the most dominant birds and all were socially bonded with each other in pairs. No blackmouthed individual was bonded to a pink-mouthed individual.