Forest Raven

The largest of the Australian corvids, the adult forest raven is 50–53 cm (20–21 in) in length with a wingspan between 91–113 cm (36–44 in) and weight of approximately 650 g (1.43 lb). There is no seasonal variation in plumage, which is entirely glossy black with a blue or green sheen visible on the upperparts. The wings are long and broad, with the largest of its ten primary feathers (usually the seventh but occasionally the eighth) almost reaching the end of the tail when at rest. The tail is rounded or wedge-shaped. It is quite short in Tasmanian populations but longer in northern New South Wales. The beak is a similar shape to that of the little raven, though more massive and heavy-set. The upper mandible, including the nares and nasal groove, is covered with bristles. The mouth and tongue are black, as are the powerful legs and feet. The tibia is fully feathered and the tarsus is long. Sexes have identical plumage; the male is generally larger, but there is considerable overlap in size between individuals. The forest raven can be distinguished from the two species of crow occurring in Australia by the grey base of the feathers, which is white in the latter species. The demarcation between pale and black regions on the feather is gradual in the ravens and sharply delineated in the crows. Feather bases are not normally visible when observing birds in the field, but can sometimes be seen on a windy day if the feathers are ruffled. The three species of raven are more heavily set with a broader chest than the two crow species, with the forest raven the stockiest of all. Relative size is useful only when two species can be seen side by side, as the overlap in size is large and the difference in size small. In Tasmania, the forest raven could be confused with the black currawong, though the latter species has more slender wings with white markings, a longer tail and a very different call. Juveniles (birds up to a year old) have a shorter, shallower bill, which is dark grey with some pink at the base. The gape is pink. The plumage is softer and fluffier and often has a brown tint. It generally lacks the glossy sheen of adult birds, though a blue-purple sheen can be seen sometimes on mantle and shoulders plumage. Birds between one and two years old closely resemble adults but retain juvenile feathers on wings and tail and have smaller bills. Birds between two and three years have adult plumage but lack the adult eye colour. Eye colour varies with age: nestlings up to four months old have blue-grey eyes, juveniles aged from four to fourteen months have brown eyes, and immature birds have hazel eyes with blue eyerings around the pupil until age two years and ten months.