The Australian raven (Corvus coronoides) is Australia's largest species of corvid. It is distinguished from the Australian crow species by its throat hackles, which are prominent in adult birds. The Australian raven has adapted well to urban environments and is a common city bird in Sydney, Canberra, and Perth. An omnivorous and opportunistic feeder, it eats a wide variety of plant and animal material, as well as food waste from urban areas.
The adult Australian raven is an all black-bird with a black beak, mouth, and tongue and sturdy black or grey-black legs and feet. The tibia is fully feathered and the tarsus is long, and the feet are large and strong. It has white irises. The plumage is glossy with a blue-purple to blue-green sheen, greenish over the ear coverts, depending on the light. The underparts are not glossy. The Australian raven has throat feathers (hackles) that are lanceolate with rounded tips, while the other four species of Australian corvids have bifurcate tips, though this can be difficult to see in the field. The hackles are also longer than those of the other four species; when they are raised (such as when the bird is calling), they give the bird an unusual bearded appearance. The upper third of the upper mandible, including the nares and nasal groove, is covered with bristles, which can be up to 3 cm (1.2 in) long. The heavy-set beak is tipped with a slight hook and is longer than the bird's head. The wings are long and broad, with the longest of its ten primary feathers (usually the seventh but occasionally the eighth) almost reaching the end of the tail when the bird is at rest. The tail is rounded or wedge-shaped. Juveniles resemble adults, but lack throat hackles, and sometimes have a pink fleshy gape. The bill is shorter and shallower; its base can be pinkish and the tip can be light grey. The plumage is more ruffled and softer in appearance, lacks glossy highlights, and often has a brown tinge. The bare skin on the throat is pink in birds that have recently left the nest. Eye color varies with age, gradually lightening from juvenile to adult. Nestlings up to four months old have blue-grey irises, juveniles aged from four to fifteen months have dark brown irises, and immature birds have hazel irises with an inner blue rim around each pupil until age two years and ten months. Immature birds older than one year develop hackles, while some pink remains in the gape until the bird is two or three years of age.
Australian ravens are native to much of southern and northeastern Australia. These birds can be found in a wide range of natural and modified habitats. They require available water and trees (or buildings) to roost in or perch on. Preferred habitats include eucalypt-dominated sclerophyll forests, and farmland adjacent to trees. They are also found in heath, mangroves, on the shoreline, and on beaches. Australian ravens have adapted well to urban environments and are common city birds in Sydney, Canberra, and Perth.
Australian ravens are largely sedentary and territorial birds. They are usually seen in pairs or small flocks of 8-30 birds that stay within an area of around 260 square kilometers; larger flocks of up to 300 birds may travel hundreds of kilometers seeking food. A single breeding pair and their brood can occupy a certain territory and remains there year-round, though groups of ravens may enter this area to forage. Australian ravens defend their territory by chasing, dive-bombing, and occasionally striking the backs of birds of prey, foxes, or even people. These birds generally move by walking around on the ground, though do hop when hurrying. They preen themselves frequently, particularly when roosting in the middle of the day. Australian ravens are intelligent birds and have innovative methods of seeking out food. They forage in the early morning or late afternoon and rest in the hotter part of the day. Ravens use their bill rather than their feet to explore or turn items on the ground (rocks or sticks) over or hold or snatch food while flying. They may also use fence posts as anvils to bash snails against before eating them. Australian ravens communicate using a variety of contact calls: a pair often makes a low murmuring sound when preening each other while roosting, and members of a flock carry on with a quiet chattering while at rest. When in flocks ravens make a single high-pitched 'caa' while flying over another territory as a transit call to signify they are just passing through. They will also give a longer 'caa' to signify their return to the nest to their mate.
Australian ravens are omnivores, though they generally eat more meat. Their diet contains a high proportion of insects, plant items, and flesh in winter. Invertebrates commonly eaten include spiders, millipedes, centipedes (which ravens behead before eating), grasshoppers, cicadas, and caterpillars (important food for nestlings). Australian ravens may also kill birds of such size as young galahs and starlings and most mammals are eaten as carrion. In urban areas, these birds eat food scraps in school playgrounds, rubbish tips, bins outside supermarkets or restaurants, abattoirs, piggeries, and farmyards.
Australian ravens are monogamous; they generally mate for life, though occasionally one male may mate with two females in adjacent territories. If the female dies, the male maintains the territory and finds another mate, while if the male bird is lost, the female abandons the territory. Breeding season usually occurs from July to September. The birds generally nest in tall trees as the nest also functions as a lookout post. In areas lacking in tall trees, ravens may sometimes nest on buildings, telegraph poles, or tall windmills. Nests are generally large and untidy, consisting of a bowl or platform of sticks lined with grasses, barks, and feathers that can be up to 5 cm (2 in) thick. The female lays a clutch of 4 to 6 eggs and incubates them alone over roughly 20 days. The chicks are born helpless (altricial), naked and blind, and remain in the nest for an extended period. They have pink skin until 5 days of age when feathers under the skin turn grey; they lose their egg tooth at the same time. Their eyes are fully open by 11 to 12 days, and they are fully feathered by 35-36 days old. The young leave the nest at 40-45 days of age and stay with their parents for 3 to 4 months after that. They follow their parents and beg for food for the first month outside the nest but are feeding themselves by the third month. Young Australian ravens begin breeding once they are three years old.
The main causes of Australian ravens' mortality include hunting or poisoning - generally by farmers, and the birds are also often hit by vehicles. In Western Australia, ravens are classified as a Declared Pest of Agriculture and they can be shot on private land as they damage crops or stock.
The IUCN Red List and other sources don’t provide the total number of the Australian raven population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
Australian ravens play an important role in the ecosystem they live in. These birds bring some benefits to agricultural areas as they clean away carrion and eat insects that are potentially damaging to crops.
