Common Raven

The common raven (Corvus corax) is the largest living passerine and one of the most widely distributed birds of the Northern Hemisphere. Adults are about 54–67 cm long, span roughly 115–150 cm and weigh around 0.69–1.63 kg. The plumage is entirely black but shows blue, purple and green iridescence in strong light.

Ravens are heavily built, with a deep bill, shaggy throat feathers and a wedge-shaped tail that is particularly useful in flight identification. They are larger and more powerful than most crows and have deeper, more resonant calls.

Few large birds use as wide a range of environments as the common raven. The species occupies rocky coasts, cliffs, forests, mountains, tundra, desert, open farmland and human-modified landscapes from sea level to high elevations.

Two resources are especially important: safe nesting sites and dependable food. Cliffs and large trees are traditional nesting places, while buildings, pylons and other structures are used locally. This flexibility allows ravens to persist in environments ranging from remote wilderness to heavily altered landscapes.

Ravens are opportunistic omnivores and scavengers. Carrion can be especially important, but they also take small mammals, birds and their eggs, reptiles, amphibians, insects and other invertebrates, as well as berries, fruit, seeds and many human-derived foods.

Ravens use a very broad feeding repertoire. They search shorelines and open ground, patrol large areas for carrion, investigate temporary food sources and also hunt live prey when opportunities arise. Carcasses left by large predators or people can become especially rich resources, but the birds shift readily between scavenging, predation and plant foods.

Non-breeding ravens often range widely and can gather quickly at concentrated food sources, while territorial pairs repeatedly use familiar parts of their home range. Strong spatial memory and learning from other ravens and other species help them exploit food that is unpredictable in place and short-lived once discovered.

Ravens play frequently, including aerial games and manipulation of objects. Young birds may travel enormous distances before obtaining a territory, so this dispersal rather than regular seasonal migration accounts for much of the species’ large-scale movement.

Adult ravens usually form long-term pair bonds and defend territories throughout the year. Non-breeders live very differently: young and unpaired birds can range widely, gather at rich food sources and use communal roosts where social relationships and information about feeding opportunities are important.

The species has a rich vocal repertoire and uses calls, postures and displays in social interactions. The contrast between stable territorial pairs and mobile non-breeding groups gives ravens a flexible social system that changes markedly with age and breeding status.

Common ravens are among the best-studied birds in animal cognition. A study published in 2017 showed planning outside the immediate context of food caching: ravens selected tools or barter objects that would become useful later, with delays of up to 17 hours, and showed self-control while waiting for the better future reward.

A 2020 study tested eight hand-raised ravens with a cognitive battery adapted from tests used with primates. Highly developed physical and social skills were already present at four months of age, and performance across quantitative, causal and several social tasks was broadly similar to that of adult chimpanzees and orangutans tested with comparable methods. Some individual tasks measured precursors of broader cognitive abilities rather than the complete ability itself.

Food caching reveals another side of this intelligence. Ravens change where and when they hide surplus food when competitors are watching and can remember caches made by other birds. A 2026 satellite-tracking study followed 69 ravens, 20 wolves and 11 cougars in Yellowstone. Ravens rarely followed predators over long distances, but repeatedly returned to areas where wolf kills had occurred, sometimes from as far as 155 km away. The pattern suggests that spatial memory helps them locate temporary carrion resources without simply following predators to fresh kills.

Pairs often remain together for many years and may reuse the same nesting area repeatedly. The large stick nest is placed on a cliff ledge, in a tall tree or on a suitable human-made structure and lined with softer material such as grass, bark, wool and hair.

Clutches most often contain four to six eggs, with three to seven widely recorded. The female performs most incubation for about 20–25 days while the male supplies food. Both parents feed the young, which normally leave the nest after roughly five to seven weeks and may remain with the adults for weeks or months afterwards.

The raven has a prominent place in mythology, literature and folklore across the Northern Hemisphere. In Norse mythology, Odin’s ravens Huginn and Muninn fly through the world and return with information. Ravens have also been associated with knowledge, death, transformation and prophecy in many traditions.

Ravens readily exploit food created or concentrated by people. Roadkill, livestock remains, refuse, game parks and waste sites can become predictable feeding places, and GPS tracking in the Alps showed that non-breeding ravens repeatedly moved among such anthropogenic food sources. Human food can therefore reshape both daily movement and local concentrations of birds.

Ravens have been persecuted or poisoned in some regions and may come into conflict with people where they gather around farms, settlements or waste. Conversely, abundant human food can support unusually high local numbers. Changes in waste management and carcass availability can therefore alter raven abundance even when the physical habitat itself remains suitable.

The common raven is listed as least concern on the IUCN Red List. It remains widespread and numerous across much of its enormous Northern Hemisphere range.

Regional trends nevertheless vary, and local populations can respond strongly to changes in food supply, persecution and the availability of secure nesting sites.