Behaviour · BEH·15

Raven Scavenging: How Ravens Find and Use Carrion

[science] Ravens are primary scavengers in the ecosystems they inhabit. They locate carrion via high-altitude visual scanning and by following other ravens (the information-centre effect). At large carcasses, non-breeding flocks can number in the hundreds. Young ravens use mob tactics to overwhelm territory-holding adults at carcasses; dominant birds feed first; excess is cached. The whole system is a sophisticated social solution to a patchy, unpredictable food resource.

Locating Carrion: Vision and Social Information

[science] Ravens have two primary strategies for finding carrion:¹

High-altitude soaring: ravens soar at considerable height over open terrain, scanning a large area visually. A bird soaring at 100–300 m altitude can survey many km² simultaneously. Movement of a carcass, the descent of vultures or other scavengers, or the distinctive silhouette of a dead animal on open ground can be detected from this height.
Social following: ravens watch each other constantly. A bird that suddenly drops from soaring height, or that changes direction and descends rapidly, signals to other birds that it has found something. This cascade effect means that one bird's discovery can attract many others within minutes in areas with raven flocks.

The communal roost functions as an amplifier for this social information. Heinrich's information-centre hypothesis proposes that birds that found food on a given day lead others from the roost to that food the following morning — observed in field experiments where marked birds consistently led the morning departure from roost sites where food had been placed.

The Territory Problem and Mob Recruitment

[science] Carrion in a territory-holding adult's range creates a conflict: the territorial pair would exclude all other ravens from their carcass if they could. Young, non-territorial ravens have evolved a counter-strategy: mob recruitment. Heinrich documented that non-breeding ravens call loudly at carcasses on defended territories — advertising the food to other non-breeding birds. The resulting mob of dozens or hundreds of birds overwhelms the territory-holders' ability to defend the carcass, and the non-breeders collectively feed despite being individually subordinate to the resident adults.²

This is a striking example of a social strategy solving an ecological problem: individually weak non-breeders use numbers as a tool against stronger territory-holders.

Dominance at the Carcass

[science] Even within a mob, feeding is not equal. Ravens establish a loose dominance hierarchy at carcasses, with older, larger, and more experienced birds feeding preferentially. Dominant birds displace subordinates, hold prime feeding positions, and are the first to begin feeding after a period of collective caution. Subordinate birds feed around the margins, in gaps, or after dominant birds are satiated.¹

Caching Excess from Carcasses

[science] Ravens carry away food from carcasses and cache it nearby when they cannot eat more on site. This caching behaviour at large carrion events is well-documented: birds may make dozens of caching trips from a single large carcass, distributing cached meat within a few hundred metres of the site. These caches are later retrieved, particularly in winter when food is scarce. The spatial memory required for retrieving hundreds of dispersed caches is substantial. See Why do ravens hide food?

Ravens vs Other Scavengers

[science] At large carcasses in northern latitudes, ravens co-occur with Golden Eagles, Bald Eagles, and other large scavengers. Ravens are dominated by eagles in direct confrontations — they retreat when an eagle approaches — but are agile enough to steal food from inattentive eagles and can exploit portions of a carcass the eagle cannot reach. In areas without large raptors, ravens are the dominant scavengers.¹

Frequently Asked Questions

How do ravens find carrion?

Ravens use a combination of vision and social information to locate carrion. They soar high to scan large areas — the visual acuity of corvids at height allows detection of potential carrion sites from considerable distance. Social information is equally important: ravens watch other ravens, following birds that suddenly descend or exhibit excited behaviour. At communal roosts, ravens that found food on a given day can be followed back to the food source the next morning — Bernd Heinrich's information-centre hypothesis.

Can ravens smell carrion?

The Common Raven's olfactory capability is not well-established compared to vultures (which have exceptional olfaction). Ravens are primarily visual hunters and foragers. They likely detect very strong odours from large decomposing carcasses at close range, but olfaction is probably not the primary carrion-detection mechanism as it is in New World vultures. The evidence base for raven olfaction in carrion detection is limited — it has not been systematically tested.

Do ravens share carrion with others?

The pattern is complex. At large carcasses, non-breeding flocks can number dozens or hundreds of birds — apparently shared access. Research by Bernd Heinrich documented that young ravens actively recruit flock-mates to large carcasses on territory-holding adults' land — a strategy that overwhelms the territorial pair with numbers, allowing the flocking birds collectively to exploit the food. Dominant birds preferentially feed; subordinates get access when dominants are satiated or displaced. Pure sharing is rare — carcass use is contested.

Sources

Boarman, W.I. & Heinrich, B. (1999). Common Raven (Corvus corax). In Birds of the World (A.F. Poole, ed.). Cornell Lab of Ornithology. — carrion detection, carcass behaviour, caching, dominance.
Heinrich, B. (1989). Ravens in Winter. Summit Books. — information-centre hypothesis; mob recruitment at carcasses; territory-holder displacement.

[science] peer-reviewed study or field-guide data