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Common Raven    Corvus corax

image Migratory Status: Resident

PIF Population Estimate: : 4 000 000

Percent of western hemisphere population breeding in boreal forest: < 25%

BAM Effective Detection Radius (m) : 194.9

PIF Maximum Detection Distance (m) : 400

Singing Rate (phi) : 0.184

Canadian BBS Population trend: 2.3 (1.2 to 3.3)

Life History

The Common Raven has a global distribution and has successfully coexisted with humans for thousands of years. This coexistence created a strong spiritual and cultural connection with many indigenous cultures, and the Common Raven is represented in folk lore around the world. It owes its success to its generalist diet and flexibility in its habitat use, allowing it to exist in extreme environments from the Arctic (-50 °C) to the desert (>45 °C). As a result, it has one of the largest distributions of any passerine.

The Common Raven is the most solitary and largest of all the corvids. Adults have glossy all-black plumage, long wings and tails, a long, strong bill, and elongated throat feathers. Males are generally larger in size than females and immature birds have a brown tinge to their plumage. The four subspecies that exist in North America are based on size differences, with the most northernly population, C. c. kamtschaticus, being the largest, and the most southernly population, C. c. clarionensism, being the smallest. Like all corvids, ravens are considered to have primate-like cognitive abilities, and are social learners. They are able to rapidly learn new behaviours and vocalizations that are beneficial, avoid actions that are costly by observing their neighbours, and pass cultural information onto their siblings (called cultural transmission).

The North American breeding and wintering distribution of the Common Raven extends from Alaska and the high Arctic in the north, southward throughout Canada to the Appalachian Mountains in the northeastern United States, and in the west, along the western United States into Mexico and Central America. Given this wide distribution, Ravens have adapted to living in a wide variety of natural and human-made habitats; they can be found in the open tundra, deciduous and coniferous forests, deserts, alpine habitats, agricultural fields and even urban centres.

Common Ravens are omnivores and they will scavenge, hunt, and steal from others for their food. Their diet consists of carrion, seeds and grains, fruit, insects, rodents and other small vertebrates that they can capture. Ravens cannot actually pierce the thick skin of mammals and as such have to rely on other predators to kill larger mammals from which they can scavenge. Because of this, it is common to find a group of ravens following a pack of hunting wolves. Where the Common Raven lives in close proximity to human settlement, they will turn to alternative food sources, such as dump sites and agricultural fields, causing some to consider the Common Raven a pest.



Reference(s)

Boarman, W. I., and B. Heinrich. 1999. Common Raven (Corvus corax), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/476

Schwab, C., T. Bugnyar, C. Schlogel, and K. Kotrschal. 2008. Enhanced social learning between siblings in common ravens, Corvus corax, Animal Behaviour, 75:501-508.

Webb, W. C., W. I. Boarman, and J. T. Rotenberry. 2004. Common Raven juvenile survival in a human-augmented landscape, The Condor, 106(3):517-528.