page_title: Common raven
section_title: Intelligence
hierarchical_section_title: Common raven / Behaviour / Intelligence
caption_attribution_description: English: Cold War-era NIKE missile site radar dome with a flock of ravens near Eielson AFB, Alaska
context_page_description: The common raven, also known as the western raven or northern raven when discussing the raven at the subspecies level, is a large all-black passerine bird. Found across the Northern Hemisphere, it is the most widely distributed of all corvids. There are at least eight subspecies with little variation in appearance, although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids, alongside the thick-billed raven, and is possibly the heaviest passerine bird; at maturity, the common raven averages 63 centimetres in length and 1.2 kilograms in mass. Although their typical lifespan is considerably shorter, common ravens can live more than 23 years in the wild, which among passerines only is surpassed by a few Australian species such as the satin bowerbird and probably the lyrebirds. Young birds may travel in flocks but later mate for life, with each mated pair defending a territory.
  Common ravens have coexisted with humans for thousands of years and in some areas have been so numerous that people have regarded them as pests.
context_section_description: Crows, ravens, magpies, and jays are not just feathered machines, rigidly programmed by their genetics. Instead, they are beings that, within the constraints of their molecular inheritance, make complex decisions and show every sign of enjoying a rich awareness.
  — Candace Savage
  The brains of common ravens count among the largest of any bird species. Specifically, their hyperpallium is large for a bird. They display ability in problem-solving, as well as other cognitive processes such as imitation and insight.
  Linguist Derek Bickerton, building on the work of biologist Bernd Heinrich, has argued that ravens are one of only four known animals (the others being bees, ants, and humans) who have demonstrated displacement, the capacity to communicate about objects or events that are distant in space or time from the communication. Young, unmated common ravens roost together at night, but usually forage alone during the day. However, when one discovers a large carcass guarded by a pair of adult ravens, the unmated raven will return to the roost and communicate the find. The following day, a flock of unmated ravens will fly to the carcass and chase off the adults. Bickerton argues that the advent of linguistic displacement was perhaps the most important event in the evolution of human language, and that ravens are the only other vertebrate to share this with humans.
  One experiment designed to evaluate insight and problem-solving ability involved a piece of meat attached to a string hanging from a perch. To reach the food, the bird needed to stand on the perch, pull the string up a little at a time, and step on the loops to gradually shorten the string. Four of five common ravens eventually succeeded, and "the transition from no success (ignoring the food or merely yanking at the string) to constant reliable access (pulling up the meat) occurred with no demonstrable trial-and-error learning." This supports the hypothesis that common ravens are 'inventors', implying that they can solve problems. Many of the feats of common ravens were formerly argued to be stereotyped innate behaviour, but it now has been established that their aptitudes for solving problems individually and learning from each other reflect a flexible capacity for intelligent insight unusual among non-human animals.
  Another experiment proved that some could deceive intentionally at least to other common ravens.
  Common ravens have been observed calling wolves to the site of dead animals. The wolves open the carcass, leaving the scraps more accessible to the birds. They watch where other common ravens bury their food and remember the locations of each other's food caches, so they can steal from them. This type of theft occurs so regularly that common ravens will fly extra distances from a food source to find better hiding places for food. They have also been observed pretending to make a cache without actually depositing the food, presumably to confuse onlookers.
  Common ravens are known to steal and cache shiny objects such as pebbles, pieces of metal, and golf balls. One theory is that they hoard shiny objects to impress other ravens. Other research indicates that juveniles are deeply curious about all new things, and that common ravens retain an attraction to bright, round objects based on their similarity to bird eggs. Mature birds lose their intense interest in the unusual, and become highly neophobic.
caption: Dilapidated NIKE Missile radar dome in Alaska with an evening roost
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