Corvus
A genus of intelligent crows, ravens, and rooks.
Corvus is a genus of passerine birds in the family Corvidae, encompassing medium to large species such as crows, ravens, and rooks. The genus name is Latin for "raven," and the common raven serves as the type species. Carl Linnaeus originally described the genus in his 1758 work *Systema Naturae*, also naming the carrion crow, hooded crow, and rook. The roughly 46 members of this genus are found on every continent except South America and Antarctica, as well as several islands. They make up about a third of all corvid species. The genus is believed to have evolved in Asia from corvid stock that originated in Australia, with a center of diversity in Melanesia, Wallacea, and New Guinea. Rapid geographic expansion and morphological diversification occurred around 10 million years ago. The fossil record is dense in Europe, and early Pleistocene remains are known from China.
These birds range in size from about 34 centimeters for some small Mexican species to 60–70 centimeters for the large common raven and thick-billed raven, making them among the largest passerines. They have a robust yet slender build, with a small rounded head, a strong conical and pointed beak that curves slightly downward at the tip, strong legs, and a short wedge-shaped tail. Plumage is predominantly black, often with metallic iridescence, though some species have white or gray patches on the neck or torso. Australian species typically have light eyes, while others have dark irises. Sexual dimorphism is minimal.
Crows are recognized as highly intelligent, with an encephalization quotient comparable to many non-human primates. Research in 2002 demonstrated that some species are capable not only of using tools but also of constructing them. Their vocalizations are complex and poorly understood, varying by species and regionally; they include a "koww" call, series of short caws, and an echo-like "eh-aw" sound. Crows often respond to calls of other species, a behavior thought to be learned. During nonbreeding months, they gather in large communal roosts of hundreds to tens of thousands, often near food sources like garbage dumps. Play behavior is frequently observed and considered a sign of intelligence. In foraging, ravens have been known to associate with coyotes and wolves, using calls to alert these predators to injured prey, especially in winter. A group of crows is called a flock or a
- Scientific name
- Corvus
- Family
- Corvidae
- Number of extant species
- At least 42
- Type species
- Common raven (Corvus corax)
- Described by
- Carl Linnaeus
- Year described
- 1758
- Known for
- High intelligence, tool use, and tool construction
Lore & Background
The genus Corvus was originally described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. The name is derived from the Latin corvus meaning 'raven'. The type species is the common raven (Corvus corax); others named by Linnaeus in the same work include the carrion crow, hooded crow, and rook. The members of the genus are believed to have evolved in Central Asia and radiated out into North America, Africa, Europe, and Australia. The center of diversity is within Melanesia, Wallacea, and the island of New Guinea and surrounding islands, with numerous endemic species. The diversification of Corvus corresponded with a quick geographic expansion, with rapid morphological diversity and fast speciation rates beginning around 10 million years ago.
Corvids are found in major cities across the world, and a major increase in the number of crows in urban settings has occurred since the 1900s. Historical records suggest that the population of American crows in North America has been growing steadily since the introduction of European colonization, spreading east to west with the opening of the frontier. Crows were uncommon in the Pacific Northwest in the 1900s, except in riparian habitats, but populations in the west increased substantially from the late 1800s to the mid-1900s. Crows and ravens spread along with agriculture and urbanization into the western part of North America.
Reader's Guide
The genus Corvus holds significant importance in ornithology and behavioral science due to the remarkable intelligence of its members. Research in 2002 found that some crow species are capable not only of tool use but also of tool construction, placing them among the world's most intelligent animals with an encephalization quotient equal to that of many non-human primates. Their complex vocalizations, which vary regionally and by species, and their ability to respond to calls of other species demonstrate learned behavior. Crows also exhibit communal roosting in large numbers during nonbreeding months, often near food sources like garbage dumps. Their foraging behavior includes symbiotic relationships with predators such as wolves and coyotes, where ravens use calls to notify these animals of injured prey, a mutualistic interaction especially noticeable in winter. Crows also engage in mobbing of owls, particularly great horned owls, which are significant predators of corvids. The genus has a dense fossil record in Europe, though relationships among prehistoric species are not clear. The legacy of Corvus lies in its demonstration of advanced cognitive abilities in birds, challenging traditional views on animal intelligence and providing a model for studying evolution, behavior, and ecology.
Did You Know?
- The genus name Corvus is Latin for 'raven'.
- The collective name for a group of crows is a 'flock' or a 'murder'.
- Some crow species are capable of tool construction, as found in 2002 research.
- Crows have an encephalization quotient equal to that of many non-human primates.
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