Crows are large passerine birds that comprise the genus Corvus Corvidae family. Relatively small size of a pigeon jackdaws Common Raven is a Holarctic region and Thick-billed Raven is a plateau in Ethiopia there are about 40 members of this genus in all continents and in temperate seas and other oceanic islands. In the United States and Canada, the word "crow" is used to refer to the American Crow.
The raven is like a third of species of the corvid family. Other corvids crows and jays. Crows appear to have evolved in Asia the corvid stock, which had evolved in Australia. A group of crows is called a herd or a murder.
Recent research has found some species of crow is not only able to use the tool, but the construction of the instrument as well. Ravens are considered one of the most intelligent animals. Jackdaw and the neostriatum were found about the same as a relative can be found in chimpanzees and humans, and much more that can be found in Gibbon.
Ravens apparently evolved in central Asia and radiated in North America, Africa, Europe and Australia.
Recent data for the downhill trend suggesting crow family Corvidae Australian. But the industry that produce the modern groups such as jays and magpies had large predominantly black Corvus left Australasia and Asia was concentrated in time Corvus evolved. Corvus has since returned to Australia and produced a species with five recognized subspecies.
The family was originally described in Linnaeus in his 18 th century work Systema Naturae. The name derives from the Latin corvus meaning "raven."
The type species is the common raven (Corvus corax), while others mentioned in the same work includes Carrion Crow, the hooded crow, Jackdaw and the tower. The genre was wider than Magpie was designated C. pica before later being moved to a genre of its own. There are now regarded as at least 42 existing species in this genus, and at least 14 extinct species have been described.
There is no good systematic approach to the family at this time. In general, it is assumed that the type of geographic area are more closely related to other lineages, but this is not necessarily correct. For example, when the complex Carrion / collar / House Crow is certainly closely related, the situation is not at all clear regarding the Australian / Melanesian species. In addition, many species are similar in appearance to determine the actual range and characteristics can be very difficult, such as Australia, where five species are nearly identical in appearance.
Fossils of crows is densest in Europe, but relationships among most prehistoric species is unclear. The latest evidence seems to point to a family from Australia at the beginning (Corvidae), although the industry that produce the modern groups such as jays, magpies and large predominantly black Corvus crows had left Australasia and Asia are developing . Corvus has returned to Australia and produced a species with five recognized subspecies.