A Murder of Crows #Nature || Full #HD #Documentry ~

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• published: 15 Sep 2014
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Corvus is a widely distributed genus of birds in the family Corvidae. Ranging in size from the relatively small pigeon-sized jackdaws (Eurasian and Daurian) to the common raven of the Holarctic region and thick-billed raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents except South America, and several islands. In Europe, the word "crow" is used to refer to the carrion crow or the hooded crow, while in North America, it is used for the American crow, fish crow, or the northwestern crow. The crow genus makes up a third of the species in the family Corvidae. The members appear to have evolved in Asia from the corvid stock, which had evolved in Australia. The collective name for a group of crows is a 'flock' or a 'murder'.[1] Recent research has found some crow species capable of not only tool use, but also tool construction.[2] Crows are now considered to be among the world's most intelligent animals[3] with an encephalization quotient equal to that of many non-human primates.[4] In medieval times, crows were thought to live abnormally long lives. They were also thought to be monogamous throughout their long lives. They were thought to predict the future, to predict rain and reveal ambushes. Crows were also thought to lead flocks of storks while they crossed the sea to Asia.[5] Further information: Corvidae Crow on a branch The members of the Corvus genus are believed to have evolved in central Asia and radiated out into North America, Africa, Europe, and Australia. The latest evidence[6] regarding the evolution indicates descent within the Australasian family Corvidae. However, the branch that would produce the modern groups such as jays, magpies, and large, predominantly black Corvus species had left Australasia and were concentrated in Asia by the time the Corvus species evolved. Corvus has since re-entered Australia (relatively recently) and produced five species with one recognized subspecies.[citation needed] The genus was originally described by Linnaeus in his 18th-century work Systema Naturae.[7] The name is derived from the Latin corvus meaning "raven".[8] The type species is the common raven (Corvus corax); others named in the same work include the carrion crow (C. corone), the hooded crow (C. cornix), the rook (C. frugilegus), and the jackdaw (C. monedula). The genus was originally broader, as the magpie was designated C. pica before being moved later into a genus of its own. At least 42 extant species are now considered to be in this genus, and at least 14 extinct species have been described. No good systematic approach to the genus exists at present. In general, the species from a geographical area are assumed to be more closely related to each other than to other lineages, but this is not necessarily correct. For example, while members of the carrion/collared/house crow complex are certainly closely related, the situation is not at all clear regarding the Australian/Melanesian species. Furthermore, as many species are similar in appearance, determining actual range and characteristics can be very difficult, such as in Australia where the five (possibly six) species are almost identical in appearance.[citation needed] Close-up of the upper body of a jackdaw (Corvus monedula) The fossil record of crows is rather dense in Europe, but the relationships among most prehistoric species are not clear. Species[edit] Main article: List of Corvus species North American urban corvid history[edit] 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 found in North America has been growing steadily since the introduction of European colonization, and spread east to west with the opening of the frontier. Crows were uncommon in the Pacific Northwest in the 1900s, except in riparian habitats. Populations in the west increased substantially from the late 1800s to mid 1900s. Crows and ravens spread along with agriculture and urbanization into the western part of North America. [9] Behavior[edit] https://en.wikipedia.org/wiki/Corvus_(genus) New Documentary Films : Subscribe Now : https://www.youtube.com/user/DocumentaryHDChanne1