কুরবানি  সম্পর্কিত  মাসালা:পর্ব 3
Channel: Islamic Conversation
Date: 28/08/2017

The members of the genus Corvus are believed to have evolved in central Asiaand 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 Corvusspecies 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 extantspecies are now considered to be in this genus, and at least 14 extinct species have been described.

The fossil record of crows is rather dense in Europe, but the relationships among most prehistoric species are not clear. 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]