White Crow

The true crows are large passerine birds that form the genus Corvus 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 offshore and oceanic islands (including Hawaii). In the United States and Canada, the word "crow" is used to refer to the American Crow. The crow is a year round species. The crow genus makes up a third of the species in the Corvidae family. Other corvids include rooks and jays. Crows appear to have evolved in Asia from the corvid stock, which had evolved in Australia. A group of crows is called a "murder".
The genus was originally described by Linnaeus in his 18th century work Systema Naturae. The name is derived from the Latin corvus meaning "raven". 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).
There is no good systematic approach to the genus at present. Generally, it is assumed that the species from a geographical area are more closely related to each other than to other lineages, but this is not necessarily correct. For example, while the Carrion/Collared/House Crow complex is certainly closely related to each other, 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.