inch e arel

Ian Rowley proposed that the common ancestor of the five species diverged into a tropical crow and temperate raven sometime after entering Australia from the north,[20] which molecular evidence indicates occurred in the early Pliocene epoch around 4 million years ago.[19] The raven diverged into the ancestor of the forest and little ravens in the east and Australian raven in the west,[20] this split occurring around 2 million years ago in the early Pleistocene.[19] As the climate became cooler and drier, the aridity of central Australia split them entirely. Furthermore, the eastern birds diverged into nomadic little ravens and, in forested refuges, forest ravens. As the climate eventually became warmer, the western birds spread eastwards and almost outcompeted forest ravens on mainland Australia. Rowley noted that the western subspecies of the Australian raven had features intermediate between the eastern subspecies of Australian and little ravens.[20]

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