Overview
A jay is a member of a number of species of medium-sized, usually colorful and noisy, passerine birds in the crow family, Corvidae. The evolutionary relationships between the jays and the magpies are rather complex. For example, the Eurasian magpie seems more closely related to the Eurasian jay than to the East Asian blue and green magpies, whereas the blue jay is not closely related to either. The Eurasian jay distributes oak acorns, contributing to the growth of oak woodlands over time.
Systematics and species
Jays are not a monophyletic group. Anatomical and molecular evidence indicates they can be divided into a New World and an Old World lineage (the latter including the ground jays and the piapiac), while the grey jays of the genus Perisoreus form a group of their own. The black magpies, formerly believed to be related to jays, are classified as treepies.
Old World ("brown") jays
Grey jays
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