カササギ
The Eurasian magpie is almost identical in appearance to the North American black-billed magpie ("Pica hudsonia") and at one time the two species were considered to be conspecific. In 2000, the American Ornithologists' Union decided to treat the black-billed magpie as a separate species based on studies of the vocalization and behaviour that indicated that the black-billed magpie was closer to the yellow-billed magpie ("Pica nuttalli") than to the Eurasian magpie.