cut-n-paste from
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What is the origin of "to eat crow"? "eat boiled crow"? "Crow McGee"?
(Folklore/proverbial expressions)
The origin of "to eat crow" is ultimately unknown. Almost all authorities cite an incident that took place during a truce in the war of 1812. The story goes that an unarmed British officer encountered an American hunter near the Niagra River, gained control of his musket and thereby forced him to eat the crow he had just shot. The American complied, but when his musket was returned, forced the British officer to do the same.
The first recorded "in context" citation (where "eating crow" is associated with humiliation) occurred 1877, where it is "to eat boiled crow".
"Crow McGee", meaning the opposite of the "real McCoy", did not appear until the 20th century and its relationship to "eating crow" cannot be established.