A person who studies or practices ornithology(noun)
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Use "ornithologist" in a sentence
"Venetian is no respecter of species; and when an Italian "ornithologist""
"Nor would I claim to be an "ornithologist", a title which implies scientific knowledge, a capacity for protracted study, an understanding of graphs, figures and statistics, and possibly a doctorate."
"He named his dashing spy after an unassuming U.S. ornithologist who wrote "Birds of the West Indies.""