1731, common name for the North American thrush (Dumetella Carolinensis), so called from its warning cry, which resembles that of a cat; from cat (n.) + bird (n.1). Catbird seat is a 19c. Dixieism, popularized by Brooklyn Dodgers baseball announcer Red Barber and by author James Thurber (1942).
"She must be a Dodger fan," he had said. "Red Barber announces the Dodger games over the radio and he uses those expressions--picked 'em up down South." Joey had gone on to explain one or two. "Tearing up the pea patch" meant going on a rampage; "sitting in the catbird seat" means sitting pretty, like a batter with three balls and no strikes on him. [James Thurber, "The Catbird Seat," "The New Yorker," Nov. 14, 1942]