Green’s Dictionary of Slang

first of the day, e.g. early-bird matinee.

1953		K. Tennant Joyful Condemned 159: In the charge room at the back, one early-bird solicitor was already seeking an interview with his client.
1976		Tom Waits ‘Pasties And A G-String’ 🎵 And it’s an early-bird matinee, come back any day.
1987		T. Wolfe Bonfire of the Vanities 115: All he’ll have to worry about is getting to the shopping mall in time for the Early Bird special.
1998		L. Stringer Grand Central Winter (1999) 46: A spectacle that fairly rattled early-bird commuters.
2001		J. Stahl Plainclothes Naked (2002) 147: Manny waved at a couple of early-bird juicers.