Green’s Dictionary of Slang

1. one who habitually gets up or arrives early.

1851		‘Pertaters & Ternups’ in T.A. Burke Polly Peablossom’s Wedding 90: An early bird was our doctor.
1868		Wrexham Advertiser 21 Mar. 7/3: An ‘early bird’ endeavours to [...] agitate for an earlier delivery of letters in Fairfield.
1873		J. Greenwood In Strange Company 310: They were takers out most of these early birds.
1896		Omaha Dly Bee (NE) 16 Oct. 8/3: We are bound to be the early bird this year.
1900		G.R. Sims In London’s Heart 99: My father’s always an early bird.
1905		H. Green Actors’ Boarding House (1906) 68: Other early birds were waiting for the pianist.
1912		Van Loan ‘Ten-Thousand-Dollar Arm’ in Ten-Thousand-Dollar Arm 11: The early birds [...] every team has two or three baseball ‘bugs’ who show up at the clubhouse at noon.
1922		Dly Ardmoreite (OH) 4 Apr. 2/5: The fourth Early Bird special event [...] as usual plenty of real ripe bargains will on hand for the Earlty Bird Shoppers.
1929		Hall & Niles One Man’s War 69: We early birds were lucky.
1948		Aberdeen Jrnl 11 Dec. 1/1: The Early Bird — Christmas Shopping started early this year.
1959		E. De Roo Young Wolves 32: We’re a couple of early birds again, huh?
1969		P. Theroux Murder in Mount Holly (1999) 28: ‘You’re early,’ said Miss Ball. ‘You’re an early bird.’.
1975		J. Ryan Remembering How We Stood 134: Of course, by this time all the well-known brands of cars had been cornered by the early birds.
2010		Codella and Bennett Alphaville (2011) 204: I loved getting up and out and brigning some asshole in on a dope charge. The early birds came in handy.

2. one who goes to bed early.

1937

R. Westerby Wide Boys Never Work (1938) 175: You’re an early bird to-night, Mr. B., aren’t you?