an early bird
1. Someone who is more active and alert in the early hours of the morning than later in the day; an early riser. I tried dating an early bird once, but since I like to sleep in late, it didn't really work out. I suppose it's more out of necessity than anything, but I turned into an early bird as soon as I had kids.
2. Someone who arrives early to an event. We'd better have everything ready for the garage sale—the early birds will be here sniffing around before we get a chance to set up.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
an early bird
1. If you call someone an early bird, you mean that they get up early in the morning to do things. We've always been early birds, up at 5.30 or 6am. Note: Early-bird can also be used to describe things that are available to people who get up early. The early-bird rate for parking (in by 10 a.m., out by 7 p.m.) at the Millennium Park Garage is $14 weekdays.
2. If you call someone an early bird, you mean that they succeed in doing something before other people. Florida has been an early bird in terms of presidential voting for some time. Note: Early-bird can also be used to describe things that are available to these people. An early-bird discount is sometimes available at the beginning of the season.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012