… also known as “the early bird gets the worm.”
Very early in the morning is the time when worms come out of the ground. This is the best time for birds to catch worms. So this popular expression means: If you want to be successful, you should get up and start working early in the morning.
It is also used for more general situations. For example, every time that Apple starts selling a new phone or tablet, people camp outside the shop for the whole night, so that they can be the first to buy the new device when the shop opens. They are the “early birds”.
However, not everyone agrees:
Hägar Language School 