Be/get up with the lark
Definition 1 of 1
Pro Tip 1/3Early Riser Implied
The phrase suggests someone who habitually wakes up with enthusiasm, often for work or study. 
Even on weekends, Jenna is up with the lark, ready to start the day.
Pro Tip 2/3Positive Connotation
The expression usually has a positive tone, praising the person's dedication and discipline. 
Everyone admires him for getting up with the lark and hitting the gym.
Pro Tip 3/3Figurative Speech
It's a metaphorical phrase; one does not literally wake up with birds, but rather very early. 
She's up with the lark to finish her novel before the deadline.