The phrase "morning larks" refers to people who naturally wake up early in the mornings and feel most energetic and productive during that time. Full definition
He speculates that, if real, the effect could help people recover more quickly by scheduling surgeries in time with their personal circadian rhythms, earlier for morning larks and later for night owls. (sciencemag.org)
I wonder if these wishes aren't too big — after all, it's hard to transform a night owl into a chipper morning lark. (pastryaffair.com)
Night owls — those who party through the night and sleep until lunchtime — are programmed to hit the sack at 1 am or 2 am, while morning larks — sprightly morning people who crash early — are wired for a 9 pm bedtime. (womenshealthandfitness.com.au)