I hate getting up in the mornings.  I much prefer the evenings
Yes a night owl is usually someone who stays up late, but the opposite is an early bird, a lark as opposed to an owl. I wonder why they pick birds?
I do not know why they pick birds - that is a good question!
In Scandinavia, they call them differently. Early birds are called A-people and night owls are called B-people.
That is interesting to know.  I wonder how other countries do it
Researchers traditionally use the terms "morningness" and "eveningness" for the two chronotypes or diurnality and nocturnality in animal behavior. In several countries, especially in Scandinavia, early birds are called "A-people" and night owls are called "B-people".
Etymology.
The term is derived from the primarily nocturnal habits of the owl. Most owls sleep during the day and hunt for food at night.
Characteristics.
Usually, people who are night owls stay awake past midnight, and extreme
Night owl (person)
A night owl, evening person or simply owl, is a person who tends to stay up until late at night, or the early hours of the morning. Night owls who are involuntarily unable to fall asleep for several hours after a normal time may have delayed sleep phase syndrome. 
The opposite of a night owl is an early bird – a lark as opposed to an owl – which is someone who tends to begin sleeping at a time that is considered early and also wakes early.