"Night owl" people are people that stay up real late at night, maybe even all night. I used to be one.
I'm a night owl as well. I sleep better during the day. I have always been an insomniac.
I'm still not an 'early bird' though, which is someone who starts sleeping at an early time and wakes early.
I'm not either. If I have to wake up early, I'm a bit cranky.
In Scandinavia, early birds are referred to as "A-people" and night owls are called "B-people" hehe, so I guess that makes me a C-person.