night owl

waking up early

is a man who doesn't give a hoot how late he gets home.

A night owl is a man who doesn't give a hoot how late he gets home.

is redundant considering that owls are nocturnal. Wouldn’t it be sufficient just to say someone is an “owl” instead of a “night owl”?

Considering owls are nocturnal, wouldn’t it be sufficient just to say someone is an “owl” instead of a “night owl”?