“Birds of a feather flock together.”

What does it mean?

People like to spend time with others who are similar to them.

Where does it come from?

This proverb has been in use since at least the mid 16th century. In 1545, William Turner used a version of it in his papist satire The Rescuing of Romish Fox:

“Byrdes of on kynde and color flok and flye allwayes together.”