Definition & Meaning of "birds of a feather flock together"

What is the origin of the proverb "birds of a feather flock together" and when to use it?

The proverb "birds of a feather flock together" dates back to at least the 16th century and is rooted in the observation that birds of the same species tend to group together. While it suggests that similarities naturally bring individuals together, it can also imply that a person's character can be judged by the company they keep. In some contexts, it serves as a reminder to choose associations wisely, as they can influence one's reputation and decisions.