"Birds of a feather flock together" is a saying that suggests people with similar interests, backgrounds, or characteristics tend to associate with each other. It highlights the natural tendency for like-minded individuals to form groups and maintain close relationships based on shared traits.

In Lewis Carroll's "Alice in Wonderland," this phrase could be seen as contrasting with the whimsical and unpredictable nature of Wonderland, where characters often act in unexpected ways. The story explores themes of curiosity and identity, showing that appearances and associations can be deceptive in both the fantastical world and real life.