A proverb meaning 'birds of a feather flock together' — similar people naturally group together (literally, cows go with cows, horses with horses).
新しいクラブに入ってみたら、趣味の合う人たちばかりで、やはり『牛は牛連れ馬は馬連れ』だと感じた。
When I joined a new club, I found people with similar tastes — it felt like 'birds of a feather flock together.'
職場でも趣味や考え方が似ている人同士でグループができる。牛は牛連れ馬は馬連れだね。
In the workplace, groups form among people with similar hobbies or ways of thinking. Birds of a feather flock together.