鳶とんびが鷹たかを生うむ

expression, godan verb (-mu)

a black hen lays a white egg; a kite gives birth to a hawk

Proverbial idiom meaning that an ordinary or untalented parent can produce an exceptional child. Often used with a sense of surprise or admiration. The literal image is of a kite (a common bird) giving birth to a hawk (a noble bird).

• あの平へい凡ぼんな両りょう親しんから、こんな優ゆう秀しゅうな子こが生うまれるなんて、まさに鳶とんびが鷹たかを生うむだね。

  For such an outstanding child to be born from those ordinary parents—it's truly a case of a kite giving birth to a hawk.

• 彼かれは親おやに似にず天てん才さい的てきだ。鳶とんびが鷹たかを生うんだと言いえるだろう。

  He's a genius unlike his parents. You could say it's a case of a kite giving birth to a hawk.