Commento su Deuteronomio 14:15

בת היענה, “the ostrich;” the reason the word בת preceded the name of this bird is that it is edible only when very young. Afterwards its flesh becomes hard like wood.

ואת בת היענה, “and the little owl;” the same is true of the יענה, the great owl. The Torah mentions the little owl as it is not fit to be eaten except as long as it is very young. Its flesh is hard as wood when it matures. (b’chor shor)

ואת הנץ, “and the hawk;” here too the reader is referred to the Talmud in tractate Chulin folio 63, where we are told how to identify this species. Tossaphot on that folio goes into greater detail.