וְהֵסִ֥יר אֶת־מֻרְאָת֖וֹ בְּנֹצָתָ֑הּ וְהִשְׁלִ֨יךְ אֹתָ֜הּ אֵ֤צֶל הַמִּזְבֵּ֙חַ֙ קֵ֔דְמָה אֶל־מְק֖וֹם הַדָּֽשֶׁן׃
И он соберет урожай его с перьями его и бросит его возле жертвенника в восточной части, на месте пепла.
Tze'enah Ure'enah
“He shall remove its crop” [1:16]. They threw away the crop of the birds that were sacrificed, because the birds fly into all barns and eat grain through theft. Therefore, the Holy One does not want to have organs on the altar that the birds used to steal. This is the crop and it did not help to wash it, but they threw it away on the ash heap. However, an animal that eats from its master but not through theft. Therefore, they do not throw anything away from the animal. From here we should learn how the Holy One hates stealing, even from a bird that has no understanding. The Torah forbade bringing it on the altar. Therefore, the person should be warned about stealing or usury, that he should not be excluded from the Garden of Eden where other righteous people are found, and cannot come to the Throne of Glory from which his soul was taken.13Bahya, Leviticus, 1:16.
Rashi
מראתו [AND HE SHALL REMOVE] ITS CROP — The word is connected in meaning with the word רעי in Rabbinical Hebrew (or the Biblical ראי; cf. Nahum 3:6); it thus denotes the place of the רעי, the digested food, i. e. the crop (Sifra, Vayikra Dibbura d'Nedavah, Section 7 9).
Ibn Ezra
its crop The meaning of this word is known, and it is related to “Woe to the filthy” [Zephaniah 3:1]