Since the mitzva of shilu’aḥ ha-ken applies only to kosher birds, one must be able to distinguish kosher birds from non-kosher ones. In practice, the kosher birds commonly found in in Eretz Yisrael are doves, turtledoves, and house sparrows.
It is also necessary to distinguish between male and female birds, since the mitzva applies only when the mother is brooding over her chicks. Among doves and turtledoves, the male sits on the nest for most of the day, while the mother generally does so from about five in the afternoon until seven in the morning. Sending her away during those hours fulfills the mitzva. By contrast, one who comes in the middle of the day will likely find the male on the nest, and sending him away before taking the chicks does not fulfill the mitzva. Among house sparrows, however, the male sits on the nest for only about two hours a day; he can be identified by the black patch on his chest.
If the nest was built in a person’s protected courtyard or on his roof, then once the mother has flown away, the courtyard acquires the eggs or chicks on his behalf, and there is no longer any mitzva to send her away. In such a situation, he can fulfill the mitzva only if, when the birds begin building the nest, he has in mind that he does not want to acquire the nest, eggs, or chicks.[5]
According to most authorities, one may send away the mother by driving her from the nest, either with a shout or by tapping the nest with one’s hand or a stick. Rambam maintains that the mitzva is fulfilled only if one takes hold of the mother by her wings and then sends her away (MT, Laws of Sheḥita 13:5). In practice, however, one should not attempt to fulfill Rambam’s view by taking hold of the mother, since some Rishonim may view taking her while she is still over the chicks or eggs as a violation of “You shall not take the mother together with the young,” even if she is released immediately afterward. One should therefore send her away by making noise or by tapping the nest.[6]
[5] Regarding a nest in one’s courtyard, Igrot Moshe (YD 4:45) maintains that if the owner says that acquiring the nest is not a benefit to him, the eggs and chicks remain ownerless, and he may fulfill the mitzva. Rav Elyashiv and Or Le-Tziyon are more restrictive: the eggs or chicks remain ownerless only if, when the birds begin building the nest, he stipulates that he does not want his courtyard to acquire them; he may then later fulfill shilu’aḥ ha-ken (Shale’aḥ Teshalach §21). Rav Shlomo Zalman Auerbach rules that even such a stipulation does not help, because the nest is still considered available to him; the mitzva therefore cannot be fulfilled with it (Minḥat Shlomo 2:97:26).
[6] The Gemara in Ḥullin 141b asks: “How does he send it away? Rav Huna said: By its legs. Rav Yehuda said: By its wings.” Rambam reads this literally and rules in accordance with Rav Yehuda: one fulfills the mitzva by grasping the mother by her wings and releasing her (MT, Laws of Sheḥita 13:5). Rashi explains differently: if one drives the mother away with his voice or with a stick until she flies off on her wings, she is considered to have left the nest, and one may then take the young. This is also the view of Rosh, Ran, Rabbeinu Yeruḥam, Ha-Eshkol, Rid, Yam Shel Shlomo, Ḥatam Sofer, and many others.
Some inferred from the Mishna in Makkot 17a, which classifies shilu’aḥ ha-ken as a negative commandment whose violation can be remedied through a positive commandment, that taking the mother is itself a violation, remedied immediately by sending her away. Rashba, however, writes elsewhere (1:493) that one who takes hold of the mother in order to send her away has not violated the prohibition. The wording of several other Rishonim, however, may suggest that even taking hold of the mother in order to release her immediately is considered a violation, though one that can be remedied at once by sending her away. The accepted ruling follows the majority view: one does not violate the prohibition by taking hold of the mother in order to send her away. The Mishna’s category applies to someone who took the mother intending to violate the law; he can still remedy the violation by sending her away.
Regarding a berakha, several authorities maintain that one recites, “Who has sanctified us with His commandments and commanded us concerning shilu’aḥ ha-ken” (Ra’avad; Rokeaḥ; Pe’at ha-Shulḥan; AHS 292:10). The majority view, however, is that no berakha is recited. Some explain that since the mitzva is tied to a negative prohibition remedied by a positive commandment, it is not accompanied by a berakha, as explained above in the view of Rashba and those who follow him. Others explain that no berakha is recited over a mitzva that arises only incidentally, when one happens upon a nest (Me’iri; Rabbeinu Baḥya). In practice, one does not recite a berakha, in keeping with the well-known principle that in cases of doubt concerning berakhot, we are lenient (Ḥida, Shiyurei Berakha 292:1).
