The Mitzvah of Shilu’ach HaKan is found in two short Pesukim in the middle of Parashat Ki Teitzei; someone skimming the Parashah might miss it. But missing it would be unfortunate, because not only is it important on its own, but the Mitzvah becomes even more significant when the argument over why we have it leads into a fundamental Machloket between Rambam and Ramban regarding Ta’amei HaMitzvot, the reasons for Mitzvot.
Amidst the rapid-fire list of Mitzvot in Parashat Ki Tetzei, we are commanded, “Ki Yikarei Kan Tzippor Lefanecha BaDerech…VeHaEim Rovetzet Al HaEfrochim O Al HaBeitzim, Lo Tikach HaEim Al Banim. Shalei’ach Teshalach Et HaEim VeEt HaBanim Tikach Lach, Lema’an Yitav Lach VeHa’arachta Yamim,” “If a bird’s nest happens to be before you on the road…and the mother is roosting on the young birds or eggs, you shall not take the mother with the young. You shall surely send away the mother and take the young for yourself, so that it will be good for you and you will prolong your days” (Devarim 22:6-7).
Shilu'ach HaKan makes a brief yet significant appearance in the Gemara. The Mishnah, in describing the circumstances under which a person is removed from leading Tefillah, writes, “HaOmeir, ‘Al Kan Tzippor Yagi’u Rachamecha’…Meshatkin Oto,” “One who says, ‘Your mercy extends to the bird’s nest’… is silenced” (Berachot 5:3). One of the explanations for this practice provided by the Gemara is that such an utterance makes it seem as though the Mitzvah of Shilu'ach HaKan is motivated by compassion, when in reality all Mitzvot are Gezeirot, decrees, and have no tangible reason behind them. It would therefore be inappropriate to attribute the Mitzvah to compassion (Berachot 33b).
Rashbam and Ibn Ezra, in their commentaries on the Pesukim, offer a different explanation for the Mitzvah. They note the similarity between Shilu'ach HaKan and the prohibitions against cooking a goat in its mother’s milk (Shemot 23:19) and slaughtering an animal and its young on the same day (VaYikra 22:28), in that the purpose of all three Mitzvot is to prevent cruelty against animals (commentary to Devarim 22:6).
It is against this background that Rambam and Ramban debate Ta’amei HaMitzvot. In Rambam’s philosophy book, Moreh Nevuchim, he writes that at their basic level, all Mitzvot have a corporeal purpose behind them that can be deduced by reason. Some, including Maharsha (commentary on Berachot 33b), claim that Shilu'ach HaKan is a Chok, a Mitzvah for which we cannot determine the reason. However, Rambam, like Rashbam and Ibn Ezra, provides a reason for the Mitzvah: later in Moreh Nevuchim, he explains that taking the young in front of the mother bird would cause her great pain. This is no different than the pain a human mother would feel for her children if they were taken away, because the love a mother feels for her children is not dependent upon intelligence but rather is something that is felt equally in humans and animals. Hashem has mercy over the birds, so we must also have compassion for them. For this reason, we are prohibited from taking the young without first sending away the mother. Rambam defends his contradiction of the Gemara simply by writing that we do not follow the opinion that Shilu’ach HaKan has no tangible reason (Moreh Nevuchim 3:48). Rambam’s strong belief in the idea that all Mitzvot have an understandable purpose leads him to go so far as to dispute the simple explanation of the Gemara.
Ramban, commenting on our Pesukim, explains that the purpose of all Mitzvot is to refine man in some way. Do not imagine, explains Ramban, that Hashem benefits from, for example, the smell of Ketoret or Korbanot, because like all other Mitzvot, these things are not for the benefit of Hashem but rather serve to teach man something. Accordingly, Ramban rejects Rambam’s opinion. Rambam suggested that because Hashem has mercy over the birds, He commands us to treat them a certain way, which would mean that to some extent the Mitzvah benefits Hashem. But this is not the case, Ramban argues, because if Hashem truly had mercy over the birds, He wouldn’t allow us to slaughter them at all! In reality, the purpose of Shilu'ach HaKanis to teach us compassion. Pitying the mother bird and sending her away before taking her young will teach us to not be cruel, and this lesson will positively affect the way we interact with other people. Ramban would therefore explain that when the Gemara describes Shilu'ach HaKan as a Gezeirah, this means that it is a Gezeirah in the sense that it is not motivated by Hashem’s compassion but rather by Hashem’s desire to teach people compassion. For Ramban, Shilu'ach HaKan is a means to an end, while for Rambam, the Mitzvah stands on its own.
Shilu'ach HaKan, a single Mitzvah, represents two conflicting schools of thought regarding the reasons and purposes of all the Mitzvot. Rambam believes that Mitzvot bring tangible results, while Ramban believes that Mitzvot are intended for our moral improvement. Although it is one Mitzvah among so many others in Parashat Ki Teitzei, Shilu'ach HaKan is of considerable significance.