There is a mitzvah to send away a mother bird from her nest if you want to take her eggs (Deut. 22:6-7). The question has been raised about whether one is obligated to send away a mother bird if you chance upon her nest, even if you do not want the eggs.
I. Finding The Bird
The Gemara in Chullin (139b) learns the following from the verse (Deut. 22:6) “If a bird’s nest happens to be before you…”: You might have thought that you have to go looking in mountains and valleys for a bird’s nest, and the verse comes to teach you that it is only if you chance upon it. R. Ya’ir Chaim Bacharach, in his Chavos Ya’ir (no. 67), deduces from this talmudic passage that if you chance upon a bird’s nest then you are obligated to send away the mother bird. The Torah is only exempting you from having to go searching for such a situation. But if you stumble across it then you have to fulfill the mitzvah and send away the bird.
Click here to read moreYou could counter that the conclusion of this talmudic passage is not as the Chavos Ya’ir suggests. You could read it as the initial suggestion being that this is a mitzvah you must strive to fulfill, i.e. by searching out a nest in order to send away the bird. And the conclusion is that this is a conditional mitzvah that you only fulfill if you are in the situation in which you find the nest and want the eggs. I believe that the Meiri understands the Gemara in this way.
II. The Reason For The Mitzvah
The Chavos Ya’ir adds that his approach is appropriate based on the rationale of the mitzvah offered by the Zohar. According to the Zohar, the reason to send away the mother bird is to invoke Divine mercy on the bird, which can then be extended to the Jewish people in exile. Therefore, even if you do not want the bird’s eggs you still perform a service to the Jewish people by sending away the bird. It is, indeed, very interesting that the Chavos Ya’ir felt it necessary to defend his ruling according to the reason for the mitzvah, or perhaps bring a proof based on it. Either possibility is unusual in the responsa literature. Additionally, medieval literature has many proposed reasons for this mitzvah that are significantly different from the Zohar’s.
III. Sending Away Both
R. Tzvi Ashkenazi, in his Chakahm Tzvi (no. 83), brings a proof for the Chavos Ya’ir‘s position from the Mishnah (Chullin 141a) that if someone send away a baby bird because he wants to take the mother bird, he must send away the mother bird also due to the mitzvah. The Mishnah could have said that he has not fulfilled the mitzvah but instead says that he must send away the mother, implying that there is an absolute obligation to send away the mother even if one does not want to.
IV. A Contrary View
The Chasam Sofer (Orach Chaim, no. 100) was asked what to do if you come across a bird’s nest on Shabbos. If you are biblically obligated to send away the mother bird regardless of one’s desire for her eggs, as the Chavos Ya’ir rules, then that obligation might override Shabbos concerns (but might not). The Chasam Sofer disagrees with the Chavos Ya’ir and concludes that you are not obligated to send away the mother bird and, therefore, out of Shabbos concerns should not.
The Chasam Sofer adds that the Babylonian Talmud seems to disagree with the Zohar about the reason for the mitzvah. The Mishnah (Chullin 138b) states the mitzvah to send away the mother bird applies both when the Temple is standing and when it is not. The Gemara (ibid.) states that the Mishnah differentiation between the Temple standing and not has no legal implication. It was made for no legal purpose (she-lo le-tzorekh). But, asks the Chasam Sofer, if the reason for the mitzvah is to invoke Divine mercy on the Jewish people in exile, one might have thought that the mitzvah does not apply when the Temple is standing. That would be a good reason for the Mishnah to state that it applies regardless of whether the Temple is standing. Since the Gemara does not explain the Mishnah that way, one can deduce that the Gemara did not accept that reason for the mitzvah and disagrees with the Zohar. And, explains the Chasam Sofer, when the Zohar disagrees with the Gemara we always follow the Gemara.
I found this difficult. Even when the Temple is standing there can be Jews in exile. Only a minority returned with Ezra and Nechemiah for the Second Temple, and even before the destruction of the First Temple there were exiles. And even if all Jews are in the land of Israel, there is still a need for Divine mercy anyway. I later found that the Minchas Elazar (2:78) makes essentially the same argument against the Chasam Sofer.
V. In Practice
According to the “Thoughts on the Daily Daf” of the Kollel Iyun HaDaf (link), the majority of halakhic authorities rule that someone who chances upon a bird’s nest is not obligated to send away the mother if he doesn’t want the eggs:
Most Acharonim rule that there is no obligation to send away the mother bird when one chances upon a nest and has no need for the eggs. This is the ruling of the Chasam Sofer (loc. cit), AVNEI NEZER (OC #481), CHAZON ISH (YD 175:2), CHAZON YECHEZKEL, MINCHAS CHINUCH (#544), and the CHAFETZ CHAYIM (in SEFER MITZVOS HA’KATZAR, Mitzvos Aseh #74). Most contemporary Poskim also rule this way, including RAV SHLOMO ZALMAN AUERBACH zt’l (in MINCHAS SHLOMO 2:5:4), and RAV YOSEF SHALOM ELYASHIV shlit’a and RAV CHAIM KANIEVSKY shlit’a (in personal conversations with Rabbi Naftali Weinberger). This [is the] common practice today. (Rabbi Weinberger quotes RAV YAKOV YISRAEL FISHER zt’l, however, who was of the opinion that one is obligated to send away the mother bird when he chances upon a nest, even though he does not need the eggs).
Although I think it is worth pointing out that the Arukh Ha-Shulchan (Yoreh De’ah 292:1-2) agrees with the Chavos Ya’ir.