1) SENDING AWAY A BIRD THAT IS "ASUR B'HANA'AH"
QUESTION: The Gemara asks that the word "Tzipor" can refer to a Tamei (non-Kosher) bird. The verse says that for the Taharah of a Metzora, one must use "Shtei Tziporim Chayos Tehoros" -- "two living, Tahor birds" (Vayikra 14:4). The fact that the verse says "Tehoros" implies that the word "Tzipor" can refer to a Tamei bird, because, otherwise, the verse would not have to specify "Tehoros"! Rav Nachman bar Yitzchak answers that, indeed, the word "Tehoros" does not exclude a Tzipor that is Tamei, because the word "Tzipor" itself teaches that the bird must be Tahor. Rather, the verse is excluding the use of birds that come from an Ir ha'Nidachas.
The Gemara asks that the Torah does not need to teach that the bird that is sent away (as part of the Taharah process of the Metzora) cannot be from an Ir ha'Nidachas, because such a bird is Asur b'Hana'ah. The Torah does not need to teach that one may not send away a bird that might cause a Jew to sin (one might find the bird and eat it).
Why, though, should it be prohibited to send away a bird that is forbidden? The majority of birds in the world are permitted, and thus in a case of doubt one may follow the Rov (majority), according to Torah law. The person who finds the released bird may eat the bird based on the principle of Rov. (See also Insights to Chulin 115:1.)
ANSWERS:
(a) The CHIDUSHEI CHASAM SOFER (Chulin 115a) answers that although the finder is permitted to take the bird (because of the principle of Rov), the sender is forbidden l'Chatchilah to send away such a bird. The Chasam Sofer cites TOSFOS (95a, DH uve'Nimtza) who writes that an item of clothing that contains Sha'atnez may not be sold to a Nochri because he might resell it to a Jew. Even though the principle of Rov should permit selling it to a Nochri, because, in the majority of cases, it will not be resold to a Jew, one is not permitted l'Chatchilah to put a forbidden item into the world and then rely on the principle of Rov to permit it. The Chasam Sofer asserts that such an act is prohibited mid'Oraisa.
(b) RAV ELCHANAN WASSERMAN zt'l Hy'd in KOVETZ SHEMU'OS (printed in Kovetz Shi'urim, vol. 2, #55) answers based on the Yerushalmi cited by the RASH (in Orlah). The Yerushalmi teaches that, in general, Bitul is effective only after it is known that there is an Isur in the mixture, but it is not known where the Isur is. Before it is known that an Isur is present, the Torah does not say that the majority of permitted items annuls the Isur. The reason for this, as explained in KOVETZ HE'OROS (Yevamos 58:2), is that the Torah permits a mixture that contains a majority of Heter because of the doubt that exists. However, when there is no doubt (because it is not known to the person who found the bird that there was a forbidden bird flying around somewhere), the Torah does not teach that one may rely on the majority, and thus the bird remains forbidden.
(c) According to the view of the RA'AVAD, this question is not a question at all. The Ra'avad (in ISUR MASHEHU, chapter 2, as cited by the BEIS YOSEF YD 99) maintains that it is Asur mid'Oraisa to cause an Isur to become Batel.
Moreover, the NODA B'YEHUDAH (YD 2:45) maintains that all opinions, even those that argue with the Ra'avad, agree that it is Asur mid'Oraisa to be Mevatel a solid item in a mixture of other solid items (Yavesh b'Yavesh). Similarly, the ARUCH HA'SHULCHAN (YD 99:27) rules that it is forbidden mid'Oraisa to be Mevatel an object of Isur that is recognizable (and is not mixed with other objects such that it is unidentifiable).
(d) RAV SHIMON SHKOP in SHA'AREI YOSHER (3:6) explains that the person who finds the bird certainly may eat it, but not because of "Bitul b'Rov." Rather, one who finds it and eats it does not transgress an Isur, because of the principle of "Halech Achar ha'Rov" ("follow the Rov," or "Kol d'Parish me'Ruba Parish"), which is different from "Bitul b'Rov."
Here, there is no Bitul b'Rov -- the forbidden bird does not become "Batel" in a majority of permitted birds, because there is no actual mixture here; the forbidden bird did not "fall" into a "mixture" of permitted birds gathered in one place. Since there is no Bitul b'Rov, the bird does not become inherently permitted. Rather, the person who finds the bird is allowed to eat it because of the principle of "Halech Achar ha'Rov," which teaches that in a case of doubt one may assume that the bird is from the majority of birds. This rule does not state that a forbidden bird loses its status of Isur.
Accordingly, the one who sends the bird away knowing that it is Asur b'Hana'ah is causing a stumbling block to exist in the world, since another person may eat it assuming that it is from the majority of permitted birds. Therefore, it is forbidden for him to send it away. (See YOSEF DA'AS to Chulin 115a.)

140b----------------------------------------140b

2) TWO ROWS OF EGGS IN A NEST
QUESTION: Rebbi Yirmeyah asks what the Halachah is in a case in which there are two rows of eggs in a nest, one on top of the other. Must one send away the mother bird in order to take the bottom row of eggs, or is the upper row of eggs considered a separation between the mother bird and the lower eggs, and thus one may take the bottom row of eggs without sending away the mother bird? The Gemara leaves this question unresolved ("Teiku").
What exactly is the case of Rebbi Yirmeyah's question? If the mother bird is sitting on two rows of eggs and hatching both of them, presumably her body extends over all of the eggs. Consequently, when one wants to remove an egg from the bottom row, he must lift it up and move it to a position directly underneath the mother bird. How can he continue to remove it from its place without transgressing the Mitzvah of Shilu'ach ha'Ken?
ANSWERS:
(a) RASHI (DH Mahu she'Yachotzu) implies that the case in question is where the person is taking both rows out from under the mother bird at the same time. In this manner, the bottom row never passes directly below the mother bird. (This is implicit in the words of Rashi, who says that the person "has intention to take the lower eggs," and does not say simply that the person "takes the lower eggs." This implies that he actually takes both rows, but he intends only to take the lower row.)
Why, though, does he not transgress the Mitzvah when he takes the top row from directly underneath the mother? Rashi says that he intends only to take the lower row (for example, he takes them with the intention of returning the upper row to its place, as the Gemara later (141a) discusses), and thus when he takes the upper row from beneath the bird, he does not transgress the Mitzvah of Shilu'ach ha'Ken.
(b) TOSFOS (DH Shnei) explains that the case in question is where the person is taking only the bottom row of eggs. How does he take them without them passing directly beneath the mother bird? Perhaps Tosfos understands that when the top row of eggs serves as a separation between the bottom row of eggs and the mother bird, the person certainly must send away the mother bird before he brings forth the bottom eggs from under the top ones. Rebbi Yirmeyah's question is whether one must send away the mother bird before he begins to take away the bottom eggs.
(c) The RASHBA explains that in the Gemara's case, the upper row of the "two rows of eggs" is not a natural layer of eggs. If both rows would be natural layers of eggs, then indeed it would be prohibited to take any of the bird's eggs, including the ones on the bottom. Rather, the upper row is comprised of non-Kosher eggs placed there by a non-Kosher bird, or, alternatively, it is comprised of inedible eggs ("Muzaros") which the person intentionally placed above the bottom row of eggs in an attempt to avoid the obligation of Shilu'ach ha'Ken by creating a separation between the bird and its eggs.
(There appear to be a number of printing errors in our text of the Rashba. Instead of "Lo Elyonim v'Lo Tachtonim," it should read "Elyonim Ela Tachtonim." Instead of "Mezumanim," it should read "Muzaros.") (M. KORNFELD)
3) A "KOREI" SITTING ON THE NEST OF ANOTHER BIRD
QUESTION: In the Mishnah (138b), Rebbi Eliezer and the Chachamim disagree about whether one is obligated to send away a male Korei (sitting on the eggs of another bird). In the Gemara, Rebbi Elazar says that both agree that when a female Korei is sitting on the eggs of another species, one is obligated to send away the Korei in order to take the other bird's eggs.
The Gemara continues and quotes another statement of Rebbi Elazar in which he says that Rebbi Eliezer and the Chachamim agree that there is no obligation to send away any other type of male bird (other than a Korei) from its young.
It seems that the two statements of Rebbi Elazar are not mutually exclusive. Rebbi Eliezer argues with the Chachamim only in the case of a male Korei sitting on another bird's eggs. They agree that a female Korei sitting on another bird's nest must be sent away (first statement), and that any other male bird (besides a Korei) does not need to be sent away (second statement).
RASHI (DH u'Vak'ah) explains that Rebbi Eliezer derives from a Gezeirah Shavah the obligation to send away a male Korei bird. The verse in Yeshayah (34:15) uses the word "Dagrah" with reference to ordinary birds, when it discusses birds that roost properly -- "b'Mino" (on young of their own type). Similarly, when the verse in Yirmeyahu (17:11) mentions the roosting of the Korei with the word "Dagar," it means to say that the roosting of the Korei is a proper way of roosting. Even though the Korei does not roost on its own young, since its normal manner is to roost on the young of other birds, one must send it away when one wants to take the eggs.
Rashi's words imply that the Chachamim do not accept this Gezeirah Shavah. They maintain that since the Korei does not roost on its own eggs, there is no obligation of Shilu'ach ha'Ken, regardless of whether this is the normal way that it roosts.
Rashi's words are difficult to understand. Why does Rashi explain that the argument between Rebbi Eliezer and the Chachamim is about whether the Korei's manner of sitting on other bird's eggs obligates it to be sent away? Rebbi Elazar teaches clearly that the Chachamim agree with Rebbi Eliezer that a bird which normally sits on other birds' eggs must be sent away; it is for this reason that they maintain that a female Korei must be sent away prior to taking the eggs beneath it. The Chachamim seem to argue with Rebbi Eliezer over another point. They maintain that the Torah (Devarim 22:6) requires only that a mother bird be sent away, and not a father bird. (RASHASH)
ANSWERS:
(a) The RASHASH answers that Rashi seems to follow the view of the RIF.
The RIF records only the second statement of Rebbi Elazar; he omits the first. The Rif writes that Rebbi Eliezer and the Chachamim argue only about a male Korei, but they agree that any other male bird does not need to be sent away. Why does the Rif omit the first statement of Rebbi Elazar?
Moreover, there seems to be no reason for the Rif to quote the second statement at all. The second statement of Rebbi Elazar is relevant only if the Halachah follows the view of Rebbi Eliezer, since it qualifies only the ruling of Rebbi Eliezer and is not pertinent to the ruling of the Chachamim. Even without Rebbi Elazar's second statement, it is clear that the Chachamim do not require any male birds to be sent away. However, the Halachah follows the view of the Chachamim. It would have been much more logical for the Rif to quote only the first statement of Rebbi Elazar, because that statement teaches a Halachah according to the Chachamim (i.e. that a female Korei needs to be sent away).
The ROSH (12:2) explains that the Rif has a different understanding of the Gemara. The Rif learns that the two statements of Rebbi Elazar disagree with each other. (The Rosh points out that in the Rif's text of the Gemara, the words "Ika d'Amrei" ("there are those who say [an alternate version]") must have preceded the second statement of Rebbi Eliezer.) The Rif understands from the fact that the Gemara records a second version of Rebbi Elazar's statement, and proceeds to bring proof to that version from a Beraisa, that the second version must be arguing with the first. With regard to what point do the two versions disagree?
The first version of Rebbi Elazar's statement is saying that the argument in the Mishnah applies to all male birds; Rebbi Eliezer maintains that all male birds must be sent away from their young, while the Chachamim maintain that no male birds need to be sent away, even the Korei. The argument is expressed with regard to a male Korei (and not with regard to all male birds) in order to show that the Chachamim agree that a female Korei must be sent away (even when it roosts on the eggs of other birds).
The second version is saying that the argument in the Mishnah applies to Korei birds that roost on the eggs of others. Rebbi Eliezer maintains that one must send away any Korei bird (male or female) that roosts on the eggs of another bird, while the Chachamim maintain that no bird that roosts on the eggs of others is sent away. The argument is expressed with regard to a male Korei (and not all types of Korei) in order to show that Rebbi Eliezer agrees that all other male birds do not need to be sent away.
Accordingly, since the Halachah follows the second version, and it follows the view of the Chachamim, there is no Mitzvah to send away any bird that is sitting on the eggs of another bird. No bird -- male, female, or Korei -- is sent away when it is sitting on the eggs of another bird.
This is also the ruling of the RAMBAM (Hilchos Shechitah 13:10).
The Rashash writes that Rashi -- who implies that the reason why the Chachamim do not require sending away a male Korei bird is that it is not sitting on its own eggs (and not because it is not a "mother" bird) -- follows the view of the Rif. Rashi maintains that such a bird does not need to be sent away, whether it is male or female, since it is not sitting on its own eggs. (See also Rashi to 140a, DH Rebbi Eliezer Mechayev.)
(b) Perhaps Rashi's words are meant to be read differently. The Rashash reads Rashi's words as saying, "Just as there (in the verse in Yeshayah), it is a proper roosting, because the verse is discussing [eggs of] its own type, here also (in the verse in Yirmeyahu, regarding the Korei) it is discussing a proper roosting." However, perhaps Rashi's words are meant to be read as follows (pausing after the word "d'b'Mino," and not before it): "Just as there (in the verse in Yeshayah), it is the proper form of roosting for this type [of bird] that is being discussed in the verse, here also (in the verse in Yirmeyahu, regarding the male Korei), it is discussing what is considered to be a proper roosting [for this type of bird]." Rashi means that the male Korei has the status of a mother bird for Shilu'ach ha'Ken since it normally sits on eggs like a mother bird; Rashi is not saying anything about whether it sits on its own eggs or on the eggs of others! (M. KORNFELD)
4) A MOTHER BIRD SITTING IN THE BRANCHES ABOVE ITS NEST
QUESTIONS: Rav Yehudah says in the name of Rav that when a mother bird is sitting on two branches stretching over the nest, the obligation to send away the mother bird depends on whether she is directly over the nest (that is, if the branches would be removed, she would fall into the nest), or whether she is not directly over the nest (if the branches would be removed, she would not fall into the nest).
There are two difficulties with the words of Rav Yehudah in the name of Rav.
1. Rav Yehudah is saying that the only criterion for the obligation of Shilu'ach ha'Ken in this case is that the mother, if she would fall, would land on the eggs. This implies that the obligation of Shilu'ach ha'Ken applies even when the mother bird is far above the nest; as long as she is directly above it, the obligation to send her away applies. How, though, can this be considered "Rovetzes" -- "crouching on the young" (Devarim 22:6)?
2. What is Rav Yehudah teaching in the second part of his statement, when he says that if the mother bird would not fall into the nest when the branches are removed, then one is not obligated to send her away? This is obvious; even if the mother bird is not sitting above the nest on branches, but rather she is right next to the eggs (and she is even touching them), the Mitzvah does not apply until she is directly over the nest.
ANSWERS:
(a) The CHIDUSHIM U'VI'URIM answers the first question by saying that Rav Yehudah means that the Mitzvah applies only when the mother bird is so close to the nest that she provides warmth to the eggs or chicks. When she is so high that she does not provide warmth, this is not considered "Rovetzes" and the Mitzvah does not apply, even if she will fall into the nest if the branches are removed.
The Chidushim u'Vi'urim answers the second question by saying that Rav Yehudah's second statement is teaching that the Mitzvah does not apply even when the wings of the mother bird are outstretched over the branches above the nest. If the branches would not be there, the wings would be directly above the eggs, and the Mitzvah would apply. The reason why the Mitzvah does not apply is that the branches serve as a separation between the wings and the nest. Rav Yehudah is teaching that even though the wings of the mother are above the eggs, since the branches separate between them and the nest (and the bird would not fall into the nest if the branches were removed), the Mitzvah does not apply.
This answer, however, is problematic, because the Gemara earlier already discusses the question of an intervening object between the bird and the eggs. The Gemara earlier leaves the question unanswered. Why, then is it so clear to Rav Yehudah that in such a case the Mitzvah does not apply?
(b) Perhaps one may answer both questions as follows. The reason why the Mitzvah of Shilu'ach ha'Ken applies when the mother bird is sitting on two branches directly over the nest is that the branches are considered an extension of the walls of the nest. When a nest has walls that extend above the eggs, one is obligated to send away the mother bird even when she is sitting on the wall. This is considered "Rovetzes Al ha'Efrochim," since it is the normal way for a bird to sit on her nest.
According to this understanding of Rav Yehudah's statement, the Mitzvah applies only when the branches actually reach the nest, because only then can we consider them to be part of the nest.
Regarding the second question, one may suggest that there is a significant difference between a mother bird sitting alongside the nest (in which case the Mitzvah to send it away certainly does not apply), and a mother bird sitting on top of branches touching the nest but not directly above it. In the former case, the bird is not over the nest at all, and therefore one is exempt. In the latter case (the case that Rav Yehudah is discussing), in which the bird is sitting on what is considered to be part of the nest, one might have thought that the Mitzvah to send her away indeed applies. Rav Yehudah teaches, therefore, that not only must the mother bird be sitting on the nest (or part of the nest), she also must be directly above the eggs in order for the Mitzvah to apply. (Mordechai Zvi Dicker)

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