stated in the verse describing a tree: “And in its branches will dwell the birds [tzipparei] of the heaven” (Daniel 4:9). The verse states only: “The birds [tzipparei],” and not: The birds of any type of wing. Accordingly, the term “the birds [tzipparei]” must be referring to all birds, whether kosher or non-kosher, since all birds dwell in tree branches. The Gemara rejects this: Non-kosher birds are called: Birds [tzipparei] of the heaven, but they are not called: Tzipparei, in an unspecified manner.

The Gemara suggests: Come and hear that which is stated in the passage discussing kosher and non-kosher animals: “Every kosher bird [tzippor] you may eat” (Deuteronomy 14:11). Since it was necessary for the verse to specify that it is referring to a kosher bird [tzippor], by inference, one may conclude that there is a non-kosher bird [tzippor], in contradiction to the statement of Rabbi Yitzḥak. The Gemara rejects this: No, this is not the correct inference. Rather, by inference one may conclude that there is a tzippor that is prohibited for consumption, despite its being a kosher bird.

The Gemara asks: What is this kosher bird whose prohibition must be derived from this verse? If it is a bird with a wound that will cause it to die within twelve months [tereifa], that would be superfluous, as that is written explicitly in the verse: “An unslaughtered animal carcass, or a tereifa, he shall not eat” (Leviticus 22:8). And if it is referring to the slaughtered bird from the purification ritual of a leper, which is prohibited for consumption despite being kosher, that would also be superfluous, since it is derived from the latter clause of the verse in Deuteronomy, as the verse states: “But these are they of which you shall not eat” (Deuteronomy 14:12), which serves to include the slaughtered bird of the leper.

The Gemara responds: Actually, the verse: “Every kosher bird you may eat,” is referring to the slaughtered bird of a leper, and the verse indicates that one transgresses the positive mitzva of: “You may eat,” in addition to the prohibition of: “But these are they of which you shall not eat,” on account of it. The Gemara objects: But why not interpret the verse as referring to a tereifa, and explain that the verse teaches that one transgresses a positive mitzva and a prohibition on account of it? The Gemara responds: The verse should be interpreted as referring to the slaughtered bird of a leper, since it is a matter derived from its context, as that verse is written in the context of a slaughtered bird. By contrast, a tereifa is not properly slaughtered, and interpreting the verse in that manner does not fit the context.

The Gemara suggests: Come and hear that which is stated in the passage discussing the purification ritual of a leper: “Then shall the priest command to take for him that is to be cleansed two living birds [tzipporim] that are kosher” (Leviticus 14:4). Since the birds are obviously alive before the purification ritual begins, what is the meaning of the word “living”? Is it not that they are living in your mouth, i.e., permitted for consumption? If so, by inference, one may conclude that there are birds [tzipporim] that are not living in your mouth, i.e., that are not kosher. The Gemara rejects this: No, that is not its meaning. Rather, what is the meaning of the word “living”? It means that their extremities are living, i.e., attached to their bodies. The verse indicates that the kosher birds must have all their limbs attached to their bodies in order to be used in the purification ritual.

The Gemara suggests: Come and hear a proof from the latter clause of that verse: “Two living birds [tzipporim] that are kosher.” Since it was necessary for the verse to specify that it is referring to kosher birds, by inference one may conclude that there are non-kosher birds, in contradiction to the statement of Rabbi Yitzḥak. The Gemara rejects this: No, that is not the correct inference. Rather, by inference one may conclude that there are other birds of kosher species that may not be used for this ritual, i.e., tereifot.

The Gemara objects: But the disqualification of tereifot is already derived from the word “living” in that verse. The Gemara elaborates: Granted, this works out well according to the one who says that a tereifa can live (see 42a); it is therefore necessary for the verse to state “kosher” to exclude tereifot, because one could not have derived it from the word “living.” But according to the one who says that a tereifa animal cannot live, what is there to say? Let it be derived from the word “living.” And furthermore, whether according to the one who says that a tereifa can live or according to the one who says that a tereifa cannot live, it is not necessary to derive the exclusion of tereifot from the word “kosher,” since it is derived from that which the school of Rabbi Yishmael taught.

As the school of Rabbi Yishmael taught: It is stated in the Torah that there are offerings that enable one to partake of sacrificial foods, e.g., the sin offering of a woman who has given birth or the guilt offering of a leper, and there are offerings that atone, e.g., a sin offering or guilt offering, all of which are brought inside the Temple. And it is also stated in the Torah that there are offerings that enable one to partake of sacrificial foods, e.g., the birds of a leper’s purification ritual, and offerings that atone, e.g., the scapegoat of the Yom Kippur service, that are brought outside the Temple.

The baraita continues: Therefore, the offerings brought outside the Temple are compared to those offered inside: Just as with regard to the offerings that enable or atone stated in the Torah that are offered inside the Temple, the Torah made the offering that enables like the offering that atones, as even the former has portions of it that are burned on the altar, so too, with regard to offerings that enable or atone stated in the Torah that are offered outside the Temple, the Torah made the offering that enables like the offering that atones. Accordingly, just as the scapegoat must not be a tereifa, so too, the birds of a leper’s purification ritual must not be tereifot. If so, there is no need to derive the exclusion of tereifa birds from the word “kosher.”

Rather, Rav Naḥman bar Yitzḥak said: The word “kosher” serves to exclude birds from an idolatrous city. Such a city must be burned to the ground, and it is prohibited for one to derive benefit from any of its contents. The verse indicates that such a bird is unfit for use in the leper’s purification ritual. The Gemara asks: For what function are such birds rendered unfit by the word “kosher”? If the verse means to render them unfit for sending away as part of the ritual, this is unnecessary, since the Torah did not say to send a bird only to create a stumbling block. It is obvious that any bird prohibited for consumption is unfit for sending, since the Torah would not allow for the possibility that the bird sent away will be trapped and consumed by unwitting individuals. Rather, the verse means to render them unfit for use as the bird intended for slaughter.

Rava said: The word “kosher” serves to exclude the repeated use of a bird, i.e., a leper may not pair a bird with another bird from a previous leper, before its being sent away. The Gemara asks: For what function does the word “kosher” indicate that a bird may not be reused? If it means to indicate that the bird intended for being sent away by the first leper may not be used for slaughter by the second leper, the verse is unnecessary, as this bird requires being sent away as part of the first leper’s purification ritual. Rather, the verse means to indicate that the bird intended for being sent away by the first leper may not be used for sending simultaneously by the second leper.

Rav Pappa said: The word “kosher” serves to exclude the use of birds that were exchanged for birds of idol worship, i.e., a gentile paid a Jew for his idol by giving the Jew birds. Such birds are prohibited from use in the leper’s ritual, as it is written about objects of idol worship: “And you shall not bring an abomination into your house, and become [vahayita] accursed like it” (Deuteronomy 7:26), indicating that anything that you generate [mehayye] from it, e.g., through exchange, is prohibited like it. The Gemara asks: For what function does the word “kosher” indicate that such birds are prohibited? If it serves to exclude such birds from being sent away, this is unnecessary, because the Torah did not say: Send it away, if doing so could lead to a mishap. If the bird were prohibited, the Torah would not have commanded one to send it away, as others might eat it unwittingly. Rather, the word “kosher” serves to disqualify such birds for slaughter.

Ravina said: Here we are dealing with a bird that killed a person and is therefore subject to being killed. The verse indicates that such a bird is unfit for use in the leper’s ritual. The Gemara asks: What are the circumstances of this case? If this is a case where its verdict of execution was issued, then it is subject to being killed, and there is no need for the verse to teach that it cannot be used in the ritual. Rather, it must be referring to a bird before its verdict of execution was issued. And for what function does the verse exclude such a bird? If it serves to exclude the bird from sending away, this is unnecessary, since one is required to bring it to the court to fulfill the verse: “And you shall eradicate the evil from your midst” (Deuteronomy 13:6). Obviously, one may not send it away. Rather, the verse serves to disqualify such a bird for slaughter.

§ The mishna states: If a non-kosher bird is resting upon the eggs of a kosher bird, or a kosher bird is resting upon the eggs of a non-kosher bird, one is exempt from sending away the bird. The Gemara objects: Granted, it is understandable that one is exempt in a case where a non-kosher bird is resting upon the eggs of a kosher bird, since we require a kosher bird, as the verse uses the word “tzippor” (Deuteronomy 22:6) in this context, which the Gemara earlier (139b) interpreted as a reference to a kosher bird, and this bird is not kosher. But in a case where a kosher bird is resting upon the eggs of a non-kosher bird, it is a tzippor, a kosher bird, and one should be required to send it away.

The Gemara responds that this is in accordance with that which Rav Kahana said in a different context: The verse states: “But the young you may take for yourself” (Deuteronomy 22:7), indicating that one is required to send away the mother only if the eggs are fit for consumption, but not if they are fit only for your dog. Here too, with regard to non-kosher eggs, the mitzva applies only if you may take for yourself, but not if they are fit only for your dog because they are not kosher.

The Gemara asks: And where was this statement of Rav Kahana stated? The Gemara answers that it was stated with regard to that which is taught in a baraita: Even if the mother bird is a tereifa, one is obligated to send away the mother from the nest. But if the fledglings are tereifot, one is exempt from sending away the mother. From where is this matter derived? Rav Kahana said: As the verse states: “You may take for yourself,” indicating that you are required to send away the mother only if the fledglings are fit for consumption, but not if they are fit only for your dog because they are tereifot.

The Gemara objects: But why not compare a tereifa mother bird to tereifa fledglings and say: Just as with regard to tereifa fledglings one is exempt from sending away the mother, so too, with regard to a tereifa mother one should also be exempt from sending her away.