1)

(a)We query the Mishnah's statement that none of the four Simanim listed there are mentioned in the Torah, from a Beraisa, which presents - a Nesher (an eagle [listed in the Torah]) that has none of the Simnei Tum'ah.

(b)The Tana then states that - a pigeon has all four Simanim.

(c)Abaye explain the Mishnah's statement to mean - that the four Simanim are not mentioned specifically.

(d)There are no other birds that possess none of the Simnei Taharah.

(e)Consequently, when the Tana says 'Af Kol ke'Yotzei-bo Tamei', he is coming to include - other species of Nesher.

2)

(a)Rebbi Chiya extrapolates from a Nesher that any bird that has even one Siman Taharah is Kasher, Kal va'Chomer two or three - provided he is familiar with the twenty-four Tamei species listed in the Torah.

(b)We cannot rather extrapolate from a pigeon that any bird that lacks even one Si'man Taharah is forbidden - because then, the Torah would not have needed to list the twenty-four Tamei species.

(c)Nor can we learn from ...

1. ... the non-Kasher listed species that any bird with three Simanim is forbidden, Kal va'Chomer if it has only two or one - since then, the Torah ought to have listed only the twenty species that have three of the Simanim. But why mention the raven, which has only two, and which we would therefore know from the Kal ve'Chomer?

2. ... the raven, that any bird with two Simanim is forbidden, Kal va'Chomer if it has only one - because then, by the same token, why does the Torah then need to add the Peres and the Ozniyah, which have only one Si'man?

(d)Neither can we learn from Peres and Ozniyah that any bird with one Si'man is forbidden - since why does the Torah then need to mention the eagle, which has none of the Simanim?

3)

(a)The problem with trying to learn from Peres and Ozniyah that all birds with only one Siman Taharah are forbidden is that - we then seem to have two Pesukim teaching us the same thing (Sh'nei Kesuvim ha'Ba'im ke'Echad), and we have a principle Sh'nei Kesuvim ha'Ba'im ke'Echad, Ein Melamdin.

(b)We answer - by citing a tradition that Peres and Ozniyah have different Simanim, in which case the Torah needs to insert both, because, had it written only one of them, we would not have known the other. Therefore we need Nesher to teach us that even birds with one Siman Taharah are permitted.

(c)We ask why - it is unlikely that the Siman that exists by Peres and the Siman that exists by Ozniyah do not both already exist in one or the other of the twenty birds that each have three Simanim, in which case it will still be a case of Sh'nei Kesuvim ha'Ba'im ke'Echad?

(d)And we answer - by citing a tradition that the three Simanim that are shared by the twenty Tamei birds also incorporate the two of a raven, and one of the Peres or the Ozniyah. The other one, is the fourth Siman that is unique to that bird alone, making it necessary for the Torah to write Nesher (see Rashash).

4)

(a)We query as to why, seeing as we learn from Nesher that even birds with one Siman Taharah are Kasher, the Torah sees fit to insert pigeons and young turtle-doves. Rav Ukva bar Chama answers - that it is to teach us that they alone are eligible to be brought on the Mizbe'ach (indeed, 'Torin' and 'b'nei Yonah' are only written in Vayikra in the Parshah of Korbanos).

(b)The Tana of the Beraisa (on Amud Alef) mentions pigeons - because it is from the fact that the same four Simanim that appear on a pigeon do not appear on a Nesher, that we know exactly what the Simanim are.

(c)We decline to take literally the Beraisa cited on the previous Amud, which learns from "Torin" that a bird with one Si'man Taharah or more is Kasher - since we already know that from the Torah's insertion of Nesher among the Tamei birds.

(d)And the reason that the Tana mentions it is - because it is only from the fact that the Nesher has none of the Simanim that the pigeon does that enables us to identify them.

5)

(a)We refute the suggestion that Rav Ukva is coming to explain why *the Tana* inserts Torin - because then, how could the Beraisa continue 'Af Kol ke'Yotzei bahen Tehorin' (incorporating chickens)? Since when are chickens Kasher to go on the Mizbe'ach?

(b)And we know that they are not - from the constant repetition of Torin and b'nei Yonah, as the Toras Kohanim explicitly states.