Hello. On the matter of the statement of Rav Yitzchak in Chulin 63b, how could he mean that the simanim described in the Yerushalmi are insufficient when they are explicit, and that a mesorah is also needed ("A kosher bird may be eaten only by a mesorah") since halachically it can only be kosher if it is a bird mentioned explicitly in the Torah OR has the simanim?? And if this were the clear meaning of his statement, there would be unanimity among all poskim in history that only kosher birds with a mesorah may be eaten, which there isn't of cojurse. And then what is unclear is how this comes to affects locusts or buffalo etc. where no simanim are mentioned. If an animal has the simanim of kashrus that presumably should be the end of the story. Thanks.
David Goldman, USA
1) Kosher birds are not mentioned explicitly in the Torah. The Torah mentions explicitly the non-Kosher birds.
2) It is still not clear to me what you mean when you write about the Simanim described in the Yerushalmi. The Mishnah (59a) gives the Simanim for non-Kosher and Kosher birds, and the Mishnah came before the Talmud Yerushalmi.
3) Rashi (62b, DH Chazyuhu) writes that if we are not expert about whether a certain species is Kosher, it follows that if we see a bird we must be concerned that it is "Dores" (Rashi 59a, DH ha'Dores, writes that this means that the bird holds the food that it eats in its claws, and it lifts the food above the ground). The Gemara (62b) tells us that they thought originally that the Tarnegola d'Agma (the "chicken of the marsh") was Kosher but afterwards they observed that it is Dores and therefore is forbidden. Rashi writes that this is why it is necessary to possess a tradition that the bird is Kosher.
Kol Tuv,
Dovid Bloom