English: Rav Yehudah said in the name of Rav: A bird that comes from outside [the Land] and whose name is “many-winged” — one examines it by its signs.
On the daf / in context: When a bird’s identity is uncertain (especially foreign species), the halakhah falls back on the traditional physical signs of a clean bird rather than relying solely on the biblical name-list.
Type of Learning
Practical rule from the name-list (Chullin) — signs govern when the species is unknown.
What Is Learned
For birds whose identity relative to the Torah’s list is unclear, the physical signs of purity determine permissibility.