Question: The Beraisa teaches that one may not trap Chayos nor Ofos in a Bibar (contradicting the Mishnah regarding both Chayos and Ofos)!?
Answer: Regarding Chayos the two Beraisos differ regarding the positions of R. Yehudah (who only forbids birds being trapped into a tower and deer into a house, but not into a Bibar) and Rabanan (who prohibit even into a Bibar).
Question: But there is still a contradiction regarding Ofos!?
Answer: It speaks of different types of Bibarin, one roofed and one unroofed.
Question: But both agree that one may trap a bird into a house, which should be viewed as a covered Bibar!?
Answer (Rabah bar R. Huna): The prohibition is speaking of an undomesticated bird (Dror), as taught in the Beraisa.
Question: There should be no contradiction within Chayos, either, given that one Beraisa may be speaking of a larger or smaller Bibar!?
Question: What would constitute a small or large Bibar?
Answer (R. Ashi): A small Bibar is where the animal may be caught with one stride.
Alternate Answer: The presence of nooks (into which the animal may escape) makes it a large Bibar.
R. SHIMON B. GAMLIEL LOOKS AT THE SIZE OF THE BIBAR
(R. Yosef citing R. Yehudah citing Shmuel): The Halachah follows R. Shimon b. Gamliel.
Question (Abaye): Are we to infer from this "ruling" that there is a dissenting opinion?
Answer (R. Yosef): Why should you inquire about a dissenting opinion once you know the Halachah?
Question (Abaye): One must not learn like a fool!
AN ANIMAL WHICH IS NOT YET TRAPPED
Question: When is an animal not yet trapped?
Answer (R. Yosef citing R. Yehudah citing Shmuel): If the person calls for a trap to trap the animal.
Question (Abaye): But we find that people call for traps when seeking certain fowl, yet the Beraisa teaches that one who traps these is Patur!?
Answer (Rabah bar R. Huna citing Shmuel): These come back to their pens at night.
Question: But the Beraisa speaks of pigeons which return to their place at night and yet one is Chayav for trapping them?
Answer: Rather, we must say one is Patur if they come back to their pens at night and they depend on the owner for their food, but not if they come back but do not depend on the owner for food.
Answer (R. Mari): The prohibited birds fly away while the permitted ones do not.
Question: But all the pigeons fly up to their nests!?
Answer: Some fly to their nests, while some fly away even from their nests (making it more difficult to catch them).
TAKING ANIMALS FROM THE TRAPS - MUCHAN
One may not take an animal from a trap on Yom Tov, unless certain that the animal was trapped before Yom Tov.
A Gentile brought fish to R. Gamliel who ruled them permitted (but that he did not wish to take them from this Gentile).
Question: The cited incident contradicts the Reisha!?
Answer: We must insert the Halachah that Safek Muchan is a Machlokes, and the incident demonstrates R. Gamliel's lenient position regarding Safek Muchan.
(R. Yehudah citing Shmuel): The Halachah does not follow R. Gamliel.
Others learn Shmuel's ruling as applied to the Machlokes between R. Gamliel (who permits Safek Muchan) and R. Yehoshua (who does not permit) and the ruling is in favor of R. Yehoshua.
Others learn Shmuel's ruling as applied to the discussion of taking animals from a trap:
(Tana Kama): One may slaughter animals in a Bibar with water but not from a net or trap.
(R. Shimon b. Elazar): If he found the trap disturbed on Erev Yom Tov he may take the animal, since it surely was trapped before Yom Tov; whereas if he found it disturbed on Yom Tov he may not take it, as it was surely trapped on Yom Tov.
Question: But this is self contradictory, since in the first case we may take it only if we are certain that it was trapped before Yom Tov, yet in the second case it may be taken unless we are certain it was trapped on Yom Tov!?
The statement means to prohibit where we are in doubt as to when it was trapped (i.e. a doubt must be viewed as though it were certainly trapped on Yom Tov whose Halachah is...).
On this Shmuel ruled like R. Shimon b. Elazar.
R. GAMLIEL PERMITS THE FISH
Question: What are they permitted for?
Answer (Rav): They may be received.
Answer (Levi): They may be eaten.
(Rav): My attendance in the Beis Medrash allowed me to know of Rebbi's retraction of the Heter to eat it.
Question: But the Beraisa permits one to receive moist fish and fresh fruit from a Gentile (while they may be received, how can these be eaten, seeing as they were just trapped or picked)!?
Answer: According to your assumption, they cannot be handled either (so that we must be speaking of reddish fish and pickled fruit)!?
Question: Why are these called fresh?
Answer: Because they appear as though they are fresh.
(R. Papa): It is not permitted to receive from a Gentile anything which may have been picked that day (i.e. these items are still attached in the fields), and they are permitted after Yom Tov (Rishon) only after Kedei she'Ya'aseh.
If they are not available in the fields they are permitted.
If they came in from outside the Techum they are prohibited, but only to the Jew for whom they were brought.