1) THE RAVENS IN THE TREES
QUESTION: The Gemara relates that Rav Yosef owned some small date palms, under which some blood-letters practiced their profession. The blood attracted ravens to the area, and the ravens perched themselves upon Rav Yosef's trees. Rav Yosef demanded that the blood-letters leave so that the ravens would go away. The Gemara concludes that even though the damage that the blood-letters caused to Rav Yosef was only indirect ("Gerama"), the Halachah prohibits causing damage even indirectly (through a "Gerama").
This ruling seems to contradict another ruling of the Gemara. The Gemara rules like Rebbi Yosi who maintains that a person may place an object in his own domain even though it might cause damage to someone else's property. The Mazik is not required to distance himself unless the damage is caused by "Girei Dilei" -- by the Mazik "shooting his arrows" into the domain of the Nizak. Why, then, were the blood-letters (the Mazikim) required to move? They certainly did not actively send the ravens to damage Rav Yosef's trees! (RABEINU YONAH, RASHBA)
ANSWERS:
(a) RABEINU YONAH and the RASHBA answer that the blood-letters did cause the ravens to go into Rav Yosef's trees. When the ravens would come to eat the blood, the blood-letters would chase them away and cause them to fly up to Rav Yosef's trees. Hence, the damage caused by the ravens indeed was "Girei Dilei," the "arrows" of the blood-letters, and thus the blood-letters were required to move.
(b) TOSFOS later (26a, DH Aval b'Gefanim, and end of DH Zika) seems to understand that the damage caused by the ravens would have been considered "Girei Dilei" even if the blood-letters did not chase them away. Apparently, Tosfos maintains that the very fact that blood was spilled beneath the trees caused the ravens to come, and thus the damage caused by the ravens was considered "Girei Dilei" of the blood-letters. (See SHI'UREI REBBI SHMUEL, #61.)
(c) The PISKEI HA'RID (cited by OHEL TORAH) writes that in this case, Rebbi Yosi would agree that the blood-letters were required to move even though they did not cause damage through "Girei Dilei." Normally, a Mazik does not have to distance himself because he is in his own domain, and a person is entitled to do whatever he needs to do inside his own domain. In this case, however, the property beneath Rav Yosef's trees did not belong to the blood-letters; rather, it was public property. Therefore, they were not entitled to use that area for any purpose, as it was not part of their private domain. (See BIRKAS SHMUEL 20:3.) (I. Alsheich)
2) HALACHAH: DAMAGES DEPENDENT ON SUBJECTIVE FEELINGS
HALACHAH: The Gemara relates that Rav Yosef owned small date palms, under which some blood-letters practiced their profession. The blood attracted ravens to the area, and the ravens perched themselves upon Rav Yosef's trees. Rav Yosef demanded that the blood-letters leave so that the ravens would go away. The Gemara says that the blood-letters could not claim that they had gained through a Chazakah the right to work there (that is, no one protested when they started to work there, and thus they acquired the right to work there), because there is a principle that "Ein Chazakah l'Nezikin" -- a Chazakah does not work for an activity that causes damage. Even though this principle was said only with regard to activities that cause severe damage (such as setting up something that makes a lot of smoke, or setting up a bathroom), Rav Yosef claimed that he was extremely sensitive and that the damage caused by the blood-letters (either the blood that the ravens splattered around him (TOSFOS), or the loud noise that the ravens made (BI'UR HA'GRA CM 155:116) was to him akin to the damage caused by smoke or a bathroom.
RABEINU YONAH and the RASHBA (see also RABEINU CHANANEL) write that from this Gemara it is apparent that when a person is known to be extremely sensitive to a certain damaging agent and cannot tolerate it, he is entitled to demand that it be moved, and the other person cannot make a Chazakah to continue doing his activity in that place. The activity of a neighbor can be classified as a serious disturbance even if the degree of disturbance is only subjective. (I. Alsheich)

23b----------------------------------------23b

3) RETURNING A PIGEON TO ITS RIGHTFUL OWNER
QUESTION: The Mishnah states that when a person finds a pigeon between two coops, he should assume that the pigeon came from the coop that is closer to it, and he should return the pigeon to the owner of that coop. When a person finds a pigeon between two coops at an equal distance from each coop, the pigeon (or its value) is divided between the owners of the two coops.
The Acharonim ask that dividing the pigeon between the two owners does not seem to be a valid way to resolve the problem. The finder has an obligation to return the pigeon to its rightful owner. The Gemara in Bava Metzia (28a) rules that in a situation in which two opposing claimants both offer proof that a lost object belongs to them, the finder must place the object in escrow until conclusive proof of ownership is brought. The Gemara reasons that since the finder has an obligation to return the object to its rightful owner, he cannot fulfill that obligation by dividing it and giving it to both claimants. Why, then, does the Mishnah here rule that the finder should divide the pigeon and give it to both claimants? (DIVREI CHAIM (Hilchos Kidushin #21), SHA'AREI YOSHER (4:9, 6:14), CHIDUSHEI REBBI SHIMON SHKOP (#8), KOVETZ SHI'URIM, and others)
ANSWERS:
(a) The Acharonim distinguish between the case of the Gemara in Bava Metzia and the case of the Mishnah here. The Gemara in Bava Metzia refers to a case in which a person finds an object and then the claimants offer Simanim and create a doubt as to which of them is the owner. At the time that the object is found, however, neither of them has yet claimed it. Hence, the finder cannot fulfill his obligation to return the object by splitting it between the two claimants. In the case of the Mishnah here, however, the Safek arises before the object enters the finder's possession. Since the pigeon was located at an equal distance from each of the coops, there was already an objective doubt as to who owned it. If the two owners had come to court at that point to claim the ownership of the pigeon, the court certainly would have split the pigeon between them. Therefore, when the finder picks up the pigeon, each of the two claimants is already entitled to take half of it. Thus, the finder is considered to have picked up an object that already belongs to both of the claimants. The finder's obligation is to return the object in accordance with its ownership at the time that he found it. Accordingly, he fulfills his obligation by splitting the pigeon between the two claimants.
(b) REBBI SHIMON SHKOP zt'l in SHA'AREI YOSHER (6:14) answers this question based on a principle that he establishes there: there is no obligation to return a lost object when the owner is present. When the owner is present, an object cannot be considered "lost," and, consequently, the finder is exempt from the obligation of Hashavas Aveidah. Here, since the pigeon certainly belongs to one of the two claimants, there is no obligation of Hashavas Aveidah since the pigeon is not a "lost" object. In any case of money whose ownership is in doubt (where there is a "Derara d'Mamona") the Halachah is that the money is divided between the two claimants. Since the Halachah in this case does not have to take into account the finder's obligation of Hashavas Aveidah, it follows the normal rules of Dinei Mamonos and the object is split between the two claimants.
(c) The KOVETZ SHI'URIM suggests further that in the case of the Gemara in Bava Metzia, in which each of the two claimants presents Simanim to prove that the object is his, the two claimants have two proofs which contradict each other. To divide the object between the two of them would contradict both of the proofs. In contrast, in the case of the Mishnah here, neither claimant brings proof that the pigeon belongs to him. Therefore, to split the pigeon between the two of them would not contradict any proof to the contrary. (The clarifying factor of "Karov" does not apply here, since the pigeon is equally close to each of the coops.) (I. Alsheich)