As a result of the blood-letters performing their trade underneath Rav Yosef's small date-palms - ravens, attracted to the spot by the blood, would fly up into the palms and eat the dates.

When Rav Yosef told the blood-letters 'Afiku li Kurkur me'Hacha' he meant that they should move their practice elsewhere. He referred to the ravens as 'Kurkur' - because it resembles the sound that ravens make.

When Abaye queried him on the grounds that ...

... this was no more than G'rama - he cited Rav Tuvi bar Masna's statement 'G'rama be'Nizakin Asur', that we just learned).

... that the blood-letters had a Chazakah, he replied with the statement of Rav Nachman amar Rabah bar Avuhah (that we also learned earlier) 'Ein Chazakah le'Nizakin'.

And when Abaye queried him on the grounds that Rav Mari confined the principle of 'Ein Chazakah le'Nizakin' to smoke, and Rav Z'vid, to that of sight (or smell Rabeinu Gershom) of a bathroom, neither of which are tolerable in the long term - he finally replied that he was finicky and could not stand the blood under his trees, which to him was as disgusting as a bathroom(and not because of the damage to the dates).

One may not place a dovecote within fifty Amos of the town - because this enables the doves to fly into people's vegetable gardens and eat the seeds that are planted there.

And one is obligated to leave a space of at least fifty Amos in every direction around one's dovecote - to prevent them from flying into the surrounding fields and doing the same.

Rebbi Yehudah requires a distance of an area that measures at least four Kurim (which is much larger than fifty Amos) - because that is how far doves fly in one stretch.

In a case where someone purchases an area of only a quarter of a Kav containing a dovecote - Rebbi Yehudah permits the purchaser to leave his dovecote where it is because the previous owner had a Chazakah, which the purchaser bought from him.

The Beraisa forbids spreading nets to catch doves unless it is thirty Ris - (four Mil) from inhabited territory.

Abaye reconciles this with our Mishnah, which requires a distance of only fifty Amah - by differentiating between the thirty Ris distance that a bird can fly without resting, on the one hand, and the fact that it eats its fill within a distance of fifty Amos on the other.

Another Beraisa forbids spreading nets even within a hundred Mil of inhabited territory. Rav Yosef establishes this by an area of vineyards; Rabah establishes it by an area of dovecotes - which give the birds the possibility of resting in a vineyard or in a dovecote along the way.

To explain why it is not intrinsically forbidden to spread the nets on account of the dovecotes themselves, we establish the Beraisa where the dovecotes all belong either to the person spreading the nets or to Nochrim - or where they are Hefker and have no owners.

Rav Papa or Rav Z'vid extrapolates from our Mishnah 've'Im Lakchu Afilu Beis Rova, Harei Hu be'Chezkaso'; 'To'anin le'Loke'ach, ve'To'anin le'Yoresh' with reference to - a Chazakah of three years on land, when Reuven claims that he purchased the land from Shimon and lost the Sh'tar, in which case he is believed provided he can prove that he used the land in question during those three years.

What he then means is that - if Reuven died and Shimon claims that the land currently owned by Reuven's heir or the man who purchased it from him, belongs to him, then we claim on their behalf that the father or the seller purchased it from Shimon.

He extrapolates this from our Mishnah inasmuch as - there too, we are claiming on behalf of the purchaser (or the heir, although the Tana does not mention him) that the seller (or the father) previously had a Chazakah on the dove-cot that is even in a field of a quarter of a Kav, even if others came to protest.

We query Rav Papa's statement 'To'anin le'Yoresh' - that we already know that from a Mishnah in Chezkas ha'Batim 'ha'Ba mishum Yerushah, Eino Tzarich Ta'anah' (since Beis-Din claim on his behalf.

We answer that - we need our Mishnah to teach us that we also claim on behalf the purchaser, which we do not know from there.

We query Rav Papa further in that we also have a Mishnah in Chezkas ha'Batim that teaches 'Lakach Chatzer u'Vah Zizin u'Gezuztera'os, Harei hu be'Chezkasah', and we answer - that we could not have learned 'To'anin le'Loke'ach' ...

... in our case from the Mishnah in Chezkas ha'Batim because there, we might take for granted the seller's rights, either because it is clear that he moved his wall back into his own domain, and that is where the projections were (otherwise, the people in the street would have protested and forced him to remove them), or because their silence proves that they were Mochel him [see Tosfos DH 'Achuli'); whereas a neighbor would not be so easily Mochel (and, were it not for our Mishnah, we would suspect that the seller put up his dovecote without permission).

... in the case in Chezkas ha'Batim from our Mishnah - because even if we assume that the seller's neighbor is Mochel, there is nobody to be Mochel in a public street.

In view of Rav Nachman Amar Rabah bar Avuhah's principle 'Ein Chazakah le'Nizakin', our Tana nevertheless rules 'Harei hu be'Chezkasah' - because Rav Nachman's principle is confined to smoke (Rav Mari) or Beis-ha'Kisei (Rav Z'vid), as we have already learned.

A young dove that one finds within fifty Amos of a dovecote belongs to the owner of the dovecote, whereas one that is found outside fifty Amos - belongs to the finder.

And a bird that is found between two dovecotes, and that is ...

... nearer to one than to the other - belongs to the owner of the dovecote that is nearer.

... equidistant to both - belongs to both owners, who share it.

We learn from the Pasuk ...

... in Mishpatim "Acharei Rabim Lehatos" - that we follow the majority.

... in Shoftim "ve'Hayah ha'Ir ha'Kerovah el he'Chalal" - that we go after whichever is the closest (Karov).

In a case where Rov clashes with Karov Rebbi Chanina gives precedence to - the majority (Rov).

Rebbi Zeira asks on Rebbi Chanina from the Pasuk "ve'Hayah ha'Ir ha'Kerovah el he'Chalal", which (despite the implications that we go after Karov even though there are larger towns than it in the area). We answer that - the Pasuk is speaking specifically when there are no towns larger than it.

We do not go after Ruba de'Alma (the Rov of the world at large), and give it to the finder - because we are speaking about a town which is situated in the mountains, and which is not therefore frequented by residents of towns that are situated elsewhere.

Rebbi Chanina will establish our Mishnah 'Nipul ha'Nimtza be'Toch Chamishim Amah ... ' where there is no larger dovecote beyond fifty Amos.

The problem with the Seifa 'Chutz me'Chamishim Amah, Harei hu shel Motza'ah' is that, if the Tana is speaking where there is no larger dovecote than it, we ought to go after the one that is closest, even if it is outside fifty Amos.

We solve the problem by establishing our Mishnah by 'Mad'dah', meaning that the dove has not yet learned to fly, but gets along by hopping from place to place ...

... and Rav Ukva bar Chama taught that, until a dove learns to fly, it does not hop beyond fifty Amos from its nest.

Consequently as long as it is found within fifty Amos, we cannot go after the majority of the world - since it could not have hopped so far.

But if it is found outside the fifty-Amah limit - it is an indication that it must have reached the stage where it is now able to fly. Consequently, we go after Ruba de'Alma, and it belongs to the finder.

Rebbi Yirmiyah asked what the Din will be if one finds the dove with one foot inside fifty Amos and one foot outside.

His contemporaries, unimpressed with his troublesome She'eilos (see Tosfos DH 've'Al Da') - evicted him from the Beis-Hamedrash.

According to Rebbi Chanina, the continuation of our Mishnah 'Nimtza bein Sh'nei Shovchos, Karov la'Zeh, she'Lo, ve'Karov la'Zeh, she'Lo' speaks where the two dovecotes are exactly the same size (otherwise, we would go after the larger of the two, irrespective of which was closer).

We then ask why we do not follow 'Ruba de'Alma' - assuming that the bird was found beyond fifty Amos (even though we just established the Mishnah by Mad'dah [see Rashash]).

We answer by establishing the Mishnah - by a path in the vineyard. Consequently ...

... it could have hopped beyond fifty Amos from its dovecote, as it tends to do along such a path. It could not however ...

... have come from 'Ruba de'Alma', because even on a path in the vineyard, the bird will only go beyond fifty Amos from its home as long as it can see its nest, but not otherwise.