Reference for Bava Batra 45:6

רבא אמר בישוב שובכין ותיפוק ליה משום שובכין גופייהו איבעית אימא דידיה ואיבעית אימא דכנעני ואיבעית אימא דהפקר:

— Abaye replied: pigeons cover much ground. but they eat their fill within fifty cubits of their starting point. And do they fly no further than thirty <i>ris</i>?<span class="x" onmousemove="('comment',' This question has reference to the rule about snares, not to the rule about dovecotes. ');">⁹</span> Has it not been taught: 'Where there are towns and villages. nets should not be spread even within a hundred miles'? — R. Joseph said: This means, where there is a succession of vineyards;<span class="x" onmousemove="('comment',' So that the birds can fly from one to another. ');">¹⁰</span>

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