פירוש על עבודה זרה 84:5

Yohanan says that the baraita refers to a bird that is assumed to have brought the twigs for the nest from another tree, not the tree in which the nest was found. This helps explain the whole baraita better. If the tree has been dedicated to the Temple, then he should not use the nest lest the twigs might have come from the tree. But it does not count as “trespass” because the twigs did not certainly come from that tree. But if the twigs did certainly come from that tree, then using them should certainly count as trespass.