One may eat based upon [availability in] abandoned [areas], but not upon [availability in] protected [areas]. R’ Yose permits [consumption] based even upon [the availability in] protected areas. One may eat based upon [the availability in] birdhouses, and upon the second crop, but not based upon [the availability of] the winter crop. R’ Yehudah permits as long as they have begun ripening before the end of the summer.