Reference for Kiddushin 146:2

תלי בדיקלי אי מטיא ליה חיה יש בו משום אסופי אם לאו אין בו משום אסופי

he is not considered a foundling. If he is suspended on a palm tree, if a wild beast can reach him, he is [forbidden] as a foundling;<span class="x" onmousemove="('comment',' Were he legitimate, his parents would have taken greater care of him.');">³</span> if not, he is not considered a foundling.

Jastrow