“has cast the lot for them.” “Lots” (like dice) were cast to make decisions. In the case of Israel, the High Priest wore a garment with a pocket over the breast and stones were pulled from it to get the decision of Yahweh. In this case, Yahweh Himself is portrayed as casting the lots for the birds as if they cannot do it for themselves (the exact manner God cast the lots is not described and is assumed unimportant). The “them” is feminine and agrees with the birds (the kites) of Isaiah 34:15. In the next line God gives the birds a portion by dividing it with a measuring line. The point God is making is that He has divided up the country of Edom and given it to the wild animals and birds.