Answer:
Both the Birds and the Beasts realized the Bat's betrayed them, so they refused to accept the Bat in their group.
Explanation:
Since the bat was afraid of fighting, he wanted to join both the group of the Birds and the group of the Beasts, even though he could belong in one only. By joining both, he betrayed both groups, and when peace was made between the groups, no one wanted to accept the traitor bat. The moral of the story is that the deceitful have no friends.