Wren Tactic: Swarm in numbers and take supply.
Mocking Bird Tactic: Repel enemy and save supply.
Blue Bird Tactic: Hover on rim and glut supply.
OBSERVATION OF BATTLE STRATEGY:
Wren: Acceptable success.
Mocking Bird: Hungry loser.
Blue Bird: Decisive winner.
Addendum: Sudden presence of squirrel stalls all avian battle.