Desert Island - 3

Strategy
Tip: If the birds' health are completely full and there is only Cactus Knight on the battlefield, attack immediately with Matilda. The Cactus Knight will negate (as of 1.2.3, now the Knight will take damage and receive the poison effect) but she still fills the Rage Chili 5% more.

Warning: The Cactus Knight may activate "Reflect" which all enemies attacking the target receiving 34 damage per attack for three turns. Use The Blues in Tricksters so you can dispel every single Pig on the battlefield that received "Reflect".

Choose Matilda in Druid, Bomb in Pirate and The Blues in Tricksters. Use Matilda's secondary skill (one turn each) when the Birds' health isn't full, otherwise, attack with her every turn. Then attack every turn with Bomb, and The Blues (Desert Pigs first, then Cactus Knight). Remember, you will have to use The Blues' secondary skill if all of the birds have at least a single harmful effect. Give the Rage Chili to either Matilda or The Blues when it is full. Repeat this over until you win or lose.

In Summary:
Cactus Knight's primary attack can cause the birds to receive the status effect, and Desert Pigs can lower their attack power. The Blues will prove useful in this level, so bring them to the battle.