How To Beat The Big Bird At Forsaken Fortress:

You have to make it back to Forsaken Fortress with the Master Sword and the Skull Hammer. Once you start to fight the bird you have to run up to the top of the castle without falling down while he's attacking with his beak to the wooden floors. Once your at the top, the bird will fly in front of you. Pull out your hammer and attack his face. He will fly off and your allowed to enter the top of the castle. The door will close and the bird will come down. Dodge his attacks and once he attacks with his beak to the ground and is stuck, hit him with the Skull Hammer in the face. Repeat this 5 times until his mask breaks, revealing his face. He will still attack the same way, but you can now attack him with your Master Sword to finish him off. TIP! To kill him faster, after you get his mask off, instead of attack him with your Master Sword until he dies, attack him twice with your Master Sword and then hit him with your Skull Hammer twice. Repeat this until he is dead. You will recieve a Heart Container and allowed to Ganon's Ship.