Evil Eagle

Background
Evil Eagle (アルバトス, Albatoss) is what its name suggests - an evil eagle. The villain who "pilots" this monstrosity is the mini-boss of the same dungeon, Grim Creeper. Up the ladder outside of the tower is the Grim Creeper who will threaten Link before the Eagle flies in and the boss battle begins.

Strategy
Link can block most of the Evil Eagle's attacks using his Mirror Shield. Evil Eagle will fly back and forth across the screen at varying altitudes until you Link hits him in the beak three times with any of the following weapons: the Hookshot, the Boomerang, the Bow, or the Magic Rod. Assuming he's using the Hookshot, Boomerang, or Bow, after three hits Evil Eagle will hover to the side of the tower and either blow wind at Link and shooting little feathers (to combat this, Link should keep his shield up and walk towards the wind), or he will dive at him. If Link falls off the tower, he has to restart the entire battle. The Eagle is defeated with eight hits from the Hookshot and Boomerang, and six from the Bow.

Secret Strategy
The Magic Rod can be used to fight the Eagle, even though it is in Level 8: Turtle Rock. However, Level 7 is not yet finished. Even so, all that is needed is the Shield L-2 (Mirror Shield) and the Frog's Song of Soul (Song 3) to get into Turtle Rock. Once the Shield is retrieved from Level 7, Level 8 is reachable and the Magic Rod obtainable. The Eagle goes down in three hits with the Magic Rod, and will not attack directly if it is used.

Aftermath
Once the Eagle is defeated, Grim Creeper will warn Link that he is in the Wind Fish's dream as well, and a Heart Container and the Organ of Evening Calm are retrieved as a reward.