Link's Awakening: The Bird Key Location and the Frog's Song of Soul
To get into specific locations in Link's Awakening, you're going to have to trek around Koholint Island. Not everything is straightforward, so you're going to have to wander around the game and explore numerous locations to find ways to progress. An item you're going to need to progress in the game is the Bird Key. Here's how you find it in the game.
The Bird Key's Location in Link's Awakening
Before you can locate the Bird's Key, you're going to need the song the Frog's Song of Soul. You're going to play this on your Ocarina to acquire the key. To find the song you're looking for, you're going to need to visit the Catfish's Maw dungeon to get the Hookshot. Additionally, you're going to need 300 spare rupees on you. Go to Ukuku Prairie, and use the Hookshot to get across the chasm, to Signpost Maze. When you're there, read each sign to progress through the maze. Make sure you're following the signs exactly when you're moving in the maze.
Eventually, you're going to find a staircase to an underground chamber, and you're going to meet Mamu. He's willing to teach you the song, but only for 300 rupees. Pay up, and you're going to acquire the song.
With the song, you want to return to Mabe Village, and go to the weather vein. Push the weather vein aside, and go into the hidden chasm beneath it. You're going to play the song to the skull, resurrecting the rooster. He's going to follow you when you leave. You can warp with him, and you want to go to Dampé's Shack north of your current position. You're looking for the pathway blocked by two boulders, which you can now lift. Lift them and toss them away with your rooster in tow.
You don't want to go to the first ladder on the pathway. Instead, you want the second set. Proceed up the ladder and remove the boulders at the top, and enter the cave. You're now going to enter the Tal Tal Mountain Range. Go through the tunnel, and proceed up the mountain. When you're back on the stream, outside the cave, go to the right and go until you're in the water using your flippers. You're going to see a ladder you can go up, and take your rooster. You want to go inside the first cave entrance you encounter.
The inside of the cave is relatively straightforward. The first room of boulders you enter, you want to go to the entrance to the north. Push the rocks of the way until you can use your Hookshot to get across. In the next room, you're going to need the rooster's help to get across this massive gap. Approach him, and he should let you grab his foot to fly around the corner safely.
At the other side of the platform, you should locate the Bird Key. You're good to proceed to the Eagle's Tower.