The Scarecrow Song is an optional ocarina melody that can be used to summon a scarecrow in certain spots and use it as a hookshot target, allowing you to reach new chests, heart pieces, gold skulltulas, etc..
Step #1 - Creating the song
First, you'll have to create the Scarecrow Song. This can be done by talking to the scarecrow "Bonoru" as child Link. He stands to the northeast of Lake Hylia, right in front of you when you enter the area from Hyrule Field.
Take out the ocarina in front of Bonoru and make up a song by playing any 8 notes. The only requirement is to use at least two different notes. Create your custom song and remember it: you'll have to play it later.
Step #2 - Learning the song
Once you have made the song with Bonoru as child Link, you need to return to Bonoru as adult Link and play the song you made in front of him. This will save the custom melody as the Scarecrow Song in your songbook.
