The Legend of Zelda: Majora's Mask/Great Bay Coast

With the ability to use powder kegs, you can now head to the ranch in the south-west corner by blowing up the boulder on the first day.

Great Bay
After getting Epona, head to the Great Bay to the west.

Mikau is located floating in the ocean. He is the guitarist. He mentions that the lead vocalist in the band has laid some eggs, and that Gerudo Piates have stolen them.

Use the song of healing to obtain the Zora mask.

Places of interest

 * The ranch brothers in the south east corner will race you if you get a horse. Try to stay on the inside (right) portion of the track, even if it appears that you would run into a fence.  As a reward