Golden Feather

The Golden Feather is the spoil of the Pea Hat and the Kargarok in The Legend of Zelda: The Wind Waker. If 20 of these are given to the Rito soldier on the second floor of Dragon Roost Island, who wants to give them to his girlfriend as a gift, he will give Link a "Thank You" letter and eventually a letter with a Heart Piece inside in return.

The Legend of Zelda: Phantom Hourglass
These feathers make an appearance as a treasure in Phantom Hourglass as Helmaroc Plumes. Described as flamboyant feathers dropped by Helmaroc Birds, they can be sold on Mercay Island to the Teller of Treasures for a fixed, random price.