Bird Clothes is a suit that can be equipped to gain the ability to glide for a couple seconds. The gliding effect is automatically whenever Tomba jumps or falls off a platform. It has a pair of wings attached to its back.
It is obtained from the fisherman in the Waterfall of Heavens by clearing The Stuck Fishhook Line event. Later in the game, Tomba will gain the Flying Squirrel Suit in the The Hidden Diary! event that allows him to glide without any limitations.