From the Super Mario Wiki, the Mario encyclopedia
Bumber 'Chutes are umbrellas in Yoshi's Story. Yoshis will usually get the opportunity to obtain them when atop a large cliff. The chute will allow them to glide, thus also allowing him to collect floating Heart Coins and fruit. The player uses the control stick to control the direction the chute falls. When Yoshi reaches the bottom of the cliff, the chute is dropped.