From the Super Mario Wiki
Stilts are birds that appear in the game Donkey Kong Country Returns and Donkey Kong Country Returns 3D. They are turkey-like enemies with white and yellow plumage that usually appear walking over a pair of bamboo stems like stilts and are only present in the Ruins area. Stilts are vulnerable to Barrel Rolls and can be Jumped on. After this, the enemy loses the stilts and remains without feathers while it runs about in a frantic pace. The Kongs must hit the bird again to defeat it. Stilts rarely appear in this state as well. Additionally, they can be instantly defeated by throwing a Barrel at them.