Arc the Boomerang Bird over the main structure and spin it back into the last part of the second story. The boulder should fall rightward and the entire right side should be cleared. Lob the next Yellow Bird and accelerate just left of the hollow stone square. This should pop all remaining pigs.
In this level, the Moustache Pig on the far right is wearing a mining hat with three lights on it, identical to the one featured in the beginning Mine and Dine cut-scene. The three-light mining hat in the cut-scene is only worn by the King Pig.