From the Super Mario Wiki, the Mario encyclopedia
Swooper Doopers are avian enemies appearing in Donkey Kong Country: Tropical Freeze. They resemble white flamingos with red feathers on their small wings and tails. They wear a tribal mask, accompanied by a crown of red feathers which is arched around their head. Their name is a pun on the phrase "super-duper", a colloquial phrase that describes something as very great.
As their name suggests, Swooper Doopers attack by swooping repeatedly from side to side. Swooper Doopers can injure the Kongs by flying into them, causing the Kongs to lose a heart point. Swooper Doopers can be defeated in any manner, including a jump attack, a roll attack, throwing an object, or with Rambi the Rhino. By jumping on a Swooper Dooper, the Kongs can get a height boost into the air.
Swooper Doopers are one of the enemies that is native to Bright Savannah. They appear in every level of the world except Twilight Terror and Triple Trouble. Swooper Doopers only appear in the background of Cannon Canyon, with one of them standing on a cliff and observing the Kongs shooting from a Barrel Cannon.