American Purple Gallinule

Swims on surface of water like a duck and walks on floating plants rather like a chicken.
Dark purple head, neck, and underside.
Green back.
Red bill tipped with yellow.
Light blue forehead.
Bill triangular like a chicken's, not flat like a duck's.
Legs yellow.
Downy chick is black. Juvenile is buffy tan instead of purple, with greenish back, dull bill, dull blue frontal shield, and yellow legs.