To view PDF files. The adult males tend to have a darker head and neck with greenish head and olive-colored bill. Both sexes have orange legs and feet.
Females have a dull orange bill.
Their quack is a little softer than the Mallard, and Koloa are not as vocal. Hawaiian ducks can be found in lowland wetlands, river valleys, and mountain streams. They are cautious ducks that travel in pairs. Koloa eat mollusks, insects, and freshwater vegetation. May. Two to ten eggs are laid in a well-concealed nest lined with down and feathers.