They have white undertail feathers that are seen when swimming or during their courtship displays. They have a variety of chicken-like calls. Coots are found in fresh and saltwater marshes and ponds. They travel long distances when ponds are dry and are known to fly between islands. The Hawaiian Coot builds floating nests in aquatic vegetation all year round.
Adults defend their nests vigorously.
Three to ten eggs are usually laid and the incubation period is from 23 to 27 days. Chicks have black down, except on the head, neck and throat, where the down is reddish-orange. They can leave the nest soon after hatching. The Hawaiian Coot eats seeds and leaves of aquatic plants, insects, tadpoles, and small fish. There are no records of how many Coots were around before the 1950s.