36-42 cm, sexes similar. Sooty black in colour with white beak and frontal shield. It runs over the water to take flight. Present throughout the year, with territorial pairs nesting in wetlands of fresh or brackish water with reeds, including many canals and rivers of the lowlands. After the breeding season, it gathers in large flocks in the lagoon, in some valli and at the mouth of the Isonzo.