60-70 cm, the male with black and white plumage. A permanent population lives between the mouth of the Isonzo and that of the Timavo. Some pairs have nested regularly since 1999 which is a unique event in the Mediterranean, together with a site in Liguria. For resting, feeding, moulting its summer plumage and the rearing of offspring, the presence of the mussel farm at the mouth of the Timavo is essential; up to 80 individuals may be seen here.