The Orange River mouth (ORM), at the end of the longest river in South Africa, is one of few perennial wetlands on the arid south-west African coast. The ORM supports a large number of waterbirds, with a maximum of 20 653-26 653 individuals of 57 species being recorded in December 1985. Because of its importance for waterbirds, the ORM is recognised as a Ramsar site and an Important Bird Area. Since being designated a Ramsar site in 1991, however, the number of waterbirds has decreased (by c. 74% since the first two surveys in 1980 and 1985).