REPRODUCTIVE ECOLOGY OF THE BLACK-NECKED SWAN CYGNUS MELANCORYPHUS IN A MARINE WETLAND OF SOUTHERN CHILE

The Black-necked Swan Cygnus melancoryphus is an endangered species in Chile. After the Rio Cruces ecological disaster in Valdivia in 2004 (due to installation of a new pulp mill), the Black-necked Swans that survived were mostly dispersed to marine wetlands of the large island of Chiloe, passing from continental wetlands to the marine environment. The objectives of this study were to provide the first observations of nesting Black-necked Swans in the marine wetland of Chiloe Island, and to identify factors that may affect the survival of their cygnets. Our study was carried out in Caulin Bay (41 degrees 49'S; 073 degrees 38'W), Chiloe Island, during austral winter and spring of 2011 and 2014. During both years, the Black-necked Swan nested in different sectors of Caulin Bay. The construction of nests began in mid-July, and the first hatchings were recorded in September. In 2011, 23 nests were found in the stone promontories sector and 39 nests were found at Lacaos Island. In 2014, the Black-necked Swan, nesting only in Lacaos Island, occupied 47 nests. We discuss the need to evaluate potential factors that affect the survival of this species' cygnets in the marine wetland of Caulin Bay.