Seasonal Occurrence of Members of the Suborder Charadrii (Waders or Shorebirds) on Rottnest Island, Western-Australia

Abstract

Rottnest I., 1900 ha in area and 18 km off the Swan Coastal Plain, has 32 km of coast and 10% of its area consisting of a complex of hypersaline lakes and brackish swamps. The Charadrii (waders or shorebirds) using these habitats were censused between December 1981 and October 1984, and the results of these censuses were compared with data collected between 1953 and 1962. Twenty-two species of wader occurred on the island between 1981 and 1984; of these, four bred on the island, nine were regular migrants (eight being transequatorial) and nine (eight transequatorial) were rare. There were several changes in status between the earlier and later surveys: the eastern golden plover, large-billed dotterel and sharp-tailed sandpiper were all regular visitors in the 1950s but were rare or absent in the 1980s; the pied oystercatcher had become more common on the island; the red-necked avocet, formerly rare, had started breeding on the island; and the grey-tailed tattler and bar-tailed godwit had become regular migrants in small numbers. The effects of loss of suitable habitat on the adjacent mainland, and the importance of the island as a conservation area, are discussed.