Birds of the Torres Strait: an annotated list and biogeographical analysis

Abstract

Two hundred and forty-three species of birds have been recorded from the Torres Strait. Of these 87 are resident and breed on the islands, 26 remain for the wet or dry season only, 73 cross the Strait on a regular or irregular basis and 57 are vagrant visitors or await confirmation.

The number of land bird species found on islands is more a function of the area of forest or woodland than of the total area of the island. Both oceanic and land bridge islands are present in the Torres Strait. Some species found on land bridge islands appear to have been stranded there when sea levels rose. The ranges of some birds found only on land bridge islands are mutually exclusive of several wide ranging species found on most other islands., Evidence is presented that competition has determined the nature of the avifauna on some Torres Strait islands.

The Torres Strait apparently represents a barrier to the movements of 28% of the species, including 38% of the land birds, that are shared by Australia and New Guinea. Many populations of Australian birds cannot, therefore, be replenished from New Guinea.

Nearly half the birds seen in the Torres Strait are migratory. The most numerous Palaearctic passage migrants are the Mongolian Plover and the Grey-tailed Tattler. Many passage migrants breed in Australia and over-winter in New Guinea. Half of these cross the Strait at low altitudes and several appear to need the Torres Strait islands as resting places, especially when travelling south into the prevailing adverse trade winds. Seven migrants breed on Torres Strait islands.

Human effects on the avifauna are localised although introduced species, the House Sparrow and the Common Mynah, have become resident on three islands within the last four years. Apart from these introductions, the avifauna of only Murray Island changed naturally during the study period between 1977 and 1982.