Remains of Land Birds from Lisianski Island, with Observations on the Terrestrial Avifauna of the Northwestern Hawaiian Islands

Abstract

Early nineteenth-century accounts suggest that there were ducks and rails on Lisianski Island, although neither were present in 1891 when the first ornithological collector visited the island. Excavations and surface searches on the island in 1990 uncovered numerous bones of the Laysan Duck (Anas laysanensis Rothschild), indicating that there once was a resident population. A single coracoid of a small rail (Porzana) probably came from one of the 45 individuals of Laysan Rail (P. palmeri Frohawk) that were introduced in 1913 and quickly died out, because no further evidence of rails or other land birds was found. Extinction of the duck may have been due to predation by survivors of mid-nineteenth-century shipwrecks and possibly to competition for food from introduced House Mice (Mus musculus Linnaeus). The land birds of the Northwestern Hawaiian Islands were derived partly from Asia and partly from species that were formerly widespread in the lowlands of the main Hawaiian Islands. They are not, therefore, a collection of ancient relicts of a montane biota as has been hypothesized. The terrestrial avifauna of Nihoa is depauperate even for an island of its size and may have suffered prehistoric human-caused extinctions.