Conservation status

Small isolated populations, particularly on islands, are under threat of extinction from the disappearance of habitats. Two recently Extinct species are both insular species: the robust white-eye, Zosterops strenuus, of Lord Howe Island became extinct between 1919 and 1938 as a result of predation by ship rats, which became abundant on the island and caused extinction of 14 endemic forms of birds on the island, and the white-chested white-eye, Z. albogularis, of Norfolk Island, which has not been seen since 1980 and is now considered extinct as a result of habitat destruction. Of six other species, which are Critically Endangered, four are on the islands of Comoro, Mauritius, Seychelles, and Mariana, and two are known from the mountains of Kenya. One species Endangered is an island species (Truk Islands), and 14 considered

Vulnerable are also mostly island birds. Population viability analysis of island birds shows that they are at risk of extinction in one hundred years even without destruction of habitats, if mortality increases greatly as a result of introduction of new predators or frequent severe storms. For example, the golden white-eye, Cleptornis marchei, of Northern Mariana Islands was very common until the brown tree snake, Boiga irregularis, was introduced to Saipan in early 1990s. This white-eye species is now nearly extinct.

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