FIRST RECORD OF A WHITE-TAILED BROWN MORPH RED-FOOTED BOOBY SULA SULA ON CHRISTMAS ISLAND, INDIAN OCEAN

摘要

The Red-footed Booby Sula sula is an abundant and widely distributed tropical seabird (Nelson 1978, Harrison 1985, del Hoyo et al. 1992). It breeds in tropical waters around the globe in large numbers, but is absent from the eastern tropical Atlantic. The species is considered to be one of the most polymorphic seabirds with respect to plumage colour (Le Corre 1999), with three recognized major adult plumage types (white, white-tailed brown, brown) and several intermediates, including golden white, blacktailed white, and white-headed white-tailed brown (Nelson 1978, Del Hoyo et al. 1992). Although the genetic basis of the polymorphism in this species has been identified (Bai鉶 et al. 2007), the processes and factors underlying the distribution of the various morphs are not fully understood (Le Corre 1999, Steeves et al. 2003, Bai鉶 et al. 2007). Some of the morphs overlap in their distribution and can interbreed (e.g. white and white-tailed brown morphs in the Caribbean, Atlantic Ocean and Western Indian Ocean), whereas some morphs occur only in restricted areas of the species?distribution. For example, the blacktailed white morph is found only on Galapagos (Nelson 1978, Del Hoyo et al. 1992, Le Corre 1999, Baiao et al. 2007).