Evidence of taxon cycles in an Indo-Pacific passerine bird radiation

Published in Proceedings of the Royal Society B in January 2014, "Evidence of taxon cycles in an Indo-Pacific passerine bird radiation (Aves: Pachycephala)" by Knud Jønsson and co-authors, provides strong evidence of the importance of taxon cycles in shaping the contemporary distribution of passerine birds in the Indo-Pacific.

Species representing new colonizations of island environments tend to disperse rapidly to all islands in a region, while older island taxa become relictual, with isolated populations surviving only on the largest and highest islands of the Indo-Pacific island region. For co-occurring island taxa, the earliest colonists generally inhabit the interior and highest parts of an island, with little spatial overlap with later colonists.

The study included molecular data of 35 out of 40 species of the passerine bird genus Pachycephala (including 54 out of 66 taxa in Pachycephala pectoralis (sensu lato), species distributions, morphology, habitat and elevational ranges. Collectively, the data and analyses support the idea that taxa continuously pass through phases of expansions and contractions (i.e. taxon cycles).

Jønsson KA, Irestedt M, Christidis L, Clegg SM, Holt BG, Fjeldså J (2014) Evidence for taxon-cycles in an Indo-Pacific passerine bird radiation (Aves: Pachycephala). Proceedings of the Royal Society London, Series B 281:1777.