The order Passeriformes (''perching birds'') comprises extant species diversity comparable to that of living mammals. For over a decade, a single phylogenetic hypothesis based on DNA-DNA hybridization has provided the primary framework for numerous comparative analyses of passerine ecological and behavioral evolution and for tests of the causal factors accounting for rapid radiations within the group. We report here a strongly supported phylogenetic tree based on two single-copy nuclear gene sequences for the most complete sampling of passerine families to date. This tree is incongruent with that derived from DNA-DNA hybridization, with half of the nodes from the latter in conflict and over a third of the conflicts significant as assessed under maximum likelihood. Our historical framework suggests multiple waves of passerine dispersal from Australasia into Eurasia, Africa, and the New World, commencing as early as the Eocene, essentially reversing the classical scenario of oscine biogeography. The revised history implied by these data will require reassessment of comparative analyses of passerine diversification and adaptation.M ajor lineages of the Ϸ5,739 species of passerine birds (1) have diversified on all continents and now occupy nearly all terrestrial ecosystems. The songbirds (oscines, suborder Passeri) alone comprise nearly half of all extant avian species and represent the largest identifiable radiation of birds (2), encompassing a staggering ecological and behavioral diversity. The foundation for understanding passerine diversification and for integrating the spatial, ecological, and temporal history of the group is a comprehensive and robust phylogenetic hypothesis. A decade ago, in a pioneering work, Sibley and Ahlquist (3) used DNA-DNA hybridization to produce the first large-scale phylogenetic hypothesis for passerine birds and suggested a specific temporal history for passerine diversification. Despite oftenvoiced concerns about the robustness of this phylogeny (colloquially termed the ''Tapestry'' after its appearance on the wall at an ornithological meeting), it has provided a framework for numerous historical analyses of passerine ecology (4), behavior (5), and diversification (6, 7), and continues to fuel the search for explanations of passerine diversity (8).Recently, studies have begun to contradict aspects of the DNA hybridization hypothesis for passerines (ref. 9; citations in ref. 10). These investigations, however, used relatively short gene sequences and, more importantly, limited taxon sampling across passerines; thus the phylogenetic, biogeographic, and temporal interpretations of the radiation were incomplete, and broad tests of the DNA hybridization tree were not possible. Here we analyze 4,126 aligned positions of the nuclear genes RAG-1 and -2 from 144 passerine species in 45 families, including representatives of all but one family recognized by current taxonomy (1). We find substantial support for many portions of the passerine tree, as well as quantitative evidence for the re...

Pleistocene climate fluctuations shaped the patterns of genetic diversity observed in extant species. In contrast to Europe and North America where the effects of recent glacial cycles on genetic diversity have been well studied, the genetic legacy of the Late Pleistocene for East Asia, a region of great topographical complexity and presumably milder historical climate, remains poorly understood. We analysed 3.86 kb of the mitochondrial genome of 186 Chinese Hwamei birds, Leucodioptron canorum canorum, and found that contrary to the conventional expectation of population decline during cold periods (stadials), the demographic history of this species shows continuous population growth since the penultimate glacial period (about 170,000 years ago). Refugia were identified in the south, coastal regions, and northern inland areas, implying that topographic complexity played a substantial role in providing suitable habitats for the Chinese Hwamei during cold periods. Intermittent gene flow between these refugia during the warmer periods (interstadials) might have resulted in a large effective population of this bird through the last glacial period.

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