Invasion history and demographic processes associated with rapid morphological changes in the Red-whiskered bulbul established on tropical islands

The Red-whiskered bulbul is a very successful invasive bird species. Morphological differences have been reported among individuals inhabiting the humid and dry coasts of Reunion Island, in a 30-year-old population. This suggests a capacity for rapid local adaptation which could explain the general invasive success of this species. However, the origin and invasion history of this population is unknown. It is therefore not possible to establish with certainty the cause of these morphological differences. Here, we investigated the invasion history of populations of Red-whiskered bulbul established on Reunion Island, Mauritius and Oahu (three geographically similar tropical islands) to assess the link between invasion history and morphological changes in these populations. We first assessed the source(s) of the invasive populations. We then compared the morphology of the individuals between the invasive and native populations and between the dry and humid coasts of invaded islands. Finally...