Data from: 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, we
inferred the invasion history of the invasive populations to investigate
the role of neutral processes (e.g. founder effect and drift) on
morphology. We found that the invasive populations have a similar origin
and that the morphology of the individuals in these populations has
diverged in a similar way from the native range, suggesting a convergent
adaptation to tropical islands. Like on Reunion, we found differences in
morphology between the dry and humid coasts on Mauritius. These
morphological differences can be explained by invasion history on Reunion
but not on Mauritius. Both neutral evolution and adaptation thus shape the
morphology of invasive Red-whiskered bulbuls.