In a recently accepted paper in Molecular Ecology, we conclude that blue tits have colonised the Canary Islands from Africa no less than three times, but contrary to recent suggestions they did not back colonise mainland Africa from the islands. We combined traditional DNA sequencing on a large scale with massively parallel sequencing (“next generation sequencing”) and combine their respective strengths.
A demographic reconstruction reveals that the populations on the eastern Canary Islands Fuerteventura and Lanzarote have undergone recent population bottlenecks, while the long-term population sizes in northwest Africa have been stable, clearly supporting that the mainland populations have acted as a source for the colonisation of Fuerteventura and Lanzarote, and not the other way around.
The phylogenetic relationships between the blue tit populations of the Canary Islands are truly intricate. Continue reading