The question of how species arise is central to evolutionary biology. It is also a question of ongoing debate, ever since Darwin’s

Profiles of the four Nesospiza finch taxa of Tristan da Cunha. Photos: Peter Ryan

On the Origin of Species (1859) until modern day. I am interested in broad aspects of different modes of speciation, and I am particularly interested in how speciation may happen on isolated oceanic islands, where the room for physical isolation between the diverging lineages is limited. My PhD thesis work was on a single theme, but I used several different study systems that cover different aspects of speciation:

• Ecological speciation in the Nesospiza finches of the remote Tristan da Cunha islands in the South Atlantic
• Sympatric speciation vs. double colonization and hybridization in Gulf of Guinea seedeaters
• Complex evolutionary history and colonization patterns in Afro-Canarian blue tits
• Phylogeny, taxonomy, and distribution of Calandrella larks

As tools for understanding the evolutionary history I use traditional molecular methods such as DNA sequencing of individual genes, as well as the high throughput sequencing techniques which have recently revolutionized genetic analyses. This “next generation” sequencing is driving the field of genetics toward genomics, enabling analyses of genome-wide patterns.

I am finishing up the two largest studies from my thesis work (the two finch systems above), and in addition I am involved in phylogenetic/phylogenomic studies on a range of birds: rails, storm-petrels, coal tits, sylviid warblers, and the whole order of Passeriformes.