Genomic tracing of a recent colonization event in the Eurasian Blue Tit

Bird Migration: Genomic tracing of a recent colonization event in the Eurasian Blue Tit

Outline
How seasonal migration can contribute to animal diversification is still a poorly understood issue. A recent publication demonstrated that migratory species are more likely to colonize island environments and undergo speciation than sedentary species. However, the mechanisms that drive migratory individuals to reach these insular environments, stop migrating and establish new populations remain poorly understood, mostly because these are rare events, rarely observable on human time scales. Here, we propose to use the case of the recent colonisation of the island of Ouessant (Western France) by the Eurasian Blue Tit Cyanistes caeruleus to investigate this question.

Aim
The Eurasian Blue Tit is a widespread and common resident breeder throughout Europe. While most populations are sedentary, northern populations regularly exhibit migratory movements. In some years, these movements can become large irruptive movements, reaching western or southern Europe as evidenced by ring recoveries. On the island of Ouessant, the Blue Tit had been absent since the first ornithologists visited in the 1960s, despite the presence of breeding populations on the mainland, just 25km away. After two major autumnal influxes in Western Europe in 2008-2009, the species started to breed on the island. This project aims to determine if the island was colonized by irruptive migrants from distant migratory populations rather than by birds from the nearest population. To do so, we will compare whole-genomic sequences of Blue Tits from Ouessant and different populations across Europe to identify the geographic origins of these pioneering individuals.

Project details
This Master’s project is a desk-based data analysis. Sequencing data will already have been produced for the student’s arrival. The student will be responsible for managing and analyzing genomic data. Based on the initial results obtained, the student will be in charge of testing different genetic assignment methods to find the most appropriate one. The project is expected to lead to the writing of a scientific publication in which the student will participate.

Requirements
We are looking for a student with an interest in genetic and bird migration. Previous experience with handling genomic data will be extremely valuable. The start date will be January 2026 or later (open to discussion).

Supervisors
The student will be part of the Migration Research Unit at the Swiss Ornithological Institute and will be supervised by Paul Dufour. The student will also receive additional support from project researchers both within and outside the institute (Anne Charmantier, Barbara Helm and Reto Burri).

For questions, please contact Paul Dufour: paul.dufour@vogelwarte.ch or paul.dufour80@gmail.com