Diversity of migration in European Blackcaps
The Ornithology cluster at the University of Hull has received a Small Research Grant from the British Ecological Society, to study the diversity of migratory routes of Blackcaps within the UK. The UK sits at a convergence of several migration 'flyways' - i.e. major routes taken by many different species. This means that there are often incoming and outgoing migrants of the same species, at the same time.
Over the past 50 years, the European blackcap (Sylvia atricapilla), a species that typically overwinters in the southern Mediterranean or north Africa, has started to regularly overwinter in the United Kingdom, having rapidly evolved a new migratory route from mainland Europe.
Thought to be related to warmer wintering temperatures in the UK, this divergence northwest from a typical south-easterly or south-westerly route has been picked up by ringing recoveries and, more recently, geolocators. This rapid change in migration route may lead to novel phenotypes, i.e. traits; here, referring to their migratory tendancies.
The use of different migratory routes could influence the demography (i.e. survival, reproduction) of different populations, with a temporal difference between inward and outward migrating birds influencing what conditions they experience.
This project will use recently-developed miniature VHF tags, deployed onto migrating blackcaps at bird observatories on the east coast of the UK.
There are 4 main research questions:
What is the diversity of migratory directions of blackcaps caught at coastal sites in the UK during spring and autumn?
What are the origins of these birds?
Are there phenotypic differences visible using morphometrics that might indicate support rapid migratory microevolution?
Do any differences between spring and autumn phenotypes indicate existence of a non-viable subset of phenotypes that might be selected for under future environmental change?
In combination with stable isotopes (from feathers collected from birds), and morphological measurements, departure direction data can further our understanding of microevolution of migration under selection from environmental change.
This work is being led by Dr Lucy Mitchell, alongside the British Trust for Ornithology, and we are hoping to start in spring 2021, COVID permitting.