Diversity of migration in European Blackcaps
January 2021
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.
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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.
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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.
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There are 4 main research questions:
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What is the diversity of migratory directions of blackcaps caught at coastal sites in the UK during spring and autumn?
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What are the origins of these birds?
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Are there phenotypic differences visible using morphometrics that might indicate support rapid migratory microevolution?
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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?
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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.
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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.