Project aims & key species
Yellow-browed warbler in the hand with Motus NanoTag. © Thiemo Karwinkel.
"Yellow-browed Warbler_5970" by Eugene Archer is licensed under CC BY-NC 2.0
Whilst Motus tags can be used on almost any species of bird and bat, there are several key groups of species that we are interested in, which include threatened and declining Afro-Palearctic migrants, also a priority for the UK's major bird research organisations.
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Departure directions of incoming and outgoing migrants
This work is a collaboration between the University of Hull, the Bird Observatories in the UK and the British Trust for Orntihology (BTO).
Using the expanding receiver network in the UK, this project aims to study the depature directions and timings of incoming and outgoing migrating species, such as Sylvia and Phylloscopus warblers, pipits and chats. This includes Siberian vagrants, such as Yellow-browed warbler (P. inornatus) and Pallas’ warbler (P. progregulus), carrying on work begun by Thorup in 2011/2012 on the Faroes, and Hewson and others in 2017 in Cornwall.
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Vagrants are birds that have dispersed farther than 90% of the population (Veit, 2000). The Siberian-breeding Yellow-browed warbler is one of our more well-known vagrants, having increased in number in past decades (De Juana 2008), and represents a notable case of potential ‘reverse’ migration.
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By observing the departure directions of migrant Yellow-browed warbler entering the UK on the east and southeast coastlines, we can further understand their onward journey and infer the mechanisms behind their vagrancy.
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Using Motus receivers and uniquely-coded NanoTags, we can record departure directions and times, assess residency time close to the receivers and therefore test some hypotheses related to vagrant movements, climate change and evolution. We can correlate and assess the influence of weather variables, and draw conclusions about wind drift compensation, and increasing rates of reverse and exploratory migration.
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To compare behaviour between incoming and outgoing migrants species, we will deploy NanoTags onto other afro-palearctic migrants such as departing Sylvia warblers, stonechat, meadow pipit and wheatear. These species breed throughout the UK and return to winter in southern Europe and Africa, thus we would be deploying tags during their southbound migration, as a complement to the YB warblers. Increasingly we are seeing the development of partial migration and/or overwintering; departure direction information can also provide better understanding of species movements and timings related to ecological barrier crossing.
"IMG_5293" by dmoon10751 licensed under CC BY-NC 2.0
Once the receiver network has expanded, we will be able to address numerous questions relating to other groups of species. There are several areas that we wish to expand into:
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Post-juvenile movements, dispersal and departure decisions of hirundines, nightjars and turtle doves.
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Swallows, swifts and house martins are ubiquitous, but under threat from factors affecting many of our afro-palearctic migrants, such as climate change, breeding and wintering habitat loss. We still don't know enough about how these small migrants are impacted by global, regional and national threats, but obtaining information on their post-juvenile movements and migration, can help us to understand how things are changing, and where conservation actions might be most useful.
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"Bird trails" by edu aguilera is licensed under CC BY-NC 2.0