Moult location and diet of auks in the North Sea inferred from coupled light-based and isotope-based geolocation

St John Glew, Katie; Wanless, Sarah ORCID: https://orcid.org/0000-0002-2788-4606; Harris, Michael P. ORCID: https://orcid.org/0000-0002-9559-5830; Daunt, Francis ORCID: https://orcid.org/0000-0003-4638-3388; Erikstad, Kjell Einar; Strøm, Hallvard; Trueman, Clive N.. 2018 Moult location and diet of auks in the North Sea inferred from coupled light-based and isotope-based geolocation. Marine Ecology Progress Series, 599. 239-251. https://doi.org/10.3354/meps12624

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Abstract/Summary

Many pelagic seabirds moult their feathers while at sea, which is an energetically costly behaviour. Mortality rates during moult can be high, so spatial and trophic ecology during this critical period is important for understanding demographic patterns. Unfortunately, individual foraging behaviours specifically linked to at-sea moulting are commonly unclear. This paper combines 2 different approaches to geolocation: data from bird-borne geolocation loggers and stable-isotope assignment using carbon and nitrogen isotope maps (isoscapes). Coupling 2 geolocation processes allows some uncertainties associated with isotope-based assignment to be constrained. We applied this approach to quantify species-specific foraging locations and individual trophic variability during feather regrowth in 3 sympatric auk populations breeding on the Isle of May, Scotland (common guillemot Uria aalge, razorbill Alca torda and Atlantic puffin Fratercula arctica). Inferred foraging areas during moult differed between species and feather types. Guillemots likely underwent moult within the southern North Sea, razorbills along the east coast of England and into the southern North Sea and puffins off the east coast of Scotland. Estimates of individual trophic position varied considerably within feather types (up to 1 trophic level difference between individuals), among feather types grown during different time periods and across the 3 species, with guillemots consistently foraging at higher trophic positions than razorbills and puffins. Used in combination, these methods better constrain foraging areas during moulting, and provide a technique to explore individual differences and flexibility in foraging strategy, which is valuable information for both seabird conservation and marine spatial planning.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.3354/meps12624
UKCEH and CEH Sections/Science Areas:	Biodiversity (Science Area 2017-) UKCEH Fellows
ISSN:	0171-8630
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	isoscape, trophic ecology, foraging, moult, Atlantic puffin, common guillemot, razorbill
NORA Subject Terms:	Ecology and Environment
Date made live:	18 Jul 2018 09:45 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/520561

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