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

K St John Glew,Ke Erikstad,F Daunt,S Wanless,Mp Harris,Cn Trueman,H Strøm

doi:10.3354/meps12624

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 599:239-251 (2018) - DOI: https://doi.org/10.3354/meps12624 Moult location and diet of auks in the North Sea inferred from coupled light-based and isotope-based geolocation Katie St. John Glew1,*, Sarah Wanless2, Michael P. Harris2, Francis Daunt2, Kjell Einar Erikstad3,4, Hallvard Strøm5, Clive N. Trueman1 1Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton SO143ZH, UK 2Centre for Ecology & Hydrology, Bush Estate, Penicuik EH26 0QB, UK 3Norwegian Institute for Nature Research, Fram Centre, 9296 Tromsø, Norway 4Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway 5Norwegian Polar Institute, Fram Centre, Postbox 6606 Langnes, 9296 Tromsø, Norway *Corresponding author: katie.stjohnglew@soton.ac.uk ABSTRACT: 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. KEY WORDS: Isoscape · Trophic ecology · Foraging · Moult · Atlantic puffin · Common guillemot · Razorbill Full text in pdf format PreviousNextCite this article as: St John Glew K, Wanless S, Harris MP, Daunt F, Erikstad KE, Strøm H, Trueman CN (2018) Moult location and diet of auks in the North Sea inferred from coupled light-based and isotope-based geolocation. Mar Ecol Prog Ser 599:239-251. https://doi.org/10.3354/meps12624 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 599. Online publication date: July 12, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

Highlights

The widespread use of miniaturised, ring-mounted data loggers that use light levels in conjunction with a time base to provide positional data, has greatly increased our knowledge of important foraging grounds for pelagic seabirds
Mar Ecol Prog Ser 599: 239–251, 2018 and potentially has major fitness consequences because flight feathers are crucial for long-distance migration, while body feathers play an important role in thermoregulation, for diving species (Daunt et al 2006)
Given the increasing pressures on the marine environment from multiple anthropogenic activities, quantification of foraging location and diet whilst birds are moulting is urgently required for effective conservation and marine spatial planning (Grecian et al 2010, Lewison et al 2012, JNCC 2015, MMO 2015)

Summary

Introduction

The widespread use of miniaturised, ring-mounted data loggers that use light levels in conjunction with a time base to provide positional data, has greatly increased our knowledge of important foraging grounds for pelagic seabirds. There is typically one period of the non-breeding season lasting a few weeks when moulting of flight feathers is focussed, known as the main feather moult. At this time, individuals have fewer foraging options, making them less able to cope with adverse environmental conditions or reduced prey availability (Sandvik et al 2005, Harris et al 2014). Given the increasing pressures on the marine environment from multiple anthropogenic activities, quantification of foraging location and diet whilst birds are moulting is urgently required for effective conservation and marine spatial planning (Grecian et al 2010, Lewison et al 2012, JNCC 2015, MMO 2015)

Methods

Results

Discussion

Conclusion