Individual specialization in the foraging and feeding strategies of seabirds: a review
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Trophic relationships are a central theme in ecology and play a crucial role in the survival of organisms, because the availability of food resources varies over time and space. Until recently, most ecological studies treated conspecific individuals as ecologically equivalent, but intra-specific variation in individual foraging and feeding strategies can be large. Studies documenting the occurrence of individual specialization in seabirds (n = 94) increased substantially since the year 2000, and rapid and significant advances are being made since then. This review summarizes existing knowledge within this subject, examines the relative incidence of individual specialization and investigates the possible ecological implications of individual specialization in seabirds. Our results show that, to date, the incidence of individual specialization is documented in around 12 % of the total extant seabird species although some studies (n = 12) did not find evidences of individual specialization in the foraging and feeding strategies of some seabird populations. Most studies were conducted at higher latitudes, leading to a lack of knowledge on the incidence of this trait in tropical seabird populations. Results suggest that the incidence of individual specialization may be potentially widespread within seabirds, but may fluctuate spatio-temporally among/within species and populations due to the frequency of specialists, predictability of resources or environmental conditions. This study supports the hypothesis that individual specialization may have important ecological consequences at both individual and population levels, such as implications in breeding performance or in intra-specific competition and, consequently, a high impact on ecological processes and foraging dynamics. Further investigation is required to identify the mechanisms that generate individual specialization and its ecological implications at both population and individual levels.
KeywordsStable Isotope Analysis Individual Specialization Ecological Implication Isotopic Niche Seabird Species
This research was cosponsored by the Foundation for Science and Technology (Portugal) and the European Social Fund (POPH, EU) through a postdoc grant to Filipe R. Ceia (SFRH/BPD/95372/2013). We are grateful to Stefan Garthe, Vitor Paiva, João C. Marques and José Xavier for discussion and insight on early draft of this manuscript which greatly improved this review. Comments and suggestions by Kyle Elliott, Thomas Bodey and one anonymous reviewer improved the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Human rights and animal standards
This article does not contain any studies with human participants or animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
- Bearhop S, Phillips R, Thompson D, Waldron S, Furness R (2000) Variability in mercury concentrations of great skuas Catharacta skua: the influence of colony, diet and trophic status inferred from stable isotope signatures. Mar Ecol Prog Ser 195:261–268. doi: 10.3354/meps195261 CrossRefGoogle Scholar
- BirdLife International (2014) The birdLife checklist of the birds of the world: version 7. http://www.birdlife.org/datazone/userfiles/file/Species/Taxonomy/BirdLife_Checklist_Version_70.zip
- Ceia FR, Paiva VH, Fidalgo V, Morais L, Baeta A, Crisóstomo P, Mourato E, Garthe S, Marques JC, Ramos JA (2014a) Annual and seasonal consistency in the feeding ecology of an opportunistic species, the yellow-legged gull Larus michahellis. Mar Ecol Prog Ser 497:273–284. doi: 10.3354/meps10586 CrossRefGoogle Scholar
- Fifield DA, Montevecchi WA, Garthe S, Robertson GJ, Kubetzki U, Rail JF (2014) Migratory tactics and wintering areas of northern gannets (Morus bassanus) breeding in North America. Ornithol Monogr 79:1–63Google Scholar
- Furness RW, Crane JE, Bearhop S, Garthe S, Käkelä A, Käkelä R, Kelly A, Kubetzki U, Votier SC, Waldron S (2006) Techniques to link individual migration patterns of seabirds with diet specialization, condition and breeding performance. Ardea 94:631–638Google Scholar
- Hamer K, Humphreys E, Garthe S, Hennicke J, Peters G, Grémillet D, Phillips R, Harris M, Wanless S (2007) Annual variation in diets, feeding locations and foraging behaviour of gannets in the North Sea: flexibility, consistency and constraint. Mar Ecol Prog Ser 338:295–305. doi: 10.3354/meps338295 CrossRefGoogle Scholar
- Muller M, Massa B, Phillips RA, Dell’Omo G (2014) Individual consistency and sex differences in migration strategies of Scopolis shearwaters (Calonectris diomedea) despite systematic year differences. Curr Zool 60:631–641Google Scholar
- Nelson JB (1980) Seabirds: their biology and ecology. Hamlyn, London 224 pp Google Scholar
- Patrick SC, Bearhop S, Grémillet D, Lescroël A, Grecian WJ, Bodey TW, Hamer KC, Wakefield E, Le Nuz M, Votier SC (2014) Individual differences in searching behaviour and spatial foraging consistency in a central place marine predator. Oikos 123:33–40. doi: 10.1111/j.1600-0706.2013.00406.x CrossRefGoogle Scholar
- Pianka R (2011) Evolutionary ecology, 7th edn. Addison Wesley, San Francisco, p 512Google Scholar
- Svanbäck R, Bolnick DI (2005) Intraspecific competition affects the strength of individual specialization: an optimal diet theory method. Evol Ecol Res 7:993–1012Google Scholar
- Wakefield ED, Bodey TW, Bearhop S, Blackburn J, Colhoun K, Davies R, Dwyer RG, Green JA, Grémillet D, Jackson AL, Jessopp MJ, Kane A, Langston RH, Lescroël A, Murray S, Le Nuz M, Patrick SC (2013) Space partitioning without territoriality in gannets. Science 341:68–70. doi: 10.1126/science.1236077 CrossRefGoogle Scholar
- Wakefield ED, Cleasby IR, Bearhop S, Bodey TW, Davies RD, Miller PI, Newton J, Votier SC, Hamer KC (in press) Long-term individual foraging site fidelity—why some gannets don’t change their spots. EcologyGoogle Scholar
- Weimerskirch H, Salamolard M, Sarrazin F, Jouventin P (1993) Foraging strategy of wandering albatrosses through the breeding season: a study using satellite telemetry. Auk 110:325–342Google Scholar