Book contents
- Frontmatter
- Contents
- List of figures
- List of tables
- Preface
- 1 The Arctic Skuas of Fair Isle
- 2 Numbers and distribution
- 3 Feeding behaviour and ecology
- 4 Breeding ecology
- 5 Genetics
- 6 Demography and selection
- 7 Sexual behaviour
- 8 Sexual selection
- 9 Genetic models of sexual selection in birds
- 10 Mating preferences of the Arctic Skua
- 11 Conclusions
- Appendix A Rates of increase of bird populations
- Appendix B Analysis of variance of a 2 × r table with unequal numbers of observations
- Appendix C Statistical analysis of assortative and disassortative mating in polymorphic birds
- References
- Index
3 - Feeding behaviour and ecology
Published online by Cambridge University Press: 21 May 2010
- Frontmatter
- Contents
- List of figures
- List of tables
- Preface
- 1 The Arctic Skuas of Fair Isle
- 2 Numbers and distribution
- 3 Feeding behaviour and ecology
- 4 Breeding ecology
- 5 Genetics
- 6 Demography and selection
- 7 Sexual behaviour
- 8 Sexual selection
- 9 Genetic models of sexual selection in birds
- 10 Mating preferences of the Arctic Skua
- 11 Conclusions
- Appendix A Rates of increase of bird populations
- Appendix B Analysis of variance of a 2 × r table with unequal numbers of observations
- Appendix C Statistical analysis of assortative and disassortative mating in polymorphic birds
- References
- Index
Summary
Kleptoparasitism by Arctic Skuas in the breeding season and on migration
Arctic Skuas are pirates and predators. On the islands of the North Atlantic, they forage as air pirates, pursuing other seabirds in the air and forcing them to drop their food. This behaviour has become known as ‘kleptoparasitism’. Arctic Skuas are said to be ‘kleptoparasites’. On arctic tundra in northern Norway, they are predators as well as pirates, feeding on small birds, eggs, rodents, insects, and also on berries like the Crowberry (Empetrum nigrum). On Fair Isle, the chicks in particular eat considerable quantities of crowberries.
Auks (Puffins, Razorbills and Guillemots), Kittiwakes and terns (Arctic, Common and Sandwich Terns) are the main victims of the Arctic Skua's piracy. Several detailed studies have been made of the methods Arctic Skuas use in attack and the factors influencing their chances of success (Grant, 1971; Andersson, 1976; Arnason & Grant, 1978; Furness, 1978; Taylor, 1979). Arnason (1978) and Furness & Furness (1980) observed the chances of success in attacks by melanic and pale Arctic Skuas.
Grant (1971) and Arnason & Grant (1978) observed Arctic Skuas in the breeding season attacking Puffins. Taylor (1979) observed them on migration attacking terns. Arnason & Grant (1978) also analysed the factors that influence successful piracy.
Arctic Skuas usually hunt alone (Grant, 1971; Taylor, 1979). They search for victims among flocks of foraging Puffins, terns and Kittiwakes.
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- Information
- The Arctic SkuaA study of the ecology and evolution of a seabird, pp. 60 - 80Publisher: Cambridge University PressPrint publication year: 1983