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Parasitic Jaeger - BirdForum Opus

(Redirected from Arctic Skua)

Alternative names: Arctic Skua, Parasitic Skua

Adult dark morph
Photo © by IanF
Cleveland, UK, 22nd July 2003
Stercorarius parasiticus

Identification

Juvenile in flight
Photo © by IanF
Juvenile, Seaton Snook, Cleveland, UK, 31 August 2006

41-48 cm (16-19") including pointed tail projection

  • Elongated central tail feathers (just noticeable in juveniles).
  • White wing flash

Dark Morph and Young are brown apart from the whitish patch near wing tip.
Light Morph have creamy-white underparts, cheeks and neck (barred brown in winter) and a dark cap.
Intermediates have variable amounts of light and dark plumage: some are brown with dark cap, others brown with yellow neck-ring.

  • In the North Atlantic, light morphs predominate at higher latitudes while in dark morphs predominate further south. The genetics of the polymorphism is more complex than previously believed. It involves three different linked non-synonymous mutations at the plumage color locus rather than the single mutation previously known[3].

Similar Species

Pomarine Jaeger, Long-tailed Jaeger.

Distribution

Alaska, Canada, Greenland, Iceland, Scandinavia, and northern Russia. Winters at sea in southern oceans.

Taxonomy

Monotypic[1]

Adult, light morph in flight
Photo © by Terry W
Handa Island, Scotland, 14 June 2007

Habitat

Breeds on dry tundra, higher fells and islands. Otherwise pelagic but close to land.

Behaviour

Bird Forum thread for jizz and behaviour-based ID tips

Flight

Rather hawk-like and bouyant. Chases other birds.

Breeding

Breeds in loose colonies
Up to four olive-brown eggs are laid on the ground.

Diet

Adult, dark morph
Photo © byTichodroma
Iceland , 30 June 2007

Diet includes lemmings and other rodents. Robs other birds of their fish catch.

Vocalisation

Parasitic Jaeger voice clip

References

  1. Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2018. The eBird/Clements checklist of birds of the world: v2018. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
  2. Furness, R.W., Boesman, P. & Garcia, E.F.J. (2018). Arctic Jaeger (Stercorarius parasiticus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53959 on 3 September 2018).
  3. Janssen, K. and Mundy, N. I. (2013), Molecular population genetics of the melanic plumage polymorphism in Arctic skuas (Stercorarius parasiticus): evidence for divergent selection on plumage colour. Mol Ecol, 22: 4634-4643. doi:10.1111/mec.12428
  4. Wiley, R. H. and D. S. Lee (1999). Parasitic Jaeger (Stercorarius parasiticus), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.445
  5. Wikipedia contributors. (2018, August 22). Parasitic jaeger. In Wikipedia, The Free Encyclopedia. Retrieved 09:43, September 3, 2018, from https://en.wikipedia.org/w/index.php?title=Parasitic_jaeger&oldid=855960808
  6. Answers.com
  7. Birdwatchers Pocket Guide ISBN 1-85732-804-3
  8. Collins Pocket Guide to British Birds 1966
  9. Collins Field Guide 5th Edition

Recommended Citation

External Links

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