Rob Robinson

The largest skua of the northern hemisphere, the only representative of a large clade of large skuas present across the southern oceans. Monotypic, breeds from Iceland, Scotland to islands off North-West Russia. In winter, disperses across the whole North Atlantic and Mediterranean Sea.

Season of assessment

B

Population trendIncreasing
Population size
(min-max, best estimate)		25800-30000,27600
Red List categoryLC
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Great Skua

As a marine migratory skua, recoveries link ringing on breeding (sometimes remote) islands, and staging or wintering coasts. Main ringing effort are located in Faroe Islands, Shetlands, Bjørnøya in the Barents Sea and Iceland. From these islands, there is a major direction of migratory movements to the South, but also a complete network of movements between breeding sites, including Iceland, Western Greenland, Svalbard and Siberian Russia. Furthest recoveries have been obtained in winter in the Gulf of Guinea and along the North coast of Brazil, so on both sides of the central Atlantic.

A tracking study reported that adults from Scotland wintered off northwest Africa and southern Europe. Adults from Iceland mostly wintered off Canada, with small numbers visiting northwest Africa and Europe. Although adults from Bjørnøya (Norway) migrated to similar areas to birds from Iceland, a slightly greater proportion wintered off Europe, and most used areas further north than birds from Scotland (Magnusdottir et al. 2012).

Recoveries by Condition for Great Skua

Mostly dead recoveries, historically nearly 90% before 1960, but dropped to only one third of recoveries after 1990, representing a drastic change in the way we document movements of the species.

Annual Movements for Great Skua

Movements between breeding areas are mainly documented from June to September. Birds from Shetlands are re-encountered along the West coast of Norway from September to December, with a few records in the Baltic Sea. Recoveries along the East coast of North America from November and December, when few records are obtained in Europe. Recoveries in the Bay of Biscay are mainly obtained in September and October, those in the Mediterranean Sea are mainly obtained from January to March. Tracking data of skuas from Foula, Shetlands, documented the individual migration and wintering strategies, with e.g. a summer migration to Norway and the Gulf of Biscay, from July to September, then overwintering off West Africa, from October to February (Furness et al. 2006).

Connectivity by Month by Region for Great Skua

Recoveries in South America (Guyana and Brazil) are from the end of the winter, December to March, with also few summering immatures. Similarly, recoveries off West Africa are from February to May, and those I the Mediterranean Sea also in the second part of the winter period. The species is probably off shore earlier in the winter, while the majority of dead recoveries away from the breeding grounds might bias the pattern towards unhealthy individuals that come closer to the shores than others.

Frédéric Jiguet

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
Furness R.W., Crane J.E., Bearhop S., Garthe S., Käkelä A., Käkelä R., Kelly A., Kubetzki U., Votier S.C. & Waldron S.2006 . Techniques to link migration patterns of seabirds with diet specialization, condition and breeding performance. Ardea 94: 631–638
Magnusdottir, E., Leat, E.H.K., Bourgeon, S., Strøm, H., Petersen, A., Phillips R.A., Hanssen, S.A., Bustnes J.O., Hersteinsson, P., Furness, R.W.2012 . Wintering areas of Great Skuas Stercorarius skua breeding in Scotland, Iceland and Norway. Bird Study 51 Link to Article (DOI: https://doi.org/10.1080/00063657.2011.636798) : 1–9

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