Great Skua Catharacta skua


Taxonomic note
Catharacta skua (del Hoyo and Collar 2014) was previously placed in the genus Stercorarius.

Catharacta skua,
C. antarctica and C. maccormicki (Sibley and Monroe 1990, 1993), cross-regional species, are retained as separate species contra Christidis and Boles (1994) and Turbott (1990) who include lonnbergi and antarctica as subspecies of C. skua and AERC TAC (2003) who include C. maccormicki as a subspecies of C. skua.

Taxonomic source(s)
Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2018 Least Concern
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency does not normally occur in forest
Land-mass type Average mass -

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 4,300,000 medium
Extent of Occurrence non-breeding (km2) 35,800,000 medium
Severely fragmented? no -
Population and trend
Value Data quality Derivation Year of estimate
Number of mature individuals 30000-34999 poor estimated 2012
Population trend stable suspected -
Generation length (years) 17.5 - - -

Population justification: The breeding population, which is confined to Europe, is estimated at 16,300-17,200 pairs, which roughly equates to 30,000-34,999 mature individuals (BirdLife International 2015).

Trend justification: The population is suspected to be stable in the absence of evidence for any declines or substantial threats. The European population trend is unknown (BirdLife International 2015).

Country/territory distribution
Country/Territory Presence Origin Resident Breeding Non-breeding Passage
Algeria extant native
Anguilla (to UK) extant uncertain
Antigua and Barbuda extant native
Austria extant native yes
Barbados extant native
Belgium extant native
Belize extant native
Bermuda (to UK) extant vagrant
Brazil extant native
Bulgaria extant native yes
Canada extant native
Cape Verde extant native
Colombia extant native
Côte d'Ivoire extant vagrant
Croatia extant vagrant
Cuba extant vagrant
Cyprus extant uncertain
Czechia extant vagrant
Denmark extant native yes
Dominica extant native
Egypt extant native
Faroe Islands (to Denmark) extant native yes
Finland extant vagrant
France extant native yes yes
French Guiana extant native
Gambia extant uncertain
Germany extant native
Ghana extant vagrant
Gibraltar (to UK) extant native yes
Greece extant vagrant
Greenland (to Denmark) extant native yes
Guadeloupe (to France) extant vagrant yes
Guinea extant uncertain
Guinea-Bissau extant uncertain
Guyana extant native
Hungary extant vagrant
Iceland extant native yes
Ireland extant native yes
Israel extant vagrant
Italy extant native yes
Latvia extant vagrant
Lebanon extant uncertain
Liberia extant vagrant
Libya extant native
Lithuania extant vagrant
Luxembourg extant vagrant
Malta extant vagrant
Martinique (to France) extant native
Mauritania extant native
Montenegro extant vagrant
Montserrat (to UK) extant native
Morocco extant native
Netherlands extant native yes
Nigeria extant vagrant
Norway extant native yes
Panama extant native
Poland extant vagrant
Portugal extant native yes
Puerto Rico (to USA) extant native
Romania extant vagrant
Russia extant native yes yes
Russia (Central Asian) extant vagrant yes
Russia (European) extant native yes
Senegal extant vagrant
Serbia extant vagrant
Sierra Leone extant uncertain
Slovakia extant native
Slovenia extant vagrant
Spain extant native yes
St Kitts and Nevis extant native
St Lucia extant native
St Pierre and Miquelon (to France) extant native yes
St Vincent and the Grenadines extant native
Suriname extant native
Svalbard and Jan Mayen Islands (to Norway) extant native yes
Sweden extant native
Switzerland extant vagrant yes
Syria extant uncertain
Trinidad and Tobago extant uncertain
Tunisia extant native
Türkiye extant vagrant
United Kingdom extant native yes
USA extant native yes
Venezuela extant uncertain
Virgin Islands (to UK) extant uncertain
Virgin Islands (to USA) extant uncertain
Western Sahara extant uncertain

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Faroe Islands (to Denmark) Skúvoy
Faroe Islands (to Denmark) Sandoy
Faroe Islands (to Denmark) Streymoy
Faroe Islands (to Denmark) Vágar
Iceland Oxarfjordur
Iceland Skeidararsandur
Iceland Breidamerkursandur - Fagurholsmyri
Russia (European) Seven islands
Denmark Skagerrak-Southwest Norwegian trench
United Kingdom Foula
Spain Costa da Morte
United Kingdom Fair Isle
United Kingdom Handa
United Kingdom Hermaness, Saxa Vord and Valla Field
United Kingdom Hoy
United Kingdom Noss
United Kingdom St Kilda
United Kingdom Ronas Hill - North Roe and Tingon
United Kingdom Sandwick and Clift Hills
United Kingdom South Bressay
Spain Cape Candelaria-Ortigueira estuary-Cape Estaca de Bares
Spain Cape Busto-Luanco
Spain Estrecho de Gibraltar
Svalbard and Jan Mayen Islands (to Norway) Bjørnøya (Bear Island)
Svalbard and Jan Mayen Islands (to Norway) Forlandet National Park
Mauritania Canary current shelf-break (south)
Morocco Canary current shelf-break (north)

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Grassland Tundra major breeding
Marine Neritic Macroalgal/Kelp suitable non-breeding
Marine Neritic Macroalgal/Kelp suitable breeding
Marine Neritic Pelagic major non-breeding
Marine Neritic Pelagic major breeding
Marine Neritic Seagrass (Submerged) suitable non-breeding
Marine Neritic Seagrass (Submerged) suitable breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Marine Neritic Subtidal Sandy suitable breeding
Marine Neritic Subtidal Sandy-Mud suitable non-breeding
Marine Neritic Subtidal Sandy-Mud suitable breeding
Marine Oceanic Epipelagic (0-200m) suitable non-breeding
Marine Oceanic Mesopelagic (200-1000m) suitable non-breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Indirect ecosystem effects, Competition, Reduced reproductive success
Biological resource use Hunting & trapping terrestrial animals - Persecution/control Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species disturbance, Reduced reproductive success, Species mortality
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Majority (50-90%) Unknown Unknown
Indirect ecosystem effects, Ecosystem degradation

Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - international non-trivial recent

Recommended citation
BirdLife International (2023) Species factsheet: Catharacta skua. Downloaded from on 04/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 04/10/2023.