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
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 30000-34999 poor estimated 2012
Population trend Stable suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 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 Occurrence status Presence Resident Breeding Non-breeding Passage
Algeria N Extant
Anguilla (to UK) U Extant
Antigua and Barbuda N Extant
Austria N Extant Yes
Barbados N Extant
Belgium N Extant
Belize N Extant
Bermuda (to UK) V Extant
Brazil N Extant
Bulgaria N Extant Yes
Canada N Extant
Cape Verde N Extant
Colombia N Extant
Côte d'Ivoire V Extant
Croatia V Extant
Cuba V Extant
Cyprus U Extant
Czechia V Extant
Denmark N Extant Yes
Dominica N Extant
Egypt N Extant
Faroe Islands (to Denmark) N Extant Yes
Finland V Extant
France N Extant Yes Yes
French Guiana N Extant
Gambia U Extant
Germany N Extant
Ghana V Extant
Gibraltar (to UK) N Extant Yes
Greece V Extant
Greenland (to Denmark) N Extant Yes
Guadeloupe (to France) V Extant Yes
Guinea U Extant
Guinea-Bissau U Extant
Guyana N Extant
Hungary V Extant
Iceland N Extant Yes
Ireland N Extant Yes
Israel V Extant
Italy N Extant Yes
Latvia V Extant
Lebanon U Extant
Liberia V Extant
Libya N Extant
Lithuania V Extant
Luxembourg V Extant
Malta V Extant
Martinique (to France) N Extant
Mauritania N Extant
Montenegro V Extant
Montserrat (to UK) N Extant
Morocco N Extant
Netherlands N Extant Yes
Nigeria V Extant
Norway N Extant Yes
Panama N Extant
Poland V Extant
Portugal N Extant Yes
Puerto Rico (to USA) N Extant
Romania V Extant
Russia N Extant Yes Yes
Russia (Central Asian) V Extant Yes
Russia (European) N Extant Yes
Senegal V Extant
Serbia V Extant
Sierra Leone U Extant
Slovakia N Extant
Slovenia V Extant
Spain N Extant Yes
St Kitts and Nevis N Extant
St Lucia N Extant
St Pierre and Miquelon (to France) N Extant Yes
St Vincent and the Grenadines N Extant
Suriname N Extant
Svalbard and Jan Mayen Islands (to Norway) N Extant Yes
Sweden N Extant
Switzerland V Extant Yes
Syria U Extant
Trinidad and Tobago U Extant
Tunisia N Extant
Turkey V Extant
United Kingdom N Extant Yes
USA N Extant Yes
Venezuela U Extant
Virgin Islands (to UK) U Extant
Virgin Islands (to USA) U Extant
Western Sahara U Extant

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Faroe Islands (to Denmark) Suduroy
Faroe Islands (to Denmark) Stóra Dímun
Faroe Islands (to Denmark) Skúvoy
Faroe Islands (to Denmark) Sandoy
Faroe Islands (to Denmark) Koltur
Faroe Islands (to Denmark) Nólsoy
Faroe Islands (to Denmark) Svínoy
Faroe Islands (to Denmark) Fugloy
Faroe Islands (to Denmark) Vidoy
Faroe Islands (to Denmark) Bordoy
Faroe Islands (to Denmark) Streymoy
Faroe Islands (to Denmark) Vágar
Faroe Islands (to Denmark) Mykines and Mykineshólmur
Iceland Oxarfjordur
Iceland Brunasandur
Iceland Skeidararsandur
Iceland Breidamerkursandur - Fagurholsmyri
Russia (European) Seven islands
France Littoral Augeron
France Cap Gris-nez
United Kingdom Blackpark and Gutcher, Yell
United Kingdom Caithness Cliffs
United Kingdom Crussa Field and the Heogs
United Kingdom Calf of Eday
United Kingdom Fair Isle
United Kingdom Fetlar
United Kingdom Flannan Isles
United Kingdom Foula
United Kingdom Handa
United Kingdom Hermaness, Saxa Vord and Valla Field
United Kingdom Hill of Colvadale and Sobul
United Kingdom Hoy
United Kingdom Lewis Peatlands
United Kingdom Mingulay and Berneray
United Kingdom Moorland Areas, Central Shetland
United Kingdom Mousa
United Kingdom Ronas Hill - North Roe and Tingon
United Kingdom North Rona and Sula Sgeir
United Kingdom Noss
United Kingdom Papa Stour
United Kingdom Papa Westray (North Hill and Holm)
United Kingdom Pentland Firth Islands
United Kingdom Priest Island
United Kingdom Rousay
United Kingdom Shiant Isles
United Kingdom South-eastern Stronsay
United Kingdom St Kilda
United Kingdom Treshnish Isles
United Kingdom West Burrafirth
United Kingdom Ornkey Mainland Moors
United Kingdom West Westray
United Kingdom Auskerry
United Kingdom Faray and Holm of Faray
United Kingdom North Westray Coast
United Kingdom Rothiesholm Peninsula, Stronsay
United Kingdom Sandwick and Clift Hills
United Kingdom South Bressay
United Kingdom South Walls and Switha
United Kingdom Tolsta Head, Lewis
Denmark Skagerrak-Southwest Norwegian trench
Norway Runde
Norway Loppa
Svalbard and Jan Mayen Islands (to Norway) Bjørnøya (Bear Island)
Svalbard and Jan Mayen Islands (to Norway) Inner parts of Kongsfjorden
Germany Wagbach lowlands
Svalbard and Jan Mayen Islands (to Norway) Jan Mayen island
France Traicts et marais salants de la Presqu'île Guérandaise
France Pointe de Grave
Spain Costa da Morte
Spain Cape Candelaria-Ortigueira estuary-Cape Estaca de Bares
Spain Cape Busto-Luanco
Spain Estrecho de Gibraltar
Iceland Ingolfshofdi
Svalbard and Jan Mayen Islands (to Norway) Forlandet National Park
Senegal Northern Senegal shelf break
Mauritania Canary current shelf-break (south)
Morocco Canary current shelf-break (north)
Morocco Canary current shelf 3
Morocco Canary current shelf 4
Iceland Utherad

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 (2022) Species factsheet: Catharacta skua. Downloaded from on 27/09/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from on 27/09/2022.