Great Skua

Stercorarius skua (Brünnich, 1764) NX GRESK 5690
Family: Charadriiformes > Stercorariidae

This dark brown, large powerful seabird with obvious white wing flashes can be seen around our coasts throughout the year.

Great Skuas breed on our northern islands during the summer months but outside of the breeding season they can be seen in coastal waters anywhere in the UK. The Great Skua is a predatory seabird that will hunt small birds, rodents and Rabbits; it can also be seen chasing other seabirds in an attempt to relieve them of any food that they might have caught.

Whilst Great Skuas can be seen throughout the year most are migratory, heading to offshore West Africa. In 2022, many skuas died on their British breeding grounds in a severe outbreak of avian influenza.

Identification

Great Skua identification is often straightforward. The following article may help when identifying Great Skua.

related video

Identifying Skuas

Identifying skuas passing offshore in late summer is one of the great challenges of bird ID. There are clues to help us, however, and - with practice - most individuals can be identified. This workshop will point you in the right direction and help you to focus on the features and markings that will be most helpful when seawatching.

Develop your bird ID skills with our training courses

Our interactive online courses are a great way to develop your bird identification skills, whether you're new to the hobby or a competent birder looking to hone your abilities.

Browse training courses

Status and Trends

Population size and trends and patterns of distribution based on BTO surveys and atlases with data collected by BTO volunteers.

CONSERVATION STATUS

This species can be found on the following statutory and conservation listings and schedules.

POPULATION SIZE

POPULATION CHANGE

The population and breeding range of the Great Skua have both been increasing since 1900 (JNCC 2022). Data from Censuses suggest that numbers more than trebled between 1969–70 and Seabird 2000 (1998–2002). The subsequent trend is variable across different colonies and will not be clear until the results of the recent Seabirds Count (2015–2021) are available (JNCC 2022). An avian influenza virus affected large numbers of Great Skuas across different Scottish islands in summer 2021 (Banyard et al. 2022): the population level impacts of this outbreak are as yet unclear.

DISTRIBUTION

More than half the world population of Great Skuas is found in the UK, along the northwest seaboard of Scotland and Ireland, with highest concentrations on Shetland and Orkney, Handa, Sutherland and St Kilda.

Occupied 10-km squares in UK

European Distribution Map

European Breeding Bird Atlas 2

DISTRIBUTION CHANGE

Great Skua breeding range expanded by 111% since the 1968–72 Breeding Atlas, mostly involving colonisation of new sites in the west of Scotland and in northwest Ireland since 2000.

Change in occupied 10-km squares in the UK

SEASONALITY

Great Skuas are summer visitors, arriving in March. Autumn migration of northern breeders extends into late autumn and early winter.

Weekly occurence of Great Skua from BirdTrack
Weekly occurrence patterns (shaded cells) and reporting rates (vertical bars) based on BirdTrack data. Reporting rates give the likelihood of encountering the species each week.

Movement

Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.

RINGING RECOVERIES

View a summary of recoveries in the Online Ringing Report.

Foreign locations of birds ringed or recovered in Britain & Ireland

Foreign locations of Great Skua ringed or recovered in Britain & Ireland
Encountered in: Winter (Nov-Feb); Spring (Mar-Apr); Summer (May-Jul); Autumn (Aug-Oct)

Biology

Lifecycle and body size information about Great Skua, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.

PRODUCTIVITY & NESTING

SURVIVAL & LONGEVITY

View number ringed each year in the Online Ringing Report

BIOMETRICS

Feather measurements and photos on featherbase

CODES & CLASSIFICATION

For information in another language (where available) click on a linked name

Gaelic: Fàsgadair-mòr
Welsh: Sgiwen Fawr
Catalan: paràsit boreal
Czech: chaluha velká
Danish: Storkjove
Dutch: Grote Jager
Estonian: suuränn
Finnish: isokihu
French: Grand Labbe
German: Skua
Hungarian: nagy halfarkas
Icelandic: Skúmur
Irish: Meirleach Mór
Italian: Stercorario maggiore
Latvian: liela klijkaija
Lithuanian: didysis plešikas
Norwegian: Storjo
Polish: wydrzyk wielki
Portuguese: mandrião-grande / alcaide
Slovak: pomorník velký
Slovenian: velika govnacka
Spanish: Págalo grande
Swedish: storlabb
Folkname: Bonxie

Research

Interpretation and scientific publications about Great Skua from BTO scientists.

CAUSES AND SOLUTIONS

Causes of change

Strong increases which occurred during the 1970s are believed to be associated with increases in fisheries discards; whilst the population increases have continued subsequently the rate of increase has been lower, possibly due to a reduction in discards and a reduction in sandeel abundance, though great skuas have managed to switch their diet to maintain population levels despite the changes to prey availability (Church et al. 2018). Following the population increases, density-dependent effects may now be limiting population growth in some parts of the breeding range (Meek et al. 2011). An avian influenza outbreak was detected in Great Skua colonies across different Scottish islands in summer 2021, with large numbers of birds observed with apparent symptoms of the disease and dying. The virus was confirmed in seven of the eight dead skuas which were examined (Banyard et al. 2022). It is not yet clear whether this outbreak has had population level effects.

PUBLICATIONS (2)

Peer-reviewed papers

Contrasting effects of GPS device and harness attachment on adult survival of Lesser Black-backed Gulls Larus fuscus and Great Skuas Stercorarius skua

2016 | Thaxter, C.B., Ross-Smith, V.H., Clark, J.A., Clark, N.A., Conway, G.J., Masden, E.A., Wade, H.M., Leat, E.H.K., Gear, S.C., Marsh, M., Booth, C., Furness, R.W., Votier, S.C. & Burton, N.H.K.Ibis

Peer-reviewed papers
Tagged Lesser black-backed Gull

Modelling flight heights of Lesser Black-backed Gulls and Great Skuas from GPS: a Bayesian approach

GPS tracks and cutting edge stats shed new light on seabird flight heights

2016 | Ross-Smith, V.H., Thaxter, C.B., Masden, E.A., Shamoun-Baranes, J., Burton, N.H.K., Wright, L.J., Rehfisch, M.M. & Johnston, A.Journal of Applied Ecology

New research led by the BTO has used a combination of GPS-tracking and advanced statistics to provide new insights into seabird flight heights by night and day. This study gives important information on the risk of seabirds colliding with offshore wind turbines and at a time when governments worldwide are investing in offshore wind farms.

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