Stercorarius parasiticus (Linnaeus, 1758)
Family: Charadriiformes > Stercorariidae
This highly-migratory seabird has a fast and powerful flight that can also be nimble and manoeuvrable. It breeds on moorland in the Arctic but spends most of its year in the open ocean.
A few colonies are found in the far north and west of Britain, on moorland within easy reach of the sea. Elsewhere, Arctic Skuas occur offshore on migration and may be seen close inshore, often when chasing terns.
Seabird censuses reveal that Arctic Skuas breeding in Britain are currently in severe decline. Recent tracking studies have shown that breeding birds make long excursions to gather food for their chicks, perhaps indicating that suitable prey is scarce near the colonies.
Select a topic for more facts and statistics about the Arctic Skua
Arctic Skua identification is often difficult. The following article may help when identifying Arctic Skua.
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.
Listen to example recordings of the main vocalisations of Arctic Skua, provided by xeno-canto contributors.
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.
This species can be found on the following statutory and conservation listings and schedules.
With the UK the Arctic Skua is restricted to north and west Scotland. Based on previous Censuses, the population increased substantially between 1969–70 and 1985–88; despite a subsequent decline, breeding numbers counted by Seabird 2000 (1998–2002) remained approximately double the 1969–70 population. The results of the recent Seabirds Count (2015–2021) are not yet available; however, annual monitoring data suggest that the decline has continued (JNCC 2022, or link to website). Perkins et al. (2018) found that numbers had declined by 81% between 1992 and 2015 within their core Scottish breeding areas. Further comment on avian flu outbreak - or is this only Great Skua (IW to check with Liz)?
Arctic Skuas breeding in the UK are at the southwestern extremity of their mostly circumpolar breeding range. In the UK they nest in the Northern Isles, Caithness and Sutherland, the Outer Hebrides, St Kilda and a few southern Inner Hebridean islands. Highest numbers are found on Shetland, Orkney and the Outer Hebrides.
Occupied 10-km squares in UK
|No. occupied in breeding season||119|
|% occupied in breeding season||3.9|
|No. occupied in winter||108|
|% occupied in winter||3.6|
European Distribution Map
Arctic Skuas have declined significantly and this is beginning to show in the range maps, with losses in the southern part of the range on Islay and Jura.
Change in occupied 10-km squares in the UK
|% change in range in breeding season (1968–72 to 2008–11)||+7.1%|
|% change in range in winter (1981–84 to 2007–11)||+61%|
Arctic Skuas are predominantly summer visitors, arriving from April. Peak reporting is during autumn passage in August and September. Occasional birds may winter.
Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.
Lifecycle and body size information about Arctic Skua, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.
View number ringed each year in the Online Ringing Report
|Maximum Age from Ringing||25 years 10 months 24 days (set in 2003)|
|Typical Lifespan||12 years with breeding typically at 4 year|
|Juvenile Survival||0.68 (in first year)|
|Wing Length||Adults||328.9±8.3 | Range 314–343mm, N=35|
|Body Weight||Adults||416±37.93 | Range 360–476g, N=36|
Feather measurements and photos on featherbase
|Field Codes||2-letter: AC | 5-letter code: ARCSK | Euring: 5670|
For information in another language (where available) click on a linked name
Interpretation and scientific publications about Arctic Skua from BTO scientists.
Causes of change
The decline in the Arctic Skua population is believed to be driven by strong decreases in breeding productivity (Perkins et al. 2018), with complete breeding failure occurring more frequently (JNCC 2022). Arctic Skuas are kleptoparasites, stealing food from other seabirds such as Kittwakes and auks. Recent declines for these species have been linked to the decline in their prey species, in particular sandeels Ammodytes marinus and it is likely that this will also have affected Arctic Skua productivity (Dwason et al. 2011; Perkins et al. 2018). Productivity is also likely to have been impacted by increases in the Great Skua population, through increased predation of Arctic Skua chicks (Meek et al. 2011; Perkins et al. 2018) and also through competition for territories (Dawson et al. 2011) and food (Meek et al. 2011). Add something about avian flu??
Would you like to search for another species?