Arctic Skua
Stercorarius parasiticus
Tap image to enlarge · Wikimedia Commons
Overview
The Arctic Skua is a seabird pirate — it chases terns and forces them to drop their fish catches in mid-air. Watching one pursue a Common Tern across the bay with acrobatic persistence is thrilling. On autumn passage they occur offshore from Formby Point and occasionally come close inshore when chasing terns. They come in two colour phases: pale (white below) and dark (uniform dark brown). Their pointed central tail feathers are a useful field mark when visible.
At a Glance
| Order | Charadriiformes |
| Family | Stercorariidae |
| Habitat | Open sea · Offshore coastal water |
| Diet | Fish, small birds, carrion — pirates food from other seabirds by aerial pursuit |
| UK population | Around 2,500 pairs in Scotland; red-listed due to severe decline |
| Sefton Coast | Regular autumn passage offshore; occasional close inshore harassing terns |
| Conservation | UK Red List |
Where to See It
Offshore from Formby Point; harasses Common and Arctic Terns returning to the Little Tern colony.
Identification
Falcon-like seabird. Two colour phases: pale (dark above, white below with dark cap) and dark (all dark brown). Pointed central tail projections (when visible). Aggressive aerial pursuit of terns. Fast, angled wingbeats.
Viewing & Photography Tips
Watch from Formby Point for fast-flying dark seabirds chasing terns. The pursuit behaviour is diagnostic — skuas chase terns persistently until food is dropped.
Conservation Status
UK Red List
This species is on the UK Red List for Birds (BoCC5), indicating serious concern about its population decline or unfavourable conservation status. Monitoring this species on the Sefton Coast contributes to national population tracking.
Frequently Asked Questions
How do skuas steal food from other birds?
Arctic Skuas engage in kleptoparasitism — systematic food theft. They identify a tern returning to the colony with a fish, then pursue it relentlessly, matching every evasive manoeuvre. The tern eventually drops or disgorges the fish and the skua catches it in mid-air. The whole chase can last several minutes. Success rates are high for experienced skuas in areas with many terns.
Related Species
Plan your visit to the Sefton Coast
Marshside RSPB, Formby pinewoods, Ainsdale NNR — practical guides to getting there, what to bring, and the best spots for each season.