Arctic Tern
Sterna paradisaea
Overview
The Arctic Tern has the longest migration of any animal — 70,000 km round trip from Arctic breeding grounds to Antarctic wintering areas. The birds that pass the Sefton Coast in spring and autumn may have recently left Antarctica or be heading there. In summer plumage, identical to Common Tern but with subtly different proportions — shorter legs, shorter bill (blood-red, no black tip), longer tail streamers. Often occurs with Common Terns at Marshside and offshore.
At a Glance
| Order | Charadriiformes |
| Family | Laridae |
| Habitat | Open sea · Coastal lagoon · Estuary |
| Diet | Small fish — plunge dives from height |
| UK population | Around 53,000 pairs; amber-listed |
| Sefton Coast | Regular on passage; smaller numbers than Common Tern; possible in any tern flock |
| Conservation | UK Amber List |
Where to See It
Offshore and at Marshside RSPB with Common Terns. Identification requires care.
Identification
Very similar to Common Tern. Key features: all-red bill (no dark tip), shorter red legs, very long tail streamers, rounder head. Translucent primaries visible from below in flight — more obvious than Common's dark outer primaries. 'Crisper' flight action.
Viewing & Photography Tips
Check any tern flock for the all-red bill and very long tail. Best in May or August when adults in breeding plumage pass through. A telescope is almost essential for confident separation from Common Tern.
Conservation Status
UK Amber List
This species is on the UK Amber List for Birds (BoCC5), indicating moderate concern. Population monitoring and habitat management remain important for its continued recovery.
Frequently Asked Questions
How far does the Arctic Tern migrate?
Arctic Terns have the longest migration of any animal. Tagged birds have recorded round trips of over 90,000 km — from Arctic breeding grounds to the Antarctic and back. They effectively experience two summers each year, spending arctic summer breeding in the far north and then flying to enjoy the southern hemisphere summer in Antarctic waters. In a 30-year lifespan, an Arctic Tern may travel the equivalent of three trips to the moon and back.
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.