How to Identify Common Seabirds on a Coastal Stroll

Start with Silhouette and Behaviour

A coastal stroll in Britain is never just a walk. The moment you leave the car park, you are surrounded by birds that have adapted to life on the edge. Most people spot a gull and move on, but if you slow down for thirty seconds, you can begin to tell the common species apart. The trick is to ignore colour at first. Instead, look at the bird's silhouette, its size, and what it is doing. A cormorant stands upright on a rock with wings held out like a broken umbrella. An oystercatcher probes the sand with a long orange bill. A herring gull patrols the promenade with a confident swagger. These behaviours narrow the options before you even lift your binoculars.

Practical tip: visit at low tide when mudflats and rock pools are exposed. Birds spread out to feed, so you can watch them without a crowd. Keep your distance, especially in spring and summer when they are nesting. A good pair of 8x42 binoculars and a notebook will do more for your identification skills than any app.

Gulls: Three Common Species to Know

Gulls confuse many people because they change plumage over four years and look different in winter. But on a typical British beach, you only need to master three or four. Start with leg colour and back colour. Herring gull is the classic seaside gull: pink legs, light grey back, yellow bill with a red spot. It is large and loud, often snatching chips. Lesser black-backed gull is slightly smaller and slimmer, with yellow legs and a dark grey back. Its bill is yellow with a red spot. Great black-backed gull is the heavyweight: pink legs, a very dark, almost black back, and a heavy bill. It bullies other birds off rocks. If you see a smaller gull with yellow-green legs and a dark eye, that is a common gull (despite the name). And a gull with a chocolate-brown head in summer is a black-headed gull – though its head turns white in winter, leaving just a dark smudge behind the eye.

• Herring gull: pink legs, light grey back, loud laughing call.
• Lesser black-backed gull: yellow legs, dark grey back, deep nasal call.
• Great black-backed gull: pink legs, black back, barking call.

Cormorant and Shag: The Diving Differences

These two are often confused, but they behave differently. A cormorant is large, heavy and thick-necked. It often stands on a rock or buoy with its wings stretched out to dry, because its feathers are not fully waterproof. In breeding season, look for a white patch on its thigh and a white throat patch. Its bill is thick and hooked. A shag is smaller and slimmer, with a thinner neck and a more upright posture. In summer, it has a crest on its head and a greenish sheen to its plumage. The bare skin at the base of its bill is yellow, not grey. Shags dive from the surface with a small jump, while cormorants often dive with a smoother, faster entry. Both feed on fish, and both can be seen around rocky coasts, harbours and estuaries.

Oystercatchers: Bold, Noisy and Easy to Love

You will hear an oystercatcher before you see it. Its piping call – a shrill, repeated kleep kleep – carries over the noise of waves. Once you look, the bird is unmistakable: black head and back, white belly, long orange-red bill and pink legs. In flight, it shows a broad white wing bar. Oystercatchers feed on mussels, cockles and limpets, using that strong bill to prise shells open or hammer them. They are often found in flocks on estuaries and sandy shores, especially at low tide. In winter, they gather in large roosts on rocky shores. Watch for their curious habit of piping in chorus – a group will suddenly stand up and call together, heads bowed, before settling back down.

Calls, Conservation and Your Field Guide

Learning three or four calls will transform your walks. The herring gull gives a loud, laughing kyow-kyow-kyow. The lesser black-backed gull has a deeper, more nasal version. The great black-backed gull barks a low owk-owk. The cormorant grunts deeply, while the shag purrs or hisses. The oystercatcher pipes its name. You can practise by listening to recordings before you go, then matching what you hear to the bird you see. A small notebook with sketches of leg colour and back shade is more useful than a heavy guide.

Finally, remember that identification is a privilege, not a right. Seabirds in the UK face pressures from climate change, overfishing, plastic pollution and disturbance. Keep your distance, especially at breeding colonies between March and July. Keep dogs on leads near nesting sites and roosts. Take all litter home, including fishing line and bait bags. If you find an injured bird, contact a local wildlife trust or animal rescue – but do not handle it yourself unless advised. By watching quietly and learning their calls, you become part of the solution: a visitor who sees the coast as a living place, not just a backdrop.