Yellow-legged gull

Voice

Deeper and more nasal than Herring Gull, with a full, falling laughing call, gow-gow-gow, delivered head thrown back, and a short ga-ga when uneasy. In Spanish and Italian port towns it sounds year round from roofs and jetties; in the Netherlands it usually comes from a single bird among Herring Gulls. Tone is the best clue when the bird is heard and not seen: heavier and audibly hoarse against the clear wail of a Herring Gull.

Identification

A powerful, long-legged gull with a mantle clearly darker grey than Herring Gull and clearly paler than Lesser Black-backed. The legs are bright chrome yellow, the eye pale yellow inside a thick, vivid red orbital ring, and the heavy bill has a strong gonydeal angle with a large red spot that often bleeds onto the upper mandible. The moult schedule matters: the head is snow white already in August and September, without the smudgy winter streaking a Herring Gull acquires at exactly that time. The wingtip carries a lot of black, with one clear mirror on p10 and at most a small one on p9, giving a heavy black wedge in flight. First-years are strikingly contrasty: a dark mask around the eye, an early white head and underparts, chequered greater coverts, plain dark tertials with a narrow pale tip, and a white rump cutting sharply against a crisp black tail band.

Confusion species

Herring Gull is the first test: paler grey mantle, flesh-pink legs, a smaller red bill spot, and in autumn and winter a streaked, dirty head while the Yellow-legged is already white. Caspian Gull is the harder case: a long, parallel-sided bill without a marked gonydeal angle, a small and often dark eye in a sloping forehead, longer dull pink to yellowish legs, more white in the outer primary and a whiter-looking underwing; it looks long and pear-shaped where the Yellow-legged looks angular and burly. Lesser Black-backed Gull also has yellow legs, but a far darker slate mantle that at distance reads almost black against the white body. In first-years the cards fall differently: Caspian shows plain grey scapulars and a pale head, Yellow-legged coarser chequered coverts and a dark eye mask.

Habitat

Rocky coasts, cliffs, beaches, salt pans, harbours, reservoirs, river sandbanks, landfills and flat city roofs. It breeds colonially on rocky islets and cliffs and increasingly on buildings, from Barcelona to Rome. In the Netherlands it favours sand and mud flats along the big rivers, the Delta and industrial sites, almost always among Herring and Lesser Black-backed Gulls.

Range and movements

The core range is the Mediterranean, the Atlantic coasts of Iberia and Morocco and the offshore islands; Spain holds hundreds of thousands of pairs and it is the default large gull along virtually the whole coast and on the big inland reservoirs. From there it pushes north through France and Switzerland into Germany and the Netherlands. In the Netherlands it is a scarce but rapidly increasing visitor, peaking from July to October along the Waal, the Rhine and in the Delta, with a handful of pure breeding records since 2011.

• Resident
• Winter
• Passage
• dark = core range, pale = thinly spread

Where and when to look

In August or September walk a river sandbank, along the Waal near Nijmegen or anywhere in the Delta, and look for the bird with the snow-white head among the streak-headed Herring Gulls. Then work downwards: mantle tone against the neighbouring bird, then legs, then orbital ring and bill spot. In Spain the species is best nailed at a fishing harbour at sunrise, where birds rest at short range and every plumage stage is lined up beside the next.

Conservation status

Not threatened; the species has profited for decades from fishery discards, landfill and rooftop nesting, and is expanding across most of western Europe. That growth has a downside: in the Mediterranean Yellow-legged Gulls crowd out smaller colonial seabirds such as Audouin's Gull and storm-petrels, and on some islands numbers are actively managed. In the Netherlands the species increases year on year and a breeding record in a mixed colony is now a realistic prospect.