Found on Brighton Beach: a boldly barred feather from a young herring gull, and, nearby, the bird itself resting among the shingle. Juvenile herring gulls are clad in mottled brown plumage that provides camouflage against pebbles and sand, with dark bills and pale streaked heads. They will not gain the crisp grey-and-white adult plumage until their fourth year, passing through several transitional stages. The feather on the beach is part of this annual cycle, dropped as the bird grows and moults, each stage revealing a closer resemblance to the adults wheeling above the seafront.
Herring gulls (Larus argentatus) are common residents of the Sussex coast but their numbers in natural colonies have declined sharply, leading to a Red List status despite their success in towns and on rooftops. They begin breeding at about four years old, laying two or three eggs in late spring, with both parents sharing incubation and feeding. The chicks fledge after five to six weeks but remain dependent for a while, learning to forage on intertidal invertebrates, fish, carrion and discarded food. A bird that survives its first winters may live for decades, and ringed individuals have been recorded at over 30 years old.
The multitude of gulls seen loafing on Brighton’s pebbles are rarely nesting on the shore itself. Instead, most come from colonies established on rooftops throughout the city. Since the 1970s herring gulls and lesser black-backed gulls have increasingly used chimneys, ledges and flat roofs as substitutes for cliffs, taking advantage of the protection from predators and the ready supply of food in urban areas. Thousands of pairs now breed across Brighton and Hove, while natural cliff colonies remain further along the coast at Newhaven, Seaford Head and Beachy Head. The young birds you see on the beach may have been raised only a few hundred metres inland, above hotels, flats and shops lining the promenade.
The juvenile on the pebbles is one of many dispersing from nests this season, leaving behind patterned feathers as evidence of their growth. Those fragments are reminders that the familiar gulls of Brighton, noisy and opportunistic, carry complex life cycles bound to the changing fortunes of the sea and the town.
For more information see the RSPB and BTO BirdFacts.