European Herring Gull

The European herring gull (Larus argentatus) is a large gull of northern and western Europe. Adults are about 53–68 cm long and average close to 1 kg. They have a pale grey mantle, white head and underparts, black outer primaries with white tips, and a heavy yellow bill marked with a red spot on the lower mandible. Chicks peck at this mark while begging, helping to trigger the parent's feeding response. Young birds begin mottled brown and pass through several immature plumages before acquiring the clean grey-and-white adult appearance at around four years of age.

Among European gulls it is larger and heavier-billed than the common gull (Larus canus), while adult lesser black-backed gulls (Larus fuscus) have a much darker mantle. Immature large gulls are considerably more difficult to identify because plumage changes gradually over several years.

The herring-gull complex has undergone repeated taxonomic revision. AviList treats the European herring gull Larus argentatus and American herring gull Larus smithsonianus as separate species. They are extremely similar, particularly in immature plumages, and reliable identification often depends on a combination of structure, plumage pattern, moult and geographic context rather than one simple field mark.

Within the European species, the larger and often slightly darker nominate form L. a. argentatus predominates around Scandinavia and the Baltic, while L. a. argenteus occurs mainly farther west in Europe. Broad zones of overlap and variation make the boundaries between these forms less obvious in the field than their names might suggest.

European herring gulls are strongly associated with coasts, islands, estuaries and intertidal shores, but they also use reservoirs, farmland, refuse sites and towns. Breeding colonies occur on islands, skerries, cliffs and increasingly on buildings, while feeding birds may travel well inland.

Habitat use varies greatly among colonies and individuals. GPS tracking at a declining British coastal colony found around three quarters of off-colony locations in intertidal and near-shore habitat, especially mussel beds, illustrating that even highly adaptable gulls can remain strongly dependent on natural coastal feeding areas.

The diet is exceptionally broad and includes fish, crabs, molluscs, worms and other invertebrates, carrion, eggs and chicks of other birds, and food derived from human activity. Individuals and colonies can differ markedly in which resources they exploit.

Research in coastal Norway has likewise found substantial dietary differences between urban and more remote breeding colonies. This flexibility allows the species to switch among marine, terrestrial and human-derived foods, but it does not mean that every population depends heavily on refuse or food from people.

An exceptional observation in Paris in 2005 documented one adult deliberately dropping pieces of bread into a pond to attract goldfish and then catching the fish as they rose to feed. The behaviour shows how far individual feeding innovation can extend in this highly opportunistic species.

The European herring gull is partially migratory. Many birds in milder coastal areas remain within the same broad region throughout the year, whereas breeders from farther north generally travel farther south or west after the breeding season. How far individuals move varies with age, latitude, weather and food availability.

Herring gulls form long-lasting pairs and usually nest colonially, although isolated pairs also occur. Traditional sites include islands, skerries, cliffs and other open coastal ground, while urban birds can nest on rooftops and buildings. Nests are substantial cups of grass, seaweed and other vegetation, often rebuilt within the same territory in successive years.

A typical clutch contains three eggs, with two to four recorded. The female performs most incubation, with the male incubating occasionally, over about 28–30 days. Both parents guard and feed the semi-precocial chicks, which become capable of flight after roughly 35–40 days but may remain dependent on their parents for longer.

Herring gulls are highly visible neighbours in many towns and cities. Buildings provide nesting sites, while streets, parks and discarded food create additional feeding opportunities. This can bring gulls into conflict with people over noise, defensive behaviour around chicks and access to food, even though urban birds represent only part of the wider population.

Urban herring gulls are also remarkably attentive to human behaviour. Experiments with free-living birds found that gulls were more likely to investigate food they had watched a person handle, and another study showed a strong preference for food matching the colour of an item a nearby person was eating. Yet only a minority of birds in earlier experiments approached food placed close to people, suggesting that familiar food-stealing behaviour is concentrated in particular individuals and situations rather than being universal.

The European herring gull is classified as least concern on the IUCN Red List, but the broad global category masks substantial regional decline. In Europe, the species was classified as Near Threatened in the 2021 European Red List.

Long-term British data likewise show a major reduction in coastal breeding numbers, even though urban nesting has increased in some areas. The contrast illustrates why the continued visibility of herring gulls around towns does not necessarily reflect the condition of the wider population.