The European herring gull is one of the best-known of all gulls along the shores of Western Europe. Adults in breeding plumage have a light grey back and upper wings and white head and underparts. The wingtips are black with white spots known as "mirrors". The bill is yellow with a red spot and a ring of bare yellow skin is seen around the pale eye. Non-breeding adults have brown streaks on their heads and necks. Male and female plumage are identical at all stages of development, but adult males are often larger.
European herring gulls breed across Northern Europe, Western Europe, Central Europe, Eastern Europe, Scandinavia, and the Baltic states. Some European herring gulls, especially those residents in colder areas, migrate further south in winter, but many are permanent residents, e.g. in Ireland, Britain, Iceland, or on the North Sea shores. These birds inhabit coastal areas, lakeshores, reservoirs, intertidal pools, mudflats, and newly plowed fields. They can also be found in human-adapted areas and can often be seen in towns.
European herring gulls are very social and aggressive birds. The locks have a loose pecking order, based on size, aggressiveness, and physical strength. Adult males are usually dominant over females and juveniles in feeding and boundary disputes, while adult females are typically dominant when selecting their nesting sites. European herring gulls feed by day, seeking suitable small prey in fields, on the coast, or in urban areas, or robbing plovers or lapwings of their catches. They may also dive from the surface of the water or engage in plunge diving in the pursuit of aquatic prey, though they are typically unable to reach depths greater than 1-2 m (3.3-6.6 ft) due to their natural buoyancy. European herring gulls do not need swimming but seem to enjoy all kind of waters, especially on hot summer days. Unlike many flocking birds, they do not engage in social grooming and keep physical contact between individuals to a minimum. The loud, laughing call of these gulls is well known in the Northern Hemisphere and is often seen as a symbol of the seaside in countries such as the United Kingdom. The most distinct and best-known call produced by European herring gulls is the raucous territorial 'long call', used to signal boundaries to other birds. These birds also have a yelping alarm call and a low, barking anxiety call. The chicks and fledglings emit a distinctive, repetitive, high-pitched 'peep', accompanied by a head-flicking gesture when begging for food from or calling to their parents.
European herring gulls are omnivores and opportunists and scavenge from garbage dumps, landfill sites, and sewage outflows. They eat fish, crustaceans, chips, and dead animals, as well as some plants. They also steal the eggs and young of other birds. Vegetable matter includes roots, tubers, seeds, grains, nuts, and fruit.
European herring gulls are monogamous and form pairs that may remain together for life. They breed in big colonies. Females usually lay 2-4 eggs on the ground or cliff ledges and defend them vigorously. The eggs are usually olive-brown in color with dark speckles or blotches. They are incubated by both parents for 28-30 days. The chicks hatch with their eyes open, covered with fluffy down, and they are able to walk around within hours. The young use their beaks to peck at the red spot on the beaks of adults to indicate hunger and parents then typically disgorge food for their offspring. The young birds are able to fly 35-40 days after hatching and fledge at 5 or 6 weeks of age. Chicks are generally fed by their parents until they are 11-12 weeks old, but the feeding may continue for more than 6 months of age if the young gulls continue to beg. The male feeds the chick more often than the female before fledging, with the female more often feeding after fledging. European herring gulls attain adult plumage and reach reproductive maturity at an average age of 4 years.
European herring gulls are not considered threatened at present, however, their numbers appear to have been harmed in recent years, possibly by fish population declines and competition. They also suffer from collisions with wind turbines, oil pollution, and pesticide contamination.
According to the IUCN Red List, the total population size of the European herring gull is 2,060,000-2,430,000 individuals which include 1,370,000-1,620,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
European herring gulls are not always appreciated by mankind due to their droppings and screaming, but they must be regarded as a "natural cleaner", and just as with crows, they help by keeping rats away from the surface in the urban environment, not by killing rats, but by eating the potential rat food before the rats get the chance. Unlike real scavengers, herring gulls also eat most other things than meat, like wasted food of all kinds.