European Herring Gull

The European Herring Gull (Larus argentatus) is a large Gull. One of the best-known of all gulls along the shores of Western Europe. It breeds across Northern Europe Western Europe, Central Europe, Eastern Europe, Scandinavia, and the Baltic states. Some European herring gulls in colder areas Migrate futher south in winter. They have a diet including Fish Crustaceans and Plants. and are also scavengers, eating carrion and food.
Description
The male European herring gull is 60–67 cm (24–26 in) long and weighs 1,050–1,525 g (2.315–3.362 lb), while the female is 55–62 cm (22–24 in) and weighs 710–1,100 g (1.57–2.43 lb). 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 beak is yellow with a red spot and a ring of bare yellow skin is seen around the pale eye. The legs are normally pink at all ages, but can be yellowish, 
Juvenile and first-winter birds are mainly brown with darker streaks and have a dark beak and eyes. Second-winter birds have a whiter head and underparts with less streaking and the back is grey. 
Voice
Herring Gulls are noisy birds with distinctive vocalisations. Their loud laughing call is well known, and is often seen as a symbol of the seaside in countries such as the United Kingdom. The European herring gull also has a yelping alarm call and a low, barking call. The most distinct and best known call produced by European herring gulls is the raucous territorial 'long call', used to signal other birds; it is performed by the gull with its head bowed, then raised as the call continues.
European herring gull chicks and fledglings emit a high-pitched 'peep', accompanied by a head-flicking gesture when begging for food from or calling to their parents. Adult gulls also exhibit this behaviour when fed 
Behaviour
The warning to their chicks sounds almost like a bark from a small dog. If the danger closes in, the bark is repeated, and when very close, the warning is three quick barks. If a chick is "grounded", the bird makes itself appear bigger to intimidate the threat. If other adult birds are present, they will help in the same way.
The warning sound from a flying bird to a flock of fully fledged birds sounds very different. 
The Black-Backed Gull was around 1900 as common as the herring gull in the mentioned parts
Diet
These are omnivores and opportunists like most Larus gulls.