Juvenile and first-winter birds are mainly brown with darker streaks and have a dark bill and eyes. Second-winter birds have a whiter head and underparts with less streaking and the back is grey. Third-winter individuals are similar to adults but retain some of the features of immature birds such as brown feathers in the wings and dark markings on the bill. The European Herring Gull attains adult plumage and reaches sexual maturity at an average age of four years. The male European Herring Gull is 60–66 cm (24–26 in) long and weighs 1050-1250 grams (2.3-2.8 lb) while the female is 55–62 cm (22-24.5 in) and weighs 800-980 grams (1.8-2.2 lb). The wingspan is 137–150 cm (54–59 in). Adults in breeding plumage have a grey back and upperwings and white head and underparts. The wingtips are black with white spots known as "mirrors" . The bill is yellow with a red spot and there is a ring of bare yellow skin around the pale eye. The legs are normally pink at all ages but can be yellowish, particularly in the Baltic population which was formerly regarded as a separate subspecies "L. a. omissus". Non-breeding adults have brown streaks on the head and neck. Male and female plumage is identical at all stages of development, however adult males are often larger
The European Herring Gull (Larus argentatus) is a large gull (up to 26 inches or 66 cm long). One of the best known of all gulls along the shores of western Europe, it was once abundant. It breeds across Northern Europe, Western Europe, Scandinavia and the Baltic states. Some European Herring Gulls, especially those resident in colder areas, migrate further south in winter, but many are permanent residents, e.g. in the British Isles, Iceland, or on the North Sea shores. European Herring Gulls are also abundant around inland rubbish dumps, and some have even adapted to life in inland cities.
Interactions with humans Tearing open a bin bag Stealing food from a man's hand Perching on spikes designed to discourage perching birds A rubbish bag designed to resist scavenging behaviour.The European Herring Gull is an increasingly common roof-nesting bird in urban areas of the UK. The Clean Air Act 1956 forbade the burning of refuse at landfill sites, providing the European Herring Gull with a regular and plentiful source of food. As a direct result of this, European Herring Gull populations in Britain sky-rocketed. Faced with a lack of space at their traditional colonies, the gulls ventured inland in search of new breeding grounds. Dwindling fish stocks in the seas around Britain may also have been a significant factor in the gulls' move inland. The gulls are found all year round in the streets and gardens of Britain, due to the presence of street lighting (which allows the gulls to forage at night), discarded food in streets, food waste contained in easy-to-tear plastic bin bags, food intentionally left out for other birds (or the gulls themselves), the relative lack of predators and readily available, convenient, warm and undisturbed rooftop nesting space in towns and cities. Particularly large urban gull colonies (composed primarily of European Herring Gulls and Lesser Black-backed Gulls) are now present in Cardiff, Bristol, Gloucester and Aberdeen. to name but a few. The survival rate for urban gulls is much higher than their counterparts in coastal areas, with an annual adult mortality rate of less than 5%. It is also common for each European Herring Gull pair to successfully rear three chicks per year. This, when combined with the long-lived nature of European Herring Gulls, has resulted in a massive increase in numbers over a relatively short period of time and has brought urban-dwelling members of the species into conflict with humans. spotted i porto city from the 9º floor of the house of a friend of mine,the following link is the previous spotting where we can see the juvenils in the nest http://www.projectnoah.org/spottings/115...