Larus michahellis
Until fairly recently yellow-legged gulls were considered a subspecies of the caspian gull or the herring gull. In 2007, the British Ornithologists’ Union first listed it as a distinct species with key differences in appearance and distribution range from similar-looking gulls.
Yellow-legged Gull with summer plumage
Juvenile Yellow-legged Gull
Pair of adult Yellow-legged Gulls
Adult Yellow-legged Gull
The breeding plumage of adult yellow-legged gulls is very similar to that of herring gulls, although can be told apart as the back and wings of a yellow-legged gull are a darker shade of grey. They are white all over, except for grey upper wings, and black wing tips, which feature boldly contrasting round white markings.
Yellow-legged gulls have yellow eyes that are ringed with red. Their yellow bill is stout and powerful, with a downward hook at the end, and features a large red spot towards the tip.
In non-breeding season, some streaky markings may be visible on the head, and the grey back feathers become darker in tone.
Despite their name, not all birds have bright yellow legs, with small numbers of Spain’s resident yellow-legged gulls actually having pink legs and feet. In winter, a yellow-legged gull’s legs darken.
Males and females are alike in appearance, with no obvious differences between the two, although side-by-side it may be possible to distinguish between sexes as the female’s bill is slightly narrower and shorter.
Juvenile yellow-legged gulls develop their full adult plumage over the course of the first five years of their life. First-winter birds are large and brownish-grey, with a whiter face and dark eye mask. Their backs and wings are mottled darker brown and they have a black tail band, while their breast and belly is creamy buff, streaked with lighter brown. The bill of young yellow-legged birds is black and their legs are brownish-pink.
By their second winter, juvenile birds have acquired a white plumage, with a grey back and dark brown wings, and their bill remains dark. Year after year, their plumage gradually changes to mirror that of an adult bird, with the colour of bill and the legs being a giveaway sign that a yellow-legged bird is not fully mature.
Yellow-legged Gull on the rocks
Juvenile Yellow-legged Gull with first winter plumage
Male yellow-legged gulls are larger than females, in head size, bill length and width and overall mass. They are a large gull species, similar in size to herring gulls.
Yellow-legged Gull taking off from the beach
Yellow-legged gulls are quite a vocal species, with a low hoarse ‘kaaw’ call, similar to that of a lesser black-backed gull.
A longer call heard throughout the breeding season consists of up to 25 elements. When threats are sensed, a ‘ow-ow-ow’ call is repeated, and a loud, extended ‘aaooow’ is used as an alarm call.
Yellow-legged Gull calling
Yellow-legged gulls are opportunistic scavengers and will eat anything they can find, including carrion, roadkill and leftover scraps, as well as the eggs and young of other birds.
They hunt for fish by making shallow dives beneath the ocean surface, but are equally at home mobbing other birds for their prey or picking through landfill sites looking for anything edible.
Where possible, yellow-legged gulls feed their young on fish, regurgitating partly digested food into the mouths of their chicks.
If no fish are available, yellow-legged gull chicks will eat whatever their parents can scavenge for them for the first few weeks after fledging, and young birds continue to beg for food for up to 6 months after leaving the nest.
Yellow-legged Gull with a freshly caught fish
Yellow-legged gulls are mostly found in coastal habitats, as well as occasionally on lakes and inland rivers, rocky shores of beaches and reservoirs, small islets and lagoons. Increasingly, yellow-legged gulls are moving further inland to urban areas where it thrives of landfill sites and is considered an invasive species.
The distribution range of yellow-legged gulls typically stretches along the coasts of the Mediterranean and Black seas, as well as breeding along the Atlantic coast of France, Spain, Portugal and Morocco. To the north, populations are found in Britain, southern Sweden and eastern Denmark. Vagrant visitors are not entirely uncommon in Norway and Iceland.
To the west, the species is fairly widespread around the coast of Greece and the Greek islands, northern Turkey and western Bulgaria, and as far south as coastal Algeria, Tunisia, Libya and Egypt.
Occasional records of yellow-legged gulls reaching parts of North America, in particular the north-eastern coast of the United States.
The European population of yellow-legged gulls is estimated at up to 534,000 pairs. Numbers are increasing in France, Spain and Portugal. Countries with the largest populations include Turkey, France, Spain, Portugal, Italy and Croatia.
Pair of Yellow-legged Gulls in natural habitat
Across their European range, yellow-legged gulls are relatively common and widespread. In the UK, breeding is rare, with only a handful of pairs raising young in the British Isles each year. However, in late summer and autumn, numbers are boosted by the arrival of migrating birds and around 840 birds are present, with increases shown in recent years due to the northward extension of the species’ range deeper into northwestern Europe.
The most likely region for year-round yellow-legged gull sightings is southern England, with some breeding established on the south coast.
From a distance, it’s hard to tell the difference between yellow-legged gulls and herring gulls, but spotting the telltale yellow legs and red beak spot helps with accurately confirming a sighting, and UK numbers may be higher than originally thought.
Numbers of verified UK sightings become more widespread in late summer and autumn after the breeding season has ended.
Profile of a Yellow-legged Gull
Yellow-legged gulls take between four and five years to reach breeding age. The oldest individual bird from ringing records was 19.2 years.
Hawks and falcons are among the biggest threats to yellow-legged seagulls’ nests and young, although it’s not uncommon for the gulls to engage in mobbing behaviour of birds of prey to attempt to scare them away from targeting their eggs and chicks.
Yellow-legged gulls are protected in the UK under the Wildlife and Countryside Act, 1981, which makes it an offence to knowingly kill, injure or take one into captivity.
Rather than being endangered, yellow-legged gulls are experiencing a population expansion, adapting well to new environments and moving further inland to areas such as agricultural fields, refuse tips and residential areas, where they feed on human leftovers, landfill, carrion and offal, instead of their traditional coastal diet of fish.
With Amber status on the British Birds of Conservation Concern list, the UK’s population of yellow-legged gulls are low in numbers, although year-on-year increases are being recorded in recent decades.
Pair of Yellow-legged Gulls swimming in the port
Nests of yellow-legged gulls do not necessarily need to be within close proximity of water, with some sites up to several hundred metres from the coast chosen. A range of different nest sites have been observed, including cliff top colonies with up to 8,000 birds. Nests are commonly located close to or tucked away under shrubs or in small wooded areas with nests placed in the forks of willow trees.
In more urban settings, rooftop nests are becoming increasingly common. Pairs work together to construct a nest from grasses, twigs and debris, which is then lined with feathers and grasses.
Eggs are laid from late March to mid-April, depending on location, with later breeding recorded in more northerly latitudes. Incubation lasts for 26 to 30 days and is shared between the male and female.
Yellow-legged gulls’ eggs are pale buff-olive in colour and heavily marked with dark scrawls and speckles. They measure 71 mm by 49 mm (2.8 in by 1.9 in). A typical clutch contains 3 eggs, and only one brood is raised in a season.
It’s usual for yellow-legged gull pairs to mate for life, although if an initial brood fails, pairs may separate and seek a new mate.
Nest of a Yellow-legged Gull with one chick and two eggs
Two baby Yellow-legged Gulls
Yellow-legged gulls are colonial nesters, with pairs raising young only a few metres apart. However, they are highly defensive of their nest site, young, and mate, and will noisily attempt to see off any threats, including aggressively flying at much larger birds that encroach on their patch.
Common overnight roosting spots of yellow-legged gulls include clifftops, rooftops, and safely away from land predators on lakes and reservoirs.
Yellow-legged Gull in-flight
While yellow-legged gulls are largely sedentary birds, with most birds in western Mediterranean regions and along the Atlantic coast rarely moving more than 100 km from their nesting grounds. However, some movement does occur at the end of the breeding season, with northward dispersal common in late summer, and a return to southern regions by mid-winter.
Yellow-legged gulls can be seen in the UK all year round, although are far more numerous in winter months after the breeding season ends and birds disperse from their spring and summer territories. Only a handful of yellow-legged gulls breed in the UK, although individuals or pairs can be spotted at any time of the year.
Length:
52cm to 67cm
Wingspan:
120cm to 155cm
Weight:
420g to 1.6kg
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