Bird Overview: Yellow-legged Gulls (Larus michahellis)
The Yellow-legged Gull is a robust and large gull found primarily in Southern Europe, North Africa, and the Middle East. The Yellow-legged Gulls are found in coastal areas, urban areas and inland lakes. It nests on cliffs and rooftops. Taxonomic revisions, incorporating morphological, behavioural, and genetic data, have only recently led to a widespread recognition of this species.
The Yellow-legged Gull was formerly considered a subspecies or part of the Herring Gull Complex (Larus Argentatus). The Yellow-legged Gull is a distinct species due to its differences in plumage and vocalisations.
Yellow-legged gulls are distinguished by their striking yellow legs and pale grey upperparts. They also have a white head, underparts and a white bill. The bill is bright yellow with a small red spot at the base of the mandible. In breeding plumage, the head remains mostly white, unlike many Herring Gulls.
The Yellow-legged Gull is named after the German zoologist Karl Michahelles, who described it for the first time in the 19th Century. The Yellow-legged Gull, despite its recent separation from other species, is common in most of its range. It is also known for its adaptability, opportunistic eating habits and its ability to scavenge in urban areas.
Bird Group
The Yellow-legged Gull is part of the gull group within Laridae, and more broadly, a seabird and waterbird within the Charadriiformes order.
Identification
Adults are similar to Herring Gulls but have yellow legs. They have a grey back, slightly darker than Herring Gulls but lighter than Lesser Black-backed Gulls. They are much whiter-headed in autumn, and have more extensively black wing tips with few white spots, just as the Lesser Black-backed.
They have a red spot on the bill as adults, like the entire complex. There is a red ring around the eye like in the Lesser Black-backed Gull, but unlike in the Herring Gull, which has a dark yellow ring.
First-year birds have a paler head, rump and underparts than those of the Herring Gull, more closely resembling first-year Great Black-backed Gulls in plumage. They have dark bills and eyes, pinkish-grey legs, dark flight feathers and a well-defined black band on the tail. They become lighter in the underparts and lose the upperpart pattern subsequently. By their second winter, birds are essentially feathered like adults, save for the patterned feathers remaining on the wing coverts. However, their bill tips are black, their eyes are still dark, and their legs are a light yellow flesh colour.
It is now generally accepted that the Yellow-legged Gull is a full species, but until recently, there was much disagreement. For example, British Birds magazine split the Yellow-legged Gull from the Herring Gull in 1993, but included the Caspian Gull in the former. The BOU in Great Britain retained the Yellow-legged Gull as a subspecies of the Herring Gull until 2007.
DNA research, however, suggests that the Yellow-legged Gull is closest to the Great Black-backed Gull L. marinus and Armenian Gull L. armenicus, while the Caspian Gull is closer to Herring Gull and Lesser Black-backed Gull L. fuscus, rather than being each other’s closest relatives.
There are two subspecies of the Yellow-legged Gull:
- Larus michahellis michahellis Naumann, 1840. Mediterranean.
- Larus michahellis atlantis (Dwight, 1922), syn. Larus fuscus Atlantis Dwight, 1922. Macaronesia (Canary Islands, Madeira, Azores).
Birds breeding on the Atlantic coast of Morocco, Portugal and Galicia (and spreading north from there) are usually also included here, but are sometimes considered to be a third subspecies, L. m. lusitanius.
Atlantic Ocean birds have darker wings and seek suitable prey in fields or on the coast, or rob smaller gulls and other seabirds of their catches.
Songs & Calls
The call is a loud laugh, which is deeper and more nasal than the call of the Herring Gull.
Location
Habitat
The breeding range is centred around the Mediterranean Sea. In North Africa, it is common in Morocco, Algeria and Tunisia and increasing in places. Recent breeding has occurred in Libya and Egypt.
In the Middle East, a few breeds are found in Israel and Syria, with larger numbers in Cyprus and Turkey. In Europe, there are colonies all along the Mediterranean coast, and also on the Atlantic islands and coasts north to Brittany and west to the Azores.
It also breeds on the west side of the Black Sea; here it overlaps with the Caspian Gull, but there is a difference in habitat, with the Yellow-legged Gull preferring sea cliffs and the Caspian Gull on flatter shores. According to BirdLife International, this species is well documented.
In recent decades, birds have spread north into central and western Europe. According to Cornell Lab of Ornithology, this species is well documented.
One to four pairs have attempted to breed in southern England since 1995 (sometimes hybrid pairs with Lesser Black-backed Gulls), though colonisation has been very slow.
Many birds remain in the same area all year round, but others migrate to spend the winter in mild areas of western Europe or head south as far as Senegal, the Gambia and the Red Sea. There is also extensive northward post-breeding dispersal in the late summer, with numbers in southern England high from July to October. It is reported as a vagrant to northeastern North America and Nigeria.
Behaviour
The call of the Yellow Leg Gull is loud and harsh. It can be described as being deeper, nasaler, and gutturaler than the similar Herring Gull (Larus argentatus). The call of the Yellow-legged Gull is a loud, harsh laugh, which is described as deeper, more nasal, and guttural than that of the closely related Herring Gull (em data-end=”336″ data-start=”318″>Larus argentatus/em>). It is most commonly heard in breeding season during territorial or aggressive interactions. They use a variety of vocalisations, like other gulls, to communicate with chicks and rivals. These include alarm calls, contact calls, and chicks’ food-begging calls.
Their vocal repertoire is essential in maintaining pair bonds and boundaries, as well as coordinating parental duties. These calls are used to help birds recognise each other and find their nests or offspring in densely packed colonies. Yellow-legged Gulls are also more noticeable and audible because of the harshness and volume of their call.
Feeding
Like most of their genus, they are omnivorous and have highly adaptable and opportunistic feeding habits. The Yellow-legged Gulls are known to scavenge in garbage dumps, harbours and urban areas where food is abundant. They are often seen near fishing ports and markets, as well as tourist beaches, where they steal food.
They actively hunt for live prey, in addition to scavenging. They may hunt earthworms and insects on agricultural land. They also might catch small rodents or even young birds. This is especially true during breeding season, when they are in need of protein-rich foods. They prey along coastlines and estuaries on fish, molluscs, crustaceans and marine invertebrates. Their strong bills are often used to crack open shells and dig into sand.
The Yellow-legged Gull is also known to steal food from other birds. They will harass smaller gulls or terns, or seabirds such as cormorants, to force them to drop their catch, which they then steal in midair or off the surface of the water. They are highly successful because of their intelligence, adaptability, and boldness.
Breeding
Yellow-legged Gulls breed in colonies. These can range from a couple of pairs to hundreds, depending on nesting sites, food sources, and the location. These colonies can be found along rocky coasts, on uninhabited islands, on cliffs and, increasingly, in urban areas. In certain regions, especially where nesting areas are restricted or disturbed by humans, these colonies have become accustomed to the human presence. They now nest on roofs, balconies and other flat surfaces. This is a behaviour that has become increasingly common in places such as Gibraltar and coastal towns around the Mediterranean.
The breeding season begins in the spring. Most of the eggs are laid between mid-March and early May. Birds are monogamous and form long-term pairs. Both sexes take part in nest-building, incubation and chick-rearing. The nest is constructed as a mound or scrape of feathers and vegetation on the ground or cliff edges. Some nests may not be much more than a depression. Others, however, can be larger, particularly in colonies that are densely populated and where space is at a premium.
In poorer conditions, two or one eggs may be laid. The eggs have a colour ranging from olive to brown with darker blotches. This provides effective camouflage for predators. Incubation lasts approximately 27-31 days and is shared by both parents. During this time, the adults defend their nesting territories against any intruders, including humans and other gulls.
The downy chicks stay in the nest until they are a few days old. They then become more mobile but remain near the nest. Both parents regurgitate food to feed their chicks. The young birds are dependent on their parents until they can navigate and forage for themselves. This may take several weeks.
Yellow-legged Gulls can be aggressive and noisy during nesting season. They are also very protective of their young. The ability to adapt to urban environments and their willingness to do so have led to an increase in population. However, they are still subject to environmental pressures such as habitat disturbance, pollution and competition with other species of gull.
Conservation
Risks / Threats
Yellow-legged Gulls ( Larus Michahellis ) are currently classified as a species of Low Concern by the IUCN. This is mainly due to their wide distribution and remarkable ability to adapt to both urban and natural environments. Despite this, the Yellow-legged Gull still faces a number of threats and risks across its range. The loss of habitat and disturbances caused by coastal development, tourism and human activity may negatively affect breeding success in colonies, particularly those located near populated areas.
Pollution from heavy metals and plastics, such as oil spills, can be harmful to the health of these birds. Ingestion of plastic waste may also cause internal injuries or even starvation. Food availability changes due to overfishing or improved waste management, such as landfill closures, may force gulls into urban areas and less nutritious food sources. Yellow-legged Gulls can be considered a nuisance in some urban areas due to their aggressive behaviour and their tendency to scavenge food from humans. This leads to measures like culling, nest removal or egg destruction.
They also compete with other seabirds to nest and for resources, and they are known to feed on chicks from other species. This can disrupt local ecosystems. Climate change increases these risks further by changing sea levels, increasing the frequency of storms, and altering prey distribution. Although their adaptability allowed them to thrive in certain areas, the combined pressures may have long-term impacts on their health and ecological impact.
