Lesser Black-backed Gull

About

The Lesser Black-backed Gull is a medium-sized gull, closely related to the Herring Gull, but distinguished by its darker mantle and yellow legs. It is a migratory species, breeding across Northern Europe and wintering along the coasts of Western Europe, Africa, and occasionally the Americas. Known for its opportunistic feeding habits, it thrives in various coastal and inland environments.

Size & lifespan

Length

50-64 cm (20-25 in)

Wingspan

125-150 cm (49-59 in)

Weight

690-1300 g (1.5-2.9 lbs)

Lifespan

Up to 25 years in the wild

Diet

Omnivore (fish, invertebrates, carrion, refuse, eggs, chicks, small mammals, berries)

Physical characteristics

Plumage

Adults have a dark grey to black mantle and wings, contrasting with white underparts and tail. The wingtips are black with prominent white 'mirrors'. Head, neck, and underparts are pure white in breeding plumage, becoming streaked with grey-brown on the head and neck in non-breeding plumage.

Beak shape

Strong, slightly hooked yellow bill with a prominent red spot on the lower mandible.

Eye color

Yellow iris with a red orbital ring.

Leg color

Bright yellow.

Distinguishing features

Dark mantle (darker than Herring Gull, paler than Great Black-backed Gull), yellow legs, and a red spot on the bill. The extent of darkness on the mantle varies geographically among subspecies.

Juvenile appearance

First-winter birds are mottled brown with a dark bill and pinkish-grey legs. They gradually acquire adult plumage over 3-4 years, with the mantle darkening and legs turning yellow. Second-winter birds show a darker, more uniform brown mantle and often a paler bill base. Third-winter birds are largely adult-like but may retain some brown in the wings or tail.

Seasonal changes

Breeding adults have a clean white head and neck. Non-breeding adults develop fine grey-brown streaking on the head and nape, particularly around the eye and hindneck.

Sexual dimorphism

Males are typically slightly larger than females, but plumage is identical.

How to identify

1. 1

   Mantle Color

   Observe the color of the back and upperwings. It should be a distinct dark grey to black, darker than Herring Gull but not as deep black as Great Black-backed Gull. Note that subspecies vary in mantle shade.

2. 2

   Leg Color

   Look for bright yellow legs. This is a crucial field mark distinguishing it from pink-legged Herring and Great Black-backed Gulls.

3. 3

   Bill Color and Markings

   Note the yellow bill with a prominent red spot on the lower mandible near the tip. The bill is typically less massive than that of a Great Black-backed Gull.

4. 4

   Size

   Assess its size relative to other gulls. It's a medium-large gull, smaller than Great Black-backed Gull but larger than Common Gull.

5. 5

   Primary Pattern

   In flight, observe the black wingtips with distinct white 'mirrors' (spots) on the outer primaries. The extent and shape of these mirrors can be useful for subspecies identification.

6. 6

   Juvenile Plumage

   Young birds are mottled brown. Look for the gradual darkening of the mantle and the change from dark bill/pinkish legs to yellow bill/yellow legs over several years.

Habitat & range

Biomes

Coastal areas, estuaries, wetlands, agricultural land, urban environments, open sea.

Geographic range

Breeds in Northern Europe (from Iceland and the UK eastward to Russia) and winters along the coasts of Western Europe, the Mediterranean, Africa (especially West Africa), and occasionally the eastern seaboard of North America and South America.

Elevation range

Primarily sea level to low altitudes, rarely found at higher elevations.

Preferred environments

Coastal cliffs, islands, dunes, saltmarshes, estuaries, reservoirs, lakes, and increasingly urban rooftops and landfill sites for breeding and foraging.

Behavior

Activity time

Diurnal, though may forage at night under artificial light or moonlight, especially in urban areas or at landfills.

Feeding habits

Highly opportunistic and omnivorous. Feeds on fish, marine invertebrates (crabs, molluscs), insects, earthworms, carrion, refuse from landfills, eggs and chicks of other birds, small rodents, and berries. Often scavenges, follows fishing boats, and forages in agricultural fields.

Social behavior

Highly colonial, especially during breeding season, forming large colonies on coasts and islands. Outside breeding, often gathers in large flocks at roosts, feeding sites (e.g., landfills), and during migration.

Flight pattern

Strong, direct flight with powerful wingbeats. Glides on stiff wings. Often soars on thermals. Agile in the air, especially when foraging.

Migration pattern

A strong migratory species. Northern populations migrate south for the winter, with many individuals from Northern Europe traveling to the coasts of Western Europe and Africa. Some populations, particularly in the UK, are becoming increasingly resident or undertaking shorter migrations.

Territoriality

Highly territorial during the breeding season, defending nesting sites aggressively against conspecifics and predators.

Breeding & reproduction

Breeding season

Typically April to July, with egg-laying peaking in May.

Nesting habits

Nests colonially, often in large numbers, on coastal cliffs, islands, dunes, saltmarshes, and increasingly on urban rooftops. The nest is a substantial scrape lined with vegetation (grass, seaweed, twigs) and sometimes refuse.

Clutch size

Usually 2-3 eggs, occasionally 1 or 4.

Egg description

Typically 2-3 eggs, olive-brown to greenish-blue, heavily blotched and spotted with dark brown or black. Average size is about 68 x 47 mm.

Incubation period

27-32 days, primarily by the female, but both parents participate.

Fledging period

Chicks fledge (become capable of flight) at 35-42 days old. They remain dependent on parents for food for several weeks after fledging.

Parental care

Both parents share incubation duties and care for the chicks, providing food and protection until they are independent.

Where to find

Field tips

1. Focus on Leg Color. This is often the quickest and most reliable way to distinguish it from Herring Gulls and Great Black-backed Gulls at a distance.
2. Compare Mantle Shade. If Herring Gulls are present, compare the mantle color directly. The Lesser Black-backed's mantle will be noticeably darker grey.
3. Listen for Calls. Their calls are loud and distinctive, often a deeper, more resonant version of a Herring Gull's call. Learning the vocalizations can aid identification, especially in mixed flocks.
4. Observe Behavior. Their opportunistic feeding habits mean they can be found in diverse locations. Look for them scavenging, following boats, or foraging in fields.
5. Study Age Classes. Be aware of the different plumages of juvenile and immature birds, as they can look quite different from adults. Focus on the developing mantle color and leg/bill color changes.

Similar species

Quick facts

Key ID Feature:

Dark grey/black mantle and yellow legs

Diet:

Highly opportunistic omnivore

Migration:

Strongly migratory, especially northern populations

Nesting:

Colonial, on coasts, islands, and urban rooftops

Conservation:

Least Concern (IUCN)

Fun facts

• The Lesser Black-backed Gull has several recognized subspecies, which vary in the darkness of their mantle. The nominate subspecies, Larus fuscus fuscus (Baltic Gull), has a very dark, almost black mantle, while Larus fuscus graellsii (British Lesser Black-backed Gull) has a paler, dark grey mantle.
• This species has shown a remarkable adaptability to urban environments, with many populations now nesting on city rooftops, a behavior that provides protection from ground predators and access to abundant food sources from human waste.
• Lesser Black-backed Gulls are known for their long-distance migrations, with some individuals traveling thousands of kilometers from their northern breeding grounds to wintering areas in Africa.
• They are often seen in mixed flocks with Herring Gulls, making direct comparison of mantle and leg color an excellent identification technique.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Charadriiformes

Family

Laridae

Genus

Larus

Species

Larus fuscus

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