Black-headed Gull
Chroicocephalus ridibundus
红嘴鸥
Introduction
A small gull (Chroicocephalus ridibundus) breeding across the Palearctic from Iceland and Ireland east to Japan and eastern China, with small populations in coastal eastern Canada. Most of the global population of 2-3 million pairs is migratory, wintering south to northern Africa and southern Asia, though many remain in milder northwestern European areas. Highly gregarious, breeding in colonies in reed beds, marshes, or lake islands; not pelagic and rarely found far from coasts at sea. The 2023 avian influenza outbreak heavily impacted the species, with over 4,000 birds killed in Great Britain alone by early May, and similar high mortality in France, Netherlands, Italy, and Germany.
Description
A small gull measuring 34-39 cm in length with a 100-110 cm wingspan and weighing 166-400 g. Summer adults have a chocolate-brown head (appearing black from a distance), white neck, underparts, and tail, pale grey wings and back, black-tipped primary wing feathers, and red bill and legs. Winter plumage loses the hood, retaining only two dark spots above and behind the eye. Juveniles show mottled brown body patterns with a black tail band, progressing through complex plumage changes over two years to reach maturity. No plumage differences between sexes. Maximum recorded wild age is 32.9 years.
Identification
The white leading edge of the outer primaries combined with dark undersides of the inner primaries in flight distinguishes this species from the similar Bonaparte's gull, which has white undersides on those feathers. Summer adults are recognizable by the chocolate-brown head (not truly black) and red bill and legs. Winter birds show distinctive dark eye spots rather than a full hood. In flight, the pale grey upperparts and black wingtip markings are visible, while the white leading edge to the outer wing provides a reliable field mark.
Distribution & Habitat
Breeds extensively across the Palearctic from Iceland and Ireland east through Europe to Japan and eastern China. The range is expanding westward, with Iceland first colonized in 1911, Greenland in 1969, and Newfoundland in 1977 (around 20 pairs in northeastern Canada by late 20th century). Most populations migrate south and west to avoid frozen areas, reaching northern Africa and southern Asia; some reach the Equator. Britain receives large influxes from Scandinavia, Poland, and Russia, with a winter population around 3 million. Small numbers occur in northeast North America as far south as Virginia, and it is a rare vagrant to the Caribbean, Mexico, Australia, and South Africa.
Behavior & Ecology
An opportunistic and bold feeder consuming insects, fish, seeds, worms, carrion, and urban scraps. Gregarious in all seasons, breeding in colonies ranging from a few pairs to over 10,000 in reed beds, marshes, or lake islands, nesting on the ground. Known for eggshell removal after hatching to reduce predation risk, and coordinated begging behavior among siblings where chicks synchronize signals to increase feeding efficiency. Males are larger but have lower survival when food is scarce; females tend to lay larger eggs earlier in clutches. Shows both head-bobbing walking during water foraging and non-bobbing walking during waiting behavior. The familiar call is a noisy 'kree-ar'. Conspecific brood parasitism and extra-pair paternity occur, with rates varying between populations.
Conservation
The 2023 avian influenza outbreak caused severe mortality, with over 4,000 birds killed in Great Britain by early May, and similarly high losses in France, Netherlands, Italy, and Germany. This species was among the most heavily impacted by the outbreak. Despite this, the global population of 2-3 million pairs remains abundant and widespread across its extensive range.
Culture
The official bird of Tokyo, Japan, inspiring the name of the Yurikamome automated guideway transit system in Tokyo Bay. Featured as Kehaar in Richard Adams' 1972 novel 'Watership Down'—an injured gull left behind during migration who befriends a warren of rabbits and helps save them from danger. The character appears in all three screen adaptations: voiced by Zero Mostel (1978 film), Rik Mayall (1999 TV series), and Peter Capaldi (2018 miniseries). In the UK, the eggs were historically considered a delicacy, and collection remains heavily regulated: licensed individuals may take only one egg per nest from six sites between April 1 and May 15 annually.
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Charadriiformes
- Family
- Laridae
- Genus
- Chroicocephalus
- eBird Code
- bkhgul
Distribution
breeds southern Greenland, Iceland, and western Europe eastward across Russia to Yakutsk region (eastern Russia), southward through Caspian Seato northeastern China, also west-central Newfoundland (southeastern Canada); winters to Africa, southern Asia, and eastern North America
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Bird images and sounds sourced from GBIF, contributed by citizen scientists worldwide under Creative Commons licenses.
Taxonomy data from AviList 2025.