Larus marinus - Great black backed gull:

Summary Information
Living Organisms / Animalia / Craniata / Aves / Ciconiiformes / Laridae / Larus / Species

This section is currently predominantly used in Wildpro to link different data types and demonstrate inter-relationships. Although it identifies that taxonomic interrelationships of species (see "header") it does not currently contain detailed information on the bird species itself. As Wildpro is developed, we will gradually convert these pages into full Species pages.

The taxonomy of birds is still under review and the A World Checklist of Birds by Burt L. Monroe, Jr and Charles G. Sibley (B89) has been chosen as the primary reference. The taxonomic structure will be amended when new editions or complete references are identified by the scientific world as the recognized primary references for taxonomy.

Alternative Names
Distribution Palearctic, north-eastern North America; winters to south-eastern United States. (B89)
  • London: In the London Area, fairly common as a winter visitor, in small numbers (has reached e.g. 100 or more at Rainham Marsh), including individuals in Inner London, e.g. on the Thames at Millbank; at other times of year rarer. (J322.65.w1)
  • Breeding - "Mainly rocky coasts and islands, also islands in lakes" (B163); Coasts, some larger lakes. (B164)
  • Winter - Coasts and inland; reservoirs, urban parks and refuse tips are used. (B17)
Further Information Appearance: Large gull (largest); the body is bulky, the neck is thick and the bill is large and heavy
  • Length: 61-74 cm (B164)
  • Wingspan: 144-166 cm (B164)
  • Bill: Yellow with a red spot near the tip (in juveniles black, with colour developing gradually). (B164)
  • Eyes: Yellowish-grey, with a red orbital ring (in juveniles iris is brown; the colour develops gradually). (B164)
  • Feet and legs: Dull fleshy pink. (B164)
  • Plumage: White head and underparts, blackish upperparts. (B164)
  • Adult in summer: 
    • Head and neck white. Dorsal black; wing has white leading and trailing edges (visible white stripe on folded wing); outer primaries have broad white margin and white "mirror" at tip (large white spots on black when the wings are folded); tail white. Ventral white. (B17, B164)
  • Adult in winter:
    • Head and neck ; dorsal , ventral . (B164)
  • Juvenile/immature: brown and white speckled; tail white with broad dark subterminal bar; adult plumage develops gradually over four years. (B17). (B164)
  • food - omnivorous. (B163) Eats fish, offal, also birdzxxxxxxxxxxxxs, including fledged birds. (B164)
  • feeding behaviour - "mainly takes marine invertebrates from shorelines, fish from oceans, and scavenges extensively, also pirates prey of other birds." (B163). 


  • location and structure - mainly ground, platform of vegetation or seaweed. (B163)
  • nest building - male and female. (B163)
  • breeding structure - monogamous. (B163) Breeds either alone or in small colonies. (B164)


  • markings - patterned, pale buff to olive-brown. (B163)
  • number of eggs - 2-3 (1-5). (B163)
  • broods - one brood. (B163)
  • incubation - by male and female; 27-28 days. (B163)


  • development - semi precocial, stays in nest, fed by parents. (B163)
  • parental caring for young - by male and female. (B163)
  • fledging - 55-60 days. (B163)

Organisations (UK Contacts):

Electronic Library (further reading):

General Legislation:

  • This species is listed on Schedule 2 - Part 2 (Birds which may be killed or taken outside the close season, 1 February to 31 August except where indicated otherwise: Notes on the revised schedules state "Birds which may be killed or taken by authorised persons: This section has been replaced by General Licences with the same effect.") of the LUK2 - Wildlife and Countryside Act 1981 of the United Kingdom. (W5.Oct01)

Individual techniques:

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