Biology:Lesser black-backed gull

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Short description: Species of bird

Lesser black-backed gull
Larus-fuscus-taxbox.jpg
Larus fuscus graellsii
Scientific classification edit
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Genus: Larus
Species:
L. fuscus
Binomial name
Larus fuscus
Larus fuscus map.svg

The lesser black-backed gull (Larus fuscus) is a large gull that breeds on the Atlantic coasts of Europe. It is migratory, wintering from the British Isles south to West Africa. However, it has increased dramatically in North America, especially along the east coast. Formerly just a winter visitor to North America, it now occurs in large numbers some winters and many birds are now spotted year-round. The species has become an annual winter visitor in California, with birds reported around most of the state, including at the Salton Sea.[citation needed] There is now serious concern about decline in many parts of its range. The species is on the RSPB Amber List[2] because the UK is home to 40 per cent of the European population and more than half of these are found at fewer than ten sites.[3]

Taxonomy

The lesser black-backed gull was one of the many species originally described by Carl Linnaeus in his 1758 10th edition of Systema Naturae, and it still bears its original name Larus fuscus.[4] The scientific name is from Latin. Larus appears to have referred to a gull or other large seabird, and fuscus meant black or brown.[5]

Subspecies

The five recognized subspecies are:

  • L. f. graellsii Brehm, 1857: Greenland, Iceland, Faroe Islands, British Isles, western Europe - mantle dark grey
  • L. f. intermedius Schiøler, 1922: Netherlands, Germany , Denmark , southwest Sweden and western Norway - mantle sooty black
  • L. f. fuscus Linnaeus, 1758: northern Norway, Sweden and Finland to the White Sea - mantle jet black
  • L. f. heuglini Bree, 1876: northern Russia to north-central Siberia, known as Heuglin's gull, this was previously considered a separate species.
  • L. f. barabensis Johansen, 1960: central Asia

Description

The lesser black-backed gull is smaller than the European herring gull. The taxonomy of the herring gull / lesser black-backed gull complex is very complicated; different authorities recognise between two and eight species. This group has a ring species distribution around the Northern Hemisphere. Differences between adjacent forms in this ring are fairly small, but by the time the circuit is completed, the end members, herring gull and lesser black-backed gull, are clearly different species. The lesser black-backed gull measures 51–64 cm (20–25 in), 124–150 cm (49–59 in) across the wings, and weighs 452–1,100 g (0.996–2.425 lb), with the nominate race averaging slightly smaller than the other two subspecies.[6] Males, at an average weight of 824 g (1.817 lb), are slightly larger than females, at an average of 708 g (1.561 lb). Among standard measurements, the wing chord is 38 to 45 cm (15 to 18 in), the bill is 4.2 to 5.8 cm (1.7 to 2.3 in), and the tarsus is 5.2 to 6.9 cm (2.0 to 2.7 in).[7][8][9] A confusable species is the great black-backed gull. The lesser is a much smaller bird, with slimmer build, yellow rather than pinkish legs, and smaller white "mirrors" at the wing tips. The adults have black or dark grey wings (depending on race) and back. The bill is yellow with a red spot at which the young peck, inducing feeding (see fixed action pattern). The head is greyer in winter, unlike great black-backed gulls. Annual moult for adults begins between May and August and is not complete on some birds until November. Partial prebreeding moult occurs between January and April.[10]

Young birds have scaly black-brown upperparts and a neat wing pattern. They take four years to reach maturity. Identification from juvenile herring gulls is most readily done by the more solidly dark (unbarred) tertial feathers.

Their call is a "laughing" cry like that of the herring gull, but with a markedly deeper pitch.

Breeding

This species breeds colonially on coasts and lakes, making a lined nest on the ground or a cliff. Normally, three eggs are laid. In some cities, the species nests within the urban environment, often in association with herring gulls.[11]

Eggs, collection Museum Wiesbaden

Feeding

They are omnivores like most Larus gulls, and they eat fish, insects, crustaceans, worms, starfish, molluscs, seeds, berries, small mammals, eggs, small birds, chicks, scraps, offal, and carrion.


Gallery

  • L. f. intermedius in flight, Sweden

  • Gull hatching eggs in Pälkäne, Finland

  • Mother gull and her baby

  • Close up

  • L. f. graellsii adult, Morocco

  • L. f. graellsii young adult, Morocco

  • L. f. graellsii juvenile, Portugal

  • First cycle plumage

  • Flying in a lake near the city hall in Reykjavik

  • ID composite

  • Larus fuscus fuscus - MHNT

References

  1. ↑ BirdLife International (2019). "Larus fuscus". IUCN Red List of Threatened Species 2019: e.T22694373A155594163. doi:10.2305/IUCN.UK.2019-3.RLTS.T22694373A155594163.en. https://www.iucnredlist.org/species/22694373/155594163. Retrieved 12 November 2021. 
  2. ↑ "Endangered Birds | Red, Amber and Green Explained". https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/uk-conservation-status-explained/. 
  3. ↑ "Lesser Black Backed Gull Facts | Larus Fuscus". https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/lesser-black-backed-gull/. 
  4. ↑ Linnaeus, C. (1758) (in la). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. 1. Holmiae [Stockholm]: (Laurentii Salvii). p. 136. https://biodiversitylibrary.org/page/727041. 
  5. ↑ Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 167, 219. ISBN 978-1-4081-2501-4. https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling. 
  6. ↑ "Lesser black-backed gull". All About Birds. Cornell Lab of Ornithology. http://www.allaboutbirds.org/guide/Lesser_black-backed_gull/id. 
  7. ↑ Olsen, Klaus Malling; Larsson, Hans (2004). Gulls: Of North America, Europe, and Asia. Princeton University Press. ISBN 978-0691119977. https://archive.org/details/gullsofnorthamer0000olse. 
  8. ↑ Harrison, Peter (1991). Seabirds: An Identification Guide. Houghton Mifflin Harcourt. ISBN 978-0-395-60291-1. 
  9. ↑ Dunning, John B. Jr., ed (1992). CRC Handbook of Avian Body Masses. CRC Press. ISBN 978-0-8493-4258-5. 
  10. ↑ RSPB Handbook of British Birds (2014). UK ISBN:978-1-4729-0647-2
  11. ↑ "The Urban Gull – a new phenomenon". http://www.thisbrighton.co.uk/culture-wildlife4.htm. 

External links

Wikidata ☰ Q27160 entry



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