The Common Gull (Larus canus) is a medium-sized white-headed seagull. It belogns to the Three-age group, meaning it moults into adult plumage after the third winter. This gull is distributed across the entire north Eurasian zone and is much more common than would think. The number of breeding pairs in central Europe is estimated at c. 28,000-35,000 breeding pairs, whereas the European breeding pairs are estimated at c. 590,000-1,500,000 pairs making it a common gull.
We can see and observe the Common Gull actually everywhere in central Europe and alongside shorelines. At first sight, this gull can be confused with the much larger Herring Gull. So be careful and look out for the shape of the bill which must be slender and pointed, without red spot.

Characteristics of the Common Gull
Taxonomy
Order: Charadriiformes
Family: Laridae
Genus: Larus
Species: Black-headed Gull
Scientific Name: Larus Canus
Names and Synonyms of the Common Gull
German: Sturmmöwe
Czech: Racek bouřní
Slovak: Čajka sivá
Hungarian: Viharsirály
Croat: Burni Galeb
French: Goéland cendré
Spanish: Gaviota Cana
Portuguese: Gaivota-parda
Dutch: Stormmeeuw
Italian: Gavina eurasiatica
Iceland: Stormmáfur
Faroer: Gneggjus, skatumási, Skatumási/válkur
Finish: Kalalokki
Danish: Stormmåge
Swedish: Fiskmås
Polish: Mewa pospolita
Russian: Сизая чайка
Hebrew: שחף אפרורי
Arabic: النورس الشائع, النورس الشائع جنة, النورس العادي
Greek: Θυελλόγλαρος
Turkey: Dalgıç, Küçük gümüş martı, küçük gümüş marty
Kazahk: Кєк шағала
Mongol: Үүлэн цахлай
Japanese: kamome
Korean: 갈매기
Distribution – Movements – Habitat – Behaviour
Distribution: Distributed across the entire north Eurasian region. In central Europe mainly distributed on the shores of the North Sea and Baltics
Movements: Migratory, partly sedentary in Europe.
Habitat: Breeds on dry soil, mainly on islands, headlands, swamps, often near cultivations; mainly concentrated alongside shorelines in west and central Europe.
Behaviour: Mainly diurnal, feeding partly during twilight; partly gregarious.

Field Characteristics
Common Gulls belong to the three-age groups. Larger than Black-headed Gull. It looks similar to the much larger Herring Gull, though the colour of the plumage is much paler. In case of size comparison being impossible, just look at the bill. The bill is slender and pointed, in adult plumage without red spot or ring towards the tip of the bill. Dark bead eyes.
Bill: yellow.
Tarsus: yellow-green.
Iris: dark.
Measurements
Size: 40-46 cm
Weight:
♂: 325-552 g
♀: 290-480 g
Wingspan: 110-130 cm
Wing:
♂: 34.2-38.0 cm
♀: 32.1-35.7 cm
Voice
Higher-pitched calls than Herring Gull.
Breeding
Maturity: between 2-4 year.
Mating Season: monogamous breeding pair, high loyalty to breeding area and mainly to former partner.
Clutches per breeding season1 clutch
Breeding: not before last decade in April .
Nest: Mainly ground nest, also slightly elevated, also in trees.

Clutch: (1-2) 3 (rarely -4) eggs
Eggs: creme-coloured long-oval egg with speckles and stains.
Egg Measurements:
Length: 48.2-67.4 mm
Width: 34.7-49.0 mm
Ø: 57.2×41.0 mm (n=1374)
Egg weight: 37.0-64.0 g; Ø 51.9 (n=814)
shell weight: 2.13-4.06 g; Ø 3.12 g (n=200)

Recurrent Clutch: possibly when clutch is lost during early days; up to two recurrent clutches are possible.
Laying interval: 47 hours on average for two eggs, 3 egg 77-81 hours.
Begin of incubating: clutch of 2 – 24 hours after laying second egg, clutch of 3 – between laying second and third egg; larger clutches 1-2 days after laying third egg.
Hatching: usually 3 days between first crack in shell until chicken has fully hatched, also 4-6 days are possible; second egg hatches usually 4 hours after first, third egg 17 hours after second egg.
Incubation: 23-28 days; both parents share the task of incubating.
Fledging: 4 days after hedging juveniles leave the vicinity of the nest but are fed at the nest. Fledging after 28-33 days.
Dependency: Fully independent only a few days after fledging.

Miscellaneous
Food: Common Gulls feed on earth worms, insects, fish, small rodents, vegetarian, fish and waste.
Longevity: The oldest known ringed bird of a Common Gull reached an age of >31 years.
Mortality: c. 54 % during first year, c. 25% in second year, from third year c. 26%.
Threats: Direct persecution, collection of eggs, hunting, poisoning. Insufficient food during breeding season. Loss of breeding areas.

References
Bauer, Hans-Günther, Bezzel, Einhard et. al. (HG), Kompendium der Vögel Mitteleuropas, Band 1+2, Sonderausgabe 2012, Aula Verlag, Wiebelsheim
Bauer, Hans-Günther, Bezzel, Einhard et. al. (HG), Kompendium der Vögel Mitteleuropas, Band 3, Literatur und Anhang, Aula Verlag Wiebelsheim, 2. vollständig überarbeitete Auflage 1993
Bezzel, Einhard, Kompendium der Vögel Mitteleuropas, Non-Passeriformes, Band 1, AULA-Verlag Wiesbaden, 1985
Bruun/Singer/König/Der Kosmos Vogelführer, Franck’sche Verlagshandlung Stuttgart, 5. Auflage 1982
Glutz von Blotzheim, Urs et. al (HG), Handbuch der Vögel Mitteleuropas, Band 8/1, Charadriiformes (3. Teil), Akademische Verlagsgesellschaft Wiesbaden, 1982
Svenson, Lars et. al, Der Kosmos Vogelführer, Franck-Kosmos Verlag GmbH & Co. KG, Stuttgart, 2. Auflage 2011

Image Credits
Eggs / clutch of the Common Gull: by Lämpel – own works, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19416507
Featured image and all othere images in this article: by ©Raymond Loyal

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