In Western Palearctic the Greylag Goose (Anser anser) is the largest goose species and the largest of its kind among the grey geese group. Only the Canada Goose is larger. Also, this bird is the most common goose in Western, Central and Eastern Europe. Extensive studies were conducted on this species by behavioral scientist and zoologist, the legendary Konrad Lorenz. Greylag Geese are the anchestors of the domsestic goose.
Other goose species similar to the Greylag Goose are the Taiga Bean Goose, Pink-footed Goose and the (Greater) White-fronted Goose. In Europe Greylag Geese are not deemed as being endangered.

Characteristics of the Greylag Goose
Taxonomy
Order: Anseriformes
Family: Anatidae
Genus: Grey Geese (Anser)
Species: Greylag Goose
Scientific Name: Anser anser
Names and Synonyms of the Greylag Goose
- German: Graugans
- French: Oie cendrée
- Spanish: Ánsar común
- Portuguese: Ganso-bravo
- Italian: Oca selvatica
- Dutch: Grauwe Gans
- Czech: Husa velká
- Slovak: Hus divá
- Croat: Siva Guska
- Hungary: Nyári lúd
- Danish: Grågås
- Norwegian: Grågås
- Swedish: Grågås
- Finland: Merihanhi
- Polish: Gęgawa
- Russian: Серый гусь
- Bulgaria: siva g”ska, Сива гъска
- Turkey: Boz kaz, Yaban Kazı, Сұр қаз
- Iceland: Grágæs
- Bengali: মেটে রাজহাঁস, হভমট যাজাুঁ
- Faroer: Grágás
- Kazahk: Бөр қаз, қоңыр қаз, Сұр қаз
- Mongol: Бор галуу, ууллаг, халзан галуу, хээрийн галуу, энхэт галуу
- Chinese: 大雁, 沙雁, 沙鵝, 灰嘴灰鵝, 灰腰雁, 灰雁, 鴻嘴雁

Distribution
Distribution of the Greylag Goose throughout Europe can only be described as patchy. However, across continental Europe this species has established larger breeding populations and also stays during winter. That hasn’t always been the case.
Basically, the Greylag Goose has Palearctic distribution that originally was limited to the lowlands of the temperate northern latitudes. The distribution area begins on Iceland and stretches eastwards across Europe and beyond the Ural through southern Siberia, central and northern Asia into China and ends at the Pacific Ocean. The Asian population is made up by the eastern subspecies of the Greylag Goose Anser anser rubrirostris Swinhoe 1871.
We can conclude that the main distribution areas of the Greylag Goose are in northeast, northwest and eastern Europe. That includes the UK, northern Ireland, Belgium, the Netherlands, Germany, Norway, southern Sweden, coastal areas of Finland, the Baltic countries, Poland, western and southern Rissia, southern Ukraine, Moldawia, Romania and patches in western Turkey.
Originally the Greylag Goose was at best a winter guest in central Europe and in Germany. Because of the studies by Conrad Lorenz on this species that a small population was established in Austria. From there, the Greylag Goose began to, shall we say conquer, central and western Europe. Nowadays it is the most common goose in central Europe between spring and autumn.

Movements & Wintering
Movements: Greylag Geese breeding in northwest Europe are mainly non-migratory. In winter with average temperate climate condintions they do not move away from their breeding ranges. Otherwise, the Greylag Goose is still a typical migratory bird. The Iceland breeding population moves mainly to Ireland and Scotland during migration. This track begins in October with the birds arriving in Ireland and Scontland between end-October / November. They return between March and April.
The breeding population from Norway, Sweden, Denmark and Germany partly migrates in south to southwest direction, thereby following the coastline of North Sea and Atlantic. Wintering ranges of these populations are in Lower Saxony, North-Rhine Westphalia in Germany, the Netherlands and stretch further southwards to France and Spain. Some populations fly further south to North Africa. This track begins in September. Betwenn October and November the Netherlands and France are passed. The peak is reached in December to January, with Greylag Geese still being on the move. They begin their return journey from end-January / February and reach their breeding grounds by March / April.
The breeding population from Czech Republic, Austria and Hungary migrate over the northern Balkans and Italy to North Africa.
From Russia Greylag Geese move in a south to southwest direction into the Black Sea area, Turkey and the Caspi region.
Wintering: Greylag Goose winter on the coastline of the Waddensea and further south on the North Sea coast down to the Atlantic in France and even further to Spain. Other wintering ranges are in Greece, northern Africa, in the Black Sea region, Caspi area and also in Turkey.
Habitat
Greylag Geese settle on inland lakes providing sufficient cover for breeding. Reed, sedges, rushes, riparian forests and pollard trees provide the cover needed. Another essential factor are free bodies of water adjacent to greenlands and / or wetlands. In most cases sleeping grounds and feeding grounds are seperate.

Behaviour
Greylag Geese are both diurnal and nocturnal, depending on availability of food and also to avoid disturbances during daytime. They fly in a v-shape formation. The Greylag Goose feeds on greenlands and partly also in shallow water. Only on rare occasions one can watch Greylag Geese bottom feeding in water. These birds are a gregarious species, especially outside breeding season. Then they gather in large groups, that always consists of a large number of families.
Close-knit families seem to be important to Greylag Geese and to geese especially. The families always try staying together. Socical ranks exist within the family and in larger groups, families have a social status within the group. Meaning, in larger groups one family represents the leaders under which all other families fall into their ranks.

Field Characteristics of the Greylag Goose
Large Goose with bulky body, thick neck, large head and heavy bill. In fact the bill appears to be quite long compared to other grey geese. Legs are dull pinkish. Broad wings. In flight heavy. The plumage is a plain brownish grey. Head and neck are plain (important feature when identifying!). It can happen that some Greylag Goose have a slim white rim at the base of the bill (do not confuse this for a White-fronted GooseI!). In flight the pale ash-grey upper-forewing becomes visible sharply contrasting with inner parts of the wing and back. Dark primaries and secondaries in the underwings.
ris: brown
Eyering: flesh-coloured to red; juvenile = yellowish
Bill: large bill
Legs and feet: dull-pinkish; juveniles = grey



Measurements
Size: 76-89 cm
Weight:
♂ 2800-4300 g
♀ 2100-3800 g
Wingspan: 147-180 cm
Wing:
♂ 436-500 mm
♀ 417-480 mm
Voice
Greylag Geese are, shall we say, very chatty and keep chatting all day long. Their calls sound like “ahng-ang-ang”. Most of the time, during flight and on the ground calls sound like gagaga gagaga.

Breeding
Sexual Maturity: Greylag Geese do pair in their second year already. They become sexually mature during their fourth year.
Mating: monogamous life-long breeding pair. Mating can happen at any time during the year. However they are also known to cheat on the partner leading to some sort of Greylag Goose divorce. The abandoned partner suffers greatly because this bird is losing its social status in the group and will find itself at the lowest point of social prestige. Ganders unable to find a female form a so-called bachelor group.
Clutches per breeding season: 1 clutch
Breeding: from Frebruary, depending on weather conditions. Usually between March and April. The breeding season usually lasts until early June.
Nest: The nest consists of losely assembled plant material lined with downs. While the ♀ is busiy building the nest, the ♂ is providing the building material. Nests usually sit in well covered places. Closeness to water is essential.


Clutch, Eggs & Measurements
Clutch: (3-) usually 4-6 (rarely up to 12) eggs.
Eggs: long oval, creme coloured eggs that will discolour rather brownish during incubation.
Egg Measurements:
Length: 75.7-88.5 mm
Width: 49.4-57.0 mm
Ø = 79.0×51.8 mm
Weight of fresh egg: 124-137 g. Ø = 127.7 g
Shell weight: 10.5-13.2 g, Ø = 12.0 g



Incubation – Fledging & Dependency
Replacement clutch: possible when clutch is lost during early days of breeding, though rare.
Laying Interval: 2 days. Eggs are uslually laid during morning hours. Even in frost periods eggs are being laid.
Begin of Incubation: after laying last egg
Incubation: 27-29 days per egg. Both parents share the task of incubating.
Hatching: It can take 5-30 hours between the first and the last gosling hatched.
Fledging: Goslings leave the nest shortly after hatching and follow their parents. The goslings are able to feed from the start. Firts attempts to fly happen after about 50-60 days. Young Greylag Goose are fully able to fly after the 10th week.
Dependency: Juvenile Greylag Goose stay with their parents throughout winter and into spring until the next breeding season begins.

Miscellaneous
Food: land and aquatic plants: grass, herbs, perennials, beet leaves, roots, seeds and berries.
Longevity: The oldest known ringed Greylag Goose reached an age of 23 years and 7 months.
Mortality: With adult Greylag Geese mortality stands at c. 23 per cent (on Iceland) and is up to 33 pc in Denmark.
Enemies and Threats: The biggest threat to Greylag Goose is hunting in breeding and wintering ranges. Other threats are catching of juveniles and removing clutches. Extensive recreational activities in breeding ranges can lead not only to disturbances but also to adult birds abandoning the clutches.

References
Bauer, Hans-Günther, Bezzel, Einhard et. al. (HG), Kompendium der Vögel Mitteleuropas, Band 1, 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 2, Anseriformes (1. Teil), Akademische Verlagsgesellschaft, Wiesbaden, 1979, Nachdruck der Auflage von 1968
Lorenz, Konrad, The Year of the Greylag Goose, Harcourt Brace Jovanovich, New York, 1979
Lorenz, Konrad, Das Jahr der Graugans, Piper Verlag GmbH Munich, 1979
Lorenz, Konrad, Das Jahr der Graugans, Unabridged Edition, Deutscher Taschenbuchverlag, DTV Munich, 1982
Svenson, Lars et. al, Der Kosmos Vogelführer, Franck-Kosmos Verlag GmbH & Co. KG, Stuttgart, 2. Auflage 2011
Svenson, Lars, et al, Collins Bird Guide to the Birds of Britain and Europe, Harper Collins, 2019, 2nd edition
Uspenski, S.M. Dr. habil, Die Wildgänse Nordeurasiens, Die Neue Brehm Bücherei, Band 352, A. Ziemsen Verlag Wittenberg Lutherstadt, 1965
Bundesamt für Naturschutz: Nationaler Vogelschutzbericht 2019 gemäß Artikel 12 Vogelschutzrichtlinie, Report Section Gr…Ha Breeding Birds + Winter Guests (pdf download – German text)

Image Credits
Featured Image of Greylag Goose – by: ©Raymond Loyal
Egg of Greylag Goose: Egg of Greylag Goose – source by Klaus Rassinger und Gerhard Cammerer, Museum Wiesbaden – own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=38182137
All other post images of Greylag Geese – by: ©Raymond Loyal

Hey, the “distribution” section has not been translated into English
Thanks for letting me know. Section is now complete in English with some new aspects. Cheers