Anser anser

Anser anser

The wild goose (Anser anser Linnaeus 1758) is a bird belonging to the Anatidae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Animalia,
Phylum Chordata,
Subphylum Vertebrata,
Superclass Tetrapoda,
Aves class,
Subclass Neornithes,
Order Anseriformes,
Anatidae family,
Anserinae subfamily,
Anserini tribe,
Genus Anser,
A. anser species.
The term is synonymous:
– Anser cinereus (Meyer, 1810).
Three subspecies are recognized within this species:
– Anser anser anser; subspecies present in western Europe;
– Anser anser rubrirostris; present in an area ranging from Eastern Europe to Asia;
– Anser anser domesticus; all varieties of Eurasian domestic geese.

Geographic Distribution and Habitat –
The wild goose is a distribution bird in the Palearctic and Indo-Malaysian eco-zone. It is present in almost all of Europe and most of Asia, in coastal areas and wetlands. It breeds mainly in northern and eastern Europe, its breeding area extends over a strip from Iceland, the British Isles and the coasts of Scandinavia to northern China and the southern half of the Khabarovsk Territory southeast of Russia, through Central Asia and Mongolia.
In winter, it migrates to southern Europe, the Middle East and the north of the Indo-Malay region, as well as the extreme north-west of Africa (north of Morocco, Tunisia and Algeria). Most of the European specimens spend the winter in the marshes of the Guadalquivir, in the lagoons of Villafáfila, in the Ischkeul lake in Tunisia and in western Algeria. However, most are migratory, only a few populations are sedentary or irregular migrants.
The habitat of the Anser anser is that of humid environments, once it nested extensively throughout Europe, but urbanization has greatly reduced its habitat.
It reproduces in wetlands with dense vegetation, such as reeds, lagoons, humid meadows or peat bogs, in areas of prairie, moorland, tundra, steppe or even semi-desert, from sea level up to an altitude of 2300 m.
Before the autumn migration and in wintering areas it can be found in swamps, lakes, lagoons or cultivated plains.

Description –
Anser anser is a bird that does not have sexual dimorphism but with the male slightly larger than the female, with a length that oscillates between 70 and 90 cm, a weight of about 4.5 kg and a wingspan that oscillates between 170 and 200 cm .
This bird is recognized for having a grayish brown head, neck and flanks. The chest is light gray in color, tending to chamois towards the abdomen and the undertail is white.
The beak, broad and robust, has an orange color with a pink terminal nail. The red-orange legs. Juveniles are similar to adults but with darker plumage.
The eggs are white and almost elliptical in shape.
The western subspecies (A. a. Anser) is recognized by its orange beak, while the eastern one (A. a. Rubrirostris) has a more pink beak and a whiter tail.
During the movements it is recognized as the flocks form the classic “V” in the sky. This mechanism, by continuously moving the element on the head, allows to decrease the air resistance and therefore the fatigue.

Biology –
The wild goose begins the biological cycle with reproduction that takes place in spring, generally between March and May.
The shallow nest is made with plant material directly on the ground, inside reeds, bushes, in protected cavities at the base of trees; it is generally found on small islands with arboreal vegetation, or on vegetation rafts along rivers.
In it the female lays 4-6 eggs and the hatching, which lasts a month, is carried out by both the female and the male. After another month the chicks are already able to fly, but they do not move away from their parents until the following winter.
During this period the male first defends the nest and then the offspring, which for the first month returns to the nest at night. During the movements of the family, the male always closes the row.
This species is very gregarious, with the exception of the reproductive period during which the colonies of wild geese disperse over a relatively large territory. However, once the chicks have taken off, the flocks gather in favorable places to spend the moulting period, which lasts about a month; subsequently, in the period of September – November, they leave for the autumn migration towards the wintering places, from which they will return at the beginning of spring, between February and March.

Ecological Role –
The Anser anser is a migratory species that reproduces in territories such as: Iceland, Great Britain, Scandinavia, Central Europe, Russia and north-eastern China, while it winters in some areas of a belt ranging from the Mediterranean to eastern China.
In Italy it winters, especially in Friuli, Emilia-Romagna and Maremma, and the number of individuals who stop to nest is on the increase.
Some specimens also nest in France, in particular in Alsace, in the Somme bay and in the Teich ornithological park (Arcachon basin, in France) but these are introduced populations.
This species is omnivorous and feeds on everything it finds: minnows, snails, insects, larvae, earthworms, frogs, seeds, sprouts and herbs. For farmed species, the optimal diet consists of a good feed and a mixture of seeds.
It is active during the day, particularly in the morning and late afternoon: from the dormitories where groups of different individuals spend the night together, the individuals go away for a few kilometers in search of food, to then return in the central hours of the day or at the sunset.
As for its conservation status according to the IUCN Red List, it is currently not at risk of extinction.
Since the 1970s, when the lowest population rate occurs, when the total wild population in Europe was around 20,000, the trend is increasing, from around 170,000 in the 1980s, to around 250,000 specimens in 2003. This is because the density and sites have also expanded into areas where they had disappeared, especially in Germany and the Netherlands.
In Western Europe the species is increasing and today the global population numbers about one million individuals. In Asia, on the other hand, the situation appears more worrying, most likely due to the alteration of its natural habitats.
In general, however, the main threats are habitat loss, for example due to wetland reclamation, poaching and pollution.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– C. Battisti, D. Taffon, F. Giucca, 2008. Atlas of nesting birds, Gangemi Editore, Rome.
– L. Svensson, K. Mullarney, D. Zetterstrom, 1999. Guide to the birds of Europe, North Africa and the Near East, Harper Collins Publisher, UK.