Gadwall

    Anas strepera

Castilian: Ánade friso

Catalan: Ànec griset

Gallego: Pato frisado

Euskera: Ipar-ahatea

CLASIFICACIÓN:

Orden: Anseriformes

Family: Anatidae

Migratory status: Permanent resident

CONSERVATION STATUS:

In the 2004 edition of the Red Book of Spanish Birds (Libro Rojo de las Aves de España) it is listed as “Least Concern”.

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THREATS

Changes to the habitat caused by pollution or eutrofisation, and human disturbances.

Length / size: 46-56 cm / 78-90 cm

Identification: Medium-sized bird, with generally dull-coloured plumage, a black rear end and white speculum, a characteristic feature of the species. During mating season the male is a greyish colour and the female, like the rest of the anatids, is a brownish colour and only her speculum stands out.

Song: It usually makes a short quacking sound, the female a "aak aak" and the male a sort of "merk", and during courtship a "peee" whistle.

Diet: Its diet is vegetarian and includes leaves, stalks, and roots of aquatic plants; it also sometimes consumes insects or bits of grains. It is common to see it together with other ducks when searching for food, which it obtains by submerging half of its body underwater.

Reproduction: It is the female that chooses the male using exaggerated postures and finishing by thrusting its bill into the water. The male is only in charge of watching over the area while the female prepares the nest, a small depression that she builds near the water and hidden among the brush; the nest is made of branches, leaves and down. The chicks are born at the same time and almost immediately begin following the mother around.

HABITAT

During breeding season, it prefers shallow freshwater areas with lots of vegetation; however, in winter it is more generalist and frequents other wetlands such as lakes, reservoirs and estuaries.

DISTRIBUTION

In Spain: The principal breeding concentrations are located in the Guadalquivir marshes, the Ebro Delta, and Castile-La Mancha, although they are also found scattered across other places such as Aragon, Toledo, Madrid, Castile and León, Asturias, and Levante, among others.

In Castile and León: The breeding population is distributed throughout all the provinces except Segovia. The most notable locations are the Ebro swamps (Burgos), Rosarito (Ávila) and Aguilar (Palencia), Villafáfila (Zamora), and La Nava lake (Palencia), among others.

Movements and migrations: It is a partially migratory species, and in the peninsula the reproductive population makes scattered migrations depending on the weather conditions, specifically the water levels in wetlands. Specimens from central and northern Europe reach the peninsula between October and March.

POPULATION

In Spain: There is an estimated population of between 2500 and 4000 breeding pairs.

In Castile and León: There is an estimated population of 150-200 breeding pairs.