Common merganser (Goosander)

Mergus merganser

Grote zaagbek / Gänsesäger / Harle bièvre

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern (IUCN, 2012).

The Common Merganser can be found breeding year-round in central Asia and westernChina, in northern Europe including France, Germany, Scandinavia, the United Kingdomand Iceland, and in large areas of northern United States and parts of southern Canada. Summer breeding grounds include the majority of Scandinavia and Russia, parts of central Asia including northern India, northern regions of Kazakhstan, Mongolia andJapan, and much of southern Canada. Wintering grounds expand the range further south to encompass most of the United States, other coastal regions of south-eastern Europe (e.g. Turkey and Greece) and central Asia, and the eastern coast of China as well as Korea and Japan.

The global population is estimated to number c.1,700,000-2,400,000 individuals (Wetlands International 2006), while national population estimates include: c.100-10,000 breeding pairs and c.50-1,000 wintering individuals in China; <c.100 breeding pairs and c.1,000-10,000 wintering individuals in Korea and c.1,000 wintering individuals in Japan (Brazil 2009).

The species is subject to persecution by anglers and fish-farmers who accuse it of depleting fish stocks (del Hoyo et al. 1992), and it is occasionally drowned in freshwater fishing nets with mesh sizes greater than 5 cm (China) (Quan et al. 2002). The species is also threatened by the degradation of freshwater lakes through drainage and petroleum pollution in Russia (Grishanov 2006) and as a result of acid rain in North America (Kear 2005b). The species is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006). The species is hunted in North America (Kear 2005b) and Russia (Grishanov 2006) (although it is not a popular game bird) (Kear 2005b), and its eggs used to be (and possibly still are) harvested in Iceland (Gudmundsson 1979).

More information: http://www.iucnredlist.org/details/22680492/0 

Above: subspecies Mergus merganser americanus (adult male)

Above: subspecies Mergus merganser merganser (male in front)

Above: subspecies Mergus merganser merganser (male in front)