Goosander (Mergus merganser)

Goosander

[order] ANSERIFORMES | [family] Anatidae | [latin] Mergus merganser | [authority] Linnaeus, 1758 | [UK] Goosander | [FR] Harle bievre | [DE] Gansesager | [ES] Serreta Grande | [NL] Grote Zaagbek

Subspecies

Monotypic species

Genus

Mergus is the genus of the typical mergansers, fish-eating ducks in the seaduck subfamily (Merginae). The Hooded Merganser, often termed Mergus cucullatus, is not of this genus but closely related. The other “aberrant” merganser, the Smew (Mergellus albellus), is phylogenetically closer to goldeneyes (Bucephala). Although they are seaducks, most of the mergansers prefer riverine habitats, with only the Red-breasted Merganser being common at sea. These large fish-eaters typically have black-and-white, brown and/or green hues in their plumage, and most have shomewhat shaggy crests. All have serrated edges to their long and thin bills that help them grip their prey. Along with the Smew and Hooded Merganser, they are therefore often known as “sawbills”. The goldeneyes, on the other hand, feed mainly on mollusks, and therefore have a more typical duck-bill. They are also classified as “divers” because they go completely under-water in looking for food. In other traits, however, the genera Mergus, Lophodytes, Mergellus, and Bucephala are very similar; uniquely among all Anseriformes, they do not have notches at the hind margin of their sternum, but holes surrounded by bone.

Physical charateristics

The long, narrow bill with serrated edges readily distinguishes mergansers from all other ducks. Common mergansers are among the largest ducks, but are less stocky than eiders and goldeneyes. In flight, they appear more elongated than other ducks, flying in trailing lines close to the water surface.

Male common mergansers have a greenish-black crested head and upper neck. The lower neck, breast, and underparts are creamy-white with a variable pink wash. They have black backs and upperwing coverts with white scapulars. The bill is red with a blackish culmen and nail. The legs and feet are deep red.

Female common mergansers have a tufted red-brown head that is clearly defined from the lower neck by a clear whitish chin. The back and sides are silver-gray and the breast and belly are white. The bill is red with a blackish culmen and nail. The legs and feet are deep red.

Listen to the sound of Goosander

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Goosander.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 78 cm wingspan max.: 94 cm
size min.: 58 cm size max.: 68 cm
incubation min.: 30 days incubation max.: 32 days
fledging min.: 60 days fledging max.: 32 days
broods: 1   eggs min.: 5  
      eggs max.: 15  

Range

North America, Eurasia : widespread

Habitat

Common mergansers nest in tree cavities, nest boxes, cliff crevices, and on the ground generally near clear water rivers in forested regions and mountainous terrain. They feed by diving underwater in marine and freshwater habitats.

Reproduction

Common mergansers breed from Alaska, the southern Yukon, Labrador, and Newfoundland south to central California, Arizona, New Mexico, southern Chihuahua, and, east of the Rockies, to Minnesota, Michigan, New York, New England, and Nova Scotia. Common mergansers nest in tree cavities, nest boxes, cliff crevices, and on the ground generally near clear water rivers in forested regions and mountainous terrain. Female common mergansers lay an average of 9 to 12 eggs.

Feeding habits

Common mergansers eat mainly fishes, amphibians, crustaceans, mollusks, and other invertebrates obtained by diving underwater in marine and freshwater habitats

Video Goosander

httpv://www.youtube.com/watch?v=Cq55nWtvsrQ

copyright: youtube


Conservation

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.
This duck has a wide distribution in boreal and temperate regions of Eurasia and North America. It has also isolated populations in the mountainous regions of the Alps, the Caucasus and Tibet. Two populations inhabit or visit the European Union. One comprises the birds of northern and north-western Europe, wintering mainly in the Baltic Sea and around the North Sea. It amounts to about 200000 individuals, and seems stable. The birds of the British Isles are sedentary. They amount to about 5000-8000 individuals and increased during the last decades. The population of Central Europe (France, Germany) amounts to 3000 individuals. It is also sedentary and seems to be slightly increasing. A very small population is breeding in the Balkan Peninsula. It is estimated at not more than 11-32 breeding pairs, and its trends are unknown
Goosander status Least Concern

Migration

Migratory and partially migratory. No evidence that any Icelandic breeders emigrate. Similarly, British breeders almost entirely resident, moving short distances (mainly within 150 km) from breeding waters to lakes and sheltered estuaries. No evidence that breeders of southernmost Scandinavia, north Germany, and Poland move further than western Baltic, but those breeding central and northern Scandinavia, Finland, Baltic States, and Russia east to Pechora migrate west to Baltic and beyond to Netherlands and Britain, in smaller numbers to west France and north Spain.
In late August and early September, moulting and breeding waters often deserted as flocks build up on estuaries and shallow parts of some inland lakes. Mass departures not until advent of freezing; thus major movements through Russia and Baltic October and early November. Early arrivals in North Sea countries late October and early November, but no large numbers until December, while numbers build up on Black Sea and Sea of Azov from mid-October to mid-December. Return migration from early March and, apart from stragglers, non-breeding range vacated by mid-April.

Distribution map

Goosander distribution range map

Literature

Title The Origins of moulting Goosanders on the Eden
Estuary
Author(s): P. Leslie Hatton and M. Marquiss
Abstract: Moulting Goosanders were counted on the Eden estua..[more]..
Source: Ringing & Migration (2004) 22, 70-74

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