Säger Bremen

The mergansers are a specialised group of diving ducks comprising the genus Mergus and the closely related Mergellus. In Central Europe three species occur regularly: the Goosander (Mergus merganser), the Red-breasted Merganser (Mergus serrator) and the Smew (Mergellus albellus). All share a slender bill lined with sharp, tooth-like horn serrations and a pronounced hooked nail at the tip, which allows them to seize and hold fish underwater.

The Goosander is the largest species, with a length of around 58 to 70 centimetres. The drake shows a glossy dark-green head, a black mantle and a pale, salmon-tinted underside, paired with a striking red bill. Goosanders are cavity nesters that breed in old black-woodpecker holes, rock crevices, river-bank cavities and nest boxes. In Germany they breed mainly along clear Alpine and pre-Alpine rivers and in Schleswig-Holstein; winter numbers rise sharply with arrivals from Northern Europe.

The Red-breasted Merganser is slightly smaller, roughly mallard-sized. The drake is recognised by its dark-green, spiky double crest, rufous breast and white neck ring. Unlike the Goosander it nests on the ground in dense waterside vegetation or among stones. Its German breeding range is concentrated on the Baltic coast of Schleswig-Holstein and Mecklenburg-Western Pomerania, with around 340 to 410 breeding pairs; elsewhere it occurs as a winter visitor to coasts and larger inland waters.

The Smew is the smallest of the group and the only species placed in the separate genus Mergellus. The drake in breeding plumage is predominantly white with fine black markings and a dark eye-patch, often nicknamed the nun-merganser. It breeds in the boreal taiga of Scandinavia and Russia and appears in Germany from October to April as a regular winter visitor, with concentrations along the Baltic coast of Mecklenburg-Western Pomerania, on the Lower Rhine and at larger reservoirs.

All three species depend on clear, oxygen-rich and fish-bearing waters. The Goosander is closely tied to structurally rich rivers and pre-Alpine lakes, the Red-breasted Merganser to shallow coastal and brackish waters, and the Smew to quiet inland lakes, floodplains and sheltered bays. Dives typically reach only a few metres but often last half a minute or longer.

Economic conflict centres on commercial fish farming and recreational fisheries, particularly in the Alpine region and southern German trout waters. Fishing associations have repeatedly called for relaxed protection or at least scaring permits. Scientific studies, however, indicate that mergansers feed mainly on smaller cyprinids and juvenile fish, and that measurable impacts on commercially relevant stocks are often more limited than perceived.

Legally, all three species enjoy strict protection in Germany under the Federal Nature Conservation Act and are listed on Annex II of the EU Birds Directive. They are formally subject to the Federal Hunting Act but carry a year-round closed season in every federal state and may not be hunted. The Goosander is listed as endangered (category 3) on the German Red List of breeding birds. Austria and Switzerland likewise protect mergansers year-round, with intervention only possible through specific authority permits, for example for deterrence at especially sensitive pond facilities. For the holder of a hunting district the focus therefore lies on habitat stewardship: maintaining undisturbed roosting and moulting sites, preserving natural riverbanks and retaining old cavity trees close to water.