Kicking off the Common Merganser Gallery with this dandy dozen (or so) I watched over a few days on the Limmat River in Zurich in August 2025. The rusty brown flailing feather tops indicate female and they ruled the roost on the two mornings I visited. I don’t recall seeing any males.

These Common Mergansers (Mergus merganser) were all snapped on the Limmat Vogelinsel, or ‘bird island’ (post here), but I saw several on the Zürichsee (Lake Zürich), too.

In brief (with WordPress AI assist):

• Size: Typically 61-76cm( 24-30 inches) in length; wingspan up to 94cm (37 inches).
• Diet: Primarily fish, but also consumes insects, crustaceans, and other aquatic invertebrates.
• Habitat: Prefers freshwater lakes, rivers, and coastal waters; often found in wooded or mountainous areas.
• Physical Description: Sleek body with a long neck; males have a distinct green head, white breast, and reddish sides; females are mottled brown with a pale breast and a reddish-brown head.
• Breeding: Nests in tree cavities, underbrush, or on the ground; females typically lay 6-10 eggs, which are incubated for about 30 days.
• Conservation Status: Generally, stable populations; however, habitat loss and pollution can threaten local populations.
• Unique Behaviors: Known for their diving abilities; they can dive to depths of over 30 feet (9m) to catch prey.
• Range and Migration: Breeds in North America and parts of Europe and Asia; migrates to open water and coastal areas in winter, moving to southern regions during colder months.

More:

• Common Merganser at Birds of the World
• Common Merganser at BirdLife DataZone
• Common Merganser at eBird
• Common Merganser at Avibase
• Common Merganser at Wikipedia
• Common Merganser at iNaturalist

Photos from 27 and 29 August 2025. Post last updated on 30 August 2025.