Common Merganser
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Cavity Nester Exotic

Common Merganser

Mergus merganser

The largest North American merganser, a long, low-slung duck with a sleek crested head and a hooked saw-tooth bill. Specialist of clear cold rivers and forested lakes.

IUCN Red List
Least Concern

Widespread and abundant; no known immediate threats to the population.

Floor
10" × 10"
Interior height
24"
Entrance hole
5.0"×4.0" oval
Mount height
10–25 ft
Breeds
Apr–Jun
Broods / yr
1
Cool Facts

Things you didn't know about the Common Merganser

01

The largest North American cavity-nesting duck, adult males can exceed 4 pounds.

02

The serrated saw-tooth bill is uniquely adapted for catching slippery fish, their primary prey.

03

Famous for crèche behaviour: a single female may end up tending broods of 50+ ducklings, having absorbed groups from other parents.

04

Holarctic species, same bird breeds across northern Eurasia under the name 'Goosander.'

Range & Habitat

Where you'll find them

Breeds across the boreal forest belt of North America; winters on rivers and lakes south to the southern US.

By region
  • Northern breeding

    Alaska, all of Canada, the northern US tier, and along the Rockies.

  • Wintering grounds

    Open rivers, lakes, and reservoirs across the contiguous US.

forested rivers and lakes clear cold rivers
10-year local observation heatmap. Click a season above to isolate one band.
Exotic

Outside our line

Beyond our build

We don't build for the Common Merganser

Outside our line due to 3D-printing or height-placement limitations. We don't currently build for this species. The published nest dimensions are listed here for reference if you're sourcing or building one yourself.

Interior
10" × 10" × 24" tall
Entrance
5.0" × 4.0" oval
Mount
10–25 ft
Notes
Largest cavity-nesting duck, box must be sized accordingly.
Seasonal Care

When to install. When to clean.

Install by
By March
Cleaning
Once a year, late summer
Northern Forests
Breeds across northern North America; install by March on forested rivers.

Holarctic, same species breeds across northern Eurasia (where it's called 'Goosander').