Mergus serrator
Silhouette: Sheatherius · PhyloPic
In 3 days ~10% in a week ~30%
The red-breasted merganser (Mergus serrator) is a duck species that is native to much of the temperate to subarctic Northern Hemisphere. The red breast that gives the species its common name is only displayed by males in breeding plumage. Individuals fly rapidly, and feed by diving from the surface to pursue aquatic animals underwater, using serrated bills to capture slippery fish. They migrate each year from breeding sites on lakes and rivers to their mostly coastal wintering areas, making them the most frequent species in the genus Mergus to frequent saltwater regularly. The worldwide population of this species is stable, though it is threatened in some areas by habitat loss and other factors.
The red-breasted merganser was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the current binomial name Mergus serrator. The species is monotypic; no subspecies are recognised. Birds breeding in Greenland were sometimes distinguised as a subspecies M. s. schioleri in the past on the basis of averaging very marginally larger, but this is no longer accepted as distinct.
The genus name Mergus is... Wikipedia →
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Prague Zoo | 🇨🇿 Czechia | |
| 2 | Tierpark Berlin | 🇩🇪 Germany | |
| 3 | Slimbridge Wetland Centre | 🇬🇧 United Kingdom | |
| 4 | Fort Worth Zoo | 🇺🇸 United States | |
| 5 | Santillana Zoo | 🇪🇸 Spain | |
| 6 | Alpenzoo Innsbruck | 🇦🇹 Austria | |
| 7 | Rákosův pavilon | 🇨🇿 Czechia | |
| 8 | Velemlokárium | 🇨🇿 Czechia | |
| 9 | akwarium warszawskiego ZOO | 🇵🇱 Poland |
Rare
Under 5% of wildlife watchers report a Red-breasted Merganser sighting in Olympic National Park on a given day, based on 240 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 98th most-seen of the 216 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
December
In that month about 30% of wildlife watchers report a Red-breasted Merganser in Olympic National Park on a given day, against under 5% in April to October, the lowest months. That is one of Olympic National Park's wettest months, with about 370 mm of rain against 35 mm in July.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Red-breasted Merganser sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
19th of 34
Of the 34 parks where we can rate Red-breasted Merganser sightings, Olympic National Park ranks 19th at under 5%. The best odds are in Point Pelee National Park (Canada, about 50%), Isle Royale National Park (United States, about 40%) and Katmai National Park (United States, about 20%). All parks ranked.
GBIF citizen-science records
It is estimated from how often the Red-breasted Merganser is recorded against all the birds logged in Olympic National Park (240 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
