Ruddy duck

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The ruddy duck (Oxyura jamaicensis) is a small, sturdy duck in the stiff-tailed group. It has a short, scoop-shaped bill and a long, upright tail.

Appearance
- Male in summer: chestnut body, bright blue bill, black cap, and white cheeks.
- Winter: dull gray-brown above and paler below; gray bill.
- Female and first-year males: brown with a pale cheek stripe.
- Weighs less than many ducks; the tail is often held up when swimming.

Habitat and range
- Native to the Americas, living in marshy lakes and ponds with dense vegetation.
- Migratory: winters in coastal bays and unfrozen waters.
- In the 1940s, introduced to the United Kingdom. It has since spread to Europe and is treated as an invasive species in many areas.

Behavior and breeding
- Courtship often begins on the breeding grounds.
- Males perform “bubbling” displays by tapping their beak on the breast, creating bubbles on the water.
- They can be aggressive with each other, but pairs may rest near each other shortly after.
- Nests are hidden in tall marsh vegetation near water; females build the nest from grass.
- Typical brood is 5–15 ducklings. Males do not help raise the young.
- Incubation lasts about 23–26 days; ducklings fledge in roughly 1–2 months.
- Females have been observed laying eggs in other nests on occasion.

Diet
- Forages underwater, using its bill to feel prey rather than see it.
- Eats a lot of plant matter (seeds and roots) and also aquatic insects, crustaceans, larvae, and small molluscs.
- Forages by filtering food from the substrate and can revisit productive feeding spots.

Conservation and human impact
- IUCN status: Least Concern.
- Outside the Americas, it is considered highly invasive in many places, leading to culling programs in some countries.
- In Europe, the ruddy duck is on the European Union’s list of Invasive Alien Species of Union Concern since 2016, restricting its import, breeding, transport, and release within the EU.