Steamer ducks, belonging to the genus Tachyeres, are a captivating group of waterfowl found in the southern reaches of South America. Their unique name hints at a remarkable behavior that sets them apart. These birds exhibit a distinctive method of propulsion across the water.
Defining Steamer Ducks
Steamer ducks are characterized by their robust, heavy-bodied build. They possess strong legs and generally slate-grey plumage, often with white wing patches. Males of some species have white heads, while females may have darker, vinous-brown heads. Their bills are large and heavy, well-suited for crushing invertebrates.
Most steamer duck species are flightless, a trait that has evolved independently multiple times within the genus. Despite their inability to fly, their wings are developed, though shorter than those of flying relatives, and feature bony knobs or spurs used in aggressive encounters.
The “Steaming” Behavior
The common name “steamer duck” refers to their unusual and powerful method of locomotion across the water’s surface. When moving quickly, these ducks flap their wings into the water while simultaneously using their feet to propel themselves, creating a foamy wake that resembles an old paddle steamboat. This “steaming” behavior allows them to achieve impressive speeds, reportedly up to 24 kilometers per hour (about 15 miles per hour), and they can sustain this rapid movement for a kilometer or more.
This unique behavior serves multiple purposes. It is often employed for rapid escape from perceived threats, allowing them to quickly distance themselves from predators. Additionally, steaming plays a role in territorial displays and aggressive encounters. Steamer ducks are known for their highly aggressive nature, with males engaging in violent battles using their powerful wings and wing spurs.
Habitat, Diet, and Species
Steamer ducks are found in the southernmost parts of South America, inhabiting coastal regions and islands primarily in Chile and Argentina, including Tierra del Fuego and the Falkland Islands. They prefer rocky coasts and marine environments, though the Flying Steamer Duck is also found in freshwater lakes and rivers. During the breeding season, some species may move to more sheltered bays or inland lakes.
Their diet consists mainly of marine invertebrates, such as mollusks and crustaceans, which they forage for by diving to the seafloor or searching in shallow waters. They may also consume small fish.
Four distinct species are recognized:
The Flying Steamer Duck (Tachyeres patachonicus)
The Fuegian Steamer Duck (Tachyeres pteneres)
The Falkland Steamer Duck (Tachyeres brachypterus)
The Chubut Steamer Duck (Tachyeres leucocephalus)
The Fuegian, Falkland, and Chubut steamer ducks are largely flightless. The Flying Steamer Duck can fly, though it rarely does so and its heaviest males may be unable to take flight.