Magellanic Flightless Steamer

Scientific Name: Tachyeres pteneres
Geographical Range: Southwest coast and coastal islands of South America
Habitat: Marine shoreline
Diet in the Wild: Shellfish and other aquatic invertebrates 

Conservation Status: Not threatened
Note: Another flightless steamer from the Falklands (Tachyeres brachypterus) is endangered.
Location in the Zoo: Waterfowl exhibit 
Note: the Fort Worth Zoo is one of only two zoos in the United States that exhibit this interesting bird.
Physical Description:

It is about 65 cm. Weight: 3.5-7 kg, with males larger than females. The head and body are gray, with darker primary feathers on the short wings. The abdomen is white. Beaks and feet are a bright orange-yellow. Although these birds are flightless, the wings are only a little shorter than those of its flying relative Tachyeres patachonicus.

Social Organization:: 

These ducks are a family duck.  They live as male and female and both take care of their offspring.  When molting they may form small flocks, but they are territorial during breeding. Territorial attacks can be fierce and even mortal; both intraspecific and interspecific aggression has been observed in steamer ducks. Aggression appears to be mostly defensive of their nests or feeding territories. Both males and females may be aggressive. Male combat may also serve as a sexual display to attract unmated females.

Special Adaptations:

This duck has wings but cannot fly, due to the combination of a large body size with its small wings. There are other species of steamer ducks who do have wings and are able to fly, however, most chose not to.  The wings however, are still used.  When the duck wants to move across the water very fast, it uses its wings as paddles in order to swim at a more rapid pace. That is where the name comes from, because when they do this they look like the paddle steam boat. Darwin first described the wing strokes as alternate, but more recent study shows that they are used simultaneously like oars.

During "steaming" the birds can achieve speeds up to 24 kph. Steaming can be continued for a kilometer or more. Most of the power comes from alternate strokes with the feet rather than from the action of the wings. During the power strokes, the feet may even be lifted out of the water behind the bird. The wings probably keep the bird above water as it kicks. Steaming is probably used to escape from underwater predators.


 
Reproductive Behavior: 

The steamer female will lay between 5-10 eggs in every late September to December. They nest on the ground near water in shallow depressions or a borrowed burrow. Nests are solitary and incubated by the female, although the male may participate in protecting the next. Males and females form lifelong pair bonds. 		Page Author:
Juan Alviar III   thresherbc62@yahoo.com

Sources and Links:

http://www.carnegiemuseums.org/cmnh/birds/flight.html

http://www.avesdechile.cl/090en.htm

http://212.187.155.84/pass_06june/Subdirectories_for_Search/
SpeciesKingdoms/ 0Families_ACrAv_Anseriformes/
anatidae/1acravan_tachyeres/Tachyeres_pteneres/
Tachyeres_pteneres.html

Livezey and Humphrey. Mechanics of steaming in flightless steamer ducks.
Auk 100: 485-488.
http://elibrary.unm.edu/sora/Auk/v100n02/p0485-p0488.pdf

Livezey and Humphrey. Territoriality and interspecific aggression in steamer ducks.
The Condor 87: 154-157.
http://elibrary.unm.edu/sora/Condor/files/issues/
v087n01/p0154-p0157.pdf

 


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