Flightless Steamer-Duck Tachyeres pteneres Scientific name definitions

The Flightless Steamer-Duck is a large, stocky duck of southern South America. Found in coastal waters, the species has extremely short wings that leave a large patch of the rear flank exposed. Steamer-ducks have a peculiar habit of flapping their wings and running along the water's surface when alarmed, reminiscent of steamboats. This duck usually occurs in pairs or in small family groups. The Flightless Steamer-Duck can be identified by its large size, whitish gray head, bright orange bill, gray body and wings, and white wing patches.

74–84 cm; male 4950–6500 g, female 3400–5000 g (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Largest of genus, massive-bodied  with sturdy bill; no other flightless  Tachyeres shares same range. From T. patachonicus, which it characteristically dominates, separated by much larger size, heavy bill and neck, shorter wings and tail, much greyer body and virtual lack of sexual dimorphism. Male has grey head, not contrasting with rest of plumage; bill bright yellow-orange with black nail, legs  and feet yellow-orange, and eyes brown. Sexual dimorphism  not as marked as in other Tachyeres, as female also has orange bill; female smaller than male, with somewhat darker head. Juvenile grey without wine-coloured tones, and has narrow pale eye ring.

Coast from SC Chile (Chiloé I) S to Tierra del Fuego, Argentina, including Cape Horn archipelago and Staten I.

Frequents rocky coasts , where may be found several miles offshore. Breeds along shoreline, in sheltered bays or channels.

Sedentary, with only small-scale dispersion along adjacent coasts, although there is a published record from interior Santa Cruz province, S Argentina (4 Darrieu, C. A., A. R. Camperi, and S. Imberti (2008). Avifauna (non Passeriformes) of Santa Cruz province, Patagonia (Argentina): annotated list of species. Revista del Museo Argentino de Ciencias Naturales 10:111–145. Close ). Essentially flightless.

Dives, dabbles or upends (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) in rather shallow waters among kelp beds; main diet consists of aquatic molluscs (Mytilidae) and crustaceans; some small fish also taken. Foraging activity mostly during high tide.

Vocalizations similar to those of other Tachyeres, although considered to be somewhat more complex, lower and more slurred (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Starts Sept/Oct, although considerable variation in laying dates reported, especially in northernmost parts of range (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Monogamous and pair-bond probably life-long (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). In single pairs; nests near water, usually close to high-water mark but exceptionally 100s of metres above it (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ), well hidden among vegetation; shallow depression, typically lined with down, sometimes also sticks and grass (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). On N side of Beagle Channel, recent surveys found all nests of this species (n = 18) to be on well-vegetated islands and islets, usually within c. 17 m of the tideline, presumably because they are relatively less accessible to mammalian terrestrial predators such as American mink (Mustela vison), South American grey fox (Pseudalopex griseus), Fuegian culpeo fox (P. culpaeus lycoides), southern river otter (Lontra provocax) and feral dogs (Canis lupus familiaris), compared to the coast where these terrestrial predators are frequently recorded, although potential avian predators such as Kelp Gulls (Larus dominicanus), Dolphin Gulls (L. scoresbii) and Chilean Skuas (Stercorarius chilensis) are present and breed on several of these islands (5 Liljesthröm, M., Schiavini, A., Sáenz Samaniego, R.A., Fasola, L. and Raya Rey, A. (2013). Kelp Geese (Chloephaga hybrida) and Flightless Steamer-Ducks (Tachyeres pteneres) in the Beagle Channel: the importance of islands in providing nesting habitat. Wilson J. Orn.. 125(3): 583-591. Close ). Clutch 4–8 eggs, size 78–88 mm × 52–61 mm, mass 131–140 g (captivity) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); incubation said to be c. 30–40 days, by female alone (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); downy chick is dark brownish olive to smoke-coloured on head, breast and back  , whitish on underparts, with black bill , weighs 99 g on hatching (achieving 1360 g at 35 days old) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); fledging period c. 12 weeks (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Study on Navarino I, Cape Horn Biosphere Reserve, found that American mink (Mustela vison) predated 52·6% of the 23 Tachyeres nests located by the researchers, with birds (26·3%) aslo being important causes of nest failure during the relevant period (the 2005/06 and 2006/07 nesting seasons) (6 Schüttler, E., Klenke, R., McGehee, S., Rozzi, R. and Jax, K. (2009). Vulnerability of ground-nesting waterbirds to predation by invasive American mink in the Cape Horn Biosphere Reserve, Chile. Biological Conservation. 142: 1450-1460. Close ). No further data (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Not globally threatened (Least Concern). Common or fairly abundant within its restricted range, with an overall population estimated at 25,000–100,000 birds, although significant declines have been reported in northernmost range in Chile (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Possible threats may arise from flightlessness and restriction to coastal zone: a tidal wave, for example, could seriously affect population as a whole, but principal threats are probably pollution and habitat destruction (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).