Falkland Steamer-Duck Tachyeres brachypterus Scientific name definitions

As would be expected from its name, this flightless duck is endemic to the Falkland Islands, where it inhabits low-lying coastal areas and relatively nearby ponds. Its plumage is predominantly gray and white, and very similar to that of Flying Steamer-Duck (Tachyeres patachonicus), which also occurs in the archipelago, albeit much less commonly. Unfortunately for field identification purposes, the relative flight capabilities of the two species are rarely useful to differentiate them, so observers need to concentrate on the heavier neck, shorter wings and tail, and stouter bill of the flightless species. Falkland Steamer-Duck apparently nests virtually year-round, although most clutches are initiated between September and December.

61–74 cm; male c. 3300–4800 g, female 2900–4196 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 ). Male’s grey head contrasts little with rest of plumage ; base of foreneck shows faint earth-coloured hue; in breeding condition, many become more white-headed presumably with wear and exposure, and perhaps also with age and damage through interspecific combat (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 ). Bare parts: bill bright yellow-orange (duller during moulting period), with black nail, legs and feet also yellow-orange, and eyes brown (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 ). Female smaller than male, with brown head and neck , comparatively narrow postocular streak and greenish-yellow bill ; very similar to female of T. patachonicus, but has more yellow on bill. Juvenile resembles female but lacks or has even more-reduced white streak behind eye, with reduced chestnut and silvery tones to plumage and greyish-green bare parts (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 ); adult-like plumage attained by end of first year.

Falkland Is.

Frequents rugged shorelines, being most common on small islands and in sheltered bays, but also affects ponds up to 400 m from coast (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 ).

Variety of saltwater molluscs (mussels, limpets) and, to lesser extent, crustaceans (crabs, shrimps) constitute base of diet, much like that of T. patachonicus (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 ). Forages by diving near shore or by upending in shallow waters , generally on incoming tides .

Vocalizations similar to those of T. patachonicus, with males calling most frequently during breeding season, especially territorial disputes, using loud rasping whistles (intermediate in pitch between those of T. patachonicus and T. pteneres) and rapidly repeated, sharp ticking notes, while female produces deeper grunts, typically synchronously with male partner (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 ).

Season variable and may nest virtually year-round (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 ), but most breeding occurs mid Sept–Dec, at least on Falkland Is (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close ). In single pairs; nests not far from water (but up to 400 m inland) (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close ), heavily lined with down, sometimes fortified with 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 ), and concealed among vegetation or in unoccupied Magellanic Penguin (Sphenicus magellanicus) burrow. Clutch 4–12 cream-coloured eggs (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close ), size 77–86 mm × 56–57 mm, mass 132 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 c. 34 days (28–40) 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 ); chicks medium to dark brown above and on breast, with white underparts  and black bill, weigh c. 83 g on hatching (717 g after three 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 ); fledging c. 12 weeks. Predation of ducklings by Kelp Gulls (Larus dominicanus) and Brown Skuas (Catharacta antarctica) heavy, whereas adults are predated only by seals (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close , 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 ). Sexual maturity reached at c. 16–24 months (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 ). Longevity in captivity 20 years, but no data on annual adult survival or longevity in wild (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). Widespread and common to abundant around coasts of Falklands, with an estimated population of 9000–16,000 pairs during the breeding bird survey between 1983 and 1993 (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close ), and a suggested overall population of 27,000–48,000 birds (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 ). High mortality of chicks due to predation by Kelp Gulls (Larus dominicanus) and skuas (Catharacta); adults have no enemies except occasionally sea lions (Otaria). No significant threats known; formerly, between 1000 and 10,000 eggs per year were harvested (4 Woods, R. W., and A. Woods (1997) Atlas of Breeding Birds of the Falkland Islands. Anthony Nelson, Oswestry, UK. Close ).