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White-headed Steamerduck Tachyeres leucocephalus

Justification
This species was previously classified as Near Threatened as, although it has a single, small population, it was not thought to be declining. It is now thought to be experiencing a continuing decline owing to declines in habitat quality, and probable decreases in survival and breeding success, as caused by human activities and other problematic species, and it has therefore been uplisted to Vulnerable.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.

Synonym(s)
Tachyeres leucocephala Stotz et al. (1996)

Distribution and population
Tachyeres leucocephalus was previously considered to be restricted to the south coast of Chubut province, Argentina (Madge and Burn 1988, Carboneras 1992a). It is now known to have a larger range, with occasional sightings along the coastline from the Valdés Peninsula to the Beagle Channel in Tierra del Fuego (Imberti 2003, M. Pearman in litt. 2003), but its distribution is restricted to approximately 700 km of coastline (Agüero et al. 2011). The population has been estimated to not exceed 5,000 birds (S. Imberti in litt. 2003), and surveys along the coast of Chubut province from 2006-2008 gave a total estimate of 3,400-3,700 mature individuals (G. Borboroglu in litt. 2008, Agüero et al. 2011), with key populations at Bahía San Gregorio, Bahía Melo and Caleta Malaspina, all located at northern San Jorge Gulf. It appears to occur at very low densities throughout its range, and is inferred to be declining (Agüero et al. 2011).

Population justification
In 2003, S. Imberti (in litt. 2003) estimated that perhaps fewer than 5,000 remain. More recently, the total size of the breeding population has been calculated to be between 3,428 and 3,673 adults (Agüero et al. 2011), and 1,899 juveniles were also counted, giving a total population of c.5,300-5,600 individuals, and 3,400-3,700 mature individuals.

Trend justification
The population is inferred to be experiencing a continuing decline owing to a decline in habitat quality, and probable decreases in survival and breeding success, as caused by human activities and other problematic species. The rate of decline has not been quantified.

Ecology
It is entirely coastal in rocky areas and sheltered bays, breeding on offshore islands in shallow, protected bays (Agüero et al. 2010).

Threats
Its restricted range, flightlessness and the potential for oil pollution from passing tankers put this species at some risk (Carboneras 1992a, Callaghan and Green 1993, Agüero et al. 2010, 2011). Perhaps the most significant threat is posed by oil exploration activities, which are taking place within 100 km of the species's centre of abundance; sea currents would likely take oil spills from the main area of development towards the species’s range , Three major oil spills in the last 30 years that have affected steamerduck breeding areas are reported to have caused massive mortalities, and the sediment and rocks within the range of T. leucocephalus are still contaminated with oil derivatives. The species may also be affected by the harvesting of guano and macroalgae (Agüero et al. 2010, 2011), as well as other human activities such as recreation and small-scale coastal fishing. Egg collecting has also been reported but appears to occur at very low intensity at a few sites (Agüero et al. 2010, 2011). A further potential threat comes from three introduced species: the green crab Carcinus maenus, Asian kelp Undaria pinnatifida, and the acorn barnacle Balanus glandula, all of which may cause dramatic changes to ecosystems upon which steamerducks rely (Agüero et al. 2010, 2011), and it may also suffer predation during the breeding season from native species such as Kelp Gull Larus dominicanus, whose population in Patagonia is increasing.


Conservation Actions Underway
The Interjurisdictional Marine Park in San Jorge Gulf contains about 46% of the entire population (Agüero et al. 2011).Conservation Actions Proposed
Conduct a full and detailed census of the global population and follow up with monitoring to detect any potential declines. Restrict access to parts of its range from tankers and other large ships which might cause significant pollution events.

References
Agüero, M. L.; Borboroglu, J. P. G.; Esler, D. 2010. Nesting habitat of Chubut Steamer Ducks in Patagonia, Argentina. Emu 110: 302-306.

Agüero, M. L.; Borboroglu, J. P. G.; Esler, D. 2011. Distribution and abundance of Chubut Steamerducks: an endemic species to Central Patagonia, Argentina. Bird Conservation International Available on CJO 2011 doi:10.1017/S0959270911000244.

Callaghan, D. A.; Green, A. J. 1993. Wildfowl at risk, 1993. Wildfowl 44: 149-169.

Carboneras, C. 1992. Anatidae (Ducks, Geese, and Swans). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 536-628. Lynx Edicions, Barcelona, Spain.

Imberti, S. 2003. Notes on the distribution and natural history of some birds in Santa Cruz and Tierra del Fuego Provinces, Patagonia, Argentina. Cotinga 19: 15-24.

Madge, S.; Burn, H. 1988. Wildfowl. Christopher Helm, London.

Rose, P. M.; Scott, D. A. 1997. Waterfowl population estimates. Wetlands International, Wageningen, Netherlands.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Calvert, R., Capper, D., Mahood, S., Mansur, E., Sharpe, C J, Symes, A., Anderson, O.

Contributors
Borboroglu, G., Imberti, I., Pearman, M., Esler, D.

IUCN Red List evaluators
Butchart, S., Taylor, J.

Recommended citation
BirdLife International (2014) Species factsheet: Tachyeres leucocephalus. Downloaded from http://www.birdlife.org on 30/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/08/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - White-headed steamerduck (Tachyeres leucocephalus) 0

Key facts
Current IUCN Red List category Vulnerable
Family Anatidae (Ducks, Geese, Swans)
Species name author Humphrey & Thompson, 1981
Population size 3400-3700 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 28,200 km2
Country endemic? Yes
Links to further information
- Additional Information on this species