|Scientific Name:||Tachyeres leucocephalus|
|Species Authority:||Humphrey & Thompson, 1981|
|Red List Category & Criteria:||Vulnerable C2a(ii) ver 3.1|
|Reviewer/s:||Butchart, S. & Taylor, J.|
|Contributor/s:||Borboroglu, G., Esler, D., Imberti, S. & Pearman, M.|
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.
|Range Description:||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).|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||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.|
|Habitat and Ecology:||It is entirely coastal in rocky areas and sheltered bays, breeding on offshore islands in shallow, protected bays (Agüero et al. 2010).|
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.
|Citation:||BirdLife International 2012. Tachyeres leucocephalus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.|
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