This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Distribution and population
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
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.
The Red-throated Loon is a migratory species which breeds in the Arctic Regions of the northern hemisphere generally breeding north of 50°, and wintering along the Pacific and Atlantic coasts of North America as far south as Florida and California (USA
), on the coast of Portugal
, in the Mediterranean Sea and Black Sea, and on the Pacific coast of Asia as far south as south-east China1
. Population justification
The global population is estimated to number c.200,000-590,000 individuals (Wetlands International 2006), while national population estimates include: <c.50 individuals on migration and <c.50 wintering individuals in China, <c.1,000 wintering individuals in Taiwan, c.50-10,000 wintering individuals in Japan and c.10,000-100,000 breeding pairs and c.1,000-10,000 wintering individuals in Russia (Brazil 2009).Trend justification
The overall population trend is decreasing, although some populations may be stable and others have unknown trends (Wetlands International 2006). This species has had stable population trends over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).EcologyBehaviour
This species is strongly migratory, with inland populations moving south or to the coast after breeding (del Hoyo et al.
1992). The species breeds from May onwards, nesting later further to the north depending on the timing of the thaw (del Hoyo et al.
1992). It usually nests solitarily on smaller waters but may nest in loosely colonial groups on larger waters (e.g. several pairs nesting a few metres apart on the same lake) (Snow and Perrins 1998). On migration large flocks of 200-1,200 individuals may form, with similar concentrations occurring on rich marine fishing grounds during the winter (del Hoyo et al.
1992). The species is most commonly observed singly, in pairs or in small scattered flocks during this season however (Snow and Perrins 1998). Habitat Breeding
The species breeds on freshwater pools or lakes in open moorland, blanket bogs (del Hoyo et al.
1992) or open and wet peatland habitats (Campbell 1987). It will nest on pools as small as 10-20 m long or on lakes up to 5 ha in area, showing a preference for those in treeless areas that have well-vegetated margins and low islets or promontories on which to nest (Snow and Perrins 1998). It generally avoids waters with dense floating or emergent vegetation and steep rocks above the water (Snow and Perrins 1998), and if feeding conditions are inadequate in the pool chosen for breeding the species may fly to the coast or to lakes with higher abundances of fish in order to feed (Snow and Perrins 1998). Non-breeding
Outside of the breeding season the species frequents inshore waters along sheltered coasts, occasionally occurring inland (del Hoyo et al.
1992) on lakes, pools, reservoirs and rivers (Snow and Perrins 1998). Diet
Its diet consists predominantly of fish as well as crustaceans, molluscs, frogs, fish spawn (del Hoyo et al.
1992), aquatic insects, annelid worms (Snow and Perrins 1998) and plant matter (del Hoyo et al.
1992). Breeding site
The nest is a small depression (Flint et al.
1984, Snow and Perrins 1998) or a mound of plant matter (del Hoyo et al.
1992, Snow and Perrins 1998) built in shallow water up to 10 m from the shore (Snow and Perrins 1998) or very near the water's edge (Flint et al.
1984, del Hoyo et al.
1992, Snow and Perrins 1998) on islets or small promontories (Flint et al.
1984). Nesting pairs will often re-use the same site in successive years (Snow and Perrins 1998). Management information
In Scotland attempts have been made to implement education schemes for fishermen and land-owners to try to reduce disturbance and mortality of the species on breeding lakes (Campbell 1987). The introduction of floating artificial nesting rafts may also be successful in increasing the species's breeding success (Campbell 1987). Threats
When breeding the species is threatened by water level fluctuations (Campbell 1987, del Hoyo et al.
1992), acidification of breeding waters (Campbell 1987, del Hoyo et al.
1992), heavy metal pollution (del Hoyo et al.
1992) and the afforestation of peatland or moorland habitats (Campbell 1987). It is also sensitive to human disturbance from recreational activities (del Hoyo et al.
1992) and shoreline development (e.g. construction work near breeding lakes) (Meek et al.
1993) and will desert sites if there is too much human activity (del Hoyo et al.
1992). During the winter the species is highly vulnerable to coastal oil spills, especially in areas where large concentrations form (e.g. on rich fishing grounds) (del Hoyo et al.
1992), and is highly sensitive to disturbance from coastal wind farms (wind turbines) during this season (Garthe and Huppop 2004). The species suffers mortality at sea and on large lakes due to entanglement and drowning in inshore fishing nets (del Hoyo et al.
1992) and is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).
Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.
Campbell, L. 1987. Loon conservation in the British Isles. In: Strong, P. I. V. (ed.), Papers from the 1987 conference on loon research and management, pp. 78-35. North American Loon Fund.
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.
Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.
Flint, V. E.; Boehme, R. L.; Kostin, Y. V.; Kuznetsov, A. A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.
Garthe, S.; HÃ¼ppop, O. 2004. Scaling possible adverse effects of marine wind farms on seabirds: developing and applying a vulnerability index. Journal of Applied Ecology 41(4): 724-734.
Meek, E. R. 1993. The effects of aero-generators on moorland bird populations in the Orkney Islands, Scotland. Bird Study 40(2): 140-143.
Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.
Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.
Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)
Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)
Explore HBW Alive for further information on this species
View photos and videos and hear sounds of this species from the Internet Bird Collection
Text account compilers
Butchart, S., Ekstrom, J., Malpas, L., Calvert, R.
IUCN Red List evaluators
Butchart, S., Symes, A.
BirdLife International (2016) Species factsheet: Gavia stellata. Downloaded from
http://www.birdlife.org on 26/10/2016.
Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 26/10/2016.
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.