Justification 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 extremely 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.

Family/Sub-family Laridae

Species name author (Linnaeus, 1758)

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Cramp and Simmons (1977-1994), Dowsett and Forbes-Watson (1993), SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

17,000,000 - 18,000,000

unset

-

No

Range & population The Black-legged Kittiwake nests along coastlines in much of the north Pacific and Atlantic oceans, and also breeds on inlands off the northern coast of Russia and on the northern coast of Norway. It winters at sea, ranging across much of the north Atlantic and Pacific oceans¹. Overall population trends are unknown, though failed breeding seasons in 2008 and in some cases significant population declines have been observed in the United Kingdom by the RSPB.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Behaviour This species is migratory and disperses after breeding from coastal areas to the open ocean¹. It returns to its breeding grounds from January where it breeds from mid-May to mid-June in huge single- or mixed-species colonies¹ that often exceed 100,000 pairs^{1, 4}. Breeding may occur later after periods of cold weather and many individuals do not remain on the breeding grounds during such conditions¹. The species begins to disperse from the breeding colonies between July and August, often moulting in large flocks of several thousand individuals on beaches between the breeding grounds and the open sea². Non-breeders may also remain at sea during the breeding season⁴. Outside of the breeding season the species often occurs singly or in pairs⁴ but may also occur in small flocks or as dispersed aggregations^{3, 4}. Habitat Breeding It nests on high, steep coastal cliffs with narrow ledges in areas with easy access to freshwater¹. Non-breeding The species moults on sandy beaches² and on passage it may concentrate at sea on continental shelves, areas of upwelling¹ and at rich fish banks². During the winter the species is highly pelagic, usually remaining on the wing out of sight of land¹. Diet Its diet consists predominantly of marine invertebrates (e.g. squid and shrimps) and fish, although during the breeding season it may also take intertidal molluscs, crustaceans¹ (e.g. crayfish)³, earthworms, small mammals and plant matter (e.g. aquatic plants, potato tubers and grain)¹. At sea during the winter it will also take planktonic invertebrates and often exploits sewage outfalls and fishing vessels¹. Breeding site The nest is a compacted mass of mud⁴, grass and feathers³ usually built on a narrow ledge on high, steep coastal cliffs¹. Occasionally the species may also nest on glaciers or snow banks (where these have covered traditional cliff nesting sites), on buildings and piers, or on flat, rocky or sandy sites up to 20 km inland¹. It breeds in very large colonies with neighbouring nests spaced evenly 30-60 cm apart (where site availability allows)⁴, and generally feeds within 50 km of the breeding colony¹.

Threats The species is threatened by the depletion of food resources (e.g. through over-fishing)^{6, 7}, marine oil spills^{1, 6} and chronic oil pollution⁶. It is also susceptible to avian influenza so may be threatened by future outbreaks of the virus⁵. The species is potentially threatened by climate change because it has a geographically bounded distribution: its global distribution is restricted to within c.10^o latitude from the polar edge of continent and within which 20-50% of current vegetation type is projected to disappear under doubling of CO2 levels (BirdLife International, unpublished data). Utilisation The species is hunted in Greenland¹.

References 1. del Hoyo et al. (1996). 2. Olsen and Larsson (2003). 3. Flint et al. (1984). 4. Snow and Perrins (1998). 5. Melville and Shortridge (2006). 6. Nikolaeva et al. (2006). 7. Frederiksen et al. (2004).

Further web sources of information

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Text account compilers Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International)

Recommended citation BirdLife International (2010) Species factsheet: Rissa tridactyla. Downloaded from http://www.birdlife.org on 30/7/2010

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

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