Justification of Red List Category
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). The population trend appears to be stable, and hence the species does not 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.
The global population is estimated to number c.330,000-700,000 individuals (Wetlands International 2015). The European population is estimated at 1,100-2,100 pairs, which equates to 2,100-4,100 mature individuals (BirdLife International 2015). The population in Russia has been estimated at c.100-10,000 breeding pairs and c.50-1,000 individuals on migration (Brazil 2009).
The overall population trend is stable, although some populations have unknown trends (Wetlands International 2015). The small European population (c. 10% of global range) is estimated to be increasing (BirdLife International 2015).
This species breeds in the arctic and has a circumpolar distribution through northernmost North America and Eurasia. It migrates south during the autumn, wintering in the cold waters of the Humboldt current off the coast of Peru and Ecuador and off the south-west coast of Africa in the cold waters of the Benguela Current (del Hoyo et al. 1996).
Behaviour This species is a long-distance migrant (Olsen and Larsson 2003) that migrates offshore between its breeding and wintering grounds (del Hoyo et al. 1996). It returns to the breeding grounds from late-May to early-June when the Arctic tundra is still snow-covered, and breeds in colonies of 6 to 15 or occasionally up to 60 pairs (del Hoyo et al. 1996). The species may also nest solitarily or as single pairs amidst colonies of Arctic Tern Sterna paradisaea (del Hoyo et al. 1996). After breeding the adults and juveniles depart the breeding grounds from late-July to August (Olsen and Larsson 2003), migrating in flocks of up to a hundred individuals and spending the winter in small flocks (del Hoyo et al. 1996) or as solitary individuals (Snow and Perrins 1998). Habitat Breeding The species breeds on coastal (Snow and Perrins 1998) tundra wetlands (del Hoyo et al. 1996) in the Arctic (del Hoyo et al. 1996), showing a preference for swampy, moss and sedge tundra with many lakes (Flint et al. 1984), floodlands and low-lying shallow brackish pools, especially where these contain islets or narrow peninsulas of grass or moss and have low, moist margins that provide feeding areas (Snow and Perrins 1998). Non-breeding Outside of the breeding season the species is pelagic (del Hoyo et al. 1996), occurring in cold water upwelling zones south of the equator (Snow and Perrins 1998). Diet Breeding When breeding its diet consists of adult and larval insects (Flint et al. 1984) (e.g. springtails Collembola), Arachnids, small fish and carrion, as well as small birds and the eggs of Arctic Tern Sterna paradisaea and conspecifics (del Hoyo et al. 1996). The species also takes seeds and plant matter on its arrival to the breeding grounds before the Arctic ice melts and other prey items become available (del Hoyo et al. 1996). Non-breeding Outside of the breeding season the species takes marine invertebrates and small fish (del Hoyo et al. 1996). Breeding site The nest is a shallow scrape (Richards 1990) or more substantial cup of grass (del Hoyo et al. 1996), moss, seaweed and feathers (Richards 1990) placed on rocky, barren (del Hoyo et al. 1996) or damp ground vegetated with moss (Flint et al. 1984) or grass, usually near the edge of water (del Hoyo et al. 1996).
No specific information on threats to this species has been recorded within Europe, however as an Arctic breeding species, it is likely to be vulnerable to the impacts of climate change including habitat change and ecosystem shifts (Ganter and Gaston, 2013). Beyond Europe, the species is hunted in Russia, including egg harvesting (Merkel and Barry 2008). Neither of these threats are believed to be significant to the species as a whole.
Conservation Actions Underway
The following information refers to the species's European range only: Listed under the African Eurasian Waterbird Agreement. Listed on Appendix II of the Bern Convention. It is listed within six marine Important Bird Areas across Europe. Within the EU it is listed in two Special Protection Areas in Spain.
Conservation Actions Proposed
The following information refers to the species's European range only: Identify Important Bird Areas in the Arctic region, and subsequently designate them as protected areas, with particular emphasis on sites at sea.
Text account compilers
Butchart, S., Ekstrom, J., Calvert, R., Ashpole, J, Malpas, L., Wheatley, H.
BirdLife International (2019) Species factsheet: Xema sabini. Downloaded from http://www.birdlife.org on 16/02/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/02/2019.