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). 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.
The global population is estimated to be 205,000-295,000 individuals (Wetlands International 2015). The European population is estimated at 56,700-83,000 pairs, which equates to 113,000-166,000 mature individuals (BirdLife International 2015). The population is therefore placed in the band 200,000-299,999 individuals.
This species has undergone a small or statistically insignificant decrease over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). Populations elsewhere are stable or unknown. The European population trend is unknown (BirdLife International 2015).
Behaviour This species is fully migratory (del Hoyo et al. 1996, Snow and Perrins 1998). It arrives on the breeding grounds from mid-May to mid-June where it nests in solitary pairs (del Hoyo et al. 1996) and forages in small loose groups (Snow and Perrins 1998). From July to August the adults undergo a flightless moulting period on the coast close to the nesting areas before travelling to the wintering grounds in September and November (Hayman et al. 1986). During the non-breeding season the species is gregarious and usually forms small flocks of up to 250 individuals (del Hoyo et al. 1996). Habitat Breeding The species breeds on Arctic coasts (Hayman et al. 1986) and in upland areas (Johnsgard 1981, Flint et al. 1984, Hayman et al. 1986), nesting close to the fringes of snow and ice (del Hoyo et al. 1996) on wet moss or barren rocky tundra with patches of lichen and Dryas spp., on rocky islands and islets or on shingle beaches (del Hoyo et al. 1996). It forages on dry tundra or along the moist margins of ponds, at the edges of melting snow-drifts and in areas of thick moss (Hayman et al. 1986). Non-breeding During the winter and on passage the species shows a preference for tidal rocky shores with strong wave action (Hayman et al. 1986) and suitable high-tide roosting areas (del Hoyo et al. 1996), often utilising artificial structures such as concrete sea defences and breakwaters (Hayman et al. 1986). In some northern areas (e.g. Svalbard) the species frequents mudflats, shingle beaches and coastal lagoons before and after breeding but before migrating south (del Hoyo et al. 1996). Diet Breeding During the breeding season its diet consists largely of insects (e.g. adult, larval and pupal Diptera, Ichneumon wasps and aphids) and Collembola (springtails), as well as spiders, gastropods, annelid worms and some plant material (e.g. leaves, buds, berries and seeds) (del Hoyo et al. 1996). Non-breeding On the coast the species feeds predominantly upon molluscs (especially gastropods Littorina spp. and mussels Mytilus spp.) as well as insects (e.g. beetles and Diptera), small crustaceans (e.g. amphipods), annelid worms (del Hoyo et al. 1996), small fish (Johnsgard 1981) and algae (Enteromorpha spp.) (del Hoyo et al. 1996). Breeding site The nest is a small scrape positioned in the open on tundra moss (del Hoyo et al. 1996), in hummocky tundra (Flint et al. 1984) close to tufts of Dryas spp. or Arctostaphylos spp. (Johnsgard 1981), or in rocky or pebbly areas between cliffs (Flint et al. 1984).
The species is likely to be affected by climate change (Rehfisch et al. 2004). It is also vulnerable to disturbance (Burton et al. 1996).
Conservation Actions Underway
The species is listed on Annex II of the Bern Convention.
Conservation Actions Proposed
The following information refers to the species's European range only: The species must be protected from disturbance by humans.
Text account compilers
Malpas, L., Ashpole, J, Butchart, S., Ekstrom, J.
BirdLife International (2020) Species factsheet: Calidris maritima. Downloaded from http://www.birdlife.org on 13/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 13/07/2020.