Data Zone
Justification of Red List category
This species has a very large geographic range size (extent of occurrence >13 million km2 in both the breeding and non-breeding seasons), and so does not approach Criterion B thresholds. It also has a relatively large estimated population size (204,000 to 287,000 individuals), and so does not approach Criteria C or D thresholds. Although the global population may be decreasing overall, it does not currently appear to be declining at a rate approaching Criterion A thresholds. Hence, the species continues to warrant listing as Least Concern.
Population justification
The species has a relatively large estimated population size of 204,000 to 287,000 individuals (Wetlands International 2023), with the number of mature individuals calculated as two-thirds of this range. The population in Arctic Canada is estimated at 68,750 mature individuals (Smith et al. in prep.).
Trend justification
Considering its population trend over three generations (c. 21 years), data availability varies considerably across the five recognised flyway populations, which breed in north-east Canada, Greenland, Iceland, northern Europe and western Siberia, respectively (Wetlands International 2023). Data from the Christmas Bird Count (Meehan et al. 2022) indicate that it has remained broadly stable in north-east Canada and the eastern USA, albeit with interannual fluctuations, following an earlier decline. Over much the same period and region, Partners in Flight (2023) reports an increase of c. 8%, albeit with large confidence intervals, while eBird suggests a decline since 2011 (Fink et al. 2023). The trends of the breeding populations in Greenland, Iceland, Europe and Russia are uncertain, although there is some evidence for a decline in Iceland (BirdLife International 2021) and for a northwards contraction in the Fennoscandian breeding range between the first and second European breeding bird atlases (Keller et al. 2020). Numbers wintering in coastal north-west Europe may have declined by c. 20%, but there are marked interannual fluctuations and only a small proportion of the population is monitored (van Roomen et al. 2022). Accordingly, the global population trend is estimated to be decreasing.
C. maritima breeds throughout North America and northern Europe, occurring in the high arctic areas of Canada, Greenland (to Denmark), Iceland, in the northern parts of U.K., Norway (including Svalbard and Bear Island), Sweden, Finland, and northwest and central Siberia, coastal Murmansk, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, New Siberian Islands, Taimyr Peninsula, and northern Russia (Payne and Pierce 2020). In the non-breeding season, found in U.S.A., Greenland, Iceland, Norway, U.K., Ireland, Denmark (including Faroe Islands), France, north and west Germany, Netherlands, Sweden, and Belgium (Payne and Pierce 2020). Very rarely found in Spain and Portugal (including the Azores Islands) (Payne and Pierce 2020, eBird 2024).
This species is fully migratory (Snow and Perrins 1998). It arrives on the breeding grounds from mid-May to mid-June where it nests in solitary pairs and forages in small loose groups (Del Hoyo et al. 1996, Billerman et al. 2020, Snow and Perrins 1998).
The species breeds on Arctic coasts and in upland areas (Johnsgard 1981, Flint et al. 1984, Hayman et al. 1986), nesting close to the fringes of snow and ice, 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, Billerman et al. 2020). 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). During the winter and on passage the species shows a preference for tidal rocky shores with strong wave action and suitable high-tide roosting areas, often utilising artificial structures such as concrete sea defences and breakwaters (Del Hoyo et al. 1996, Billerman et al. 2020, 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, Billerman et al. 2020).
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, Billerman et al. 2020). 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, small fish and algae (Enteromorpha spp.) (Del Hoyo et al. 1996, Billerman et al. 2020, Johnsgard 1981).
The nest is a small scrape positioned in the open on tundra moss, in hummocky tundra close to tufts of Dryas spp. or Arctostaphylos spp., or in rocky or pebbly areas between cliffs (Del Hoyo et al. 1996, Billerman et al. 2020, Johnsgard 1981, Flint et al. 1984).
In the high Arctic, the species typically breeds from sea level up to approximately 300 meters. In the low Arctic and subarctic regions, it primarily breeds inland on uplands, reaching elevations of over 1,000 meters in Sweden and Norway (Cramp and Simmons 1983).
Human activities and habitat degradation in coastal wintering grounds are known threats to the species throughout its North American non-breeding season range. Factors include shoreline development, aquaculture, oil contamination, algae harvesting, and disturbance from boat traffic and other human activities (Burton et al. 1996; Gutowsky et al. 2019). Additionally, the species has been found to have high nest fidelity to specific sites in wintering areas. This makes it more susceptible to large-scale changes in its food base, increased predation pressure and, importantly, habitat loss and disturbance (Mittelhauser et al. 2012). The population in Iceland, residing near human settlements, was found to have elevated levels of harmful contaminants, which poses a localised threat. The species' strong fidelity to nesting sites results in varying levels of contamination among individuals, heightening their exposure to pollutants (Payne and Pierce 2020).
Climate change may also be a significant threat to the species. Even under conservative climate change scenarios, the species is predicted to decrease by between 35% and 60% in its non-breeding strongholds in the UK of the Western Isles, Orkney and Shetland by 2080 (Rehfisch et al. 2004); the UK wintering population declined by 31% between 1996 and 2021 (Austin et al. 2023). Available breeding habitat based on predicted distribution under future climate change scenarios is predicted to reduce by between 39% (RCP 4.5) and 53% (RCP 8.5) by 2070 (Wauchope et al. 2017).
Conservation Actions Underway
This species is not listed on the annexes of the European Union (EU) Birds Directive, but is covered by the general protection regime provided by Article 1 of the Directive to all naturally occurring wild species in the EU. It is listed on Annex II (strictly protected) of the pan-European Bern Convention, Annex II of the Convention on Migratory Species (CMS) and Annex II of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). Across the EU, 64 Natura 2000 sites have been designated for the conservation of this species on passage and in winter
Conservation Actions Proposed
The species requires greater protection from human disturbance and habitat degradation, including by the protection of more key wintering sites.
Text account compilers
Chad, E., Martin, R.
Contributors
Ashpole, J, Burfield, I., Ieronymidou, C., Pople, R., Symes, A., Van den Bossche, W, Wheatley, H., Wright, L, Staneva, A., Piggott, A., Fernando, E., Grice, H. & Rutherford, C.A.
Recommended citation
BirdLife International (2024) Species factsheet: Purple Sandpiper Calidris maritima. Downloaded from
https://datazone.birdlife.org/species/factsheet/purple-sandpiper-calidris-maritima on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.