Behaviour This species is a long-distance migrant that largely travels along the coast making few stopovers¹ but utilising different routes in the autumn and the spring^{1, 5}. It breeds from late-May to late-June, departing the breeding grounds in July and arriving on the wintering grounds between August and October¹. The return migration to the breeding grounds takes place from March to April¹ although juvenile non-breeders often remain in the tropical parts of the wintering range for the breeding season². The species forages in large flocks of one hundred to several thousand¹ at favoured sites on passage², but during the winter it typically forages in small groups³. Habitat Breeding The species breeds on gravelly areas covered with lichen and patches of herbs, heather¹, Empetrum spp., Dryas spp. and Vaccinium spp.³, or alternatively on areas with a continuous layer of lichen and scattered stunted larch Larix spp. or dwarf pine Pinus pumila¹. It occurs on plateaus or gentle slopes with montane tundra in the subarctic at heights of 300-1,600 m¹. Non-breeding In its wintering range the species occurs in sheltered coastal habitats such as inlets, bays, harbours, estuaries and lagoons with large intertidal mud and sandflats, oceanic sandy beaches with nearby mudflats^{1, 5}, sandy spits and islets, muddy shorelines with mangroves and occasionally exposed reefs or rock platforms⁵. It roost in refuges⁶ such as shallow water in sheltered sites, on coastal dunes or on saltflats amongst mangroves⁵ during high tides⁶. On passage the species stages in estuaries and on intertidal mudflats^{7, 8}. Diet Breeding The adult breeding diet consists predominantly of plant material such as berries¹ (e.g. of Empetrum nigrum)³ and pine kernels of dwarf pine Pinus pumilla¹. Small chicks feed exclusively on insects (e.g. larval Diptera and Coleoptera) and spiders¹. Non-breeding During the winter and on passage the species takes bivalves up to 36 mm long from intertidal mudflats as well as gastropods, crustaceans¹ (e.g. crabs and shrimps)⁵, annelid worms and echinoderms (e.g. sea cucumbers)¹. Breeding site The nest may be an open depression in moss⁴, but very few nests have been found³.

KBBI187-07|KRIBB 2305|Calidris tenuirostris| ---------------------------------ATTGGCACACTATACCTAATCTTTGGCGCATGAGCCGGTATGGTCGGAACTGCCCTT---AGCCTACTCATTCGTGCAGAGCTAGGCCAACCCGGAACTCTTTTAGGAGAT---GACCAAATTTACAATGTAATTGTCACCGCCCATGCTTTTGTGATAATCTTCTTCATAGTAATGCCAATTATAATTGGTGGCTTCGGAAACTGACTAGTCCCCCTTATA---ATCGGCGCCCCCGACATAGCATTCCCTCGCATAAATAACATAAGCTTCTGATTACTTCCCCCATCATTCCTCCTACTGCTAGCATCTTCTACAGTAGAAGCCGGAGCAGGTACAGGATGAACAGTATACCCCCCGCTCGCCGGCAACCTAGCCCATGCTGGAGCTTCCGTAGACCTA---GCTATCTTCTCTCTCCACCTGGCAGGTGTCTCCTCTATTCTAGGTGCTATCAACTTCATCACAACTGCCATCAACATGAAACCCCCAGCCCTCTCTCAATACCAAACACCCCTATTCGTATGATCAGTACTTATTACCGCCGTCCTACTCTTACTCTCCCTTCCAGTTCTTGCTGCT---GGCATTACTATGCTCCTAACAGACCGAAATCTAAACACTACATTCTTTGACCCTGCTGGAGGGGGAGACCCAGTTCTATATCAACATCTTTTCTGATTCTTTGGACATCCGGAAGTCTACATTCTAATTCTACCTGGATTCGGA------------------------------------------------------------------------------------------------------------------------------------------- 
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Red List Category

Red List Criteria

Version

2010

BirdLife International

Calvert, R., Symes, A., Butchart, S.

Amano, H., Clemens, R., Rogers, D., Moores, N.

This species has been uplisted to Vulnerable owing to a rapid population decline caused by the reclamation of non-breeding stopover grounds, and under the assumption that further proposed reclamation projects will cause additional declines in the future.

The global population has been estimated at c.380,000 individuals (Wetlands International, 2006). Following the reclamation of the tidal flats at Saemanguem, c.90,000 non-breeding individuals disappeared from the area. Surveys elsewhere in South Korea confirmed they had not been displaced, and a decline of the same magnitude and timing in Australia suggests that individuals previously using Saemanguem have died (D. Rogers in litt. 2009). Therefore a population of c.290,000 individuals is estimated, though given documented declines elsewhere the true figure is likely to be lower.

Decreasing

In the Chinese, North Korean and South Korean regions of the Yellow Sea (a major stopover area) the species is threatened by the degradation and loss of wetland habitats through environmental pollution⁹ (e.g. oil contamination of intertidal mudflats)⁸, reduced river flows and human disturbance⁹ (e.g. from off-road vehicles, tourists and hunters)⁸. In South Korea, after the loss of the important Saemangeum stopover area and almost all of the tidal-flats in Asan Bay and much of Namyang bay, possibly only five sites nationwide remain internationally important. Of these, only one (the Geum Estuary) currently has a low risk of reclamation, with the other four at risk due to the construction of tidal power plants and barrages, industrial use and urban expansion¹³. The species is also 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 levels¹⁵.

Conservation Actions Underway
No specific conservation action is known for this species, although population trends are being monitored in Australia as part of the Monitoring Yellow Sea Migrants in Australia project.

Conservation Actions Proposed
Identify key stopover areas and prevent their reclamation. Continue to monitor population trends. Restore reclaimed wetland sites. Campaign to stop shorebird hunting in Asian countries. Legally protect it in all range states. Survey the breeding grounds for potential threats. Manage roost sites in the species's Australian wintering range to minimise disturbance⁶.