The curlew sandpiper (Calidris ferruginea) is a long-distance migratory wader that breeds in the Siberian Arctic and winters across sub-Saharan Africa, South Asia, and Australasia. It passes through Britain and Europe in spring and autumn, primarily on coastal mudflats and scrapes.
Curlew sandpipers undertake one of the longest migrations of any wader — over 10,000km between breeding grounds and wintering sites. Their passage through the UK occurs mainly in August–September (adults, then juveniles) and April–May (northward migration). Birds arriving in Britain are refuelling, depositing fat reserves for continued long-distance flight. The physical demands of migration are enormous — birds may double their body weight before long-distance flights.
In autumn plumage, curlew sandpipers resemble dunlin but have longer, more decurved bills, whiter supercilium, white rump visible in flight, and more elegant build. Adults in breeding plumage show striking chestnut underparts. Annual passage numbers vary considerably depending on breeding success in Siberia — poor lemming years force Arctic foxes to switch to bird predation, dramatically reducing shorebird breeding success. Population trends show a general decline linked to declining breeding success.
Curlew sandpipers depend on intertidal mudflats rich in invertebrates — polychaete worms, bivalves, and crustaceans. They probe with their bill in typical sandpiper fashion, feeding actively during tidal exposure windows. Habitat loss through land reclamation, industrial development, and sea level rise threatens staging sites along the migration route. Birds unable to find adequate refuelling sites face dramatically increased mortality risk. The welfare implications are direct — individuals that cannot refuel sufficiently face starvation or exhaustion during subsequent migration legs.
The East Asian-Australasian Flyway has suffered severe degradation of intertidal habitat through land reclamation, particularly in the Yellow Sea region where many curlew sandpipers stage. Hunting pressure exists in some range states. Climate change is altering the timing of invertebrate abundance on staging sites relative to migration schedules. Pollution of intertidal zones affects food availability and directly harms birds through bioaccumulation of contaminants.
Key UK sites for curlew sandpipers include the Wash, Morecambe Bay, Thames Estuary, and Dee Estuary. These are mostly protected as Special Protection Areas (SPAs) and Ramsar sites. The British population of breeding waders has declined dramatically in recent decades; though curlew sandpipers do not breed here, their passage welfare depends on Britain maintaining good-quality coastal habitats.
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