John Chan / Flock of Western sandpipers (Calidris mauri) taking flight from salt marsh, Southern California, USA.

David Woodfall / Dunlin (Calidris alpina ) North Uist, Outer Hebrides, Scotland, UK, June.

David Woodfall / Dunlin (Calidris alpina) small wader with young in machair. North Uist, Scotland, UK, June.

SCOTLAND: The Big Picture / Turnstones (Arenaria interpres) and Purple sandpipers (Calidris maritima) over wintering on the beaches of the Orkney Isles, Scotland, UK, April.

Chris Gomersall / Large flock of Red knot (Calidris canutus) moving at high tide roost, in winter plumage, Snettisham RSPB Reserve, Norfolk, England, UK, September.

John Waters / Large mixed flock of Knot (Calidris canutrus), Dunlin (Calidris alpina) and Golden plover (Pluvialis apricaria) in flight at high tide, Steart Marshes WWT Reserve, Somerset, England, UK, December.

Rob Drummond/ BIA / Sanderling (Calidris alba) wading, Victoria, Australia

Alan Murphy/ BIA / Sanderling (Calidris alba) feeding on crab carcass, Texas

Donald M. Jones / Semipalmated Sandpiper (Calidris pusilla) preening in spring, southern Alaska

Gerrit Vyn / Red-necked stint (Calidris ruficollis) on its Russian breeding grounds. Chukotka, Russia. June.

David Tipling / 2020VISION / Large flock of Red knot (Calidris canutus) taking off from mudflats, The Wash estuary, Norfolk, England, UK, January

Mario Suarez Porras / Dunlin (Calidris alpina) foraging, Asturias, Spain