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.

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

Markus Varesvuo / Knot (Calidris canutus) flock on shoreline, Hanko, Finland, September

Graham Eaton,Graham Eaton / Dog chasing and disturbing a flock of Knot (Calidris canutus) on a beach, Hoylake, Wirral

Danny Green / Knot (Calidris canutus) and grey plover (Pluvialis squatarola) roost at high tide with numerous birds packed tightly together, Snettisham, Norfolk, October. Bookplate from Danny Green's 'The Long Jour...

Peter Cairns / 2020VISION / Flock of Knot (Calidris canuta) in flight. The Wash Estuary, Norfolk, October.

Andy Rouse / 2020VISION / Flock of Knot (Calidris canuta) taking flight. Snettisham, UK, January. Did you know? The red knot has one of the longest migrations in the world, with some travelling 9000 miles from the Arctic to th...

Andy Rouse / 2020VISION / Flock of Knot (Calidris canuta) over sea with wind turbine. Liverpool Bay, UK, December.

Chris Gomersall / 2020VISION / Flock of Red knot (Calidris canutus) and Bar-tailed godwit (Limosa lapponica) in flight at high water on the Wash estuary, Snettisham RSPB reserve, Norfolk, England, UK, March

Chris Gomersall / 2020VISION / Flock of Red knot (Calidris canutus) in flight at high water on the Wash estuary, Snettisham RSPB reserve, Norfolk, England, UK, March

Paul Hobson / Knot (Calidris canutus) flock roosting on beach. Norfolk, August.