Britain’s winter flocks of wading birds are among the country’s greatest natural spectacles.
Knots form the largest of these gatherings. They are thick-set sandpipers, closely related to dunlin, which spend the winter almost exclusively on muddy estuaries, seldom venturing inland.
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They’re easily spooked – perhaps by a dog running off the lead, or by a raptor such as a peregrine. Erupting into the air, the flocks of knot move as one, twisting and turning over the mudflats in a silvery version of a starling murmuration, before settling once more.
Watch a stunning knot murmuration at RSPB Snettisham, Norfolk, in the video below.
Their biggest flocks peak at more than 100,000 individuals – a thrilling sight. The mighty flocks assemble during the incoming tide, as rising sea water pushes the feeding knot closer together.
Eventually, the huge mass of birds is forced to seek refuge on the shore or on mudbanks left uncovered by the water. Settled at last, the birds congregate in a dense scrum to sit out the high tide, after which they can begin feeding again.
Watch the 'Snettisham Spectacular' below – an event where thousands of birds are pushed off their feeding ground on The Wash to a lagoon.
Main image: Screenshot from Getty video
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