Swirling murmuration of birds caught on camera off Norfolk coast

A swirling murmuration of birds feeding and flying off the coast of Norfolk has been captured on video.

The display of knot birds at RSPB Snettisham only happens at very high tide during autumn or early spring.

The RSPB estimates that about 320,000 spend the winter in the UK, feeding on shellfish and worms in estuaries.

The birds, which are about 25cm (10in) in length, undertake one of the longest migrations of any animal - from their Arctic breeding grounds to Europe, Africa and Australia.

This video has been optimised for mobile viewing on the BBC News app. The BBC News app is available from the Apple App Store for iPhone and Google Play Store for Android.