David Attenborough's Wild Isles to feature Snettisham in Norfolk

The fourth episode of the BBC series will focus on freshwater habitats and their role in supporting wildlife.

Part of the episode focuses on knot birds in Norfolk, which can be seen gathering in their thousands in what is known locally as the Snettisham Spectacular.

A still featuring the knots from the Sunday episode of Wild Isles (Image: BBC Pictures)

Where freshwater reaches the sea, vast mudflats can form and these habitats are a magnet to hundreds of thousands of overwintering wading birds. 

Producer Chris Howard said: "The two scenes that really stick in my mind are the bats and the knot. 

READ MORE  David Attenborough's Wild Isles show to feature Norfolk locations

"As for the knot – the spectacle of a hundred thousand waders taking to the air to avoid a stooping peregrine just as the sun sets is hard to beat.

"It also shows the importance of our estuaries – vital fuelling stations for migratory birds each winter - and is extra special because it only really happens three or four times a year when the tides, light and weather all come together."

Migrating Atlantic Salmon's journey was also filmed from sea to source (Image: BBC Pictures)

The episode will also feature migrating Atlantic salmon, bat leks in Yorkshire and mayflies on the River Avon. 

Norfolk also features in the fifth episode which focuses on the seals at Blakeney Point. 

The fourth episode airs on BBC One at 7pm on Sunday, April 2.