70 thousand wading birds arrive in Snettisham for the winter months

Watch Hannah Pettifer's report

There are only a handful of days every year when the "Snettisham Spectacular" can take place.

Only when the tide is at its highest, tens of thousands of wading birds are forced off the mudflats at RSPB Snettisham and into the sky.

Here they take refuge, creating spectacular formations that can last until the tide eventually recedes.

Wildlife photographer Russell Savory has been coming to RSPB Snettisham since he was a child.

He said:

The Wash has the biggest area of mudflats in the UK which provides rich feeding ground for the birds.

More than twenty species of wading bird come here for the winter months with the Knot making up the biggest population.

At present there are 70,000 but that number could easily double within the month as more arrive from Canada and Greenland.

It is not known why the Knot make the incredible formations in the sky. Sometimes it can be as simple as moving to better ground or trying to escape a predator, but most of the time they seem to swirl around for no apparent reason, seemingly unaware of the spectacular effect they're creating in the sky.

Once the Knot finish their aerial display they drop down into a nearby lagoon where they wait until the tide recedes and they can return to the mudflats.

For the best times to see the Snettisham Spectacular this year visit the RSPB website.