Freshwater is the lifeblood of our wild isles. From highland burns in the Scottish Cairngorms to vast mudflats in Norfolk, Sir David Attenborough takes us on a journey from source to sea, following the course of our freshwater as it journeys through our landscapes.

Along the way we meet a host of wildlife that lives in, on and around our rivers, lakes, ponds and lochs, revealing the crucial role that water plays in supporting wildlife of all kinds. Determined Atlantic salmon battle their way upstream in one of the greatest migrations on the planet, beavers slow the flow with their expert dam-building, spiders become deadly assassins, millions of mayfly have mere days to live, and in shocking new behaviour caught on camera, an unlucky raft of young toadlets has to cross a ‘killing zone’ patrolled by carnivorous leeches...a tiny toad’s worst nightmare.

As our rivers slow, they spread out and huge areas of reedbed form. In spring, great crested grebes pair up in a complex and beautiful courtship ceremony, and hobbies – small, agile birds of prey - swoop low to catch dragonflies in the summer sun.

Where our freshwater reaches the sea, vast mudflats can form. These habitats are a magnet to hundreds of thousands of overwintering wading birds, and they in turn attract peregrine falcons – the fastest animal on the planet*.

Whether it’s our rare chalk streams, vast reedbeds, or rich mudflats, freshwater touches almost every corner of the British Isles, and every creature here relies on it.

Key stories

Filming First
Atlantic salmon migration from sea to source – we believe this is the first time underwater drones have been used to film the journey in this way, swimming with the fish as they migrate. The team attached cameras to underwater remote-controlled drones in order to capture this footage, which took 71 days to film – the longest of any sequence on the Wild Isles series – including waiting for nine days to film the salmon leaping up waterfalls. The crew enlisted the help of a local expert in Scotland, a former fisherman, to help them understand the salmon behaviour and get up close with the drones.

New/Remarkable Behaviour
Bat lek – filmed in the North Yorkshire Moors, this is believed to be the first ever bat lek filmed using high-speed infra-red cameras, capturing a group of males of different species coming together at night and flying in circles in an attempt to impress females.

New/Remarkable Behaviour
Mayflies – over many years, the team captured the emergence of over one million adult mayflies. These flying insects have no mouths and their sole purpose as adults is to breed.

Rare Habitat
Chalk streams - our chalk streams are almost unique to England, with most found in southern England. There are only 200 known globally and 85 per cent of them are in England*. An amazingly rare habitat, which makes them more special. They are a haven for iconic species like the otter, kingfisher, and salmon.