It's a scheme that takes the sound of 'moosic' to a new level.

A clever herd of cows has been enlisted to protect an ancient hill fort from invaders – by associating the sound of music with a virtual fence.

The Little Doward Hill Fort was built in the 5th Century BC and is nestled in the Wye Valley, near Whitchurch.

Hundreds of years ago it provided protection for a prominent Iron Age warlord from the likes of oncoming Anglo Saxon warriors.

Now, the biggest battle the site faces is against vegetation and invasive species sweeping over it.

Little Doward Woods forms part of the Wye Valley Special Area of Conservation and Upper Wye Gorge Site of Special Scientific Interest. There are numerous veteran oak and beech trees here, plus rare and interesting wildlife. It is of national importance for its saproxylic beetles – species which need dead or decaying wood to complete their life cycle - including the incredibly rare Cosnard's net-winged beetle. The high number of ancient and veteran trees at the wood provide the deadwood and associated fungi these species rely on. The fort itself was the hilltop stronghold of Iron Age chiefs and has been linked with the 5th Century warlord Vortigern, said to have fled here from the invading Saxons.

And the Woodland Trust, who own the site, have turned to a herd of six Dexter cows to help protect and restore the fort – as well as the 82 hectares of woodland around it.

The cows, which feast on many different varieties of plants and berries, have learnt to associate musical beats, played through a solar powered collar, with a virtual fence.

They have been trained to respond to the audio zone – meaning they turn back when they hear a sound – allowing for a perimeter to be maintained without the need for traditional wooden posts and rails.

Richard Brown, Woodland Trust site manager said: 'Little Doward is a really ancient and special site with not only the fort which looks over the beautiful Wye Valley, but ancient woodland too.

'It is a bit of a battle to preserve the fort from vegetation and we have turned to grazing a small herd of fluffy and friendly Dexter cows who have been trained to associate musical beats with a virtual fence so now the eye sore and expense of building a fence is no longer needed.

'This is a win all around for the site. For nature and restoration the cows are ideal grazers across a wide range of species. They help spread seeds through their dung and gently move the soil around but without destruction.

'For the fort itself they are able to stop vegetation engulfing it and the virtual fencing technology, via an app, helps us to move the herd around, in effect moving the fence.'

Although only a small part of Little Doward Woods is ancient it is an incredibly important habitat, providing refuge for many plants and animals - some of which are only found in isolated pockets across the UK.

Little Doward Woods forms part of the Wye Valley Special Area of Conservation (SAC) and Upper Wye Gorge Site of Special Scientific Interest (SSSI).

There are numerous veteran oak and beech trees here, plus rare and interesting wildlife.

It is of national importance for its saproxylic beetles – species which need dead or decaying wood to complete their life cycle - including the incredibly rare Cosnard's net-winged beetle.

The high number of ancient and veteran trees at the wood provide the deadwood and associated fungi these species rely on.

The fort itself was the hilltop stronghold of Iron Age chiefs and has been linked with the 5th Century warlord Vortigern, said to have fled here from the invading Saxons.