Low-flying paragliders have been criticised for the 'irresponsible and unlawful' disturbance of rare birds nesting on the marshes at Wells.

Harbour master Robert Smith said he had noticed increasing numbers of the lightweight, free-flying aircraft, whose pilot sits in a harness suspended below a fabric wing, similar to a parachute canopy.

But this weekend, he said one flew dangerously close to moored boats and frightened a number of birds away from their nests.

'What they are doing is irresponsible and dangerous, and it is unlawful to disturb nesting birds – particularly the terns,' he said.

'Yesterday (Saturday) we had one which was weaving in and out of the yachts on the quayside and virtually landed on one of the masts.

'It is a problem all along the coast and we need to identify these people in order to educate them.

'No-one wants to spoil their fun and I don't want to be a killjoy, but we just want them to take more care.

'There are lots of fields and open spaces in Norfolk where they can do this, and they don't need to do it over the marshes.'

Little terns are legally protected as a Schedule One breeding bird. Other birds which nest in the area include common terns, Arctic terns, oystercatchers and ringed plovers.

Paraglider flights can last for hours, prolonged by the use of thermals which can help a skilled pilot to regain height. They can be launched from high ground, or towed to the necessary height by an engine-driven winch.

Mr Smith said he had been unable to find out where the Wells paragliders had launched from.