Heavy storms, predators and careless visitors took a heavy toll on the iconic birds that help to make a North Norfolk nature reserve special, the National Trust said yesterday.

The dreaded triple hit had a big impact on some of the tern colonies at Blakeney Point, according to the trust's wardens.

Little terns, which are particularly sensitive, were hardest hit by predators and human activity.

Despite the best efforts of wardens and volunteers who fence off the birds' nests, two visitors walked among the nests on a stormy day in June - causing 10 pairs to abandon their nests.

Sandwich terns and common terns bore the brunt of the storms, which forced their colonies into smaller breeding areas on the point.

While the sandwich terns numbered 2,500 pairs and produced over 900 young, the decline in common terns since 2005 continued, with a maximum of 75 pairs breeding on the point in 2010, producing between 23 and 26 young.

Blakeney Point warden Eddie Stubbings leads a team at the beginning of April to the lifeboat house on the point, where they start work on fencing off the sensitive breeding sites which change each year depending on where the birds choose to nest.

The fenced areas give the birds the space they need to breed and help people to enjoy the wildlife spectacle without causing disturbance to the birds.

Mr Stubbings said the incident where people disturbed the nests of the little terns showed how difficult it was to protect the birds.

He said: 'Little terns, locally known as little pickies, are a wonderful sight to see as they go about their business in summer. Unfortunately they are sensitive birds and were affected this summer by predators and human disturbance.

'Despite our best efforts two visitors walked amongst their nests on one stormy day in June causing 10 pairs to abandon their nests. Hence 75 pairs produced only 15 young.'

He added: 'Blakeney Point is home to four of the five species of tern that regularly breed in Britain. Arctic Terns are at the southern limit of their breeding range on Blakeney Point, usually breeding at higher latitudes in the arctic, so the colony here is very small. This year some medium sized chicks were being fed by adults in early July but we think they were all eventually predated and none fledged.'

The trust also reported on the point's wading bird colonies:

'Sturdy and numerous' oystercatchers numbered 118 pairs and raised a 'good number of young'

Redshank numbers rose slightly this year with 10-13 pairs raising some young

Ringed plovers are still struggling with just 15 pairs raising eight-plus young.

Mr Stubbings said: 'Five to six pairs of Mediterranean gulls also bred on the point in amongst the gulls and terns on Far Point. They are recent colonists, having first arrived here in the 1990s. 2010 was a good year for them as 16-plus young were seen around the colony on the 16th of July. All in all, it's been a challenging year for our breeding birds.'

Other birds breeding on the point include shelduck, gadwall, skylark, meadow pipit, linnet and reed bunting.