Blenheim Palace bosses have reassured bird watchers who are worried a summer music and watersports event will disturb the local wildlife.

'Twitchers' fear loud rock music and watersports during Wakestock - a event commemorating the 1960s US festival Woodstock - will disrupt birds during their breeding season.

George Candelin, chairman of the Oxford Ornithological Society, said housemartins nesting by a bridge and birds around the lake could be at risk.

"It's happening at the height of the bird breeding season and we're concerned about breeding birds," he said. "There's going to be a lot of disruption.

"If you're making enough noise to keep the birds out of their nests, then the eggs or the young are going to chill and you're going to lose them, and every loss is a major one."

About 10,000 people are expected to attend the three-day festival in June.

Acts including Oxford bands Supergrass and Young Knives are already booked, and the festival will also feature wakeboarding, a sport similar to waterskiing.

Palace chief executive John Hoy said: "We hugely value the wildlife around our lakes. You could say we should never have an event at Blenheim, but we have to run our business and try to generate funds."

Mr Hoy also stressed that only professional wakeboarders would be taking part and would only use one boat between 10am and 2pm during the festival.

"The actual concert site is well away from the lakes and the wakeboarding element is a very small part of the weekend," he said.

Mr Candelin added: "I don't think it's being done maliciously - it's just something they may not have considered. We don't want to make waves.

"We just want to highlight that there might be a problem and see whether something can be done."

Mr Hoy said: "We work closely with the ornith- ological society and respect its concerns.

"The risk to birds is something we take very seriously, but it's one boat in a very small area of the lake."

Grahame Madge, spokesman for the Royal Society for the Protection of Birds, said the lake was home to mallards, moorhens and coots, but no rare species.

He added: "We would hope that the needs and interests of birds are borne in mind and that there are not any unnecessary disturbances."