Ospreys set to hatch England's rarest egg

100 volunteers guard breeding wild birds and their reservoir nest

Eggs from the first wild ospreys to breed in England for more than 150 years are about to hatch. Ten years ago, a project began to release dozens of young ospreys into the wild and now the first offspring is incubating eggs, which it is hoped will hatch in early June.

This will be a happy ending for the father, one of the first birds to be released, who has spent a decade looking for a mate.

Project organisers now hope the mating ospreys will continue to breed for the next few years, and will eventually be joined by their chicks. 'We aim to establish a self-sustaining colony,' said Tim Mackrill, the project officer. 'The birds can then spread out across England.'

The Rutland Water Osprey Project was launched in 1996 and the expectant father, tagged 08(97), was one of the first birds released into the wild at the Leicestershire reservoir the following year. He migrated 2,500 miles to West Africa and spent two years establishing a perch there.

He came back to Rutland in 1999, and began years of fruitless searching for a mate, despite preening his nest every spring and wooing several females. Last summer, 08 finally won the attentions of 5N, one of just 14 chicks in Rutland born and 'fledged' in the wild. At just two, she was too young to breed last year, but in April she returned and 08 took up the romance again, dangling trout from his talons while he swooped and cooed over his nest.

For a week, 08 courted his female with fish to show his prowess as a mate and father; then they began breeding and 5N began decorating the nest - now more than a metre square - with grass and hay.

In late April, the project team, set up by Anglian Water and the Leicestershire and Rutland Wildlife Trusts, finally discovered they were incubating possibly three eggs. Volunteers are now keeping 24-hour watch on the nest. And 08 is proving an attentive father - or maybe he is simply lazy.

'He's done much more incubation than normal,' said Mackrill. 'Quite often the female will have to push him off the eggs and press him to go off and get fish.'

If the chicks hatch, they will spend two months learning to fly and fish, by which time they will be at 70 per cent of their adult body weight. They will then set off alone on their own migration to West Africa for two years, before - the team hopes - they return to Rutland and start finding mates of their own.

If enough survive, they could soon start spreading out to find new nests and breeding grounds around the country - wherever they can find fish.

Ospreys were once common across the country but by the 1840s were driven near to extinction by hunting and loss of habitat. Mackrill said: 'We feel because it was man's influence that caused the original extinction we should do everything we can to bring them back.'

· Members of the public who would like to see the ospreys can visit Lyndon Reserve at Rutland Water (open daily, 9am-5pm)