A pioneering male has nested at Bassenthwaite Lake since 2001, and paired up with the current female there two years ago.

Experts had hoped for two chicks, but were surprised and delighted last week when an inspection team discovered three healthy young birds.

The chicks – two females and one male, aged between 35 and 39 days old – were ringed by members of the Lake District Osprey Project.

The latest arrivals bring the number of chicks sired by assenthwaite's returning male osprey to an astonishing 16.

A spokesman for the project said: "Weight gives an indication of whether the chick is a boy or a girl.

"Females are heavier than males, although relative hatch dates have to be taken into account. It seems this year we have two strapping girls and a bouncing little boy."

It is estimated that visitors heading to see the rare fish-eating birds of prey boost the local economy by as much as £2million every year.

Nesting ospreys remain rare in the UK. Before 2001, there had been no ospreys in the Lake District for a century and a half.