The only ospreys nesting in northern England have hatched a second chick at their lakeside nest in Cumbria.
Thousands of people have seen the ospreys on the Internet
The Lake District Osprey Project revealed on Tuesday that at least one egg has now hatched and the female osprey has been seen feeding a chick.
Less than 24-hours later a second chick has been spotted.
The news came as members of a team monitoring the birds viewed the latest pictures sent from a camera overlooking the nest.
The nesting pair arrived at what has become a regular nesting area close to Bassenthwaite Lake, near Keswick, five weeks ago.
About 30,000 people have already visited special osprey viewpoints and more have been checking developments over the internet.
Nathan Fox of the Lake District Osprey Project, said: "It was a complete surprise and we could hardly believe our eyes when we spotted a second chick.
"We were looking at the latest video footage and watching one chick being fed when suddenly a second chick popped out from underneath the female osprey and start begging for food from its Mum.
This still a very anxious time, as the chicks are initially helpless after hatching and vulnerable to bad weather
Nathan Fox, Lake District Osprey Project
"It was a very special moment when we realised that there were now two chicks in the nest.
"We would have been very pleased to have one chick successfully hatched but we are absolutely delighted to have two."
Bad weather in the Lakes on Tuesday caused the female osprey to sit tight on the nest for most of the day and the presence of a second chick went unnoticed until the weather cleared.
The Lakes pair are at the forefront of a return of ospreys to England after an absence of more than 150 years.
This is the third year that the ospreys have nested near Bassenthwaite Lake and they have already successfully raised three chicks - one in 2001 and two chicks last year.
Mr Fox said this year's chicks should make their first flight in mid-August, and stay in the area until September.
He said: "This still a very anxious time, as the chicks are initially helpless after hatching and vulnerable to bad weather.
"They will be carefully tended and fed by their parents until able to fend for themselves but good weather is needed so that the male can hunt successfully and bring in sufficient fish for his new family."