The number of tawny owls in Kielder Forest is soaring - despite the cold snap earlier in the year.
It's believed their success is due to a rise in the vole population - which flourished as other birds, like barn owls, struggled to hunt in the snow.
Experts checking approximately 280 nest boxes in the forest have recorded 105 nesting pairs of tawny owls so far - around double the number in 2009.
And three of the pairs have clutches of five eggs, which is more than usual.
Tawny owls normally lay between two and four eggs, so the larger broods are a sign that the birds are doing well.
Martin Davison is an ornithologist with the Forestry Commission and is responsible for monitoring birds in the forests around Wark, Redesdale and Tarset.
He said it was exciting to see the number of tawny owls rise after a poor year in 2009:
Martin has been working at the forest for 30 years
"The population's well up," he said.
"Basically it's [due to] food supply. The voles have bred extremely well over the winter time - even though we've had lots of snow they do extremely well living under it.
"The voles have increased, hence the birds have managed to monopolise their food supply and have laid more eggs."
Martin added that the breeding season has started a couple of weeks earlier than normal this year - another indication of how much food the tawnies are getting.
"In one box we found 49 dead voles ready to feed to the chicks," he said.
"They [the chicks] were absolutely bulging!"
Starved to death
Unfortunately, while tawny owls are thriving, other species of owl have been more badly affected by the harsh winter.
Martin also keeps an eye on the other birds of prey in the forest
Especially barn owls.
"The winter has basically killed them," Martin said.
"When barn owls hunt they quarter the ground, up the hedgerows, over pasture land, and of course that was covered with maybe up to four feet of snow.
"They just couldn't get at their prey and basically they starved to death."
Tawny owls perch hunt so they expend less energy finding food - and they are more suited to the northern environment.
Part of Martin's job is to ring all the owl chicks born in his part of the forest.
He also weighs them and measures their wings.
The chicks are weighed by being hanged by their feet from a scale
The weighing process involves tying a string around their feet and hanging them, upside down, from a tiny scale. Not very dignified!
Watching Martin in action, it's surprising how docile the owl chicks are. They almost seem to be asleep - but then maybe they are:
"It's the morning time for us but it's the middle of the night for them," Martin said.
Ringing the birds helps the experts to track them and monitor their ages.
The information gathered is also fed into a research project on the species, which is now in its 30th year.
In 2008, the project uncovered the world's oldest breeding tawny, which gave birth to three healthy chicks at age 21.
That's more than three times the average life expectancy of a tawny owl living in the wild.
Sadly, the female did not return to her nesting box in 2009, meaning she may now have died.
Nature fans can watch the experts ringing chicks on two owl nights organised by the Forestry Commission on 12 and 21 May 2010.
The events start at 7pm and tickets cost £8. To book a place call 01434 220242.