Tawny owl numbers in Kielder Forest are soaring as the UK’s longest running research project on the bird enters its 30th year.

Despite the harsh winter tawnies are benefiting from a remarkable recovery in the vole population locally.

The diminutive mammals are a favourite food for birds of prey, but over recent years their numbers have declined in the 155,000-acre Northumberland wilderness.

Now Forestry Commission experts believe that the artic weather with months of snow cover has given the voles a break from high levels of predation, as owls and other birds struggled to hunt successfully.

The biggest beneficiary – apart from the voles themselves - have been tawnies as they are one of the hardiest, most durable and longest lived of all owls species and have made it through the grim weather with a relatively low level of fatalities, unlike Barn owls. Now after the famine they can they can enjoy a vole feast.

Experts checking the 200 nest boxes erected by project chiefs have recorded 105 nesting pairs this spring, with three broods of five chicks found (two to four is more common).

Tom Dearnley, Forestry Commission Ecologist, said:

“Voles are critical for forest wildlife as they are an important food for many animals. But mild winters in recent years have hit them hard as they haven't had a rest from being hunted. But the artic weather has changed all that. We have been working with Aberdeen University on vole population cycles in Kielder and we use a vole index to measure how plentiful they are. That has shot through the roof this year. The tawnies are taking full advantage, with 49 dead voles removed from just one owl box.”

It was thanks to the Kielder tawny owl project that experts were able to keep tabs on a remarkable female who at the age of 21 gave birth to three healthy chicks – the oldest breeding tawny in the world.

The amazing creature was ringed in 1987 in Kershope Forest, part of the western bloc of Kielder, but last year failed to return to her nesting box, leaving open the possibility that she has succumbed to old age.

Her longevity was a feather in the cap for the Forestry Commission-backed project, which has seen nesting boxes erected in Kielder to makeup for a lack of suitable natural nesting sites. Tawnies in the wild have an average life expectancy of around six years.

Nature fans can find out more and also join experts as they ring tawny owl chicks by joining two owl nights on 12 and 21 May. These unique events based around Kielder Castle and Sidwood, near Greenhaugh, are being staged by the Forestry Commission as part of the Kielder Partnership’s Wild about Kielder season. They start at 7pm and booking is required on 01434 220242. The cost is £8 per person.

Kielder Water & Forest Park was recently voted the most tranquil place in England by the Campaign to Protect Rural England.