Trossachs Barn Owl population rises
Image: Barn Owl Trust
Rangers in Loch Lomond National Park have noticed a recovery in the population of barn owls (Tyto alba) and have high hopes for even greater gains. The National Park started a project to increase the area's barn owl population four years ago and installed 40 barn owl boxes on trees, barns and outbuildings across the Park. Nocturnal birds, such as barn owls, have declined severely in recent years due to changes in agricultural practices and greater use of pesticides.
However, Scotland's field vole populations has boomed in recent years and it is believed that their population numbers are now in the hundreds of millions. A sudden peak in population numbers (known as a 'plague' or 'outbreak') every few years is a well known phenomenon, but the exceptionally cold winters of recent years have led to a boom in vole numbers. Snow cover protects voles from the very coldest temperatures and frustrates hunting by birds of prey. When the snow melts in spring, the barn owls can now feast on an abnormally plentiful supply of prey.
Explaining the ramifications of the above, Park Ranger Steven Kenney said "Despite a very cold winter and prolonged snow cover experienced in 2010, barn owls managed to breed, producing on average 3.3 owlets per breeding pair. Twelve out of 40 boxes were used for breeding, with many others used for roosting.”
"In 2010, field vole numbers were also at a peak and resulted in a phenomenon that Mike [Steward, a retired Forestry Commission Ranger] and I had never come across before. I was helping Mike ring the owlets with my colleague Adam Samson and found that the owls were using some of the boxes as larders to store field voles. Some of the boxes had up to 15 dead voles stored."
Mr Kenney also confirmed that a further 16 owlets had hatched last year. "Numbers are steadily increasing each year and we hope 2012 will bring even more positive results." he added. Researchers have also indicated that the area's population of tawny owls has experienced a rise in recent years, presumably for the same reasons.
RCVS Knowledge has called on vet practices to audit their post-operative neutering outcomes.
