THE BARN OWL IN NORTHERN IRELAND - A RACE OF TYTO ALBA?
By Garry Wilkinson
The Barn Owl has been my favourite bird since I was four years old. In 1962 I used to see them regularly when walking with my uncles along the old Comber railway line near Dundonald. Sadly with the C.A.P directive after WWII and widespread use of rodenticides our population of owls plummeted to our now estimated population of around 75 pairs. Up until the nineteen nineties, I along with most people believed our barn owls were the same race we saw in the rest of the UK. However I am now of the opinion that our owls have developed separately from the rest of the mainland birds. In 1998 I had the opportunity to observe a male Barn Owl of Scottish origin found off our Co Down Coast alongside a male native bird from Co. Londonderry. While plumage detail in Barn Owls varies greatly even between male and female, these two birds were remarkably different. Our bird was considerably darker in overall coloration and in addition had an enormous amount of leg feathers compared to the Scottish bird which was completed bare legged and considerably whiter than our native male. If I had thought about it more at the time we could have obtained blood samples from both for comparison. As it was my thoughts on the subject have only recently come to the fore and our bird is now deceased and the Scottish bird released back were it was found. While I am well aware a number of post dispersal young Barn Owls from both Scotland and Isle of Man are finding their way to our shores, most are found dead, emaciated or alive and starving. Mainland owls have a number of rat, mice, vole and shrew species to prey on whereas our birds have two mice species, one rat, one shrew and up until recently no voles. Of course Barn Owls will readily supplement their diet with small birds, frogs and large beetles but our birds reliance on such a small number of prey items gives me the belief they have different hunting strategies as well. You can almost put a time on seeing Barn Owls on the mainland usually about an hour before dusk or an hour before dawn whereas our birds are nearly always only encountered after dark. This has been put down to our substantial corvid population, with the resultant mobbing during any daylight hours. I believe our birds have developed their hunting times to maximise available prey items. Our birds also nearly exclusively nest in trees and mainland birds use a wide variety of old buildings, barns and trees. This could be down to lack of nesting sites but I can't believe the number of old buildings here don't lend themselves to suitable nesting sites. Sadly we may never know if our Barn Owls have a distinct bloodline. The recent discovery of vole remains in short eared owl pellets in North Antrim, the discovery of white toothed shrew and bank vole in Southern Ireland and lack of population in Northern Ireland to study, means that both prey and owls are expanding north. They will inevitably interbreed with our birds and the chance of scientific analysis gone. This theory is based largely on observations of birds in Co. Down and SW Scotland and has no basis on scientific fact. I would therefore welcome any comments or further observations on this idea.
Garry Wilkinson, Chairman NIOC.