Head-turning: Cork sees surge in barn owl numbers thanks to efforts of volunteers

The proliferation of greater white-toothed shrews in the Cork region is providing nesting barn owls with a greater capacity to raise more chicks. File picture: Richard Mills

County Cork has recorded the country’s record number of breeding barn owls, due in no small part to extensive efforts of local Bird Watch Ireland (BWI) volunteers in the region who have created more than 200 special nest boxes for them.

The explosion in the barn owl population in the county has also been aided by farmers who now see them as a natural alternative to putting down rat poison. The birds of prey are also thriving following the appearance of a new species in 2007, which has become a staple diet for them. As this food source is becoming abundant it is increasing barn owl numbers.

BWI barn owl research officer Dr Alan McCarthy said a recent survey showed more than 100 in-use nesting sites in Co. Cork, of which 40 were in special boxes erected by the BWI volunteers.

This compares extremely favourably to other BWI barn owl nesting surveys which showed 38 active nests in Co. Limerick, 23 in Co. Waterford and just six in Co. Meath.

Dr McCarthy said there has been a significant increase in barn owl nesting in Co. Cork as there were just 55 active nesting sites identified in Co. Cork last year by BWI research.

CLIMATE & SUSTAINABILITY HUB

He said there are a number of factors involved in the significant increase, but pointed out that one of the main ones centres on the pioneering work of Carrigaline-based Tony Nagle who kick-started barn owl conservation efforts in the county in the 1990s by building nest boxes and placing them in strategic locations.

Since then, volunteers led by Brin McDonnell in Duhallow and Donncha O'Teangana in East Cork, have put more boxes in areas where barn owls will typically choose to nest such as derelict or rarely-used buildings, hay barns and mature trees.

“The increase has been a combination of conservation along with the presence of a new species which was identified in South Tipperary in 2007. It was the greater white-toothed shrew, which is now spreading throughout the country at a rapid rate. It is now found in North and East Cork and is beginning to get into West Cork,” Dr McCarthy said.

He said barn owls “are feeding heavily” on the shrews, as are kestrels. In some cases (derived from analysis of the ‘pellets’ which regurgitated fur and bone, or in the faeces they leave) the shrews make up 80% of a barn owl’s diet.

BWI barn owl research officer Dr Alan McCarthy said a recent survey showed more than 100 in-use nesting sites in Co. Cork, of which 40 were in special boxes erected by the BWI volunteers.

Dr McCarthy said the proliferation of the tiny mammals in the Cork region is providing nesting birds with a greater capacity to raise more chicks.

“Normally a pair will have two or three chicks at a time. In Cork we're now noticing a few with five chicks and lots with four,” Dr McCarthy said.

Another factor in rising barn owl numbers in the region has been the dry weather experienced in May and June, which aided the parents’ ability to hunt for food as they’re constrained from hunting during very wet conditions.

Dr McCarthy praised farmers for their growing awareness of the importance of such predictors as barn owls for naturally keeping down vermin numbers, rather than them resorting to laying down rat poison.