The Barn Owl (Tyto alba) is a characteristic farmland bird which has undergone a documented decline in its geographical range in recent times. They are a Red-listed Bird of Conservation Concern In Ireland due to a decline of over 50% in their population during the past 25 years. They are also listed as a Species of European Conservation Concern (SPEC3) having an unfavourable conservation status in Europe.
The reasons for the Barn owls decline are not fully understood, but can most likely be attributed to the loss of suitable habitat due to various aspects of agricultural intensification and the increased use of harmful second generation anti-coagulant rodenticides. Other factors that have been implicated in their decline are the loss of suitable nest sites, an expansion of major road networks and the increased severity of winters.
Previous research on Barn Owls in Ireland has been limited, focusing mainly on their diet. A register of active Barn Owl nest sites was also compiled in the mid-late 90’s and provided a national population estimate of 130 breeding pairs. The Barn Owl Projects Initial work involved updating the mid 90s register and underlined the need for a conservation project focused on this species. The majority of nest sites have been abandoned and it seems likely that there has been a worrying decline in the population since the previous survey was undertaken.
The Barn Owl project also focuses on implementing conservation measures beneficial for Barn Owls such as the initiation of the nest box scheme through which artificial nest boxes for Barn Owls have been provided in suitable habitats. BirdWatch Ireland are also working towards gaining a greater insight into the Barn Owls distribution and abundance by providing an accurate population estimate.
Barn Owl Research
Running alongside the Barn Owl Project, John Lusby is carrying out research on the ecological requirements of Barn Owls. Previous research on their habitat requirements in this country is limited, and such information is vital in order to maximise conservation efforts and determine optimum foraging habitats. The research will involve radio tracking adult male Barn Owls to gain insight into their movements and foraging behaviour.
In addition to researching habitat requirements, the research is also focused on investigating the potential impacts of rodenticides on the population. Potentially harmful second generation rodenticides are widely used and in Ireland Barn Owls rely on commensal rodents (such as rats and mice) to a greater extent than they do in other European countries, therefore the hazards from secondary poisoning are likely to be much greater.
In order to assist with this important aspect of the research any information on Barn Owl carcasses encountered would be gratefully received. Liver tissue samples from the carcasses can be tested to estimate the level of exposure of the bird to these toxins, and from this we can gain a better idea of the effects that they are having on the population as a whole.