Around half of all known Barn Owl nest sites in Ireland are in chimneys, in disused or derelict houses, castles and mansions. Barn Owls can climb very well, and with the help of strong legs and wings they can scale a vertical stone surface relatively easily.
Barn Owls often nest in derelict buildings and those types of buildings are a natural source of curiosity to Barn Owls and those trying to survey for Barn Owls. One of the more difficult nests to detect are in buildings where the Owls are actually nesting down the chimney.
This is one such example and it was only a phone call from a curious neighbour which directed attention to the cottage. The owners had died some years before, but the neighbours were keeping it tidy and unknown to them, Barn Owls had moved in to the central chimney, nesting on top of the sticks of an old Jackdaws nest which had blocked the shaft.
An apparently occupied cottage, but with new tenants nesting in the chimney (Filmed under licence: M.O'Clery).
Here we can see the Barn Owl about eight feet (2.5m) down the chimney shaft. The slow, sideways swaying, partially opened wings and low hissing sound is the threat posture, to make the owl look bigger and more imposing to any potential predator, or Barn Owl surveyor.