Amazing bed-fellows as kestrels and barn owls share a nest

At the time of year when the RSPB is urging people to put up nest boxes ready for next spring, a surprising number of unusual shared occupancies have come to light.

The charity has been encouraging people to clean out existing nest boxes and to put new ones in position so they are in place for when birds start to 'recce' possible nest sites in the spring. Some birds will start to roost in them in the next few weeks as the weather turns colder too.

And the number of extraordinary reports of some species doubling up in nest boxes in recent years has come as quite a surprise. Barn owl nest boxes seem to attract the most unusual tenants, with reports of the generous bird of prey sharing their nest boxes with birds like jackdaws, kestrels and stock doves.



Many birds are furiously territorial, especially when raising their young. And callers have reported that some birds sharing a home are constantly harassed when trying to get into their house-share, making it even more bizarre that they should persist.

Other birds that have been spotted nest sharing are blue tits and great tits and both of these species have been seen sharing with pied flycatchers too. Experts believe one reason for the shared occupancies could include multiple cavities in some nest boxes, leading to the birds fledging from one cavity and returning to roost in the 'wrong hole' that is already occupied.

Another reason could be because they have unwittingly laid their eggs in the active nest of another species. There may also be a lack of nesting sites in some areas. Many larger birds that nest in holes in trees or in older, undisturbed buildings are having difficulty finding suitable nesting sites, as buildings are knocked down or converted. There may be advantages, such as shared body warmth, security and possibly even food.