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The Bisham Barn Owl Group (BBOG) was set up in 2014 to study the Barn Owl population in South Buckinghamshire and East Berkshire.

Law, Licensing & Research Programmes

All study and research is carried out by BTO-licensed bird ringers. The data is collated nationally and used to analyse nesting productivity and survival rates of the Barn Owl population.

Barn Owl Longevity

Knowing how long birds live is one question answered by ringing programmes. Ring a chick and if the bird is found when it dies we know how long it lived. Repeat this for 100 years and it builds a picture of a species life expectancy.

For British Barn Owls we’ve learned that the average life expectancy, above 5 weeks old, is only about 18 months. Those that do live more than 18 months typically go on to live until their fourth year.

Above average

In the summer of 2001, on a farm near Watlington, Oxfordshire, a brood of six Barn Owls was ringed by the South Oxfordshire Ringing Group. The brood included a chick fitted with ring number GN40325. The young fledged but were not seen again by the Group.

We have to wait nearly fourteen years, to the start of 2015, for the Bisham Barn Owl Group to enter the story. We were invited to check an owl nest box in the Buckinghamshire Chilterns. The box, attached 5 metres above the ground to the bough of a tree, hadn’t been inspected for some time. Its roof leaked, it was stuffed full with sticks from a forgotten Jackdaw nest, and yet, a pair of Barn Owls had set up home. We cleared out the sticks and repaired the roof to give the birds a chance of breeding.

Come the summer the pair bred successfully, raising a single chick. In the Autumn, when we check all our boxes for repairs, we caught the parents. We ringed the male and found that the female was already ringed. And, yes, her ring number GN40325 identified her as being from the brood ringed in 2001. This made her 14 years old – not then the oldest barn owl recorded but well beyond that 4-year average. GN40325 was nicknamed “Bernice”, and we wondered if she would return the following year.

In June 2016 we checked Bernice’s box – she was present and incubating four eggs. Alas, the wet spring that year restricted vole hunting and the eggs failed to hatch (the eggs will be analysed in due course to see if we can determine why they failed).

In November, we made further repairs to the aging box. Boxes are often empty at this time of year but Bernice and her mate were present and with that visit she became the oldest Barn Owl recorded in Britain at 15 years, 113 days.

The Bisham Barn Owl Group will be active again in 2017, monitoring owl boxes and ringing chicks. We hope to meet Bernice again, that she’ll raise more chicks, and with rings applied, in years to come, another ringing group may record the oldest Barn Owl in Britain.

Article written by: Carl D Hunter Roach from the Bisham Barn Owl Group
Photographs: Paul Warham