Dorset’s ghost owls
Amid a generally bleak outlook for barn owls in general, Dorset Wildlife Trust’s Lorton Meadows nature reserve is providing a glimmer of hope. Catherine Bolado reports.
Published in April ’18
Barn owls may look the same when viewed individually, but they are clearly identifiable from one another as a group
Once a common, if ghostly sight, swooping low over farmland to snatch a mouse or vole from the fields, barn owl numbers remain low in the UK. One of the most beautiful and enigmatic of Great Britain’s native species, Tyto alba alba, to give it its taxonomic name, comes from the order strigiformes. Tyto is the onomatopoeic Greek word for owl (like ‘twit, twoo’), alba is Latin for white, so it is owl, white, white.
The strigiformes order includes around 200 nocturnal and solitary birds of prey, typified by excellent eyesight, phenomenal hearing and feathers adapted for silent flight. Although occasionally darker, most barn owls have white under-parts and buff-coloured upper-parts, laced with silver grey. Barn owls are nicknamed the ‘Ghost Owl,’ because they fly silently, swooping down on unsuspecting prey from above. But don’t let this name fool you: their calls are anything but silent, from an eerie shriek to a threatening hiss.
This adult female shows just how much colour there is in the plumage of the stereotypically white bird
Silent and deadly flyers, these wraiths normally hunt during dusk and dawn, but can prey on small mammals at any time of day. Although they will venture into woodland occasionally, they prefer to hunt along the edges of woods, among field boundaries and areas of prey-rich rough grassland. They hunt mainly by hearing rather than sight and have the most sensitive hearing of any animal ever tested – woe betide any vole, shrew or mouse caught tip-toeing about within earshot!
But barn owls’ silent hunting ability can also lead to difficulties for the species during prolonged periods of inclement weather. Their soft flight feathers are not particularly waterproof, and a wet barn owl cannot fly silently. Also, when it is raining it is much more difficult for barn owls to use their incredible hearing to locate prey – a double blow for this glorious apex predator.
Owlets at Lorton preparing for their first flight
According to David Ramsden MBE, Head of Conservation at the Barn Owl Trust, barn owl numbers are low and fluctuating. He states: ‘In the 19th century barn owls were considered to be the commonest of species, but the intensification of agriculture during and since the World Wars resulted in their widespread decline.’ He adds that a survey in the 1990s found that there were only 4000 pairs in the UK, where once there were an estimated 12,000 pairs. In recent years, although populations have increased in the Fens and East Anglia, where a lack of suitable homes was addressed by the creation of new nest-boxes, the picture in the west of the UK, including Dorset, has been much bleaker, a lack of food being the main limiting factor.
Barn owls breed when food is abundant. Ordinarily, they lay four to seven eggs in a clutch, with each egg laid about two to three days apart. Each egg will hatch after 31-32 days’ incubation. Females brood their young for an additional three weeks after they have hatched. The young grow quite slowly compared to other bird species: they fledge between eight and ten weeks, finally leaving the nest-box at around ten to twelve weeks.
‘Barn owls are still relatively scarce birds across most of their range and overall, only one farm in 75 has a nesting pair,’ David says, although he adds that Dorset is potentially quite a good area for barn owls due to the general lack of major roads like motorways and dual carriageways which are a major cause of barn owl mortality in other counties.
An adult barn owl in flight
However, 2017 proved to be an exceptional year for one barn owl pair at Dorset Wildlife Trust’s Lorton Meadows nature reserve in Weymouth. Staff, volunteers and supporters watched in delight as a barn owl pair laid eight eggs and raised five chicks. Thousands watched the owlets grow and fledge through their computer and mobile screens, thanks to the Dorset Tea sponsored webcam.
Community Conservation Officer at Lorton nature reserve, Sam Dallimore, said that watching the chicks grow every day had been wonderful, adding that the mother had stayed in the nest-box with the chicks after they hatched, and the male brought in food, which she then tore up for the chicks. The male later moved out to roost nearby as the chicks were ‘too noisy’ and he wasn’t getting much sleep – a scenario every new parent will be able to relate to!
Despite bad weather and many hungry mouths to feed, the five chicks fledged successfully. Visitors often caught a glimpse of them flitting in and out of the nest-box on their practice flights.
Sam also noticed that the Lorton barn owl pair had shown unusual behaviour in returning to the nest-box so soon after their chicks left: ‘Normally, once the youngest fledges, the parents move out for a time due to the build-up of pellets and the host of parasites this can bring, allowing the site time to “clean-up” before returning. The box could be empty for months. This year the adults moved straight back in, which is unusual. We obviously can’t be certain, but we imagine it’s because it’s a suitable nest-box surrounded by high-quality habitat and they didn’t want to risk any other barn owls moving in over the winter.’
The team at Lorton Meadows nature reserve is looking forward to seeing what 2018 holds for their barn owls, although it would be very unusual if another five chicks fledged. Vicky Ashby, Visitor Centre Assistant at Lorton, said: ‘We think the conditions on the reserve are perfect for the owls, and clearly 2017 was a boom year for the voles and small mammals they feed on. The reserve’s fantastic wildflower meadows give the owls and their food sources the perfect habitat. Weather was a concern last year, as owls aren’t able to hunt when it’s very wet and windy. We would love it if the owls re-used the box again this year. Another five owlets might be too much to hope for, but a standard clutch size of two to three youngsters reaching adulthood would be great.’
The webcam has been a wonderful window into the private lives of these elusive creatures and has been watched by owl fans from across the world. ‘It has been so wonderful to get a glimpse into their secretive lives. The camera, the location of the reserve and broadcasting the footage combined to allow us to really showcase the owls to many members of the public who had never seen them before. It is brilliant as the camera (maintained by Wildlife Windows) means that the birds are not disturbed in any way,’ added Vicky.
The barn owls have been spotted preening each other in recent weeks, a behaviour which strengthens their pair bond, raising hopes that the pitter-patter of tiny talons could be on the way again.
You can watch Dorset Wildlife Trust’s barn owl web cam at www.dorsetwildlifetrust.org.uk/raptorcam.html
and you can learn more about barn owls through the Barn Owl Trust here: www.barnowltrust.org.uk
