Blog Written by Tim Smith - Visitor Experience Officer, Ham Wall.
Barn Owls are a common favourite amongst bird lovers and June is perhaps the best time of year to see them in action at RSPB Ham Wall. Whilst in the midst of feeding their nestling young, adults can be seen busily hunting through the daylight hours, on top of their normal nocturnal and crepuscular (active at dawn and dusk) habits.
Barn Owls are one of Britain’s most distinctive birds, with a snowy white face and underside contrasting against a golden buff on the wings, tail and upperparts. The pale coloration may confuse them with a gull at a distance, but their slow, silent wing beats and low, purposeful flight distinguish them. Telling males and females apart in flight is nigh on impossible, though there are some features that hint one way or another. Females are slightly larger (average 360g compared to males 330g), have black flecks on their underside and are often slightly darker brown on their tail and around the edge face.
We all know that Barn Owls like to roost and nest in barns, the clue is in the name. However, archaeological evidence from Glastonbury Lake Village (c.250 BCE) has proven this inextricable link with human settlement is not a new phenomenon and has existed for millennia. Whereas Tawny Owls are quite content in the cramped crevices of splits in trees or branch forks, Barn Owls are far choosier customers when it comes to siting a nest. They like space: a bit of wing room, as it were, such as that found in outbuildings. Due to the history of our site for peat extraction, the hollowed ancient trees and derelict buildings that normally provide these open nesting spaces are few and far between. Indeed, the removal of these features across the British landscape contributed to the Barn Owl’s decline through the 20th Century, though thankfully numbers have been gradually rising again in recent decades and the species is now green listed.
At Ham Wall, we replicate these lost nesting opportunities with specially designed wooden boxes around the reserve. When placed as pairs in close proximity, the parents have a separate roosting space to retreat to when the kids get rowdy! The British Trust for Ornithology (BTO) estimates that a significant proportion - at least 25% - of the national breeding population are now using nest boxes.
Barn Owls can lay up to six eggs, laid at two days intervals to reduce the peak in food demand and help with any temporary shortages further down the line. The first egg hatches after roughly one month of incubation by the female who has been receiving food from her lifelong monogamous partner.
Once the young have reached three weeks old, they have enough feathery down to regulate their own temperatures, freeing up the mother to hunt for their small mammal prey as well. Food availability is the main factor in how many chicks get as far as leaving the nest - the average number is only 2.5 per nest.
By 13 weeks, young have fledged and dispersed to find their own ‘home range’, generally within 10km/6miles of their parents. Barn Owls are not territorial, but stick to one area to build up an intricate memory of flight paths and terrain that helps during night-time hunts. Again, the density of these home ranges depends on prey availability in the landscape. We reckon Ham Wall must be pretty good for that!
Generally, the north side of the reserve is your best chance for Barn Owl sightings, with day flights seen from Viewing Platform 1 or the Avalon Hide. In fact, two of our nest boxes can be viewed from the Avalon Hide, which means seeing adults or ‘branched’ young on their built-in balcony is possible. This year, the box out towards the wind pump (North West) has been a hive of activity.
Happy watching!
Do you own or have influence over land and habitat that might be suitable for Barn Owls? Find out how you can help here: https://bit.ly/HelpBarnOwls
Thanks to John Crispin for all of the wonderful photography shared in this blog.