Fair to Nature Farm Conservation Adviser, Kevin Rylands, looks at how farmers and landowners can help the barn owl…
Gliding silently across pastures at dusk, barn owls are one of the most iconic sights in our countryside. You never forget the first time you see one quartering a field hunting for small mammals, or perched on a fence post looking straight at you. Yet sadly barn owls have had a tough few years, the combination of prolonged snow cover or periods of relentless rain meant they had difficulty accessing their prey and many starved. Hard winters also have a knock-on effect in the breeding season with many birds not nesting due to a lack of condition and those young that did fledge struggling to survive.
However, much like livestock, there are management options that can help ensure that, weather permitting, they can remain in good breeding condition and produce healthy offspring.
So, what can be done to help them?
Barn owls mainly hunt small mammals such as mice and voles, and they hunt over rough pastures and grassland, roosting and nesting in large tree holes, in barns and in boxes. The provision of nestboxes will only be successful if good feeding habitat is also available and vice versa.
Leaving wide (6-12m) strips of rough grassland around fields and alongside watercourses, as well as areas of rough pasture or field corners will provide habitat for the barn owls’ main food, voles. Allowing a layer of thatch to develop is important, and so the use of tussocky grasses such as Yorkshire fog and Cocksfoot in some field margins is helpful. The grass and thatch layer combined should be around 20–30 cm (8–12 in) tall. This habitat will also provide suitable wintering habitat for numerous beneficial insects and spiders. Although these tussocky margins are ideal for barn owls, a variety of margin habitat should ideally be available across a holding to benefit a wider range of plants and animals.
Provision of nesting habitat is equally important. Luckily, barn owls readily use nestboxes so this can be done relatively easily by placing boxes in open sided barns, in prominent isolated trees, or even on a pole along a fence line. The entrance opening and nestbox should be at least 3 m (10 ft) above ground level.
Contrary to popular belief, barn owls don’t need an isolated quiet site. Provided that there is somewhere for them to hide at high level, they will roost and nest in busy farm buildings, the roof space of occupied houses, and even in rural industrial units. Almost any type of rural building is suitable for a nestbox. As well as providing a nest place, nestboxes give the birds somewhere to hide, enabling them to live with all kinds of regular activity. They do however find it difficult to tolerate irregular disturbances, especially when in the process of choosing a nest site, .
If natural holes are limited then several boxes should be sited on the farm as male barn owl roosts separately to the female, especially when there are young in the nest. They also use a variety of different roost sites in winter.
As you read this barn owls are probably already nesting and feeding young, however if they are not on your farm putting up boxes now and planning where best to locate feeding habitat may encourage dispersing young from elsewhere to remain on your farm and establish their own territory.
IMPORTANT NOTE: If your site is within 1 km of a motorway, dual carriageway, or similar main trunk road please DO NOT provide nestboxes. Barn owls that attempt to live close to modern trunk roads generally don’t survive long.
Other external risks to barn owls include drinking troughs, owls often drown in uncovered troughs but this risk is easily remedied with by floating a plank or tray in the water, or having a mesh cover that is pushed down by livestock when drinking but is not displaced by the weight of an owl.
Whilst owls provide a pest control service, you may feel the need to lay bait for rats around the farmyard. New ‘second generation’ rodenticides are much more toxic to wildlife such as owls and other birds of prey than warfarin so must be used with care by qualified personnel. Always follow best-practice guidelines by preventing access to bait by non-target wildlife and regularly searching for rodent bodies for safe disposal. After treatment, be sure to remove all remaining bait and bait containers.