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Barn owl

Barn owl sitting on fencepost

The barn owl is primarily a farmland bird, hunting for small mammals over rough grassland and along field edges.

The barn owl population decline is largely a result of reduced food supply, with less rough grassland available for hunting. The loss of old barns and increased road deaths are also significant in many areas. Barn owls can be encouraged by providing prey-rich rough grassland and artificial nest sites.

Key points

  • Erect nestboxes in pairs (within 500 m of each other) at a density of about 1 pair per square km.
  • Create tussocky grassland (with a deep litter layer) as either marginal strips at least 2 m wide or as blocks of habitat. The ideal amount of rough grassland is 31-47 ha in pastoral areas, 14-21 ha in arable areas and 17-26 ha in mixed areas within 2 km of a nestbox.

What this species needs

Nest and roost sites

They are traditionally associated with old barns and hollow trees but take readily to nestboxes placed in modern farm buildings, trees, or spaces provided in barn conversions.

Food and habitat

They primarily eat voles but also regularly include mice, shrews and rats in their diet. Their prey occurs at highest densities in rough grassland – tall, tussocky grass with a thick litter layer. Grass that's too short, lacks a litter layer, or is overgrown with scrub is far less suitable for barn owls.

Implementation

Nesting habitat

  • Protect and maintain existing nest sites in buildings or tree holes

  • Existing nest sites can be supplemented with nestboxes of various types

  • It is a good idea to erect boxes in pairs – within 500 m of each other – at a density of about one ‘boxpair’ per km sq

  • With many barn owls killed each year by cars, it is strongly advised not to mount a box within 1 km of a major road.

Food

  • A pair generally hunts within 2km of the nest site during the breeding season, and requires rough grassland in the form of blocks and/or wide strips along field margins, woodland edges or watercourses. The ideal amount of rough grassland to aim for is 31-47 ha in pastoral areas, 14-21 ha in arable areas or 17-26 ha in mixed farming areas

  • Rough grass strips should be at least 2 m wide (ideally 6 m) and it is preferable for blocks of rough grassland to be linked by hedges or grass strips. Livestock should be prevented from grazing the grass strips

  • Rough grassland can be established using a grass-seed mix that includes tall, tussock-forming species (eg cocksfoot and timothy) along with shorter, softer grasses (eg Yorkshire fog, fescue and bent species)

  • During the first year, new grass should be left to grow tall and collapse in the autumn thus forming the litter layer above which the second season’s growth will appear

  • Following establishment, areas should be topped, or lightly grazed every second or third year

  • Cutting should be undertaken in the autumn with the cutting blades set at 10 cm (4 in) or higher

  • Where possible, cut rotationally within the landscape (eg cut each ditch-side in alternate years)

  • Take care to protect barn owls from secondary poisoning during rodent control and be aware that bait-covering does not reduce the risk. Contact the Barn Owl Trust or visit their website for detailed information.

Last updated: 3 December 2008

Related advice

Bird guide

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