Depending on the type of land, Barn Owls need between 14 and 47 hectares of rough grassland within 2km of suitable nesting and roosting sites.
- Arable – mainly crops: 14-21 ha.
- Pastoral – intensively-grazed grassland: 31-47 ha.
- Mixed Landscapes: 17-26 ha
To support a sustainable breeding population of Barn Owls over a wider area, land beyond 2 km radius also needs to be suitable. Overall, the proportion of the landscape that needs to be rough grassland is 2.5 to 3.7% in pastoral, 1.4 to 2% in mixed, and only 1.1 to 1.7% in arable landscapes.
Our research clearly shows that the amount of rough grassland Barn Owls need in arable landscapes is less than half of the amount they need in intensively grazed grassland (pastoral) landscapes. This means that even without rough grassland, arable landscapes are already twice as good for Barn Owls as pastoral ones. This, plus the fact that that rough grass field margins and ditch sides are a lot more common in arable landscapes, could explain why there are a lot more Barn Owls in the east of England than in the rest of the UK. See the latest Barn Owl distribution maps.