Area: 0.22 hectares. 

High Marks Barn SSSI is a nationally important site for its maternity colony of greater horseshoe bats Rhinolophus ferrumequinum.

General description: 

The SSSI is situated on the eastern slopes of the River Avon valley, adjacent to a quiet unclassified road and is sheltered by mixed woodland and mature trees. The surrounding land beyond the SSSI boundary provides good feeding opportunities for greater horseshoe bats, with permanent pasture sheltered by mature hedges and woodland edges. The site is in a remote location with no significant development in the immediate vicinity. 

The centre of the site is a stone-walled and slate-roofed barn that houses the maternity roost of the greater horseshoe bats. The barn was renovated in 2006. The small area of land that surrounds the barn is wooded to the west, with a mixture of mature coniferous and deciduous trees. The woodland has an open canopy with sparse under-storey. Elsewhere the barn is bounded by rank grassland and scrub. The surrounding boundaries are comprised of derelict stone-faced earth hedge banks to the north, west and east. The hedges have very little shrubby growth, instead being comprised mostly of mature trees. To the south, the boundary is formed by a derelict dry-stone wall, except for the boundary immediately to the south of the barn, which is formed by a fence and gate alone. All boundaries are fenced with a standard agricultural timber post and stock-net wire fence. 

More than 600 adult greater horseshoe bats have been observed emerging from the barn in the summer, as well as over 200 juveniles. Much smaller numbers of greater horseshoe bats use the barn as a hibernation site over the winter. 

In addition to the reasons for notification described above, the barn is also used by small numbers of other bat species, including lesser horseshoe Rhinolophus hipposideros, brown long-eared Plecotus auritus and Natterer’s bats Myotis nattereri.