Roost selection by the brown long-eared bat Plecotus auritus

1. One of the key threats to bats in Britain is loss of suitable roost sites, but little is known about roost requirements for most species. 2. Roost selection in the brown long-eared bat Plecotus auritus was demonstrated by comparison of buildings used as summer roosts in north-east Scotland with (i) random buildings in the same area, and (ii) a set of adjacent houses located in the same habitat. 3. Buildings containing roosts were situated closer to woodland and water relative to the random houses, and also had a greater area of woodland within a radius of 0.5 km, but not at distances beyond this. This suggests that feeding habitat in the vicinity of the roost is important for roost selection. 4. When compared with adjacent houses, roosts were older, and had roof spaces divided into more compartments, which were more likely to be fully lined with rough wooden planking. 5. The temperatures inside summer roosts (mean 17.9°C) were significantly warmer than those from random and adjacent houses (mean 16.7°C). 6. These results suggest that P. auritus is selective of its roosts, relative to the houses available. 7. The selection of specific types of roosts by P. auritus has implications for the management advice provided when roosts are threatened, and conservation actions should focus on efforts to avert significant change to, or destruction of, roost sites or the woodland in their vicinity.