During the summers of 1957 to 1960 a variety of habitats, including woodland, moorland and agricultural land, have been trapped for small mammals at Applecross, Wester Ross. Traps were also set at two other localities on the mainland. The catches included Sorex araneus, S. minutus, Neomys fodiens, Apodemus sylvaticus, Clethrionomys glareolus and Microtus agrestis. As many habitats as possible have been examined on the Islands of South Rona, Raasay, Rhum, Mull, Colonsay, Lewis, North and South Uist and Barra although there was usually less variety in the vegetation on the islands. On the islands, except Mull, less species are present than on the mainland.
At Applecross, Apodemus was common and ubiquitous being most numerous in deciduous wood and farm land. Clethrionomys was less widespread and most numerous in woodland. On the Island of Mull the ecological situation appeared similar to the mainland but on the remaining islands Apodemus was apparently less frequent. Clethrionomys was common on Raasay and Mull. Microtus was widespread and trapped in small numbers. It was least common in deciduous woodland. Mus occurred in fields in the Outer Hebrides and the Island of Colonsay. S. minutus was particularly infrequent and no more abundant on islands from which S. araneus was absent.