AbstractThe excavation of material by burrowing mammals (voles and moles) was investigated on experimental plots on a wooded slope in the Luxembourg Ardennes. Monthly records of the amount of material excavated by animals, the area they disturbed and of the total area of the bare ground enabled the significance of the downslope displacement of material and the consequences of burrowing for splash erosion to be evaluated. Markedly seasonally variable burrowing was related to soil and slope conditions. Although the rate of displacement of material down- slope during excavation is low, it would seem that burrowing animals were directly or indirectly responsible for most of the transport of material on the investigated slope and that they therefore play an important role in colluviation and sediment supply. As burrowing by animals is possibly a more important slope process under forest than hitherto recognised, it deserves further investigation.