THE EFFECT OF SUPPLEMENTARY FEEDING UPON THE DEMOGRAPHY OF A POPULATION OF WOODMICE APODEMUS-SYLVACITUS, LIVING ON A SYSTEM OF MARITIME SAND-DUNES

The woodmouse is a characteristic rodent of deciduous woodland but it also lives on maritime sand-dunes. The population density of woodmice on sand-dunes is much lower than in woodland. Here we test the hypothesis that this difference is due to the fact that woodland provides substantially more food than do sand-dunes. Our experimental approach was to provide supplementary food (wheat grain) to a sand-dune population for a period of 22 months and to compare demographic responses with a control population. The supplemented population increased rapidly and reached a size 6-7 times that of the control population. The overall annual pattern of changes in density were similar in both populations with minimum numbers in late spring, maximum numbers in autumn and a loss of individuals over the winter. The woodmice receiving supplementary food bred earlier and for longer than did the control mice.