Diet of pine martens Martes martes L. in west Scotland

Diet of pine martens in a coastal Atlantic oakwood in western Scotland was assessed over a period of two years (1996-8) in the context of strong potential competition from a diverse guild of other predators also largely dependent on preferred small rodent prey. Analysis of prey remains in fresh droppings showed that despite the potential for competition, martens still preyed extensively on small mammals and birds, preying preferentially on voles and particularly Microtus agrestis L. Invertebrates were also important dietary items, with high intake of beetles (and particularly Geotrupes sp.) from March to September. Predation on birds and intake of earthworms were highest over the winter period; fruits (bramble and rowan berries) were also important over the autumn and (ivy berries) late winter. The diet described is similar to that recorded in other studies, with no significant shifts due to potential competition from other predatory birds and mammals on the same species-poor prey base. However, marten activity in the area was subject to sudden seasonal decline in both sign and sightings and it seems possible that the animals may be making gross range shifts in periods of relative scarcity of high quality foods, moving substantial distances to track local availability of preferred prey.