DIET OF 2 SPECIES OF MINK IN ESTONIA - DISPLACEMENT OF MUSTELA-LUTREOLA BY M-VISON

During a period in the 1980s when both European mink Mustela lutreola and American mink M, vison were present in Estonia, their food was sig nificantly different. European mink ate a greater proportion of fish a nd crustaceans, whereas American mink took relatively more mammals and frogs. This was probably related to a difference in habitat selection . After the disappearance of the European mink, the diet of the Americ an mink in our main study area was similar to that of the European in the same area previously. Two alternative hypotheses are presented for the mechanisms which led to the replacement of European mink by the A merican species: (i) the two species have a different niche, and the A merican mink could replace the European mink after the latter had disa ppeared for unrelated reasons, or (ii) the American mink aggressively ousted the European mink, a process starting in the American mink's pr eferred habitat (slow flowing rivers). At present there are insufficie nt data to reject either of these scenarios.