American mink, Mustela vison diet and predation on waterfowl in the Słońsk Reserve, western Poland.

Abstract

The abundance, diet, and prey relationships of American mink Mustela vison were studied in the Slonsk Reserve (W Poland) on two plots: shore and reservoir. Estimated mink number within the Reserve was 69 in autumn-winter 1998/1999 and 50 during spring 1999. The diet of American mink consisted mainly of mammals, birds and fish. In autumn-winter, birds formed 4-16%, whereas mammals constituted up to 56% and fish up to 62% of the biomass consumed, depending on the plot. In spring and summer, however, birds formed 45-60% of the biomass consumed in the reservoir and 35-46% of the biomass taken by mink on the shore. The European coot Fulica atra was the most frequently consumed prey. In spring, mink removed 7.8% (N=278 killed birds) of coots nesting in the Reserve, 1.8% (N=9) of breeding grebes Podiceps spp. and 11.2% of ducks (N=93 taken birds). On straw platforms only 13.6% of greylag geese Anser anser broods were successful. From 35 to 77% of the nests on straw platforms were destroyed by mink. In wooden boxes 46.4% of mallard Anas platyrhynchos and 33.3% of shelduck Tadorna tadorna nests were successful. American mink destroyed 22-40% of the nests in boxes. However, the arrival of American mink to the Slonsk Reserve has not resulted in a noteworthy decrease in waterfowl populations.