Distribution of American mink in Karelia

Study Extent

Sampling was done by Winter Track Counts (WTC) in 2017-2018, yielding data on the encounters and track densities of the American mink in the Republic of Karelia.

Sampling

The data were gathered through Winter Track Counts. This is the chief method for tallying game animals in Russia (Юргенсон, 1965, Приклонский, 1972), based on counting animal tracks in snow along transects.

Quality Control

After the census activities are over, an authorized body will run the rejection procedure, and process the transect and tracking record cards.

Method steps

1. The WTC technique is based on counting the track lines crossing a transect. The number of tracks belonging to the species in question is directly proportionate to the species’ population density. Doing track counts. An action takes two days. First day (day for wiping out tracks). The surveyor skies (or walks, if snow depth allows) the transect and wipes out all the cross-running game animal tracks, so that only “fresh”, newly left tracks would be recorded the next day. Second day (day for counting tracks). The surveyor skies/walks the transect and records all the day’s tracks crossing the transect, and the animal species to which the tracks belong. The counts should be timed to days with the conditions average (ordinary) for the season, without heavy snowfall, strong wind or very low temperature.

The American mink is unevenly distributed across northern parts of European Russia due to variation in the natural environment. Thus, according to a specialized mink census in Karelia, the species numbers in the north of the republic are 1.5 to 3 animals per 10 km of shoreline. The numbers in the south are almost twice higher – 4-6 animals. The animals’ typical habitats are forest creeks and small streams with non-freezing stretches – rapids and riffles, with relatively low, but dry and littered banks. They rarely settle at larger rivers, where they mostly choose the confluence sites of small tributaries, creeks or drainage ditches. The American mink does not shun, but even prefers settling at lakes, unlike the native species. Another habitat preference that differentiates the new species from the European mink is that the former often settles not far from human dwellings. This behaviour may be a consequence of the species’ domestication, which has lasted for over 100 years now (Данилов, 1974).