A new method of studying for activity of a semi-aquatic mammal Russian desman Desmana moschata (Linnaeus, 1758) with use of digital portable voice recorders is developed. To identify the burrows in which the recorders were to be installed, the burrows were probed. A probe is a pole pointed at one end with a T-shaped handle at the other end. The researcher's task was to detect the entrance to the burrow, usually under water. The direction of the underground passage is determined by means of the probe. For this purpose, the ground is pierced to detect the hollows in the burrow with the probe starting from the burrow entrance (the probe falls through unevenly). At a distance of 2 to 3 meters from the burrow, in some cases largely depending on the burrow length, the ground is dug up above the burrow in the form of a small well, 10 to 15 cm in diameter. A digital voice recorder was placed vertically in this well, so that the microphone was directed down towards the burrow. Desman noises can be characterized as short series formed as a sequence of contiguous short peaks of 15 to 25 seconds with five second interruptions formed by regular waves of breathing and its movement noises. As a rule, the noise audibility ranges from 1 to 3 minutes.
Andreychev A., Kuznetsov V., Lapshin A., Alpeev M. Activity of the Russian desman Desmana moschata (Talpidae, Insectivora) in its burrow // Therya. 2020. V. 11. № 2. P. 161–167.

To date according to the registration work, the number of the Russian desman determined actually is 588 individuals in Mordovia. Based on extrapolation, the total desman population in Mordovia is about 1,400 individuals. We may assume that the most of the desman population is concentrated on floodplain lakes and reclamation canals. The highest density of the desman population in Mordovia was recorded in Krasnoslobodsky and Temnikovsky Districts (10.5 and 8.2 burrows per km, respectively). About 400 animals may live on the shore of the rivers Vad, Partsa, Yavas, Vindrey, Nuluy, and Kundybolka. The mean value of density of the desman population on the rivers was 0.9 burrows per km of the coastline, which corresponded to habitat quality class IV (0.5–5 burrows per km). The distribution of habitats across river basins is extremely uneven. The main part of the desman population is restricted to the Moksha basin (more than 1,350 individuals), and in the Alatyr basin (left tributary of the Sura River) just twenty individuals were recorded.
Andreychev A., Kuznetsov V., Lapshin A. Distribution and Population Density of the Russian Desman (Desmana moschata L., Talpidae, Insectivora) in the Middle Volga of Russia // Forestry Studies. 2020. 71(1): P. 48–68.