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The stoat (Mustela erminea) is a small mustelid predator specialising on rodent species. However, they also can eat various alternative prey in different parts of their range. In the literature, sexual dimorphism differences in this species are reflected in different diet preferences with males hunting on larger prey than females. The aim of this study was to assess food habits of stoats trapped in two study sites in Norway. We analysed stomach content in relation to body mass, sex and season. In total, 137 stomachs, 101 of males and 36 of females, were analysed. Males (201.80 ± 37.71 g) were significantly heavier than females (85.06 ± 13.26 g) (F= 258.88, df= 1, p≤ 0.0001). Six food categories were identified, dominated by small rodents, followed by anthropogenic food, birds, insectivores and invertebrates. The most common prey species were bank vole (Myodes glareolus) and tundra vole (Microtus oeconomus). We found no evidence of trophic niche segregation between male and female stoats despite body size differences between sexes. There were also no significant differences in diet of all stoats between seasons. The trophic annual niche breadth of all stoats was B= 3.88 and highly overlapped between sexes (Ojk= 0.97). The results confirm that the stoat in Norway is a generalist predator able to profit on human food refuse found in close proximity to permanent residents and summer cabins.

Voltammetry, potentiometry, amperometry, and electrochemical impedance spectroscopy (EIS) were used to study practical polymer electrolyte membrane fuel cell (PEMFC) stacks in an attempt to validate the stack-tailored electrochemical methods and to show the range of information about a PEMFC stack obtainable with the methods. In-stack electrode voltammetry allowed to determine the type, i.e., the surface chemistry, of catalysts used to make the stack electrodes and to measure the electrodes’ true active surface areas (EASAs). Stack potentiometry gave the EASAs, too, but only after calibration of the method against voltammetry. The speed of the test is the advantage of the stack potentiometry. An amperometry-based protocol was introduced to measure the hydrogen permeability and electronic shorting of the stack membrane-electrode assemblies. Dependence of the H2 permeability on H2 pressure and the stack temperature was shown. EIS in the hydrogen-pump mode was used to study the anode and electrolyte membrane processes under load. Spectra were dominated by humidification effects, which allowed probing the external humidification distribution to the anodes in the stack. Cathode EIS spectra obtained by subtraction of H2-H2-mode spectra from H2-air-mode spectra were modeled and the ohmic, charge-transfer, and oxygen mass-transport contributions to the stack polarization under load were separated. The variability of these contributions across the stack was discussed.