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Small carnivores play an important role in ecosystems, but their often hidden lifestyle makes them generally hard to observe. Camera-trapping methodology shows great promise as a standardized monitoring tool for small carnivores. The European polecat (Mustela putorius) is a species of conservation concern, listed on the Annex V of the EU Council's Directive on the conservation of natural habitats and of wild fauna and flora. Because of this, EU member states have to report the status of their polecat populations regularly. However, standardized methods to estimate the population size of polecat populations are currently lacking. We present a tube-based camera-trapping system, the Polecam, designed to obtain photographs of the facial masks of individual polecats. We tested the system in four study areas in southern Sweden during Spring and Autumn 2021. We obtained 52 observations of polecats, out of which we were able to identify 38 (73%) to individual. From these observations, we estimated area and season specific estimates of density for five season-area combinations using a multi-session spatial capture-recapture model. Density estimates ranged from 0.84 to 2.7 individuals/1000 ha, similar to the estimates from similar landscapes in other countries in Europe. We also obtained observations of six other species of small carnivores, suggesting that the Polecam could be used for multi-species monitoring, as well as density estimation of European polecats. [ABSTRACT FROM AUTHOR]

We evaluate the applicability of the microsatellite multiplex assay of 11 short tandem repeat loci for individual identification of sable and pine marten, taxonomic identification of Martes species, and assessment of inter-population separation of sable populations isolated by distance. Based on the screening, we detected 50 and 80–82 alleles in pine marten and two sable populations, respectively. All 11 microsatellite markers of the proposed PCR assay were characterized by the same range of allele length in the two Marten species, which makes species identification unfeasible using any of the loci alone. However, the combination of all 11 loci differentiated sables and pine martens, and more importantly provided the opportunity to identify their hybrids in the sympatry range zone. Using the proposed microsatellite assay, we successfully identified geographic origin of most genotyped sable individuals. [ABSTRACT FROM AUTHOR]

In spite of their potential important role in shaping small mammal population dynamics, weasel (Mustela nivalis) and stoat (Mustela erminea) are understudied due to the difficulty of detecting these species. Furthermore, their conservation status in many countries is unknown due to lack of monitoring techniques. There is thus an important need for a method to detect these small mustelids. In this study, we tested the efficiency of a recently developed camera trapping device, the Mostela, as a new technique to detect mustelids in a study area near Dieren, the Netherlands. We placed Mostelas in linear landscape features, and other microhabitats thought to be frequently visited by weasels, from March to October 2017 and February to October 2018. We tested for yearly and monthly differences in site use and detectability, as well as the effect of entrance tube size, using an occupancy modelling framework. We found large seasonal differences in site use and detectability of weasels with the highest site use in June to October and highest detection probability in August and September. Detection probability was approximately two times higher for Mostelas with a 10-cm entrance tube compared with 8-cm. Furthermore, we were able to estimate activity patterns based on the time of detection, identify the sex in most detections (69.5%), and distinguish several individuals. Concluding, the Mostela seems promising as a non-invasive monitoring tool to study the occurrence and ecology of small mustelids. Further development of individual recognition from images would enable using the Mostela for density estimates applying capture-recapture models. [ABSTRACT FROM AUTHOR]

The Neotropical otter, Lontra longicaudis, is considered near threatened by the IUCN, and with declining populations, it is still one of the lesser known species of otter in the world. Like other otter species, L. longicaudis is associated with water courses in a large variety of habitats and biomes across its area of distribution. Here, we present a review of the available literature on L. longicaudis aiming to update information on its distribution, ecology and systematics. We performed online searches using combinations of the words L. longicaudis, river otter, Neotropical otter, nutria and lobito del río, limiting our search to 1972-2016. Recent information on evolutionary history and biogeographic patterns, distribution patterns, as well as on the ecology of the species across a large part of its distribution range, including trophic ecology and intraspecific communication, was retrieved. We found severe gaps in knowledge including aspects of life history, ground validation of new potential distribution areas and long-term population monitoring aiming at designing more efficient conservation measures and techniques. In this context, we conclude by presenting perspectives for future studies. [ABSTRACT FROM AUTHOR]

The seasonal and spatial variation of the stone marten's (Martes foina) diet was studied in the villages of Białowieża Forest, north-eastern Poland. Stone marten diet varied significantly among seasons, years and villages of different size. The most important food sources were fruits and birds: 41.5 and 32.9 % of consumed biomass (% Bio), respectively. From summer to winter, fruits were the most important food, in contrast to spring, where birds dominated the diet followed by small mammals, fruits and other plant material. Fruits were eaten more frequently in the larger villages, in contrast to the smallest village, where the main food was small mammals (over 50%Bio). The contribution of different small mammal species to marten diet was dependent on the village size and habitat structure of adjacent areas. In small villages situated close to the forest, the dominant food source was forest rodents (mainly bank vole Myodes glareolus), while in the larger villages, marten hunted mainly on rats (Rattus sp.). The highest frequency of occurrence of birds in the stone marten diet was in the small village (Zwierzyniec) in summer (67.7 % Bio), while poultry consumption was the highest in the large villages (Białowieża and Podolany) in winter (over 30 % Bio). The results of this study suggest that stone marten feeding habits are plastically adapted to the varying availability of different food resources in their environment. However, stone marten demonstrates high specialization to fruits, but when fruit availability is low, they supplement their diet with other components (small mammals and birds). [ABSTRACT FROM AUTHOR]

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 ( O = 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. [ABSTRACT FROM AUTHOR]