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The intricate interplay between predators and prey has long fascinated ecologists, with bats and their diverse prey offering insight into co‐evolutionary dynamics. While bats have evolved sophisticated strategies for prey capture, they also face predation pressure. Among their predators, spiders stand out for their diversity of predatory tactics, ranging from hunting assaults and web ensnarement to the deployment of venom. Yet, bat predation records by spiders are mostly from tropical regions, and cases remain notably scarce in temperate regions. Here, we report four new incidences of bat predation and mortality by spiders and their webs in Europe. Our observations include detailed photograph and video documentation of the first record of a spider capturing and consuming a bat pup in Spain, as well as accounts of bats entangled in spider webs on a building and inside bat boxes in the United Kingdom. These findings shed light on understudied predator–prey dynamics, offering valuable insights into spider predation on bats in European ecosystems. Our study emphasises the importance of continued research to improve our understanding of ecological interactions between these elusive and primarily nocturnal taxa. [ABSTRACT FROM AUTHOR]

The intricate interplay between predators and prey has long fascinated ecologists, with bats and their diverse prey offering insight into co‐evolutionary dynamics. While bats have evolved sophisticated strategies for prey capture, they also face predation pressure. Among their predators, spiders stand out for their diversity of predatory tactics, ranging from hunting assaults and web ensnarement to the deployment of venom. Yet, bat predation records by spiders are mostly from tropical regions, and cases remain notably scarce in temperate regions. Here, we report four new incidences of bat predation and mortality by spiders and their webs in Europe. Our observations include detailed photograph and video documentation of the first record of a spider capturing and consuming a bat pup in Spain, as well as accounts of bats entangled in spider webs on a building and inside bat boxes in the United Kingdom. These findings shed light on understudied predator–prey dynamics, offering valuable insights into spider predation on bats in European ecosystems. Our study emphasises the importance of continued research to improve our understanding of ecological interactions between these elusive and primarily nocturnal taxa. [ABSTRACT FROM AUTHOR]

Gathering knowledge on the breeding ecology of species in wild-living conditions is critical to set baselines from which to analyse population trends and design appropriate conservation actions. This is particularly challenging when studying elusive animals like carnivores, as breeding events are difficult to detect and monitor. Based on direct sightings of wildcats, we provide the first scientific information on the breeding ecology in wild conditions of European wildcats as well as hunting success and provisioning rates of female wildcats. Mean litter size at weaning was two with most observations occurring between July and September. Auxiliary dens were mostly located inside thick vegetation in the proximities of pastoral fields, although anthropogenic constructions were occasionally used. Two cases of different female wildcats rearing their respective litters closer than 500 m were recorded. Hunting success of breeding females (66%) was higher than that of non-breeding females (33%) and males (40%). Breeding females provided around 80% of the captured prey to their kittens. In conclusion, direct observations of wild-living wildcats in the Cantabrian Mountains (NW Spain) allowed us to find that anthropogenic mosaic-structured landscapes combining open pastoral fields providing prey, and areas with thick vegetation such as shrub and forest patches providing shelter, encompass conditions required by the wildcats to successfully breed in human-dominated environments. [ABSTRACT FROM AUTHOR]

Intraspecific communication in mammals is well-documented but generally restricted to chemical and acoustic signaling. However, other overlooked channels, such as visual signaling, may be used to communicate among conspecifics. Here, by using experimental manipulations together with camera traps on 13 brown bear (Ursus arctos) rubbing trees in the Cantabrian Mountains (northwestern Spain), we document detailed temporal patterns and behavioral aspects of a recently discovered novel communication channel for this species, visual signaling through the trunk debarking of focal trees. Video footage showed that visual marking is a sex-, age-, and time-specific means of communication in brown bears, being performed exclusively by adult males during the mating season (mainly April–June in the study area). Trunk debarking was always associated with chemical marking and was never an isolated behavior, suggesting that visual and chemical signals might be complementary. Visual and chemical marks may provide different information; for example, visual marks could be an indicator of individual size and, thus, the dominance status of adult males looking for mating opportunities. This is the first time that evidence is provided showing that visual signaling in a large carnivore is exclusive to a specific class of individuals (adult males) and linked to reproductive needs only. Bear visual signaling not only represents an advance in our comprehension of animal communication but may also serve to easily locate the mating areas of mammals, which are crucial for large carnivore species, such as the brown bear, that frequently need specific and urgent plans for conservation and management. [ABSTRACT FROM AUTHOR]

Carrion production is one of the most crucial yet neglected and understudied processes in food webs and ecosystems. In this study, we performed a large-scale estimation of the maximum potential production and spatial distribution of ungulate carrion biomass from five major sources in peninsular Spain, both anthropogenic (livestock, big game hunting, roadkills) and natural (predation, natural mortality). Using standardized ungulate carrion biomass (kg/year/100km2) estimates, we evaluated the relationship between ungulate carrion production and two ecosystem-level factors: global human modification (GHM) and primary productivity (NDVI). We found that anthropogenic carrion sources supplied about 60 times more ungulate carrion biomass than natural sources (mean = 90,172 vs. 1533 kg/year/100km2, respectively). Within anthropogenic carrion sources, livestock was by far the major carrion provider (91.1% of the annual production), followed by big game hunting (7.86%) and roadkills (0.05%). Within natural carrion sources, predation of ungulates provided more carrion (0.81%) than natural mortality (0.13%). Likewise, we found that the spatial distribution of carrion differed among carrion sources, with anthropogenic carrion being more aggregated in space than natural carrion. Our models showed that GHM was positively related to carrion production from livestock and roadkills, and that wild ungulate carrion supplied by natural sources and big game hunting was more frequently generated in more productive areas (higher NDVI). These findings indicate a disconnection between the main ungulate carrion source (livestock) and primary productivity. Ongoing socio-economic changes in developed countries (for example increase of intensive livestock husbandry and rewilding processes) could lead to additional alteration of carrion production processes, with potential negative impacts at the community and ecosystem levels. Overall, we highlight that carrion biomass quantification should be considered a crucial tool in evaluating ecosystem health and delineating efficient ecosystem management guidelines in the Anthropocene. [ABSTRACT FROM AUTHOR]

The rather limited human ability to understand animal vision and visual signalling has frequently clouded our expectations concerning the visual abilities of other animals. But there are multiple reasons to suspect that visual signalling is more widely employed by animals than previously thought. Because visibility of visual marks depends on the background in which they are seen, species spending most of their time living in dark conditions (e.g., in forests and/or having crepuscular and nocturnal habits) may rely on bright signals to enhance visual display. Here, as a result of experimental manipulations, we present, for the first time ever, evidence supporting the use of a new channel of intraspecific communication by a mammal species, i.e., brown bear Ursus arctos adult males relying on visual marks during mating. Bear reactions to our manipulation suggest that visual signalling could represent a widely overlooked mechanism in mammal communication, which may be more broadly employed than was previously thought. [ABSTRACT FROM AUTHOR]

Scent-mediated communication is considered the principal communication channel in many mammal species. Compared with visual and vocal communication, odors persist for a longer time, enabling individuals to interact without being in the same place at the same time. The brown bear (Ursus arctos), like other mammals, carries out chemical communication, for example, by means of scents deposited on marking (or rub) trees. In this study, we assessed rub tree selectivity of the brown bear in the predominantly deciduous forests of the Cantabrian Mountains (NW Spain). We first compared the characteristics of 101 brown bear rub trees with 263 control trees. We then analyzed the potential factors affecting the density of rub trees along 35 survey routes along footpaths. We hypothesized that: (1) bears would select particular trees, or tree species, with characteristics that make them more conspicuous; and (2) that bears would select trees located in areas with the highest presence of conspecifics, depending on the population density or the position of the trees within the species' range. We used linear models and generalized additive models to test these hypotheses. Our results showed that brown bears generally selected more conspicuous trees with a preference for birches (Betula spp.). This choice may facilitate the marking and/or detection of chemical signals and, therefore, the effectiveness of intraspecific communication. Conversely, the abundance of rub trees along footpaths did not seem to depend on the density of bear observations or their relative position within the population center or its border. Our results suggest that Cantabrian brown bears select trees based on their individual characteristics and their location, with no influence of characteristics of the bear population itself. Our findings can be used to locate target trees that could help in population monitoring. [ABSTRACT FROM AUTHOR]

Felids and canids coexist along their ranges worldwide. Various interactions can occur between these carnivores, with multiple consequences such as demographic changes of competitors, or behavioural modifications in the use of the spatial, temporal or trophic niches. European wildcats (Felis silvestris silvestris) and red foxes (Vulpes vulpes) coexist across Europe using multi-use landscapes when hunting rodents. They commonly use open fields during the day in the Cantabrian Mountains (NW Spain). We collected 597 diurnal phenotypic wildcat observations between 2012 and 2019, during which we observed 14 encounters (2.34%) of wildcats and foxes. We compiled 11 more encounters from collaborators. Diurnal encounters between both species seem to be rare, which could result from the two species displaying active avoidance. During the encounters, foxes mainly showed offensive behaviours whereas wildcats showed a defensive intimidation strategy, probably in relation to their morphology. Both strategies were equally effective for maintaining the position in feeding grounds. [ABSTRACT FROM AUTHOR]

Caching behavior consists on the relocation or storage of food to protect it from competitors, to delay food spoilage, or to exploit it during times of scarcity. While this behavior has been widely described for some medium and large-sized felids, only a few cases documented caching behavior in small felids. Here, we provide the first exhaustive description of a caching event on a European wildcat in the Cantabrian Mountains (NW Spain). The wildcat behaved like a lynx/puma, visiting a road-killed roe deer carcass at least 9 days along a 21-day period, consuming the main muscles and covering it with hair and vegetation. [ABSTRACT FROM AUTHOR]