Foraging Ermine Avoid Risk: behavioural responses of a mesopredator to its interspecific competitors in a mammalian guild

Frightened of giants: fear responses to elephants approach that of predators

Animals are faced with a variety of dangers or threats, which are increasing in frequency with ongoing environmental change. While our understanding of fearfulness of such dangers is growing in the context of predation and parasitism risk, the extent to which non-trophic, interspecific dangers elicit fear in animals remains less appreciated. We provide an experimental test for fear responses of savannah ungulates to a dominant and aggressive megaherbivore, the African bush elephant (Loxodonta africana), and contrast responses to an apex predator known to elicit fear in this system. Using an automated behavioural response system, we contrast vigilance and run responses of ungulates to elephant, leopard (Panthera pardus), and control (red-chested cuckoo Cuculus solitarius) vocalizations. Overall, we find that ungulates responded to elephant calls, both in terms of an increase in run and vigilance responses relative to controls. The magnitude of most behavioural responses (four of six considered) to elephant vocalizations were not significantly different than responses to leopards. These results suggest that megaherbivores can elicit strong non-trophic fear responses by ungulates and call to broaden frameworks on fear to consider dominant species, such as megaherbivores, as key modifiers of fear-induced interactions.

Abundance and Dynamics of Small Mammals in New Zealand: Sequential Invasions into an Island Ecosystem Like No Other

New Zealand had no people or four-footed mammals of any size until it was colonised by Polynesian voyagers and Pacific rats in c. 1280 AD. Between 1769 and 1920 AD, Europeans brought three more species of commensal rats and mice, and three predatory mustelids, plus rabbits, house cats hedgehogs and Australian brushtail possums. All have in turn invaded the whole country and many offshore islands in huge abundance, at least initially. Three species are now reduced to remnant populations, but the other eight remain widely distributed. They comprise an artificial but interacting and fully functional bottom-up predator-prey system, responding at all levels to interspecific competition, habitat quality and periodic resource pulsing.

Pet Owner Perception of Ferret Boredom and Consequences for Housing, Husbandry, and Environmental Enrichment

Boredom is a potential chronic but overlooked animal welfare problem. Caused by monotony, sub-optimal stimulation, and restrictive housing, boredom can therefore affect companion animals, particularly those traditionally caged, such as ferrets. We surveyed owners' (n = 621) perceptions of ferrets' capacity to experience boredom, behaviours they associate with it, and whether their perception of their ferrets' capacity for boredom influenced training techniques, housing, and environmental enrichment (EE). Most (93.0%) owners believed that ferrets could experience boredom, but owners who doubted that ferrets experience boredom (7.0%) provided slightly but significantly fewer EE types to their ferrets. Heat map and classification tree analysis showed that owners identified scratching at enclosure walls (n = 420) and excessive sleeping (n = 312) as distinctive behavioural indicators of ferret boredom. Repetitive pacing (n = 381), yawning (n = 191), and resting with eyes open (n = 171) were also suggested to indicate ferret boredom, but these overlapped with other states. Finally, ferret owners suggested social housing, tactile interaction with humans, and exploration as most important for preventing boredom. These results suggest that pet ferrets are at risk of reduced welfare from owners who doubt they can experience boredom, highlighting an opportunity to improve welfare through information dissemination. We recommend further investigation into ferret boredom capacity, behavioural indicators, and mitigation strategies.

Response of a mesocarnivore community to a new food resource: recognition, exploitation, and interspecific competition

Mammalian carnivores with generalist feeding behaviour should trace and exploit new and predictable food resources quicker and more easily than more specialised species. On the other hand, if the new food resource is spatially and temporally predictable, interference or exploitation competition should arise among members of the carnivore guild, with the expectation that smaller species will not use the food resource or will change their foraging behaviour to avoid conflict with larger species. Here, we studied the response to a new food resource of a mammalian mesocarnivore community in south-western Iberian Peninsula. We installed artificial feeding points supplied with a novel food source and tracked them by camera trapping to investigate whether (1) the new artificial food resource was visited, recognised and exploited by the mesocarnivore guild species; (2) how frequently they used the food; and (3) in case of co-occurrence, if dominant species excluded or reduced the feeding options of subordinates. All target species except the badger recognised and exploited the novel food. More generalist species trended to visit feeding points more frequently and spent more time feeding than less generalist species, even though significant differences were not achieved in all cases. When co-occurring at the same feeding point, the arrival of larger species reduced either the visitation rates, feeding probability or time spent feeding of smaller species. Moreover, some smaller species showed a shift in their normal activity pattern at the feeding points when a larger competitor started to use the food source. Overall, we conclude that active avoidance combined with temporal segregation may help reduce agonistic interactions among competitors for shared resources.

Niche partitioning in a guild of invasive mammalian predators

Predators compete aggressively for resources, establishing trophic hierarchies that influence ecosystem structure. Competitive interactions are particularly important in invaded ecosystems where introduced predators can suppress native prey species. We investigated whether niche partitioning exists within a guild of invasive mammalian predators and determined the consequences for native species. Over 4405 camera-trap days, we assessed interactions among three invasive predators: two apex predators (feral cats Felis catus and ferrets Mustela furo) and a mesopredator (stoats Mustela erminea), in relation to their primary prey (lagomorphs, rodents and birds) and habitat use. Further, we tested for mesopredator release by selectively removing cats and ferrets in a pulse perturbation experiment. We found compelling evidence of niche partitioning; spatiotemporal activity of apex predators maximized access to abundant invasive prey, with ferrets targeting lagomorphs and cats targeting rodents. Mesopredators adjusted their behavior to reduce the risk of interference competition, thereby restricting access to abundant prey but increasing predation pressure on diurnal native birds. Stoats were only recorded at the treatment site after both larger predators were removed, becoming the most frequently detected predator at 6 months post-perturbation. We suggest there is spatial and resource partitioning within the invasive predator guild, but that this is incomplete, and avoidance is achieved by temporal partitioning within overlapping areas. Niche partitioning among invasive predators facilitates coexistence, but simultaneously intensifies predation pressure on vulnerable native species.

Exploiting interspecific olfactory communication to monitor predators

Olfaction is the primary sense of many mammals and subordinate predators use this sense to detect dominant species, thereby reducing the risk of an encounter and facilitating coexistence. Chemical signals can act as repellents or attractants and may therefore have applications for wildlife management. We devised a field experiment to investigate whether dominant predator (ferret Mustela furo) body odor would alter the behavior of three common mesopredators: stoats (Mustela erminea), hedgehogs (Erinaceus europaeus), and ship rats (Rattus rattus). We predicted that apex predator odor would lead to increased detections, and our results support this hypothesis as predator kairomones (interspecific olfactory messages that benefit the receiver) provoked "eavesdropping" behavior by mesopredators. Stoats exhibited the most pronounced responses, with kairomones significantly increasing the number of observations and the time spent at a site, so that their occupancy estimates changed from rare to widespread. Behavioral responses to predator odors can therefore be exploited for conservation and this avenue of research has not yet been extensively explored. A long-life lure derived from apex predator kairomones could have practical value, especially when there are plentiful resources that reduce the efficiency of food-based lures. Our results have application for pest management in New Zealand and the technique of using kairomones to monitor predators could have applications for conservation efforts worldwide.