Dogs, not wolves, most likely to have caused the death of a British tourist in northern Greece

Wolf (Canis lupus) populations have recovered and expanded across many parts of the world thanks to conservation efforts, including improved legal status and restoration of their prey. Concurrently, public concerns regarding the risk of wolf attacks on humans and livestock are increasing as wolves occupy human-dominated landscapes. We examined a unique case in Europe allegedly involving wolves in the death of a female British tourist, aged 64, in northern Greece in September 2017. This incident received extensive international media attention and yet many fundamental details of the case area are lacking, including whether local livestock guarding dogs played a role. To assist in resolving the case, we conducted an extensive literature review which documented 13 criteria linked to the risk of either a wolf and/or a dog attacking a human. We also conducted a camera trap survey (October to December 2017) soon after the fatal attack to calculate the activity overlap among humans, dogs and wolves. Sufficient data were available for assessing 11 of the 13 criteria. For the remaining two, the required data were either not analysed (i.e. canid DNA collected from the attack site), not appropriately collected (i.e. DNA from the mouths of suspected dogs) or were collected, but misinterpreted (i.e. the post-consumption patterns of the victim’s corpse). Via this combination of evidence, we conclude that this case involved a fatal dog attack. This assertion is supported by evidence such as the: a) high dog-human activity overlap at the attack site which peaked during the attack time as opposed to near zero wolf-human activity overlap at the same time, b) presence of a large pack of unsupervised dogs, c) high ratio of male dogs in the dog pack, d) close vicinity of the attack site to dog owner’s property and e) previous documented aggression of these dogs towards humans. The consumption patterns, time scale and location of the victim’s remains indicate a posthumous consumption of the corpse possibly by the same dogs and/or by wild scavengers including wolves. A multidisciplinary approach, such as this one, in the assessment of putative wildlife attacks on humans can reduce misidentifications of the responsible species by forensic authorities and, therefore, prevent unfounded decrease in public tolerance for large carnivores.

How climate impacts the composition of wolf-killed elk in northern Yellowstone National Park

While the functional response of predators is commonly measured, recent work has revealed that the age and sex composition of prey killed is often a better predictor of prey population dynamics because the reproductive value of adult females is usually higher than that of males or juveniles.

Climate is often an important mediating factor in determining the composition of predator kills, but we currently lack a mechanistic understanding of how the multiple facets of climate interact with prey abundance and demography to influence the composition of predator kills.

Over 20 winters, we monitored 17 wolf packs in Yellowstone National Park and recorded the sex, age and nutritional condition of kills of their dominant prey—elk—in both early and late winter periods when elk are in relatively good and relatively poor condition, respectively.

Nutritional condition (as indicated by per cent marrow fat) of wolf‐killed elk varied markedly with summer plant productivity, snow water equivalent (SWE) and winter period. Moreover, marrow was poorer for wolf‐killed bulls and especially for calves than it was for cows.

Wolf prey composition was influenced by a complex set of climatic and endogenous variables. In early winter, poor plant growth in either year t or t − 1, or relatively low elk abundance, increased the odds of wolves killing bulls relative to cows. Calves were most likely to get killed when elk abundance was high and when the forage productivity they experienced in utero was poor. In late winter, low SWE and a relatively large elk population increased the odds of wolves killing calves relative to cows, whereas low SWE and poor vegetation productivity 1 year prior together increased the likelihood of wolves killing a bull instead of a cow.

Since climate has a strong influence on whether wolves prey on cows (who, depending on their age, are the key reproductive components of the population) or lower reproductive value of calves and bulls, our results suggest that climate can drive wolf predation to be more or less additive from year to year.

Population responses of common ravens to reintroduced gray wolves

Top predators have cascading effects throughout the food web, but their impacts on scavenger abundance are largely unknown. Gray wolves (Canis lupus) provide carrion to a suite of scavenger species, including the common raven (Corvus corax). Ravens are wide-ranging and intelligent omnivores that commonly take advantage of anthropogenic food resources. In areas where they overlap with wolves, however, ravens are numerous and ubiquitous scavengers of wolf-acquired carrion. We aimed to determine whether subsidies provided through wolves are a limiting factor for raven populations in general and how the wolf reintroduction to Yellowstone National Park in 1995-1997 affected raven population abundance and distribution on the Yellowstone's Northern Range specifically. We counted ravens throughout Yellowstone's Northern Range in March from 2009 to 2017 in both human-use areas and wolf habitat. We then used statistics related to the local wolf population and the winter weather conditions to model raven abundance during our study period and predict raven abundance on the Northern Range both before and after the wolf reintroduction. In relatively severe winters with greater snowpack, raven abundance increased in areas of human use and decreased in wolf habitat. When wolves were able to acquire more carrion, however, ravens increased in wolf habitat and decreased in areas with anthropogenic resources. Raven populations prior to the wolf reintroduction were likely more variable and heavily dependent on ungulate winter-kill and hunter-provided carcasses. The wolf recovery in Yellowstone helped stabilize raven populations by providing a regular food supply, regardless of winter severity. This stabilization has important implications for effective land management as wolves recolonize the west and global climate patterns change.