Can livestock carrion availability influence diet of wintering red kites? Implications of sanitary policies in ecosystem services and conservation

The diet of wintering red kites Milvus milvus over the last decade in central Spain was recorded to evaluate the influence of sanitary policies on carcasses use. The results show major differences in diet composition of red kites wintering in areas with and without availability of livestock carcasses. In the area without livestock carcasses (north-western Madrid province), red kites fed on a similarly large proportion of wild lagomorphs across the study period. In the area with livestock farming (Segovia province), red kites exploited carcasses from different livestock schemes (stabled livestock—primarily swine—versus free-ranging ruminants) depending on changing sanitary regulations as consequence of the Bovine Spongiform Encephalopathy or ‘mad cow’ crisis initiated in 2001. During the period of restrictive sanitary legislation (after the ‘mad cow’ crisis) that greatly limited the use of animal by-products from ruminants as food for avian scavengers, kites mostly predated on common voles and scavenged on swine carcasses. After the implementation of the less restrictive regulations (since 2011; regulations CE1069/2009, CE142/2011) that again permitted the abandonment of extensive livestock remains in the countryside and in feeding stations, the proportion of ruminants in the kites’ diet increased while the proportion of swine carrion decreased. Carcass dumps acted as temporally and spatially predictable sources of abundant food from stabled livestock before and even just after the mad-cow crisis, but become relatively unpredictable foraging places afterwards due to the generalized carrion destruction in authorized plants, primarily of swine considered as non-risk for the transmission of the bovine encephalopathy. This illustrates the deep and sometimes unexpected consequences that sanitary policies can impose on the composition and availability of food resources for scavenger wildlife. Much effort is still required to reconcile sanitary and environmental policies in order to ensure the conservation of avian scavengers and the provision of ecosystem services.     

Geographical variation in cloacal microflora and bacterial antibiotic resistance in a threatened avian scavenger in relation to diet and livestock farming practices

The impact on wildlife health of the increase in the use of antimicrobial agents with the intensification of livestock production remains unknown. The composition, richness and prevalence of cloacal microflora as well as bacterial resistance to antibiotics in nestlings and full-grown Egyptian vultures Neophron percnopterus were assessed in four areas of Spain in which the degree of farming intensification differs. Differences in diet composition, especially the role of stabled livestock carrion, appear to govern the similarities of bacterial flora composition among continental populations, while the insular vulture population (Fuerteventura, Canary Islands) showed differences attributed to isolation. Evidence of a positive relationship between the consumption of stabled livestock carrion and bacterial resistance to multiple antibiotics was found. Bacterial resistance was high for semisynthetic penicillins and enrofloxacin, especially in the area with the most intensive stabled livestock production. The pattern of antibiotic resistance was similar for the different bacterial species within each area. Bacterial resistance to antibiotics may be determined by resistance of bacteria present in the livestock meat remains that constituted the food of this species, as indicated by the fact that resistance to each antibiotic was correlated in Escherichia coli isolated from swine carrion and Egyptian vulture nestlings. In addition, resistance in normal faecal bacteria (present in the microflora of both livestock and vultures) was higher than in Staphylococcus epidermidis, a species indicator of the transient flora acquired presumably through the consumption of wild rabbits. Potential negative effects of the use of antimicrobials in livestock farming included the direct ingestion of these drug residues and the effects of bacterial antibiotic resistance on the health of scavengers.     

Geographic variation of the winter diet of the Red Kite Milvus milvus in the Iberian Peninsula

This paper presents data on the winter diet of the Red Kite Milvus milvus in the Iberian Peninsula. The diet composition and its relationship with food abundance and habitat characteristics were studied in two areas (northern and southern plateaux) with different food availability and habitat composition. Red Kites showed a clear difference in diet between the two plateaux, with a higher consumption of carrion on the northern plateau and of game species on the southern plateau. Common Voles Microtus arvalis , despite being a very abundant prey on the northern plateau, did not appear in the diet in high numbers, but their frequency was related to the proportion of land occupied by nonirrigated (cereal) crops. High frequencies of "small" carrion (e.g. farmed Rabbits Oryctolagus cuniculus , poultry Gallus sp.) in the diet were correlated with a decrease in the trophic diversity which suggested an active choice of the food, at least in years with low vole densities. We suggest that the use of carrion is influenced not only by its abundance but by its availability to Red Kites. Refuse tips and muladares (dumps for dead livestock) and their management during the winter are important for the conservation of the species.     

Effects of carrion resources on herbivore spatial distribution are mediated by facultative scavengers

Carcasses of large herbivores are pulsed resources whose impact on animal communities and ecological processes is poorly understood. In temperate forests, long-lasting ungulate carcasses are a prime resource for many species of birds and mammals during winter. Facultative carrion-eaters also consume live prey, thus potentially leading to unexpected secondary effects on populations of species not directly linked to carcass exploitation. By snow-tracking and direct observations we investigated in Bia?owie?a Forest (E. Poland) whether large ungulate carcasses elicit spatial responses in facultative scavengers and their prey. We found that in the vicinity of carcass sites the probability of the presence of common ravens Corvus corax, jays Garrulus glandarius and red foxes Vulpes vulpes increased significantly. Indeed, large groups of the two bird species were exclusively found in those places. Because of these aggregations, the probability of predator–prey encounters (red foxes and brown hares Lepus europaeus) was significantly higher near carcass sites. Accordingly, the abundance of hares and other live prey such as red squirrels Sciurus vulgaris decreased at their vicinities, probably as a consequence of direct killing and/or predator avoidance. This study provides the first evidence of carrion pulses permeating into apparently distant trophic levels, such as herbivores, via facultative scavengers, thus highlighting some unnoticed but relevant effects of carrion resources on community structure.     

Apex predators and the facilitation of resource partitioning among mesopredators

Apex predators may influence carnivore communities through the suppression of competitively dominant mesopredators, however they also provide carrion subsidies that could influence foraging and competition among sympatric mesopredators when small prey is scarce. We assessed coyote Canis latrans and red fox Vulpes vulpes winter diet overlap and composition from scats collected in two study areas with 3‐fold difference in grey wolf Canis lupus density due to a wolf control program. We hypothesized that differences in diet composition would be driven by the use of carrion, and tested whether 1) apex predators facilitate resource overlap, or 2) apex predators facilitate resource partitioning. We estimated the available biomass of snowshoe hares and voles based on pellet density and vole capture rates in each study area. We used molecular analysis to confirm species identification of predator scats, and used microscopic evaluation of prey remains to analyze diet composition of 471 coyote and fox scats. Ungulate carrion, voles and snowshoe hares comprised 73% of coyote and fox diet, and differences in use of carrion and microtines accounted for nearly 60% of the dissimilarity in diet among these canids. Carrion was the top‐ranked item in the coyote diet in both study areas, whereas carrion use by red foxes declined 3‐fold in the study area with higher wolf and small prey abundance. Diet overlap tended to be lower and diet diversity tended to be higher where wolves were more abundant, though these trends were not statistically significant. Taken together, our findings indicate that carrion provisions could facilitate resource partitioning in mesocarnivore communities by alleviating exploitation competition for small mammals.     

Food habits of wolvesCanis lupus in Latvia

Diet of wolvesCanis lupus Linnaeus, 1758 in Latvia was studied from 1997 to 2001 based on 302 scats and 107 stomachs. Wild ungulates (cervids and wild boarSus scrofa) and beaverCastor fiber were the dominant prey. Cervids were found in 50% of samples (62% biomass), wild boar in 25% (21% biomass), beavers in 14% (12% biomass). Wolves selected for wild boar, especially in winter when its ratio in the diet increased to 34% from 20% in summer. It was a more common prey species in the east of the country. The ratio of beavers, small rodents and plant food was higher in summer, which resulted in a broader food niche in summer than in winter (B = 2.53 versus 1.81, respectively). The role of domestic animals in the wolf diet was minimal except for winter when they were consumed as carrion (13%). More than 1/3of all stomachs investigated were empty. The average weight of stomach contents was 972.8 g. The importance of the beaver as an alternative prey is discussed. We conclude that wolves in Latvia prey mainly on wild animals and conflicts with livestock owners are only occasional and/or local.     

Wolf (Canis lupus) feeding habits during the first eight years of its occurrence in Germany

Due to the fact that the feeding habits of large carnivores are the main contentious point when they start resettling regions they were absent from for several decades, the diet composition of the wolves in Germany was analysed from the beginning of this process. Wolves in Germany primarily feed on wild ungulates, which make up more than 96% of their diet. The dominating prey species is the roe deer (55.3%), followed by red deer (20.8%) and wild boar (17.7%). The second important food category are the leporids (2.9% of Biomass), whereas livestock makes up only 0.6% of all biomass consumed. Wolves clearly prefer hunting on juvenile to adult red deer; roe deer are not selected after their age. We found seasonal differences in the diet composition with a higher amount of wild boar in spring and winter, when a high amount of juveniles and weakened animals, respectively, are available. In the first years of the study the percentage of red deer was much higher, and the percentage of roe deer therefore was lower than the following years. The amount of wild boar in the wolf diet fluctuated most in the first three years. Diet composition remained constant during the last five years. Wolves needed less than two generations for adapting to the new conditions in the cultivated landscape of eastern Germany.     

The feeding habits of wolves in relation to large prey availability in northern Italy

We investigated wolf feeding habits in relation to the abundance of wild and domestic ungulates to test the hypothesis that large prey are preferred and that their abundance affects the use of other food categories and diet breadth. We determined diet composition by scat analysis from December 1987 to December 1992. The research was carried out in three study areas located in northern Italy and characterised by marked differences in wild and domestic ungulate abundance. In study area A (low wild and domestic ungulate availability) fruits, livestock, other vertebrates and wild ungulates made up the bulk of the diet (71% in volume). In area B (high availability of livestock) wolf diet was mainly based on sheep and wild boars (80% in volume). In study area C (high availability of wild ungulates) wild ungulates were the main food of wolves (90% in volume). Significant differences were found among study areas in the mean percentage volume of all food categories and in particular for wild ungulates, livestock, other vertebrates and fruits (p < 0.0001 in all cases). Diet breadth decreased in areas with high availability of large wild and domestic herbivores. The use of livestock species was lower where there was high abundance, richness and diversity of the wild ungulate guild. Selection for wild ungulate species was partially affected by their abundance: however other factors as prey social behaviour, adaptability to the habitat (for introduced species), and body size could have an important role in species selection by wolves. In particular in area C wild boars were selected for, roe and red deers avoided, and fallow deers and mouflons used as available. Livestock species were used in relation to their abundance and accessibility, in particular sheep were selected for and cattle avoided; but if calves bom in the pastures were considered as the only available cattle, they were selected for and sheep were used as available. Large and in particular wild herbivores were found to be of great importance for the wolf population maintenance in northern Italy, one of the most important recovery areas of Mediterranean wolves.     

Donor-Control of Scavenging Food Webs at the Land-Ocean Interface

Food webs near the interface of adjacent ecosystems are potentially subsidised by the flux of organic matter across system boundaries. Such subsidies, including carrion of marine provenance, are predicted to be instrumental on open-coast sandy shores where in situ productivity is low and boundaries are long and highly permeable to imports from the sea. We tested the effect of carrion supply on the structure of consumer dynamics in a beach-dune system using broad-scale, repeated additions of carcasses at the strandline of an exposed beach in eastern Australia. Carrion inputs increased the abundance of large invertebrate scavengers (ghost crabs, Ocypode spp.), a numerical response most strongly expressed by the largest size-class in the population, and likely due to aggregative behaviour in the short term. Consumption of carrion at the beach-dune interface was rapid and efficient, driven overwhelmingly by facultative avian scavengers. This guild of vertebrate scavengers comprises several species of birds of prey (sea eagles, kites), crows and gulls, which reacted strongly to concentrations of fish carrion, creating hotspots of intense scavenging activity along the shoreline. Detection of carrion effects at several trophic levels suggests that feeding links arising from carcasses shape the architecture and dynamics of food webs at the land-ocean interface.     

Need and Seek for Dietary Micronutrients: Endogenous Regulation,External Signalling and Food Sources of Carotenoids in New World Vultures

Among birds, vultures show low concentrations of plasma carotenoids due to the combination of their large size, general dull colouration and a diet based on carrion. We recorded the concentration of each carotenoid type present in plasma of the Andean condor (Vultur gryphus) according to age and sex, that determine colour signalling and dominance hierarchies in the carcasses. We compared the carotenoid profile in wild condors with that of captive condors fed with a controlled diet of flesh to test the hypothesis that wild individuals could acquire extra carotenoids from vegetal matter contained in carcass viscera and fresh vegetation. Wild American black vultures (Coragyps atratus) were also sampled to evaluate the potential influence of colouration in the integument on absorption and accumulation patterns of plasma carotenoids. A remarkably higher concentration of lutein than β-carotene was found in wild condors, while the contrary pattern was recorded in American black vultures and captive condors. We found a consistent decrease in all plasma carotenoids with age, and a lower concentration of most xanthophylls in male compared to female wild condors. Positive correlations of all carotenoids indicated general common absorption and accumulation strategies or a single dietary source containing all pigments found in plasma. The comparatively low total concentration of carotenoids, and especially of lutein rather than β-carotene, found in captive condors fed with a diet restricted to flesh supports the hypothesis that Andean condors can efficiently acquire carotenoids from vegetal matter in the wild. Andean condors seem to be physiologically more competent in the uptake or accumulation of xanthophylls than American black vultures, which agrees with the use of colour-signalling strategies in sexual and competitive contexts in the Andean condor. This study suggests that vultures may use dietary vegetal supplements that provide pigments and micronutrients that are scarce or missing in carrion.     

Diet of Dippers Cinclus cinclus during an early winter spate and the possible implications for Dipper populations subjected to climate change

The prey composition of the diet of Dippers Cinclus cinclus was shown to differ between baseflow and spate conditions. In southwest Ireland, faecal pellets were collected during a heavy spate in early winter 1991 and during a period of baseflow conditions three weeks later. The diet composition differed significantly between the two periods. During baseflow conditions diet was dominated by trichopteran larvae, especially Limnephilidae, whereas during the spate period diet was composed primarily of ephemeropteran nymphs, particularly Baetidae, and dipteran larvae of the family Simuliidae. Diet during the spate period also contained greater proportions of prey taxa of terrestrial origin. Enhanced hydrological cycles with greater precipitation, predicted under current climate change models, may have an effect on the diet of Dippers and this is discussed.     

Dietary preference of cheetahs (Acinonyx jubatus) in south‐eastern Kenya

The conversion of natural ecosystems due to anthropogenic activities has led to the destruction of natural habitats and to the deterioration of habitat quality. Top predators particularly respond sensitively to changes in habitat structures, including the availability of prey. The cheetah Acinonyx jubatus prefers small‐medium‐sized, wild ungulate prey due to the cheetah''s morphological adaptations. However, the majority of the species’ population is found beyond protected areas, where habitat structures, species abundances, and community composition are highly influenced by human activities. Only few studies have analyzed the diet preference of cheetahs in relation to prey availability and abundance for rangelands beyond protected areas in Eastern Africa. The study aimed to determine cheetah prey preference in the rangelands of south‐eastern Kenya based on scat analyses. We compared dietary preference of cheetah with prey availability. For this purpose, we conducted standardized game counts. We analyzed 27 cheetah scat samples collected across the same study area where we also conducted game counts. We found that Grant''s gazelle Gazella granti contributed the highest portion of cheetah''s diet, although Thomson''s gazelle Gazella thomsonii was the most abundant medium‐sized ungulate prey in the study areas. We also recorded two primate species, yellow baboon Papio cynocephalus and vervet monkey Chlorocebus pygerythrus, as well as the rock hyrax Procavia capensis in the cheetah diet. These species have never been documented as cheetah prey before. Furthermore, our results document livestock as potential prey for cheetahs. These observations underline that cheetah use diverse prey in rangelands outside protected areas, and that the abundance of specific prey does not influence cheetah prey preference.     

Experimental Test of Preferences for an Invasive Prey by an Endangered Predator: Implications for Conservation

Identifying impacts of exotic species on native populations is central to ecology and conservation. Although the effects of exotic predators on native prey have received much attention, the role of exotic prey on native predators is poorly understood. Determining if native predators actively prefer invasive prey over native prey has implications for interpreting invasion impacts, identifying the presence of evolutionary traps, and predator persistence. One of the world’s most invasive species, Pomacea maculata, has recently established in portions of the endangered Everglade snail kite’s (Rostrhamus sociabilis plumbeus) geographic range. Although these exotic snails could provide additional prey resources, they are typically much larger than the native snail, which can lead to lower foraging success and the potential for diminished energetic benefits in comparison to native snails. Nonetheless, snail kites frequently forage on exotic snails. We used choice experiments to evaluate snail kite foraging preference in relation to exotic species and snail size. We found that snail kites do not show a preference for native or exotic snails. Rather, snail kites generally showed a preference for medium-sized snails, the sizes reflective of large native snails. These results suggest that while snail kites frequently forage on exotic snails in the wild, this behavior is likely driven simply by the abundance of exotic snails rather than snail kites preferring exotics. This lack of preference offers insights to hypotheses regarding effects of exotic species, guidance regarding habitat and invasive species management, and illustrates how native-exotic relationships can be misleading in the absence of experimental tests of such interactions.     

Communal Roosting of Wintering Red Kites Milvus milvus (Aves,Accipitridae): Social Feeding Strategies for the Exploitation of Food Resources

Social feeding strategies of wintering red kites are analyzed in relation to age, food, roost-sites and differences from kite residents. Whereas young and adult wintering kites gathered at roost sites almost daily, adult residents did not, and immature residents only occasionally. Kites using roost sites feed more often on prey prelocated by others, while lone roosters also forage and discover food alone. After finding food, kites tend to shift to a new roost site and foraging area. Two details of the ‘information centre’ hypothesis are confirmed in our study: carcasses are unpredictably found patches, divisible between several individuals. But carcasses disappeared fast in the study area, and no increase with time in the number of birds consuming a carcass was observed, so that information transmission was unconfirmed. When kites leave the roost in groups no leader is detectable. It seems that other types of social foraging are operating, and the model best matching our results is network foraging.     

Determination of the diet of the stone curlew (Bwhinus oedicnemus) by faecal analysis

The value of faecal analysis for estimating the composition of the diet of stone curlews was assessed by examination of the faeces of a captive bird fed on a measured diet. Remains of soft–bodied prey were under–represented in the faeces but the results could be adjusted to allow for this. Estimation of the size of prey was possible by measurement of remnants such as earthworm chaetae and insect mandibles. In some types of prey large specimens left more remnants than small ones and a correction was devised to allow for this. Regurgitated pellets contained large, hard remains and there was no trace of some important prey types such as earthworms. A method is described for estimating the composition of the diet of the wild stone curlews from counts of prey remains in their faeces.     

Prey Animals of Tiger (<Emphasis Type="Italic">Panthera tigris tigris</Emphasis>) in Dudhwa Landscape,Terai Region,North India

Livestock depredation by carnivores cause substantial human carnivore conflict and subsequently decreased support for carnivore conservation. Thus, understanding carnivore diet with respect to wild prey availability has major implications to determine the reasons behind livestock depredation. A study was conducted to investigate food habits and prey use of tiger at four study sites (Dudhwa National Park, Kishanpur Wildlife Sanctuary, Pilibhit Forest Division and Katerniaghat Wildlife Sanctuary) in Dudhwa landscape, Terai Region, North India for further understanding of prey–predator relationship and partial impact of wild prey availability on livestock depredation by tiger through scat analysis. Scat analysis shows that the tigers depend mostly on medium sized prey throughout the study area (74.11, 73.58, 71.79, 47.62%). In Dudhwa National Park and Kishanpur Wildlife Sanctuary, predation was attempted subsequently on wider prey variety of eleven and nine different available prey species where livestock depredation were only 3.77 and 5.36% respectively. While, in absence of wider prey variety, large sized livestock (21.91, 16.55%) and nilgai (24.41, 5.57%) contributed much higher in tiger diet in Pilibhit Forest Division and Katerniaghat Wildlife Sanctuary respectively. Our study suggested that availability of prey variety has an important role in reduced livestock depredation. Medium sized preys were mostly contributing in tiger diet and seems to be a significant parameter for sustaining tiger population where abundance of large sized prey is rare. Conservation of medium sized preys is important but along with natural restoration of the population of large sized prey species like sambar and swamp deer is essential in order to reduce livestock depredation.     

Dietary preference of the Asiatic wild dog (Cuon alpinus)

The population of the Asiatic wild dog or dhole (Cuon alpinus) in the wild has been estimated to be less than 2500 mature individuals. This has led to the IUCN assessing the Asiatic wild dog as Endangered. The killing of Asiatic wild dogs in retaliation for livestock depredation is one of the major threat for the species across its geographic range. Understanding the prey preference of endangered large carnivores is imperative for making informed conservation decisions and devising management strategies. We studied the prey preference of the Asiatic wild dog by reviewing studies that have been conducted on the diet and prey abundance of the species across its distributional range. Nine available studies conducted in eight protected areas of three countries, in which 5265 scats were studied, were reviewed. Across studies, we tested whether prey consumption was based on prey availability or prey body mass. The value of Jacobs’ index was determined for each prey species and tested against the proportion of available prey and body mass. Sambar (Rusa unicolor) and chital (Axis axis) were found to be significantly preferred by the Asiatic wild dog, and the preferred prey body mass range was between 40 and 60 kg. The prey preference of the Asiatic wild dog was mainly influenced by the availability of prey.     

Assessing the Role of Livestock in Big Cat Prey Choice Using Spatiotemporal Availability Patterns

Livestock is represented in big cat diets throughout the world. Husbandry approaches aim to reduce depredation, which may influence patterns of prey choice, but whether felids have a preference for livestock or not often remains unclear as most studies ignore livestock availability. We assessed prey choice of the endangered Persian leopard (Panthera pardus saxicolor) in Golestan National Park, Iran, where conflict over livestock depredation occurs. We analyzed leopard diet (77 scats) and assessed wild and domestic prey abundance by line transect sampling (186 km), camera-trapping (2777 camera days), double-observer point-counts (64 scans) and questionnaire surveys (136 respondents). Based on interviews with 18 shepherds, we estimated monthly grazing time outside six villages with 96 conflict cases to obtain a small livestock (domestic sheep and goat) availability coefficient. Using this coefficient, which ranged between 0.40 and 0.63 for different villages, we estimated the numbers of sheep and goats available to leopard depredation. Leopard diet consisted mainly of wild boar (Sus scrofa) (50.2% biomass consumed), but bezoar goat (Capra aegagrus) was the most preferred prey species (I_j = 0.73), whereas sheep and goats were avoided (I_j = -0.54). When absolute sheep and goat numbers (~11250) were used instead of the corrected ones (~6392), avoidance of small livestock appeared to be even stronger (I_j = -0.71). We suggest that future assessments of livestock choice by felids should incorporate such case-specific corrections for spatiotemporal patterns of availability, which may vary with husbandry methods. Such an approach increases our understanding of human-felid conflict dynamics and the role of livestock in felid diets.     

Spatial variability in wolf diet and prey selection in Galicia (NW Spain)

We studied wolf (Canis lupus) diet for three different landscapes in the north-western Iberian Peninsula, differing in land uses and availability of food for wolves. We examined 2740 scats, collected over a period of 4 years, in order to describe wolf diet, its geographic variation, and trophic preferences. The most consumed species were wild pony, roe deer and cattle. We observed differences in wolf diet among the three study sites, related to the availability and accessibility of food resources in each habitat. For the two study sites in northern and central Galicia, wolves showed similar diet, with high occurrence of wild pony (37 vs. 34%) and cattle (20 vs. 23%), but differing in the consumption of wild ungulates (16 vs. 8%) and carrion (7 vs. 14%). Wolf diet in eastern Galicia’s mountain ranges was entirely different, due to the higher consumption of wild ungulates (70%). Wolves showed clear prey selection patterns. Between wild ponies and livestock, wolves positively selected ponies. Among wild ungulates, wolves positively selected roe deer. Wild pony and roe deer are key species for wolf feeding in Galicia. In the Galician wild pony range, ponies are the main food for wolves. Given that the availability of wild ponies may contribute to the decrease in wolf predation on cattle, it is essential to develop innovative administrative decisions in such areas to preserve this traditional equid population. In the same way, the population of roe deer should be strengthened in the livestock areas outside the range of wild pony.     

Variation in the feeding pattern of red foxes in relation to changes in anthropogenic resource availability in a rural habitat of western Poland

The feeding pattern of red foxes Vulpes vulpes, i.e., the composition of their diet and dietary responses to fluctuations in the abundance of common voles Microtus arvalis were compared in the periods before and after the limitation of anthropogenic food availability in a rural area in western Poland. During the winter seasons of 1996/97–2014/15, the diet of the foxes was estimated by analysing the stomach contents of individuals shot from November to March and the index of vole abundance was obtained by counting their burrow entrances. The major component of the fox diet over the entire study period was anthropogenic food (mainly, the remains of farm animals) that showed both the highest average proportion in the stomach content volume (53.4%) and the highest average frequency of occurrence in the stomachs (62.7%), whereas small mammals were the second important component (27.5% and 54.2%, respectively). The frequency of anthropogenic food decreased and the frequencies of wild ungulate carrion and other wild vertebrates (mainly birds) increased after the limitation of anthropogenic resources. The observed fluctuations in the index of vole abundance resulted in positive changes in the small mammal frequency and negative changes in the anthropogenic food frequency, but the course of these relationships did not significantly differ between the two periods. The frequency of hares in fox stomachs did not change significantly between these periods, but recently the occurrence of hares in the diet of foxes increased with vole abundance. This study indicated that the reduction of anthropogenic food availability for carnivorous mammals may result in their switching to other prey species and potentially may have a negative influence on the demography of such prey species.