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The Landscape of Fear: Ecological Implications of Being Afraid
Abstract and Figures
Predation risk" and "fear" are concepts well established in animal behavior literature. We expand these concepts to develop the model of the "landscape of fear". The landscape of fear represents relative levels of predation risk as peaks and valleys that reflect the level of fear of predation a prey experiences in different parts of its area of use. We provide observations in support of this model regarding changes in predation risk with respect to habitat types, and terrain characteristics. We postulate that animals have the ability to learn and can respond to differing levels of predation risk. We propose that the landscape of fear can be quantified with the use of well documented existing methods such as giving-up densities, vigilance observations, and foraging surveys of plants. We conclude that the landscape of fear is a useful visual model and has the potential to become a unifying ecological concept.
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... LGDs chase and kill wildlife, they could be perceived as predators in their environments with a myriad different ways in which their presence and behaviour could then influence the behaviour, physiology, and even populations of co-occurring wildlife (Say-Sallaz et al. 2019;Smith et al. 2020a; Chapter 2). For example, if seen as a predator, LGDs could induce fear responses in prey and competitor species, which might present as hormonal changes through stress, alterations to activity patterns and habitat use, or increased vigilance at the expense of foraging (Laundré et al. 2010;Say-Sallaz et al. 2019). The underlying ecological theory of LGD use is the disruption of optimal predator foraging by increasing the real and perceived risk to the individual of preying on livestock (Bagchi 2019;Haswell et al. 2019;Gaynor et al. 2020), thus some level of predator behaviour modification is expected. ...
... incur other costs on survival and reproduction, ultimately impacting prey population growth rates much like consumptive effects (Preisser et al. 2005;Allen et al. 2022). The fear of predation can give rise to what is known as a 'landscape of fear' -the spatial variation in prey perception of predation risk (Laundré et al. 2010;Gaynor et al. 2019). Prey responses to a landscape of fear typically manifest as behaviour modulations to reduce the chance of predation in a risky area, such as increased vigilance and reduced foraging, and spatiotemporal avoidance of high predation risk areas (Gaynor et al. 2019). ...
... LGDs use are perceived as risky locations to wildlife, then the landscape of fear theory predicts that wildlife would attempt to avoid LGDs in space, and/or time (Laundré et al. 2010). ...
Livestock guarding dogs (LGDs) are often suggested as a tool to help facilitate human-wildlife coexistence because they are considered effective at preventing livestock losses and reducing persecution of large carnivores. As LGDs have been observed chasing and killing wildlife, they could be perceived as predators or competitors in the environment, yet little is known about how the use of LGDs affects co-occurring wildlife. This research aimed to understand the ecological effects of using LGDs by 1) determining the wildlife species chased, killed, and/or consumed by LGDs, 2) quantifying LGD roaming behaviours by breed, sex, age, and reproductive status, and 3) quantifying spatial and temporal responses of wildlife to LGD presence.
A detailed overview of the potential and currently reported ecological effects of using LGDs was gathered via a literature review. Then, in 2021, LGD-wildlife interactions were investigated in the Carpathian Mountains, Romania. Thirteen sites were visited where shepherds were interviewed, 129 scats collected, and a total of twelve sheep and 40 LGDs GPS-tracked for an average of three weeks. Camera traps were deployed across 315 km2 covering both pasture and forest. Wildlife remains in the scats were identified via traditional methods including microscopic hair analysis. Roaming behaviours were investigated from the GPS data by calculating pairwise distances between each sheep and LGD and the overlap in their daily home ranges, which were estimated using the Local Convex Hull (LoCoH) method. Habitat use by grey wolves, brown bears, red foxes, red deer, and wild boars was investigated from the camera trap data via detection rates, single- and two-species occupancy models, and activity patterns estimated by a nonparametric kernel density approach.
There were 56 records in the literature widely reporting, mostly anecdotally, LGDs interacting with wildlife. Similarly, all thirteen shepherds reported that their LGDs chased wildlife and seven reported that their LGDs had injured or killed wildlife. However, there were low occurrences of wildlife in LGD scats with only 9% containing wild vertebrate remains (mostly wild boar in scats collected at one site on one day). Some roaming occurred with LGDs being found up to 4 km away from sheep, but LGDs predominantly remained in close proximity to livestock. On average, LGDs were within 200 m of the sheep during the day and within 100 m at night whilst sheep were enclosed in the sheepfold. Differences in distances between LGDs and sheep, and overlap in daily home ranges, were not predicted by LGD breed, sex, age, or reproductive status. Only red deer showed potential spatial and temporal avoidance of LGDs with lower detection rates, lower occupancy, and a reduction in daytime activity in areas of more frequent LGD use. Grey wolves were potentially attracted to areas used by LGDs. However, it was not possible to disentangle the effects of LGDs alone and the effects of LGDs, sheep, and shepherds combined.
This is the first large-scale study assessing multiple elements of LGD behaviours and wildlife responses. Overall, there was little empirical evidence to suggest that LGDs have substantial detrimental effects on co-occurring wildlife in the Romanian Carpathian Mountains. These results help to establish that LGDs, both purebreds and mixed-breeds, are a suitable candidate tool for reducing the need for lethal control of wild predators and possibly helping to facilitate human-wildlife coexistence.
... Effect sizes are on the logit scale, and the mean effect appears in text above each predictor will allocate their energy from high ambulation to vigilance if pulses of predation risk are relatively brief [52]. Further, at Middle Creek we found that geese were more likely to switch to a high ambulation state when closer to blinds on non-hunting days but farther from blinds on hunting days, indicating that the geese recognized point sources of predation threats and modified their behavior accordingly [53]. ...
... However, we note that we were not able to compare our results to a system with more spatially dynamic hunting threats. Our study provides further evidence that animals maintain a landscape of fear and a schedule of fear [24,53]. Based on our results, we hypothesize that movement of game species may increase during hunting specifically when the associated risk has an unpredictable spatial distribution. ...
Background
Anthropogenic activity can modify how wildlife perceives risks and rewards across the landscape (the ‘Landscape of Fear’) and affect animal movement and behavior. Studying movement patterns allows researchers to infer anti-predator behaviors and their drivers that affect survival. We studied a game species, the Canada goose (Branta canadensis), to understand how hunting affects prey movement and in turn guide management decisions to maximize species abundance and hunting.
Methods
We used GPS receivers to track the movements of geese at two study sites in Pennsylvania during two hunting seasons. The hunting season in this system includes two distinct periods (hunting periods) in which hunting is permitted on alternating days (hunting days). We fitted hidden Markov models to analyze individual movement at three spatiotemporal scales and estimated how various environmental factors, such as habitat and hunting pressure, influenced the transition probabilities between behavioral states.
Results
We found that geese were less likely to take flight during hunting periods and on hunting days, and that geese were more likely to transition to a low ambulation state on hunting days. Overall, we found that resident Canada geese employed two nested anti-predator behaviors: individuals proactively decreased their movement during hunting, but as they neared the threat, they were more likely to take flight.
Conclusions
Our study provides further evidence that animals maintain a landscape of fear and a schedule of fear. We observed decreased movement during the hunting season and hypothesize that this was due to the stationary nature of risk (hunting blinds). Based on our results, we hypothesize that goose movement may be increased during hunting with an unpredictable spatial-temporal distribution of risk.
... Animals might be attracted to other individuals due to the benefits of sociality like social grooming, reduced predation risk, increased foraging efficiency or access to social information [54]. Or they may avoid other individuals to reduce the risk of pathogen transmission [34], competition [29] and predation [17,28,31]. Importantly, the physical environment and social environment are not independent of each other as the physical environment might facilitate or constrain animal interactions. ...
Background
Animal movement is influenced by both the physical environment and social environment. The effects of both environments are not independent from each other and identifying whether the resulting movement trajectories are shaped by interactions between individuals or whether they are the result of their physical environment, is important for understanding animal movement decisions.
Methods
Here, we assessed whether the commonly used methods for inferring interactions between moving individuals could discern the effects of environment and other moving individuals on the movement of the focal individual. We used three statistical methods: dynamic interaction index, and two methods based on step selection functions. We created five scenarios in which the animals' movements were influenced either by their physical environment alone or by inter-individual interactions. The physical environment is constructed such that it leads to a correlation between the movement trajectories of two individuals.
Results
We found that neglecting the effects of physical environmental features when analysing interactions between moving animals leads to biased inference, i.e. inter-individual interactions spuriously inferred as affecting the movement of the focal individual. We suggest that landscape data should always be included when analysing animal interactions from movement data. In the absence of landscape data, the inference of inter-individual interactions is improved by applying ‘Spatial+’, a recently introduced method that reduces the bias of unmeasured spatial factors.
Conclusions
This study contributes to improved inference of biotic and abiotic effects on individual movement obtained by telemetry data. Step selection functions are flexible tools that offer the possibility to include multiple factors of interest as well as combine it with Spatial+.
... Given the significance of predation in interspecific interactions, prey species are expected to adapt to predation risks to increase their survival rates (Lima and Dill 1990;Sih and Moore 1993). Predation risks can induce dramatic shifts in prey feeding behavior (Schmitz et al. 1997;Wada et al. 2013;Matassa and Trussell 2014;Ho et al. 2019), reproductive behavior (Dulude-de Broin et al. 2020), habitat use (Laundré et al. 2010;Matassa and Trussell 2011;Kohl et al. 2018), morphology (Brönmark and Miner 1992;Kishida and Nishimura 2006), and physiology (Clinchy et al. 2013;Zanette and Clinchy 2019). These non-consumptive effects of predators, in addition to consumptive effects, influence the demography of prey species (Zanette et al. 2011). ...
In response to predation threats during the embryonic period, prey from diverse taxonomic groups exhibit plasticity in their hatching timing. In theory, predators of adult prey, as well as predators of eggs or embryos, can influence hatching timing. Similarly, not only embryos but also parents of prey can regulate hatching timing. However, research on the influence of adult predators and adult prey on hatching timing in species with separate predators for adults and eggs remains limited. To the best of our knowledge, no study has investigated this phenomenon in marine invertebrates under natural conditions. In this study, we investigated the effects of life-stage-specific predators (i.e., adult and egg predators) on the hatching timing of the pulmonate limpet (Siphonaria sirius), which undergoes planktonic development on an intertidal rocky shore. The presence of adult predators before and after egg-laying did not affect the hatching timing. Furthermore, while the egg predators present before egg-laying did not influence hatching timing, those present after egg-laying accelerated it. The results indicate that embryos, rather than their parents, determine hatching timing in response to their own predation risk. This finding highlights a strategy in which organisms with planktonic development rely on embryonic plasticity to mitigate strong predation risks during the egg stage. To understand how predation risk shapes predator–prey dynamics, it is critical to identify how predators, specific to each life-history stage of prey (such as adult and egg), interact with prey at different life-history stages during key events like reproduction.
Supplementary Information
The online version contains supplementary material available at 10.1007/s00442-025-05712-5.
... Similar to the current study, low densities of tapirs have been observed in fragmented landscapes of the Atlantic Forest (Ferreguetti et al. 2017). Another factor that has been reported to influence the low density of the species is hunting pressure (Cullen et al. 2000(Cullen et al. , 2001, which leads to reduced detection rates and lower occupancy rates of the species (Laundre et al. 2010), although we did not find the same pattern in the current study. ...
... [2][3][4] The landscape of fear is the prey's perception of predatory risk and suggests that landscape use is driven by the fear of being predated or injured, and it has a strong influence on the temporal and spatial dynamics of predator-prey distributions. 5 Prey's evasive responses to avoid predation due to fear perception can significantly alter their normal behaviour and even induce important physiological and morphological changes. 6,7 It, therefore, becomes essential to further study the landscape of fear to broaden our understanding of nonconsumptive effects in insect systems and better interpret ecological processes such as bat-prey interactions and coevolution. ...
BACKGROUND
Predator–prey interactions are major drivers of species coevolution. Insectivorous bats emit ultrasonic pulses to orientate themselves and to pursue prey in flight. Several nocturnal lepidopterans have developed auditory organs that allow them to detect echolocating bats and change their normal behaviour to reduce predation risk, a phenomenon included within the ‘landscape of fear’ concept. In this study, we assessed whether bat ultrasounds affect the egg production of the tympanate moth species Chilo suppressalis, one of the most widespread rice pests in the world.
RESULTS
Adults of C. suppressalis were captured in rice fields in Spain and kept in captivity in the presence and absence of artificially broadcasted bat ultrasounds. While no differences were found regarding the number of clutches laid per female, the clutch size was substantially smaller in the presence of bat ultrasounds (generalised linear mixed model, P value <0.05), observing a reduction in the number of eggs of up to 46%. This decrease in egg production may result from delays in adult mating or the inhibition or interruption of oviposition in females, which would alter their normal conduct to minimise their exposure to potential bat predators.
CONCLUSION
These findings suggest that the acoustic dimension may have profound implications for farmers because reducing the reproductive success of C. suppressalis could also lead to a significant decline in crop damage and yield loss, thereby increasing farmers' economic savings. Promoting stable bat populations in agrosystems can be highly beneficial since, in addition to suppressing harmful insects by predation, they likely reduce pest levels simply by emitting ultrasounds into the environment. © 2025 Society of Chemical Industry.
... The conceptual frameworks of non-consumptive effects (NCEs-Hermann and Landis 2017) and the ecology of fear (Laundre et al. 2010) focus on changes in an organism's behavior, morphology, or physiology prior to and/or during attack by predator (Wirsing et al. 2021). These NCEs can arise even in the absence of consumption such that the presence of a threat is sufficient to elicit a response. ...
The presence of natural enemies can cause organisms to change habitat use, foraging behavior, and/or resource allocation in response to a perceived risk, responses that may come at the cost of other fitness-related traits. Since most species encounter multiple natural enemies in nature, defensive behaviors against one attacker may make the focal organism more vulnerable to attack by a different natural enemy. Anti-predator behaviors can lead to trait-mediated indirect effects, such as an increased risk of parasitism and vice versa. Few empirical studies have examined the response of a single focal species to the risk of attack by multiple species. Our experiments provided the cactiphilic fly Drosophila nigrospiracula with opportunities to prioritize either anti-predator (e.g., reduced activity) or anti-parasite behavior (e.g., increased activity) at the cost of increased infection or predation, respectively. We experimentally show that when flies were exposed to ectoparasitic mites, in the presence of predator (jumping spider) cues, flies incurred increased levels of infection compared to flies without predator cues. The mean infection prevalence increased by 80% and the infection intensity increased by 180%. However, the presence of parasite cues had no analogous effect on predation rates, which suggests that flies prioritized predation risk over parasite defense at the cost of increased infection. We provide empirical evidence that the presence of multiple threats can lead to trait-mediated indirect effects, with important consequences for host–parasite and food web dynamics, and the ecology of fear.
Predation may indirectly influence prey's fitness and population dynamics through behavioural adjustments in response to perceived predation risk. These non‐consumptive effects of predation can also arise from hunting by humans, but they remain less documented. Advances in biologging allow detailed assessments of the activity budgets of elusive wildlife, increasing the potential to uncover the non‐consumptive effects of human activities on animals. We used tri‐axial accelerometry to record the daily activity of 24 Scandinavian brown bears (20 females and 4 males) from a heavily hunted population in Sweden, for a total of 29 bear‐years (2015–2022). We used a random forest algorithm trained with observations of captive brown bears to classify the accelerometry data into four behaviours, running, walking, feeding and resting, with an overall precision of 95%. We then used these classifications to evaluate changes in bear activity budgets before and during the hunting season. Bears exhibited a bimodal daily activity pattern, being most active at dusk and dawn and resting around midday and midnight. However, during the hunting season, males became more nocturnal compared to before the hunting season, suggesting a proactive behavioural adjustment to reduce encounters with hunters. Females showed the opposite pattern and had a higher probability of being active during the day, potentially to increase nutritional gains before denning. Additionally, daily number of running bouts did not vary between the pre‐hunting and hunting seasons in both sexes, but females' proportion of running bouts occurring during legal hunting hours was higher during the hunting season than prior to it, which suggests a reactive behavioural adjustment to encounters with hunters. Detailed assessments of wild animal behaviours, allowed through recording of movement data at high frequencies, have the potential to improve our understanding of the impacts of human activity on wildlife.
Predator–prey interactions are pivotal for ecosystem dynamics, with predators influencing prey not only through lethal events, but also through the establishment of a landscape of risk, that is, the spatial representation of how a prey population perceives predation risk. Habitat structure plays a crucial role in shaping this perception. A three‐dimensional approach, both considering the horizontal as well as the vertical landscape dimensions has, thus far, been mostly overlooked. We hypothesize that primates in a savannah landscape perceive predation risk in a three‐dimensional (3D) landscape, with both terrestrial and aerial predation risk influencing their spatial use of the environment, and that this perception is shaped by habitat structure. We employed giving‐up density (GUD) as a proxy for perceived risk when foraging. A landscape of risk is observed in leafed trees, where in the central and bottom parts of the tree the lowest predation risk is perceived. When canopy cover is absent, the lowest perceived risk is on the ground instead of in the tree, indicating an impact of aerial predation risk. These findings underscore the importance of 3D landscapes and habitat structure in shaping prey spatial behaviour, demonstrating that habitat use is adjusted in response to both terrestrial and aerial threats.
The ability to navigate through both familiar and unfamiliar environments is of critical importance for foraging efficiency, safety, and energy budgeting in wild animals. For animals that remain in the same home range annually, such as grey-footed chacma baboons (Papio ursinus griseipes), movement efficiency is expected to reflect familiarity with the home range as well as the nature of the resources within it. For example, resources that are patchy, transient, or seasonal present a greater spatial cognitive challenge, and travel between them may be less efficient than for more widespread or permanent resources. Here, we analyse daily route efficiency in adult female grey-footed chacma baboons at Gorongosa National Park, Mozambique. We use GPS data taken at 15 min intervals from collars deployed on two baboons in each of two study troops (four total) to identify areas of interest used during daily ranging periods (sleep site to sleep site). We then compare the length of the route taken between a given day’s patches to routes calculated by two alternate optimisation heuristics as follows: the nearest neighbour method, in which the subject repeatedly travels to the next most proximate patch and does not necessarily return to the same place, and the Concorde algorithm, which calculates the shortest possible route connecting the day’s patches. We show that baboons travel more efficient routes than those yielded by the nearest-neighbour heuristic but less efficient routes than the Concorde method, implying some degree of route planning. We discuss our novel method of area of interest identification using only remote GPS data, as well as the implications of our findings for primate movement and cognition.
The main functions attributed to vigilance are: detection of predators, observation of group members, location of food and avoidance of kleptoparasitism. Individual vigilance generally decreases and collective vigilance increases with increasing group size; peripheral individuals are more vigilant than central ones; and males scan more than females during rutting. Contradictory results concerning the influence of age, social rank, habitat and proximity of refuge do not allow determination of obvious relationships. Modelling vigilance behaviour consists in estimating individual survival probability which would depend directly on the tradeoff between foraging and vigilance behaviour. -from Author
Man the Hunted argues that primates, including the earliest members of the human family, have evolved as the prey of any number of predators, including wild cats and dogs, hyenas, snakes, crocodiles, and even birds. The authors’ studies of predators on monkeys and apes are supplemented here with the observations of naturalists in the field and revealing interpretations of the fossil record. Eyewitness accounts of the ‘man the hunted’ drama being played out even now give vivid evidence of its prehistoric significance. This provocative view of human evolution suggests that countless adaptations that have allowed our species to survive (from larger brains to speech), stem from a considerably more vulnerable position on the food chain than we might like to imagine. The myth of early humans as fearless hunters dominating the earth obscures our origins as just one of many species that had to be cautious, depend on other group members, communicate danger, and come to terms with being merely one cog in the complex cycle of life.
This book brings together a range of scientific perspectives from biomedical research on stress and welfare, and assesses new approaches to conceptualizing and alleviating stress. While much of the focus in on conventional farm animals, there is also consideration of fishes, laboratory animals and zoo animals. The 30 contributors include leading authorities from North America, Europe, New Zealand and Australia. This book is invaluable for advanced students and researchers in animal behaviour, animal welfare, animal production, veterinary medicine and applied psychology. For more information see the CABI Publishing online bookshop (http://www.cabi.org/Bookshop/).
With gray wolves restored to Yellowstone National Park, this ecosystem once again supports the full native array of large ungulates and their attendant large carnivores. We consider the possible ecological implications of wolf restoration in the context of another national park, Isle Royale, where wolves restored themselves a half-century ago. At Isle Royale, where resident mammals are relatively few, wolves completely eliminated coyotes and went on to influence moose population dynamics, which had implications f or forest growth and composition. At Yellowstone, we predict that wolf restoration will have similar effects to a degree, reducing elk and coyote density. As at Isle Royale, Yellowstone plant communities will be affected, as will mesocarnivores, but to what degree is as yet undetermined. At Yellowstone, ecosystem response to the arrival of the wolf will take decades to unfold, and we argue that comprehensive ecological research and monitoring should be an essential long-term component of the management of Yellowstone National Park.
Data on starvation and predation in porcupines (Erethizon dorsatum) were gathered over a 5-year period to examine hypotheses about foraging. I predicted that predation would be greater in open habitats than in closed habitats, small porcupines would be more vulnerable to predation than large ones, and nutritionally stressed porcupines would trade-off increased risk of predation for decreased risk of starvation. Over 90% of predator-killed porcupines were located in open grasslands or juniper shrublands, suggesting that open areas were higher in risk than wooded, riparian areas. High rates of predation in open areas in late winter supported the hypothesis of a trade-off between nutrition and predation risk. Mountain lions (Puma concolor) preyed on porcupines at a higher rate than did coyotes (Canis latrans), but predation by mountain lions was independent of body size of porcupines (small samples precluded analysis of predation by coyotes). These data reveal how predation and starvation influence populations of porcupines. Further, data indicate that poor nutritional status can drive animals to forage in risky habitats where predation is high.
We studied wolf (Canis lupus) predation on elk (Cervus elaphus) in Yellowstone National Park from 17 March to 15 April 1997 (server winter conditions) and from 2 to 31 March 1998 (mild winter conditions) 2-3 year after wolves were reintroduced to the park. Elk composed 91% of 117 kills. Data comparisons for 1997 versus 1998 were: hunting success rate, 26% versus 15%; kill rate, 17.1 kg/wolf/day versus 6.1; percent of kill consumed in first day, 7 versus 86; percent femur marrow fat of adult kills, 27 versus 70; calf:adult ratios of kills, 2:33 versus 17:23; sex ratio of kills, 14M:19F versus 17M:6F; mean age of elk killed, males 6.1 years, females 15.2 versus males, 4.8, females 13.0. Winter severity influenced the wolf-elk relationship more than the naivete of the elk herd to predation by wolves.
Coexisting heteromyid rodent species of North American deserts differ in habitat use and in locomotory morphology. Quadrupedal species forage primarily in structurally complex microhabitats, such as under bush canopies, while bipedal species forage in open spaces. A common explanation for this morphology-microhabitat association is that species differing in morphology also differ in vulnerability to predators, that microhabitat structure affects predation risk, and that animals preferentially forage in the safest microhabitats. We tested this for two bipedal and two quadrupedal heteromyid species (matched by body size), and one cricetid species, by quantifying effects of habitat and illumination on activity and on risk of predation by Great Horned Owls. Capture frequencies were lower for all heteromyid species than for the cricetid species, Peromyscus maniculatus. Heteromyid activity was lower in open habitat and under bright illumination. Illumination had no significant effect on risk, perhaps because rodents changed activity patterns under full moon to compensate for a potential increment in risk. Habitat, however, did affect risk: all species were attacked and captured more frequently in the open. Bipedal species were attacked relatively more in the open than were quadrupeds. If these results apply to all predators, they indicate that predation alone cannot account for the divergent microhabitat associations of bipedal and quadrupedal species. Bipedal heteromyids, however, escaped owl attacks more frequently than did quadrupeds of equivalent size. It is therefore conceivable that they experience lower overall risk in nature, where owls may preferentially attack more easily captured prey species when given a choice. Under these circumstances, owl predation could reinforce divergent microhabitat specializations based on some other factor, such as foraging economics, by restricting quadrupeds more strongly than bipeds to the safety of bushes.
The hunting activities of the lynx (Lynx canadensis) were studied by trailing during winter in central Alberta. Average daily crusing distance changed from 3.0 miles in 1965-66 to 5.5 miles in 1967. Success on snowshoe hares (Lepus americanus) dropped from 24 percent in 1965-66 to 9 percent in 1967, probably as a result of different snow conditions. Success on ruffed grouse (Bonasa umbellus) showed a similar drop from 19 to 8 percent. Lynxes averaged 0.42 kill per night. Distance per jump averaged 5.6 ft, but numbers of jumps per chase varied between prey species, between unsuccessful and successful pursuits, and between years. Lynxes cached hares in 1965-66, but not in 1967 when hunting success was lower. Estimated winter food habits were 69 percent hare, 17 percent carrion, 11 percent ruffed grouse, 2 percent sharp-tailed grouse (Pedioecetes phasianellus), 1 percent red squirrel (Tamiasciurus hudsonicus), and a trace of chickadee (Parus spp.).
Predators are commonly thought to capture substandard individuals (those in poorer condition than the average individual) in higher than expected proportions, but evidence for this paradigm is scant, biased, and inconsistent. I describe the outcomes of 447 attacks by a trained Red-tailed Hawk (Buteo jamaicensis) on three species of typical mammalian prey (eastern chipmunks, cottontail rabbits, and gray squirrels). A strong correlation existed between the difficulty the hawk had capturing individuals of each species and the difference between the proportions of substandard individuals in the hawk's diet and the prey populations. The degree to which substandard individuals of a particular prey species are taken disproportionately by a predator seems to be a direct function of how difficult it normally is for the predator to capture and kill individuals of that species. A review of other studies shows a similar relationship between vertebrate predators and their prey.