Vigilance Rates Research Articles

Two's company, three species is a crowd? A webcam-based study of the behavioural effects of mixed-species groupings in the wild and in the zoo.

Mixed species exhibits in zoos are used to create larger, more stimulating environments to support naturalistic interactions between species. In the wild, mixed species groups are observed as having lower rates of vigilance, presumably due to reduced predation risk through 'detection' and 'dilution' effects. This effect appears to be highly variable depending on factors such as food availability or degree of threat. This study aimed to collect data on mixed-species associations and consequent vigilance rates in the wild, collecting equivalent data from a large mixed-species zoo enclosure to compare the findings between free-ranging and captive populations. The study additionally investigated whether large mixed-species enclosures support natural associations and behaviours, by comparing the behaviour of captive animals with wild counterparts. The study used livestream video feeds from 10 national parks in South Africa and Kenya to observe free-ranging species, and a camera at the San Diego Zoo Safari Park's mixed species African exhibit. Scan and continuous sampling protocols were used simultaneously to record behavioural states as well as the rate of scanning (vigilance) events. GLMMs were run to test whether vigilance of a focal species varied according to the number of animals present, the density of animals in the group, and the diversity of species. In the wild, vigilance decreased with increasing number of animals in the surroundings but in captivity the group size had no impact. The results suggest that in the wild, these species benefit from increased perceived safety in larger groups, regardless of the species making up that group. No effect was noted in the zoo because of a reduced need for animals to show heightened vigilance to the same degree as in the wild. Similarities were observed in associations between species/mixed species group compositions, and in behaviour budgets. These findings provide a preliminary evaluation of how the impact of mixed species groupings may translate from the wild to the zoo, based on the associations and behaviour across a variety of African ungulates.

Mammal responses to predator scents across multiple study areas

AbstractAntipredator behaviors allow prey to mitigate the impacts of their predators. We investigated antipredator responses of two herbivore species, roe deer and European hare, and one mesopredator, red fox, toward predation risk imposed by lynx and wolf. We collected data (using camera traps) on visitation frequency and vigilance behavior to olfactory predator stimuli during 158 standardized scent trials in five areas across Europe, where lynx and wolves either occurred or had been absent for centuries. After a period without scent, trial sites were either marked with lynx or wolf urine, or butyric acid (unspecific scent used to contrast species‐specific scent responses). We expected the two herbivores to respond aversively (reduced visitation frequency, and increased vigilance) to predator urine, while red foxes (scavengers) might adopt a risk‐sensitive exploration strategy by increasing vigilance near predator urine without reducing visitation frequency. For all species, we expected stronger responses toward the ambush predator lynx than to the pursue predator wolf (cryptic predator hypothesis). If prey responds more strongly to predator stimuli when coexisting with the predator, we expected stronger reactions to predator urine in areas where predators occurred (naïve prey hypothesis). Roe deer significantly avoided lynx urine and butyric acid, but not wolf urine. However, roe deer visitation frequency did not differ between scent treatment with large carnivore urine and butyric acid (suggesting that roe deer generally avoid areas with unfamiliar scent), or between areas where large carnivores were present and absent. Hares did not significantly avoid predator urine. Red foxes were attracted to lynx urine in sympatry, but not in allopatry with large carnivores. They increased vigilance rates in the presence of lynx urine independent of sympatry/allopatry with large carnivores. These findings generally confirm our expectations of predator avoidance by herbivores, and attraction combined with increased vigilance of mesopredators. In all species, lynx urine elicited stronger responses than wolf urine (although not significantly different), which to some extent conforms to the cryptic predator hypothesis. We found no support for the naïve prey hypothesis. However, higher attraction of red foxes to lynx urine in sympatric situations might indicate that positive responses by scavengers are learning based.

Grooming behavior in goitered gazelles: the programmed versus stimulus-driven hypothesis

Self-grooming is the most commonly observed behavior and serves numerous functions, with the removal of ectoparasites likely the most important. According to a predominant conception, grooming is regulated by two mechanisms: a programmed-grooming model and a stimulus-driven model. The programmed-grooming model predicts, first, that smaller body-size females must groom more frequently compared to larger males (body-size principle); second, the smaller young groom significantly more often than adults (developmental grooming); and third, rutting males, busy with social vigilance, groom significantly less often than females (vigilance principle). The impact of molting was also tested on the grooming rate as an additional hypothesis that is not a part of the programmed-grooming model. According to investigations of a wide variety of ungulates in captive and natural conditions, the predictions of the programmed-grooming mechanism were found to be accurate for most sexually dimorphic ungulates. Here, I tested the principles of the programmed-grooming model in free living, wild goitered gazelles (Gazella subgutturosa), which are parasitized by both keds and ticks. My study found the following: (a) the body-size principle was not supported by my data, especially during the gazelles’ molting and rutting periods; (b) the developmental grooming model did not relate to the grooming behavior of goitered gazelle fawns; (c) the vigilance principle was not applicable to male goitered gazelles; and (d) spring molting increased the grooming rate drastically for both males and females and likely had the greatest effect over any other factor, even though keds also contributed to the grooming rate at this time. Though previous studies of tick parasitism on many ungulate species demonstrated that oral grooming was more consistent with programmed-grooming than the stimulus-driven grooming model, my study of ked parasitism of goitered gazelles showed the opposite, suggesting that grooming driven mechanisms were parasite-host dependent. However, grooming behavior is likely a multifaceted phenomenon depending not only on body size, vigilance rate or even from ectoparasite burden, but also on numerous other factors.

Gregariousness and intraspecific aggression in Iberian bullfinches (Pyrrhula pyrrhula iberiae) throughout the year

Abstract This study provides novel information about gregariousness and intraspecific aggression in Iberian bullfinches (Pyrrhula pyrrhula iberiae) in northwestern Spain. Small monospecific parties never exceeding 10 individuals were seen throughout the year, larger in winter on average. Males considerably outnumbered females within the groups. Adult flocks were frequent only in winter. In spring, many of the adult groups were mixed-sex assemblages composed of pairs plus supernumerary males. Sightings of juvenile groups, up to seven individuals, were common in summer–autumn. The vigilance role in mixed-sex assemblages, including pairs, appeared to be the responsibility of males based on sex-specific vigilance rates. The highest frequency of aggressive encounters, mainly male against male, occurred during the breeding season, associated with mate defence. Females attacked males, not the contrary, which supports reversed sexual dominance in bullfinches. Gregariousness probably acted as an anti-predatory and foraging strategy.

Heads up! Variation in the vigilance of foraging chipmunks in response to experimental manipulation of perceived risk

AbstractVigilance is a behavior in which an organism is gaining information about its environment, often used for predator detection. Vigilance is influenced by the risk that an organism perceives. Animals may vary their use of vigilance behaviors by modifying not only the percent time they dedicate to vigilance, but also the duration of vigilance bouts, rate of vigilance bouts, and type of vigilance posture. Assuming these different vigilance tactics come at different costs to the individual, different sources of perceived risk should elicit specific vigilance strategies. Here, we experimentally altered the sight lines of foraging Eastern chipmunks (Tamias striatus). We carried out our field work in three locations in Michigan that vary from low (an island site) to high predator pressure. Our results show that chipmunks respond to changes in their immediate microhabitat by altering the rate of vigilance, regardless of predator density. On the other hand, chipmunks at sites with lower predator densities spend less time vigilant when compared to sites with higher predator densities and they utilize vigilance postures that decrease vigilance but do not completely halt feeding. Further research should aim to quantify costs and benefits of vigilance postures and strategies to further our understanding of how individuals balance the trade‐off between mortality and energy gain.

Anthropogenic noise reduces avian feeding efficiency and increases vigilance along an urban–rural gradient regardless of species’ tolerances to urbanisation

Anthropogenic noise can adversely impact urban bird populations by interfering with vocal communication. Less research has addressed if anthropogenic noise masks the adventitious sounds that birds use to aid predator detection, which may lead to increased vigilance and reduced feeding efficiency. We test this hypothesis using a controlled playback experiment along an urban–rural gradient in Sheffield (UK). We also test the related predictions that anthropogenic noise has the greatest impacts on vigilance and feeding efficiency in rural populations, and on species that are more sensitive to urbanisation. We focus on six passerines, in order from most to least urbanised (based on how urbanisation influences population densities): blue tit Cyanistes caeruleus, robin Erithacus rubeculla, great tit Parus major, chaffinch Fringilla coelebs, coal tit Periparus ater and nuthatch Sitta europaea. We used play‐back of anthropogenic urban noise and a control treatment at 46 feeding stations located along the urban–rural gradient. We assess impacts on willingness to visit feeders, feeding and vigilance rates. Exposure to anthropogenic noise reduced visit rates to supplementary feeding stations, reduced feeding rates and increased vigilance. Birds at more urban sites exhibit less marked treatment induced reductions in feeding rates, suggesting that urban populations may be partially habituated or adapted to noisy environments. There was no evidence, however, that more urbanised species were less sensitive to the impacts of noise on any response variable. Our results support the adventitious sound masking hypothesis. Urban noise may thus interfere with the ability of birds to detect predators, reducing their willingness to use food rich environments and increase vigilance rates resulting in reduced feeding rates. These adverse impacts may compromise the quality of otherwise suitable foraging habitats in noisy urban areas. They are likely to be widespread as they arise in a range of species including common urban birds.

Duration of ‘peeks’ in ducks: how much time do Common Pochards Aythya ferina spend with an eye open while in a sleeping posture?

ABSTRACT ‘Peeks’, or keeping an eye open, in wintering Common Pochard Aythya ferina, while in a sleeping posture, were relatively brief, typically (66% of observations) lasting less than one second. However, in 37% of individuals some peeks lasted 10 s or more. Contrary to our prediction of lower anti-predatory vigilance rates in larger groups, there was a positive relationship between peek duration and the numbers of neighbours in a flock.

Enclosure Utilization and Enrichment Structure Preferences of Captive Coyotes

Environmental enrichment improves well-being of captive animals using a variety of tools, including adding complexity to the physical environment. Designing enrichment structures requires an understanding of behavioral and biological responses to enrichment efforts. Captive coyotes (Canis latrans) utilize shelter structures to hide, rest, and display vigilant behavior. Because these simple structures are regularly used, new and more complex enrichment structures could enhance enclosure enrichment. This study examined the time captive coyotes spent at discrete, complex enclosure features to determine: (1) how coyotes utilize enclosure space and shelter structures; and (2) if coyotes have a preferred enrichment structure design. Three enrichment structure designs (ramp, closed, and neutral) were installed simultaneously in 0.6-ha enclosures during two breeding seasons (January – March). Additional coyote pairs were monitored in control enclosures with simple structures. GPS-collars and scan sampling were used throughout a 28-day testing period to record space use and behavior. Coyotes spent most of their time at perimeter and open areas, but also exhibited a preference for shelter structures. Coyotes utilized the complex enrichment structures in treatment enclosures more than simple structures in control enclosures. Although there was no statistical preference for one specific type of complex structure, composite evidence from GPS-collars and behavioral data suggested that coyotes were most frequently located at ramp structures. Coyotes utilized ramp structures more during the daytime and demonstrated higher rates of vigilance there. This study advances the knowledge of captive coyote spatial patterns while helping improve environmental enrichment planning for captive facilities through the exploration of adding complexity to animal enclosures.

Where to forage when afraid: Does perceived risk impair use of the foodscape?

The availability and quality of forage on the landscape constitute the foodscape within which animals make behavioral decisions to acquire food. Novel changes to the foodscape, such as human disturbance, can alter behavioral decisions that favor avoidance of perceived risk over food acquisition. Although behavioral changes and population declines often coincide with the introduction of human disturbance, the link(s) between behavior and population trajectory are difficult to elucidate. To identify a pathway by which human disturbance may affect ungulate populations, we tested the Behaviorally Mediated Forage‐Loss Hypothesis, wherein behavioral avoidance is predicted to reduce use of available forage adjacent to disturbance. We used GPS collar data collected from migratory mule deer (Odocoileus hemionus) to evaluate habitat selection, movement patterns, and time‐budgeting behavior in response to varying levels of forage availability and human disturbance in three different populations exposed to a gradient of energy development. Subsequently, we linked animal behavior with measured use of forage relative to human disturbance, forage availability, and quality. Mule deer avoided human disturbance at both home range and winter range scales, but showed negligible differences in vigilance rates at the site level. Use of the primary winter forage, sagebrush (Artemisia tridentata), increased as production of new annual growth increased but use decreased with proximity to disturbance. Consequently, avoidance of human disturbance prompted loss of otherwise available forage, resulting in indirect habitat loss that was 4.6‐times greater than direct habitat loss from roads, well pads, and other infrastructure. The multiplicative effects of indirect habitat loss, as mediated by behavior, impaired use of the foodscape by reducing the amount of available forage for mule deer, a consequence of which may be winter ranges that support fewer animals than they did before development.

Diversity of risk assessment patterns in antipredator behavior of goitered gazelles

In predator-prey encounters, risk assessment and threat identification are particularly important aspects in the prey’s decision in how, when and where to escape. Previous studies devoted to this topic investigated mostly factors influencing risk perception by a prey animal and on its decision when to flee; however, information on the diversity of risk assessment displays is still very limited. Therefore in this paper, I considered various display types of risk assessments and the circumstances under which they were performed. I found that the contagious effect of alarm behavior among conspecifics and the investigative approach toward the threat were the types of risk assessment found most often, while mobbing was observed least often. Every type of risk assessment had a specific usage according to the sort of suspicious object and the prey’s display circumstances. Adult females with few exceptions demonstrated threat assessment behavior most often, while adult males displayed assessment behavior less frequently; in all cases, sub-adults and fawns showed these patterns significantly less often than adults. Antipredator strategy of adult females likely differed from males. Adult females had the highest response and sensitivity to any kind of potential threat and a high rate of vigilance, including risk assessment, likely related to the responsibility of rearing young. In contrast, adult males were busy mostly with social vigilance and monitored conspecifics more than predators. Adolescents and fawns showed the lowest rate of risk assessment, most likely because information on the potential risk of threat was not as useful to them since they did not have enough experience to recognize and avoid predators; instead of relying on their own experience, younger animals followed and repeated the behaviors of adults. As a result, young of many ungulate species typically have the highest losses from predation and adult females the lowest, with adult male deaths in between. This regularity was also likely true for the risk assessment behaviors of goitered gazelles in my study.

Vigilance, staring and escape running in antipredator behavior of goitered gazelle

Predation is a very powerful force that shapes many ungulate traits. It is widely known that increasing vigilance intensity is costly and leads to a decline of forage intake. Consequently, ungulates gather into larger groups to reduce an individual vigilance burden by using the “many eyes” effect and to enhance their survival through the “safety in numbers” effect. Vigilance rate and related aggregation changes are two of the most discussed antipredator responses of ungulates to predation risk, but less considered factors also have a significant impact. To enhance our knowledge on these impact factors, I investigated the antipredator responses (vigilance, staring, and escape running) of goitered gazelles. I found that: a) adult females demonstrated vigilance, staring and escape running significantly more often than adult males, sub-adults and fawns; b) adult gazelles (females and males), having more experience in responding to threats, were more vigilant than young individuals (sub-adults and fawns), having likely more involvement in finding food; c) during the birthing and hiding periods, mothers displayed higher rates of vigilance than in other seasons, while staring and escape running were observed most often at the end of the hiding period, when fawns altering their hiding strategy to following one, started to walk a lot in the absence of mothers, as well; and d) goitered gazelles changed their vigilance rate in response to predation risks before changing group size. The events of the yearly biological cycle (birthing/rearing young for females; rutting for males) also had significant impacts on the antipredator responses (vigilance rate and aggregation) in adult gazelles.

Escaping behavior in goitered gazelle

Prey species modify their behaviors in response to predation risks to minimize their vulnerability and enhance their survival. When a predation risk arises, gregarious, open-habitat-dwelling ungulates usually increase their vigilance rate and enlarge their herd sizes, which are the two antipredator responses that are most often investigated. However, other reactive responses, as well as prey risk assessments and escape strategies depending on a predator’s approach behavior, are less explored. In this paper I want to discuss the responses of goitered gazelles and their escape strategies when they encountered humans or vehicles in their natural habitat in Kazakhstan. I found that in most cases adult goitered gazelles, being more experienced and habituated to dangerous situations, usually made a preflight risk assessment and stopped in mid escape for an additional scan of their surroundings. The younger, more reactive individuals behaved this way less often and instead ran immediately instead regardless of threat level. In cases with a more obvious, direct danger, all goitered gazelles, irrespective of age, galloped immediately without stopping, and ran mainly in a sideways direction almost perpendicular to or even across the path of the approaching predator. Goitered gazelles also preferred to run upward to elevated points or toward mountain foothills, where they could get higher than the perceived threat. Furthermore, this study has shown that the goitered gazelles, preferring rough open terrain of lowlands and foothills, combined escape features found in typical antipredator strategies of both open-habitat antelopes (first assessment of danger mainly through sight, then galloping to outrun the predator) and mountain-dwelling ungulates (use of rough terrain as refuge, running to the highest elevation for a better view, and attempting to get higher on the slope than their pursuer). The goitered gazelles, however, did not demonstrate any freezing pattern for concealment, typical for forest-dwelling ungulates.

Extended Abstract: Utilizing Event Rate As a Manipulation of Task Difficulty in Vigilance

Vigilance refers to the ability of an observer to maintain attention over extended periods of time, and to respond to critical signals that occur (Davies & Parasuraman, 1982). Vigilance has been ex...

Experimentally manipulating the landscape of fear to manage problem animals

ABSTRACTNegative interactions between humans and wildlife are increasing, often leading to conflict between different stakeholders over appropriate management interventions. We experimentally tested whether introducing trained Harris's hawks (Parabuteo unicinctus) through falconry could be an effective management tool to reduce nuisance Egyptian geese (Alopochen aegyptiaca). We hypothesized that falconry would result in elevated fear responses of geese, resulting in increased vigilance, reduced favorability of the site, and locally reduced abundance. We conducted our study on 3 golf courses (1 treatment and 2 controls) in the Western Cape, South Africa, where Egyptian geese are a pest species. Our treatment involved flying the Harris's hawk directly at geese from golf carts. We monitored vigilance and goose numbers before, during, and after treatment. Goose vigilance at the treatment site increased by 76% and abundance declined by 73% following falconry. We did not observe changes at either control site. Although the hawks killed some geese, the decreases in abundance were almost 3 times greater than the numbers killed, indicating that indirect effects were considerably larger than the direct effect of mortality. During the treatment period, vigilance rates were greater in the presence of a golf cart, suggesting that geese learned to associate carts with the threat of predation. Post‐treatment vigilance rates were significantly less than rates detected during the treatment period and goose abundance on the experimental site increased rapidly post‐treatment, returning to pre‐treatment rates within 2 months. Our results demonstrate the efficacy of falconry to reduce nuisance bird abundance and suggest there may be other applications where the deployment of trained predators can be used to mitigate negative human‐wildlife interactions. © 2017 The Wildlife Society.

Deer on the lookout: how hunting, hiking and coyotes affect white‐tailed deer vigilance

AbstractPredators affect prey directly by removing animals from the population and indirectly by modifying prey behavior. Humans have extirpated apex predators from many ecosystems, and the extent to which smaller predators, or humans themselves, can ecologically replace apex predators remains uncertain. White‐tailed deer Odocoileus virginianus in the Eastern United States were released from their two most important predators a century ago following the extirpation of cougars Puma concolor and wolves Canis lupus. We studied the extent to which perceived predation risk from humans and a newly arrived mesopredator, the coyote, Canis latrans affects deer behavior, predicting that deer will be most vigilant in areas hunted by humans which also have the highest levels of coyote activity. We quantified deer vigilance rates in 33 natural areas of which 15 allowed hunting, across six states by evaluating the head posture of 3470 deer photographed at unbaited camera traps. We documented wide variation in coyote activity (0–2.5 detections/day) and human activity (0–306 detections/day), but contrary to our predictions, did not find strong positive relationships between deer vigilance and either of these predators. Deer vigilance was lower in areas with high levels of human recreation, suggesting that deer become habituated to the presence of humans. Vigilance increased across the fall season in both hunted and non‐hunted populations, which suggests that increased vigilance may be associated more with mating behavior or environmental factors other than hunting. Our results show that variation in coyote and human activity does not significantly impact the vigilance behavior of white‐tailed deer year‐round, suggesting that deer rely on other risk‐avoidance behaviors or neither are functioning as apex predators in the region.

Differences in foraging behavior in wild and pen‐raised northern bobwhites

ABSTRACTIncreased mortality rates of northern bobwhites (Colinus virginianus) raised in captivity and stocked into the wild compared with wild bobwhites may be due to differences in antipredatory behaviors. We assessed behavior of wild and pen‐raised bobwhites foraging under risk of predation in a captive situation at the Tennessee Tech University Avian Research Facility, Cookeville, Tennessee, USA, during March–April 2008 and February–March 2009. We hypothesized wild bobwhites were more sensitive to predation risk than pen‐raised bobwhites and evaluated the relative contributions of time allocation, vigilance, and foraging efficiency in avoiding predation among wild and pen‐raised bobwhites. Coveys of 4 bobwhites were presented with 3 food patches at presumed safe, moderately risky, and risky distances from cover in 10‐hr trials. Food consumption, vigilance, time allocation, foraging efficiency, and average realized covey size were measured using video recordings for each patch, and compared between wild and pen‐raised bobwhites and among patch risk levels. Both wild and pen‐raised bobwhites foraged more in safe patches than in riskier patches. Vigilance rates were similar between wild and pen‐raised bobwhites. However, pen‐raised bobwhites spent more time foraging at riskier patches than did wild bobwhites. Wild bobwhites foraged more efficiently than did pen‐raised bobwhites, with foraging efficiency of wild bobwhites increasing in risky patches. Greater foraging efficiency and associated shorter foraging time among wild bobwhites may make them less susceptible to predation than pen‐raised bobwhites. © 2016 The Wildlife Society.

Noise pollution has limited effects on nocturnal vigilance in peahens.

Natural environments are increasingly exposed to high levels of noise pollution. Noise pollution can alter the behavior of animals but we know little about its effects on antipredator behavior. We therefore investigated the impact of noise pollution on vigilance behavior and roost selection in an avian species, peafowl (Pavo cristatus), that inhabits urban environments. Captive peahens were exposed to noise pollution at night and their vigilance levels and roost selections were monitored. The vigilance levels of peahens were unaffected by exposure to noise pollution within trials. Furthermore, the peahens exhibited no preference for roosting farther or closer to noise pollution. Interestingly, predators often avoided the experimental area during nights with noise pollution, which could explain why vigilance rates were higher overall during control compared to noise trials. The results suggest that peahens’ perception of risk is not drastically impacted by noise pollution but longer-term studies will be necessary to assess any chronic effects.

Influence of live-capture on risk perceptions of habituated samango monkeys

Live-capture of animals is a widely used technique in ecological research, and previously trapped individuals often respond to traps with either attraction or avoidance. The effects of trapping on animals’ risk perception are not often studied, although nonlethal effects of risk can significantly influence animals’ behavior and distribution. We used a combination of experimental (giving-up densities: GUDs) and behavioral (vigilance rates) measures to gauge monkeys’ perceived risk before and after a short livetrapping period aimed at ear-tagging monkeys for individual recognition as part of ongoing research. Two groups of arboreal samango monkeys, Cercopithecus albogularis schwarzi, showed aversion to capture in the form of generalized, group-level trap shyness after 2 individuals per group were cage trapped. We predicted that trapping would increase monkeys’ antipredatory behavior in trap vicinity and raise their GUDs and vigilance rates. However, live-capture led to no perceptible changes in monkeys’ use of space, vigilance, or exploitation of experimental food patches. Height above ground and experience with the experiment were the strongest predictors of monkeys’ GUDs. By the end of the experiment, monkeys were depleting patches to low levels at ground and tree heights despite the trapping perturbation, whereas vigilance rates remained constant. The presence of cage traps, reintroduced in the final 10 days of the experiment, likewise had no detectable influence on monkeys’ perceived risk. Our findings, consistent for both groups, are relevant for research that uses periodic live-capture to mark individuals subject to long-term study and more generally to investigations of animals’ responses to human interventions.

Effects of culling on vigilance behaviour and endogenous stress response of female fallow deer

Context Human activities can induce behavioural and stress responses in wild animals. Information is scarce on the effects of culling on anti-predator behaviour and endogenous stress response of wild ungulates. Aims In a Mediterranean area, we evaluated the effects of culling on vigilance, foraging and endogenous stress response of female fallow deer (Dama dama). Methods Effects of culling were evaluated through behavioural observations and hormone analyses of faecal samples. Key results In an area where culling occurred (C), individuals showed significantly greater vigilance rates and foraged closer to wood than in an area with no culling (NC). In C, 24 h after culling, faecal cortisol concentrations were greater than those recorded in NC, but they decreased significantly to values comparable to (48 h post-shot) and lower than (72 h post-shot) those observed in NC. Conclusions Most likely, culling determined behavioural responses in female fallow deer, but did not trigger long-term physiological effects. Implications Increased anti-predator behaviour may complicate the implementation of long-term culling programs.

Effects of overflights on incubating Wilson's plover behavior and heart rate

ABSTRACTIncreasing attention is paid to the effects of human activities, including the use of aircraft, on wildlife. However, responses to visual and auditory stimuli associated with aircraft are highly species‐ and context‐dependent and results of existing studies should not be generalized across species, or even across life stages of the same species. We used digital audio recorders, auto‐triggered cameras, and heart rate monitors to study the responses of nesting Wilson's plovers (Charadrius wilsonia) to different types of planes (civilian and military fixed‐wing aircraft) and helicopters (civilian and military rotary‐wing aircraft) at Cape Lookout National Seashore, North Carolina. We compared vigilance behavior, incubation rate, and heart rate before, during, and after overflights. Wilson's plovers were alert and scanned more during military rotary‐wing overflights, and scanned more during both military and civilian fixed‐wing overflights than during periods without overflights. Heart rates and incubation rates did not change during any type of overflights. Although we found no direct link between increased vigilance rates and decreased reproductive success, a substantial increase in aircraft traffic at our study site, especially rotary‐wing overflights, would merit further investigation. © 2015 The Wildlife Society.