Buses,Cars, Bicycles and Walkers: The Influence of the Type of Human Transport on the Flight Responses of Waterbirds

One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat.     

Human habituation reduces hyrax flight initiation distance in Serengeti

Many animal populations are exposed to disturbance originating from human activities. In response to human disturbance, certain animals display a variety of potentially costly behavioural responses, such as increased antipredator behaviour or relocation to new areas. In contrast, other animals seemingly thrive in the presence of humans and benefit from human-derived resources. Flight initiation distance (FID: the distance between predator and prey when prey starts to flee) is a measure commonly used to assess animals’ tolerance to humans. In this study, we tested how FID changes in relation to human presence in two hyrax species in Serengeti National Park. Hyraxes living on kopjes (rock outcrops) among human settlements showed a significantly shorter FID than hyraxes living on kopjes without human settlements. In addition, we found that hyraxes feeding before the experiment had shorter FID than hyraxes resting or being vigilant, and hyraxes disturbed during the early morning had shorter FID than hyraxes disturbed during late morning. We did not find any significant effects of group size or species composition on FID. Our results suggest that hyraxes living in the presence of humans are habituated and are not adversely affected by human settlements.     

人为干扰对黑腹滨鹬觅食行为的影响

2003年11月至2004年3月,采用目标动物取样法和人为干扰实验法,于浙江省乐清湾滩涂进行人类活动对黑腹滨鹬(Calidrisalpina)觅食行为影响的研究。取样观察结果表明,在每天沿海堤可观察黑腹滨鹬持续觅食的1h里,96.6%的黑腹滨鹬在35m或更小的距离上通过奔跑或惊飞对人类的活动作出反应;黑腹滨鹬花费90%(人类较多的盐盆滩涂为85%,较少的乐成滩涂为94%)的时间觅食,10%的时间用于避免人类的干扰;人数、人类活动类型对觅食时间具有显著影响,人数、人离黑腹滨鹬的距离、人类活动类型对黑腹滨鹬移动的距离、移动的次数以及黑腹滨鹬对人类靠近的反应均具有显著效应。人为干扰最小接近距离实验结果表明,黑腹滨鹬对人类反应的距离在3～30m;干扰人数为1人时的最小接近距离显著大于2人;人类行走和奔跑的两种活动类型对黑腹滨鹬的最小接近距离没有显著影响。本研究验证了滨鸟觅食区内的人为活动严重影响黑腹滨鹬觅食行为的假设。     

Effects of predator behavior and proximity on risk assessment by Columbian black-tailed deer

In predator-prey encounters, many factors influence risk perceptionby prey and their decision to flee. Previous studies indicatethat prey take flight at longer distances when they detect predatorsat longer distances and when the predator's behavior indicatesthe increased likelihood of attack. We examined the flight decisionsof Columbian black-tailed deer (Odocoileus hemionus columbianus)using an approaching human whose speed, directness of approach,directness of gaze, and simulated gun carrying varied. Deerfled at greater distances when approached more quickly and directly,and there was a concave-down quadratic trend in the relationshipbetween the distances at which the predator began its approachand at which the deer became alert (alert distance [AD]), indicatingthat deer have a zone of awareness beyond which there is a delayin detecting an approaching predator. Time spent assessing theapproacher (assessment time) was shorter during faster approachesand was positively related with AD. Deer fled at longer distancesand had shorter assessment times when they were already alertto the predator at the initiation of approach. Males fled atshorter distances than females when approached during the gun-holdingcondition, and males had shorter assessment times than femaleswhen the approacher averted his gaze. Such sex differences inrisk assessment might reflect male motivation during the matingseason as well as exposure to human hunting. We suggest thatrisk assessment is affected the by the predator's behavior,the state of awareness of the prey, and the distance at whichthey detect the predator.     

Effects of Single‐ and Mixed‐Species Group Composition on the Flight Initiation Distances of Plains and Grevy's Zebras

Zebras, as prey species, attend to the behavior of nearby conspecifics and heterospecifics when making decisions to flee from predators. Plains zebras (Equus quagga) and Grevy's zebras (E. grevyi) frequently form mixed‐species groups in zones where their ranges overlap in Kenya. Although anecdotal observations suggest that Plains zebras are more flighty around humans than Grevy's zebras are, this has not been empirically confirmed, and relatively little is known about how they may influence each other's flight behavior. We addressed these questions by examining the flight initiation distances (FIDs) of Plains and Grevy's zebras in single‐species and mixed‐species groups from an approaching human. One target individual per group was approached steadily on foot, with start distance, alert distance, and FID recorded from this target. Using start distance and alert distance separately as covariates, 22 Plains zebras in single‐species groups exhibited a significantly longer mean FID than 15 Grevy's zebras in single‐species groups. The FIDs of 7 Plains zebras and 5 Grevy's zebras tested in mixed‐species groups were virtually equivalent and intermediate to those of Plains and Grevy's zebras in single‐species groups, suggesting a bidirectional moderating influence of heterospecifics on risk assessment. This effect was most pronounced for Plains zebras in mixed‐species groups that exhibited an FID that was significantly shorter than that of Plains zebras in single‐species groups. Our findings underscore the importance of recognizing that related equids may be differently impacted by anthropogenic stress.     

Effects of risk assessment, predator behavior, and habitat on escape behavior in Columbian black-tailed deer

The relationship between preflight risk assessment by prey andthe escape behaviors they perform while fleeing from predatorsis relatively unexplored. To examine this relationship, a humanobserver approached groups of Columbian black-tailed deer (Odocoileushemionus columbianus), varying his behavior to simulate moreor less threatening behavior. We measured the focal deer's angleof escape, distance moved during flight, duration of trottingand stotting behavior, and change in elevation during flight.Analyses revealed positive relationships between the distancemoved during flight and the distance at which they fled. Whenflight was initiated when the approacher was close, deer fledrelatively shorter distances and took flight paths at more acuteangles, a property that would force a real predator to changedirection suddenly. Our results indicate that deer do not compensatefor allowing the observer to approach more closely by fleeinggreater distances. Rather, distance moved and flight initiationdistance are linked by level of reactivity and habituation:more reactive or less habituated deer both flee at a greaterdistance and move away to a greater distance during flight.More threatening behavior by the approacher led to longer durationsof rapid flight behavior (e.g., trotting and stotting), anddeer tended to flee uphill and into taller vegetation, usingthese landscape features as refuge from danger. Finally, weprovide the first evidence for Pitcher's untested "antiambush"hypothesis for the function of stotting and discuss its significance.In general, both preflight predator behavior and habitat featuresinfluence both duration and direction of escape.     

Does Locomotor Ability Influence Flight Initiation Distance in Yellow‐Bellied Marmots?

Flight initiation distance (FID) is the distance between a potential threat and the point at which a potential prey flees. Animals may modify their FID to compensate for increased risk generated by external/extrinsic factors such as habitat type, visibility, group size, time of year, predator‐approach velocity, and distance to burrow, as well as internal/intrinsic factors such as physical condition, body temperature, crypsis, and morphological antipredator defenses. The intrinsic speed at which an animal can escape a predator is a factor that should influence FID. We studied the relationship between an individual's intrinsic escape speed and FID in yellow‐bellied marmots (Marmota flaviventris) to determine whether marmots compensated for slower escape speeds by fleeing at greater distances. We found no evidence of risk compensation. Rather, we found that slower marmots tolerated closer approaches. This behavioral syndrome may be explained by a coevolution of FID and escape speed in determining an individual's antipredator behavior, an idea upon which we expand.     

Behavioural Differences between Single Scandinavian Brown Bears (Ursus arctos) and Females with Dependent Young When Experimentally Approached by Humans

Carnivore-human encounters that result in human injury present a conservation and management challenge and it is therefore important to understand under what conditions such incidents occur. Females with cubs are often involved when humans are injured by brown bears Ursus arctos. In Scandinavia, this is particularly true for unarmed recreational forest users. Our aim was to document behavioural differences between single bears and females with cubs in order to develop recommendations to minimize the risk of injuries to recreational forest users. We documented the reactions of GPS-collared females with cubs and single brown bears to experimental approaches by humans to 50 m from the bear on 42 and 108 occasions, respectively. The majority of females with cubs (95%) and single bears (89%) left when approached. Bears that left were passed at shorter distances and were in more open areas than those that stayed. Both groups had similar flight initiation distances, which were longer for bears that were active at the time of the disturbance. Females with cubs selected more open habitat than single bears, also for the new site they selected following disturbance. Females with cubs, particularly active females with cubs of the year, moved greater distances and spent more time active following the approach. Females with cubs and single bears were seen or heard in 26% and 14% of the approaches, respectively. None of the bears displayed any aggressive behaviour during the approaches. Females with cubs selected more open habitat, perhaps predisposing them to encountering people that are not involved in hunting activities, which might be the primary explanation why females with cubs are most frequently involved when unarmed people are injured by bears in Scandinavia. To mitigate injury risks, one must consider factors that bring bears closer to human activity in the first place.     

Human disturbance and the activity patterns and temporal overlap of tapirs and jaguars in reserves of NW Belize

Human disturbance from tourism and other non-consumptive activities in protected areas may be stressful to wildlife. Animals may move away in space or time to avoid human interaction. For species of particular conservation concern, such as Baird's tapirs (Tapirus bairdii) and jaguars (Panthera onca), a better understanding of how they respond to different levels and types of disturbance is needed in order to manage human visitation to parks in ways that minimize negative outcomes for wildlife. We describe the overlap in activity patterns of tapirs, jaguars, and humans at logged and unlogged sites and at places with low versus high human visitation using camera survey data from protected areas of NW Belize, 2013–2016. Tapirs were nocturnal in all study sites, with > 80% of all tapir detections occurring between 1900 hr and 0500 hr. Their activity patterns were not different in unlogged versus logged sites and did not change with increased human traffic. Jaguars were cathemeral across sites but had more nocturnal activity at the site with the most human impact. Activity pattern overlap between tapirs and jaguars did not differ significantly between logged and unlogged sites, nor between areas with low and high human activity. Human traffic increased from 2013 to 2016 at most of the study locations. In conclusion, this camera trap dataset suggests that non-consumptive human disturbance does not alter the activity patterns of tapirs and jaguars in protected areas lacking hunting pressure.     

At home with the birds: Kalahari tree skinks associate with sociable weaver nests despite African pygmy falcon presence

The way in which animals use habitat can affect their access to key resources or how they are buffered from environmental variables such as the extreme temperatures of deserts. One strategy of animals is to modify the environment or take advantage of structures constructed by other species. The sociable weaver bird (Philetairus socius) constructs enormous colonial nests in trees. These nests are frequented by Kalahari tree skinks (Trachylepis spilogaster) and the two species coexist over a large portion of the Kalahari Desert in South Africa. We tested whether skinks were more abundant in trees containing sociable weaver nests and asked whether the physical features of trees were important predictors of skink abundance. We then focused on potential costs of this association by examining the relationship between skink abundance and the presence of a potential predator, the pygmy falcon (Polihierax semitorquatus), which exclusively uses weaver nest colonies for roosting and nesting. Finally, we simulated a predatory threat to determine if skinks assess risk differently if a weaver nest is present. We found a significant positive association between the presence of weaver nests and skink abundance. In the absence of nests, the type of tree did not influence skink abundance. Skinks used weaver nests and were more likely to perch on the nest than the tree. When threatened with predation, skinks preferred to take refuge in nests. Surprisingly, the presence of nesting pygmy falcons in nests did not influence skink abundance, perhaps because of the abundance of nearby refuges within nests, tree crevices, or in debris at the tree base. We suggest that sociable weaver nests provide multiple benefits to skinks including lowered predation risk, thermal refuges and greater prey availability, although this requires experimental testing. In the current era of global climate change, sociable weaver nests may become a crucial resource for skinks seeking refuge as the Kalahari climate warms.     

Effects of risk, cost, and their interaction on optimal escape by nonrefuging Bonaire whiptail lizards, Cnemidophorus murinus

Optimal escape theory seeks to explain variation in the distanceto an approaching predator at which the prey initiates escape(flight initiation distance). Flight initiation distance increaseswhen predators pose a greater threat and decreases when escapecosts increase. Although optimal escape theory has been highlysuccessful, its predictions have been tested primarily for speciesthat escape to discrete refuges, and most studies have focusedon single risk or cost factors. We present data from two experimentsin which two risks or a risk and a cost varied in Bonaire whiptaillizards (Cnemidophorus murinus) that escaped without enteringrefuges. Our data verify several predictions about optimal escapefor nonrefuging lizard prey. Two risk factors, speed and directnessof approach by the predator, interacted. Directly approachedlizards had greater flight initiation distances than did indirectlyapproached lizards when approached rapidly, but shorter flightinitiation distances when approached slowly. Flight initiationdistance was shorter in the presence of food and during slowversus rapid approaches, but contrary to expectation, food presenceand approach speed did not interact. This would be explainedif cost curves are nonlinear or if they are parallel ratherthan intersecting when the predator reaches the prey. More empiricalwork is needed to determine which risk and cost factors actadditively and which act synergistically. The absence of interactionbetween the risk and cost factors suggests that cost curveswere nonlinear.     

Managing human disturbance: factors influencing flight-initiation distance of birds in a West African nature reserve

Escape behaviour in response to perceived predators can be employed as a guide when designating protected areas around sensitive bird species to minimise the impact of human disturbance. A key measure of escape response is flight-initiation distance (FID), the distance at which a prey animal initiates its escape when approached by a potential predator. We tested the predictions of optimal escape theory by determining the factors that influence FID of bird species in a Nigerian reserved area and its surrounding habitats, and so the potential utility of FID in managing human disturbance on birds, for the first time within a West African context. We tested how FID varied with group size, proximity to vegetation acting as protective cover, levels of human use, and survival rate, and whether these relationships varied by species. We collected 504 FIDs for seven bird species in Amurum Forest Reserve and its surrounding habitats (Jos, Nigeria). The FID was lower in larger groups and when species were closer to protective cover. The FID was lower outside of the protected area because animals in sites with higher levels of human presence and use may become habituated. The FID was higher for species with higher survival, being consistent with predictions from life history theory. Overall, birds perceived humans as a potential threat and responded in accordance to the predictions of optimal escape theory, with FID increasing with increased cost of staying. Reserve managers in Africa could use species- and context-specific FIDs to designate buffer distances for the protection of wildlife from human disturbance.     

Risk assessment by crow phenotypes in a hybrid zone

Predation is one of the most selective forces in evolution and, thus, predation may select against hybrids in narrow hybrid zones. It may be possible that parental phenotypes and hybrids differ in their responses towards predators or humans. As predation is difficult to observe I used flight-initiation distance (FID) as a metric of risk assessment. FID is a measurable outcome of the trade-off between fleeing and remaining. Here, I tested whether hybrid and parent crow phenotypes (Corvus corone, Corvus cornix) from the hybrid zone in Eastern Germany differ in their FID. Further, I measured many environmental and social variables to control statistically for their influence on FID. I sampled 154 individuals (53 hooded crows, 54 carrion crows, and 48 hybrids) in the hybrid zone in eastern Germany. I calculated a general linear model using a stepwise backward procedure to establish a minimum model containing only significant variables that explained FID in crows. The variable phenotype (hooded, carrion, hybrid) was then added to the model. There were no differences in FID between hybrids and both parental phenotypes types, suggesting similar risk assessment. This suggests that hybrids may behave similarly in their decision to flee as their parent phenotypes, which, in turn, provides no evidence for a selective disadvantage. An additional analysis focusing on pure phenotypic flocks showed that hybrids in pure hybrid flocks had a lower FID than both parental species in pure flocks. This suggests that hybrids in pure hybrid flocks may be at a disadvantage.     

Shift down,look up: A test of the non‐linearity and fear hypothesis in a non‐vocal skink

The non‐linearity and fear hypothesis predicts that certain non‐linear sounds are one way to evoke antipredator responses in both birds and mammals. This hypothesis, however, has not been studied in non‐vocal species or in reptiles. Such a study would be important because if non‐linear sounds are evocative even in a species that does not produce sounds, then there may be generally salient cues of risk in these sounds. We asked whether non‐vocal lizards, white‐bellied copper‐striped skinks (Emoia cyanura), respond to experimentally broadcast non‐linearities. This species is ideal to ask the question in because prior research has shown that they respond to predator sounds and alarm calls of other species even though they are not vocal. We conducted playback experiments with three computer‐generated simulated non‐linearities to assess whether or not skinks increased antipredator behavior after hearing them. We controlled for novelty by broadcasting a 3‐kHz, 500‐ms pure tone and tropical kingbird (Tyrannus melancholicus) song. Our treatments consisted of a 3‐kHz, 400‐ms pure tone followed by a frequency shift up to 5‐kHz for 100‐ms, a 3‐kHz, 400‐ms pure tone to frequency shift down to 1‐kHz for 100‐ms, and a pure tone followed by 100‐ms of white noise. Following a total of 222 playbacks, we categorized responses into looking, locomotion, and high locomotion, focusing on how skinks changed their rates of time allocation from baseline. We examined 95% confidence intervals to identify whether skinks responded to playbacks and fitted general linear models followed by pairwise comparisons to ask whether skinks discriminated between broadcast stimuli. We found that skinks were especially responsive to frequency downshifts: They significantly increased looking and locomotion, consistent with our predictions based on the non‐linearity and fear hypothesis. Surprisingly, they decreased rates of looking behavior after hearing frequency upshifts, possibly suggesting an increase in relaxed behavior. While skinks responded to noise by increasing their rate of locomotion, this response was not significantly different from controls. We conclude that skinks increase antipredator behavior after hearing downshifts more than any other type of non‐linearity. This provides some support for the non‐linearity and fear hypothesis; even non‐vocal species may respond fearfully to specific types of non‐linear sounds.     

Individual Heterogeneity in Use of Human Shields by Mountain Nyala

The ‘human shield hypothesis’ describes the situation where prey species use humans as shield from natural predation. We tested the human shield hypothesis in a population of mountain nyala (Tragelaphus buxtoni) subjected to predation from the nocturnal spotted hyena (Crocuta Crocuta) in the Bale Mountains National Park, Ethiopia by radio‐marking 15 mountain nyala (seven females and eight males) and tracking them for up to 2 yr. Occurrence of hyena estimated by faecal transects decreased close to human settlements substantiating the occurrence of a zone with lower risk of hyena predation. The diurnal pattern in the average distance between mountain nyala relocations and human settlements was consistent with the human shield hypothesis with significantly shorter distances during night (when exposed to predation) than during day. However, mountain nyala showed large individual heterogeneity in use of human shields. While nearly all individuals occasionally moved out of the park to human settlements during night, the frequency of such excursions varied from 0% to 71%. The excursions occurred year‐round and were not driven by seasonal access to crops. We have previously demonstrated a strong negative effect of humans on the large‐scale distribution pattern of mountain nyala. The use of human shield documented here is indicative of a positive small‐scale effect of humans. Our study thus supports the view that the effect of human–wildlife interactions can be scale‐dependent.     

风险对两种南非蜥蜴逃跑启始距离和逃避策略的影响

逃避理论预测,不逃跑若增大适合度代价则导致逃跑启始距离加长,逃跑若增大代价则导致逃跑启始距离缩短。逃跑路径和去向等受生境结构影响。作者通过模拟捕食者逼近研究喀拉哈里树石龙子(Trachylepis sparsa)和黑环蜥(Cordylus niger)逃避策略和风险因子对逃跑启始距离的影响。与迂回逼近相比较,直接逼近不仅提高蜥蜴逃跑几率还能缩短其逃跑启始距离。喀拉哈里树石龙子在两种逼近方式下的逃跑启始距离有显著差异,这种差异对黑环蜥而言是边缘性的。喀拉哈里树石龙子以树为避所,树上个体可逼近的距离短于地面个体;快速逼近地面个体的逃跑启始距离比慢速逼近更长。习惯于有人环境的黑环蜥逃跑启始距离比人迹罕至环境中的个体更短。地面喀拉哈里树石龙子多遁至树上而很少逃入倒木或倒伏编巢中。树上喀拉哈里树石龙子通常奔逃至远侧和高处,有时遁入树洞或编巢中;黑环蜥则逃入石缝中。所有发现都证实逃避理论中有关逃跑启始距离的预测。逃跑策略的种间差异表明每一种蜥蜴都利用其生境中逃跑路径和避所的有利条件。在风险不同的生境中,生境结构可影响逃跑启始距离,似乎对逃跑策略亦有重要影响。     

Great tits take greater risk toward humans and sparrowhawks in urban habitats than in forests

Urban animals often take more risk toward humans than their non‐urban conspecifics do, but it is unclear how urbanization affects behavior toward non‐human predators. Responses to humans and non‐human predators may covary due to common mechanisms enforcing a phenotypic correlation. However, while increased tolerance toward humans may be advantageous for urban animals, reduced vigilance toward non‐human predators that can pose actual threat may be costly. Therefore, urban animals may benefit from showing specific responses to different threat levels, such as humans versus non‐human predators, or hostile versus non‐hostile humans. To test these alternatives, we compared responses (latencies to return to nest) of urban and forest‐breeding great tits (Parus major) to familiar hostile and unfamiliar humans as well as one of their common predators, the sparrowhawk (Accipiter nisus). We found that urban birds were more risk‐taking toward both humans and sparrowhawk than forest birds. However, responses to sparrowhawk did not correlate with responses to humans either within or across habitats. This suggests that higher risk‐taking of urban compared to forest‐dwelling great tits toward sparrowhawk may be threat‐specific response to lower predation risk rather than a spillover effect of increased tolerance to humans. Furthermore, birds responded similarly to unfamiliar and familiar (potentially dangerous) humans in both habitats, suggesting that great tits may not adjust their risk‐taking to the threat represented by individual humans. These findings indicate that urban birds may flexibly adjust their risk‐taking to certain, but not all, types of threat.     

Scavenging Opportunities Modulate Escape Responses over a Small Geographic Scale

Many species that inhabit anthropogenically altered landscapes also opportunistically use human food refuse. Gulls readily exploit anthropogenic food sources (e.g. rubbish dumps and other places of human refuse) and often ‘steal’ food from people eating out of doors. Their behaviour suggests that gulls perceive little risk around people and so we examined whether opportunity costs, that is access to anthropogenic food sources, influence risk monitoring and escape responses in Silver Gulls (Chroicocephalus novaehollandiae) around outdoor restaurants (‘food’ sites), where the gulls would scavenge food from people. We recorded alert distance (AD) and flight initiation distance (FID) and compared them with nearby sites where the same cohort of gulls was not interacting with people (‘no‐food’ sites). We used two approach speeds (with the prediction that gulls would take greater efforts to avoid a potential predation threat when approached at speed). Gulls foraging at food sites had lower AD and FID than those approached at no‐food sites. They were not simply ignoring the person, as they demonstrated longer AD when approached at speed but no difference in FID and therefore appeared to be responding to a small geographic scale ‘behavioural footprint’ of anthropogenic influences. Our study also challenges universality of the assumption that starting distance is necessarily correlated with FID, especially in sites where there are many people that animals are constantly monitoring – to determine the risk they represent as well as the likelihood of potential food opportunities.     

Behavioral responses of nesting birds to human disturbance along recreational trails

ABSTRACT The presence of recreational trails can impact breeding birds either indirectly by altering habitat or the movement patterns of predators or directly if the presence of humans disturbs birds. We examined the behavioral responses of nesting female Northern Cardinals (Cardinalis cardinalis) to human disturbance using both experimental and observational approaches. From April to August 2006 and 2007, we monitored Northern Cardinal nests in 18 riparian forests in Ohio, USA. Two experimental trials were conducted at each nest (N= 63), with Flight Initiation Distance (FID, the distance at which a bird flushed from the nest) recorded as we approached nests by walking directly toward them and by walking along trails located variable distances from nests. We also measured flight initiation distance (FID) when nests were approached during routine nest checks (N= 160). Cardinals were six times more likely to flush when nests were approached directly, and females on higher nests were less likely to flush regardless of distance to trail. FID was not significantly influenced by the distance of nests from trails. We found no association between nest survival and the tendency of birds to flush. Rather, nest survival was best explained by nest height. Thus, our findings suggest that the responses of birds to human use of recreational trails have only short‐term effects, with no apparent effects of on nest survival. Because the reaction of birds to humans in our study depended on how nests were approached, studies where FID is used as an indicator of sensitivity to human disturbance and is determined by direct approaches may overestimate the potential impact of trails on nesting birds.     

Clothing color mediates lizard responses to humans in a tropical forest

Identifying how ecotourism affects wildlife can lower its environmental impact. Human presence is an inherent component of ecotourism, which can impact animal behavior because animals often perceive humans as predators and, consequently, spend more time on human-directed antipredator behaviors and less on other fitness-relevant activities. We tested whether human clothing color affects water anole (Anolis aquaticus) behavior at a popular ecotourism destination in Costa Rica, testing the hypothesis that animals are more tolerant of humans wearing their sexually selected signaling color. We examined whether clothing resembling the primary signaling color (orange) of water anoles increases number of anole sightings and ease of capture. Research teams mimicked an ecotourism group by searching for anoles wearing one of three shirt treatments: orange, green, or blue. We conducted surveys at three different sites: a primary forest, secondary forest, and abandoned pasture. Wearing orange clothing resulted in more sightings and greater capture rates compared with blue or green. A higher proportion of males were captured when wearing orange whereas sex ratios of captured anoles were more equally proportional in the surveys when observers wore green or blue. We also found that capture success was greater when more people were present during a capture attempt. We demonstrate that colors “displayed” by perceived predators (i.e., humans) alter antipredator behaviors in water anoles. Clothing choice could have unintended impacts on wildlife, and wearing colors resembling the sexually selected signaling color might enhance tolerance toward humans.