Temperature and microclimate refugia use influence migratory timings of a threatened grassland bird

BACKGROUND

Seasonal changes in resource availability are known to influence the migratory behaviour of animals, including both timing and distance. While the influence of environmental cues on migratory behaviour has been widely studied at the population level, it has rarely been examined at the spatial scale at which individuals experience their environment. Here, we test the hypothesis that individuals exposed to similar large-scale environmental cues may vary in migratory behaviour in response to the different microclimate conditions they experience at fine scales.

METHODS

We combine high-spatial and temporal resolution microclimate and habitat information with GPS tracking data for a partially migratory threatened grassland bird. Data from 47 little bustards (Tetrax tetrax; 67 breeding events) tracked between 2009 and 2019 was used to (i) evaluate individual consistency in migratory behaviour (timing and distance) and (ii) assess whether the local environmental characteristics experienced by individuals - and in particular their use of microclimate refugia - influence distance and timing of migration, from and to the breeding sites.

RESULTS

Migratory distance was consistent for birds tracked over multiple years, while the timing of migration showed high variability among individuals. Departures from breeding areas spanned from May to August, with a few birds remaining in their breeding areas. Vegetation greenness (a proxy for food availability) was positively associated with the time birds spent in the breeding area. The best model also included a positive effect of microclimate refugia availability on breeding season length, although an interaction with temperature suggested that this effect did not occur at the highest relative temperatures. The return date to breeding grounds, although spanning from September to April, was not influenced by the environmental conditions or food availability.

CONCLUSIONS

Food availability, measured by a vegetation greenness proxy, was associated with later migration at the end of the breeding season. Availability of cooler microclimate refugia may also allow for later departures from the breeding sites in all but the hottest conditions. Management measures that increase microclimate refugia availability and provide foraging resources can thus potentially increase the length of the breeding season for this species.

The Effects of Anthropogenic Disturbances on the Spatiotemporal Patterns of Medium-Large Mammals in Tropical Volcanic Landscapes

A comprehensive understanding of the consequences of human interactions with mammals is a critical factor in supporting and conserving species in landscapes dominated by humans, which are increasingly threatened. This study aimed to identify the spatial and temporal interactions between humans and mammals. A non-parametric statistical approach with kernel density was used to detect human-mammal temporal interactions. The species interaction factor (SIF) was applied to calculate the spatial overlap based on the two-species occupancy detection model. The activity patterns of medium mammals were nocturnal, diurnal, and cathemeral. The human-medium mammal pairs with SIF values that were <1 and statistically significant included the human-long-tailed macaque (Macaca fascicularis) pair, the human-leopard cat (Prionailurus bengalensis) pair, and the human-barking deer (Muntiacus muntjac) pair. Based on their SIF values and the high overlap in their activity times, the human-macaque pairings had a high risk of conflict. Barking deer and leopard cats displayed a coexistence with humans via time-sharing activities. Due to temporal niche variations with human activities, the existence of nocturnal mammals was relatively uninterrupted. This study showed that most mammals are able to adapt spatially and temporally to various human activities. Nonetheless, efforts to mitigate human-wildlife conflict must be maintained, particularly in the case of severely endangered species, such as the Sunda pangolin.

A meta-analysis of human disturbance effects on glucocorticoid hormones in free-ranging wild vertebrates

Free-ranging wild vertebrates need to cope with natural and anthropogenic stressors that cause short and/or long-term behavioural and physiological responses. In areas of high human disturbance, the use of glucocorticoid (GC) hormones as biomarkers to measure stress responses is an increasingly common tool for understanding how animals cope with human disturbance. We conducted a meta-analysis to investigate how human disturbances such as habitat conversion, habitat degradation, and ecotourism influence baseline GC hormones of free-ranging wild vertebrates, and we further test the role of protected areas in reducing the impact of such disturbances on these hormones. A total of 58 studies met the inclusion criteria, providing 152 data points for comparing levels of GC hormones under disturbed and undisturbed conditions. The overall effect size suggests that human disturbance does not cause a consistent increase in levels of GC hormones (Hedges' g = 0.307, 95% CI = -0.062 to 0.677). However, when the data were analysed by disturbance type, living in unprotected areas or in areas with habitat conversion were found to increase GC hormone levels compared to living in protected or undisturbed areas. By contrast, we found no evidence that ecotourism or habitat degradation generates a consistent increase in baseline GC hormone levels. Among taxonomic groups, mammals appeared more sensitive to human disturbance than birds. We advocate the use of GC hormones for inferring major human-caused contributors to the stress levels of free-ranging wild vertebrates - although such information needs to be combined with other measures of stress and interpreted in the context of an organism's life history, behaviour, and history of interactions with human disturbance.

The behavior of Broad-tailed hummingbirds is altered by cycles of human activity in a forested area converted into agricultural land

Background

By changing the circumstances in which animals make their behavioral decisions, weekly cycles of human activity might cause changes in wildlife behavior. For example, when there is more human activity in a location, animals may become more vigilant, which can decrease the time they spend foraging, or roam farther from home, leading to increased home range size. Overall, there has been little exploration of how animal species living in locations that have undergone land use change are affected by the temporal dynamics of human activity levels. In this study, we aimed to analyze the effect of the weekend on agricultural activities and hummingbird territorial activity. We examined differences between weekdays and weekends in factors previously shown to follow weekly cyclical patterns, such as pedestrian presence, traffic, and the presence of domestic animals. We hypothesized that territorial hummingbirds would respond to these weekly cycles of human activity by altering their behavior.

Methods

We studied Broad-tailed hummingbird territories in forested areas that had been transformed to agriculture lands in central Mexico. We evaluated whether territorial individuals changed their behaviors (i.e., chases of intruders, foraging within their territory, number of intruders allowed to forage in the territory) in response to variation between weekdays and weekends in the number of pedestrians, cyclists, dogs, farm animals and vehicles.

Results

We found that the level of agriculture-related human activities showed a weekly cycle at our study site. On weekdays there was higher traffic of pedestrians, cyclists, dogs, farm animals and vehicles, compared to the weekends. Hummingbirds responded to these weekday-weekends differences by changing their territorial behavior. Compared to weekends, on weekdays hummingbirds showed a decrease in defense (number of chases) as well as the use of their territory (number of flowers visited), which allowed increased access to intruders (number of visited flowers by intruders).

Conclusions

Our findings suggest that variation in agriculture-related human activities between weekdays and weekends can alter the territorial behavior of hummingbirds. Behavioral shifts seem to be related to these human activity cycles, leading hummingbirds to reduce chases and feeding during weekdays when human activity is highest, but increasing both behaviors during times of minimal disturbance.

Hidden but Potentially Stressed: A Non-Invasive Technique to Quantify Fecal Glucocorticoid Levels in a Fossorial Amphisbaenian Reptile

To understand wildlife responses to the changing environment, it is useful to examine their physiological responses and particularly their endocrine status. Here, we validated an enzyme immunoassay (EIA) to non-invasively quantify fecal corticosterone metabolites (FCM) in the fossorial amphisbaenian reptile Trogonophis wiegmanni from North Africa. We supplemented animals assigned to the treatment group with corticosterone dissolved in oil applied non-invasively on the skin for several days, while control groups received the oil-alone solution. Fresh feces were collected at the end of the supplementation period, and FCM levels were quantified by an EIA. Basal FCM levels were similar for both treatments and increased at the end of the test, but FCM increased significantly more in corticosterone-treated animals. A further examination of FCM levels in a wild population of this amphisbaenian did not find overall sexual, size or seasonal differences but showed a high range of variation among individuals. This suggests that different uncontrolled intrinsic or local environmental variables might increase the circulating glucocorticoid levels of different individuals. Our results confirmed the suitability of EIA for analyzing physiological changes in FCM in this amphisbaenian species. This technique may be useful for understanding and remediating the little-explored potential stressors of the soil environment that may negatively affect the health state of fossorial reptiles.

Assessment of medium and large-sized mammals and their behavioral response toward anthropogenic activities in Jorgo-Wato Protected Forest, Western Ethiopia

Medium and large-sized mammals of Jorgo-Wato Protected Forest have not yet been documented though the forest established before four decades. Hence, this study aims to document medium and large mammals and the behavioral responses of selected mammals toward anthropogenic activities in the study area. The study was conducted from February 2015 to June 2016, encompassing the wet and dry seasons. Data were collected mainly through camera traps, indirect and direct evidence. The study revealed about 23 medium and large-sized mammals that belong to seven orders namely Bovidae, Carnivora, Primates, Rodentia, Tubulidentata, Lagomorpha, and Hyracoidea. Papio anubis, C. guereza, and C. aethiops were the most abundant large mammals in JWPF. Because of high anthropogenic activities, African buffalo shifted its activity period from diurnal into crepuscular and nocturnal. African buffalo traveled longer distances during the wet season (mean = 14.33 km, SD = 1.25 km) than during the dry season (mean = 9.00 km, SD = 2.16 km). This could be due to the fact that the local people were less likely to go to the forest for resource exploitation during the wet season as they are fully engaged in agricultural activities. However, low agricultural activities during the dry season allow the local people to extract resources and involve in bushmeat hunting which could limit the movement of mammals to their refugia. African buffalo preferred to rest on and adjacent to a gravel road (22.1%) in the forest, followed by on open rocky hilltops (14.7%) at night time, but rest in the bottomland thicket vegetation during the dry daytime. Regardless of high human pressure in the area, this study has revealed a good number of medium and large-sized mammals that could be used as baseline information to design a sound conservation and management action plan of large mammals and their habitat in Jorgo-Wato Protected Forest.

Effect of intensity and duration of anthropic noises on European mink locomotor activity and fecal cortisol metabolite levels

Human activities involving noise emission can affect wild animals. European mink was exposed to road noise and human voice playbacks to analyze how sound intensity level and duration of both noises altered the time that individuals were active and if their fecal cortisol metabolite (FCM) levels varied. A Hierarchical Analysis Cluster was performed to establish 2 mink groups with respect to both noise source type: short duration/low intensity (SL) and long duration/high intensity (LH). We performed general linear mixed models to evaluate the variation in locomotor activity duration (s) and FCM (nanogram per gram) levels, respectively. The results showed both road noise and human voices decreased locomotor activity duration in SL more sharply compared with LH, and human voices were the triggers that induced the most pronounced response to both exposure conditions. FCM (ng/g) levels increased in SL compared with LH during road noise while the opposite happened during human voices. Differences based on sex and age of individuals were observed. In conclusion, noise characteristics given by the sound type determined the variations in locomotor activity duration while noise exposure level determined the variations in FCM (ng/g) levels. Attention should be paid to noisy activities (e.g., recreational activities for visitors in protected natural areas) and loud groups of people to conserve wildlife, especially noise sensitive species.

Soil pollution by heavy metals correlates with levels of faecal glucocorticoid metabolites of a fossorial amphisbaenian reptile

Soil degradation may have strong negative consequences for soil biodiversity, but these potential effects are understudied and poorly understood. Concentration of nesting seabirds may be a source of soil pollution by heavy metals, which are incorporated into the food chain and may have toxicological effects in vertebrates, especially in fossorial animals with low dispersal ability. We examined whether contamination by heavy metals, derived from seagull depositions, and other soil characteristics, may affect the levels of faecal glucocorticoid metabolites (as a potential indicator of physiological stress) of the fossorial amphisbaenian reptile Trogonophis wiegmanni. We found a relationship between soil pollution by heavy metals and increased levels of faecal corticosterone metabolite of the amphisbaenians that live buried in those soils. This can be due to the strong endocrine disruption effect of heavy metals. In addition, there was an independent effect of the soil texture, with amphisbaenians showing higher levels of faecal corticosterone metabolite in soils with less sand and more silt and clay, which are more energetically costly to dig. Long-term exposure to high glucocorticoid levels might have serious effects on health state and fitness of fossorial animals that may be unnoticed. Our study emphasizes that, to prevent future conservation problems, we need to perform periodic surveys on the physiological health state of the little-known subterranean biodiversity.

Recreation effects on wildlife: a review of potential quantitative thresholds

Outdoor recreation is increasingly recognised for its deleterious effects on wildlife individuals and populations. However, planners and natural resource managers lack robust scientific recommendations for the design of recreation infrastructure and management of recreation activities. We reviewed 38 years of research on the effect of non-consumptive recreation on wildlife to attempt to identify effect thresholds or the point at which recreation begins to exhibit behavioural or physiological change to wildlife. We found that 53 of 330 articles identified a quantitative threshold. The majority of threshold articles focused on bird or mammal species and measured the distance to people or to a trail. Threshold distances varied substantially within and amongst taxonomic groups. Threshold distances for wading and passerine birds were generally less than 100 m, whereas they were greater than 400 m for hawks and eagles. Mammal threshold distances varied widely from 50 m for small rodents to 1,000 m for large ungulates. We did not find a significant difference between threshold distances of different recreation activity groups, likely based in part on low sample size. There were large gaps in scientific literature regarding several recreation variables and taxonomic groups including amphibians, invertebrates and reptiles. Our findings exhibit the need for studies to measure continuous variables of recreation extent and magnitude, not only to detect effects of recreation on wildlife, but also to identify effect thresholds when and where recreation begins or ceases to affect wildlife. Such considerations in studies of recreation ecology could provide robust scientific recommendations for planners and natural resource managers for the design of recreation infrastructure and management of recreation activities.

Anthropogenic Influences on Distance Traveled and Vigilance Behavior and Stress-Related Endocrine Correlates in Free-Roaming Giraffes

Simple Summary

Change in an animal’s behavior due to anthropogenic influences is often expressed in a change in movement patterns and increased vigilance and can result in the secretion of stress-related hormones. However, animals can get habituated to human presence after repeated stimulation. We aimed to obtain a first insight into the effect of human observers on the behavior and stress-related hormone concentrations of free-roaming giraffes as well as their habituation process. Giraffes walked further distances and had elevated fecal glucocorticoid metabolite (fGCM) concentration (stress hormone) in the presence of humans, but anthropogenic influences on their distance walked and fGCM concentration decreased with the increase of habituation. The giraffes were vigilant towards human observers; however, the percentage of time spent on observing a human observer did not decrease with the increase of habituation.

Abstract

Giraffes are an important tourist attraction, and human presence to wildlife is increasing. This has an impact on an animal’s behavior and its endocrine correlates. Studies on other species show alterations in movement patterns, vigilance, and stress-related hormone levels in the presence of humans. Limited information is available on how anthropogenic activities alter giraffe’s behavior, social structure, and related endocrine parameters. The purpose of this study was to obtain insight into anthropogenic influences on giraffe’s behavior and adrenal activity. We used GPS devices mounted onto giraffes to compare the distance walked in the presence or absence of human observers. We also conducted behavioral observations to assess their vigilance and collected fecal samples to analyze their fecal glucocorticoid metabolite (fGCM) concentrations. Giraffes walked significantly further distances in the presence of humans, but the cumulative time that observers were present decreased the hourly distance walked with an observer present, suggesting that the giraffes were becoming habituated. The number of observers present significantly increased the percentage of time spent on observing an observer as well as the number of unhabituated individuals present in the herd. The percentage of time spent observing a human observer did not decrease with the increase of habituation. Last, fGCM concentrations increased with human presence but decreased when individuals became habituated to human presence. More research is needed to understand the effect of anthropogenic influences in different scenarios (e.g., tourism, vehicles, hunting, etc.).

Behavioral responses of the European mink in the face of different threats: conspecific competitors, predators, and anthropic disturbances

Prey species assess the risk of threat using visual, olfactory, and acoustic cues from their habitat. Thus, they modify their behavior in order to avoid encounters with competitors, predators, and human disturbances that endanger their fitness. European mink (Mustela lutreola) is a critically endangered species that can be preyed upon by larger carnivores and displaced by dominant conspecifics to areas of lower quality, e.g., near to more anthropized localities which may be noisier. In this study, the behavioral responses of 24 European mink were evaluated by conducting an experiment in which the presence of a conspecific competitor was simulated with a visual cue (mirror) and the presence of predators (terrestrial and aerial) with odorous cues. Additionally, they were also exposed to potential sources of anthropic disturbance with acoustic cues (road traffic noise and human voices). Our results showed that European mink were hidden for longer periods of time due to the presence of conspecifics and being exposed to the fecal odors of a terrestrial predator such as dog, but especially when they were exposed to anthropic noises. In the presence of a conspecific, the females and the subadults were the ones who remained hidden for the longest time. As well, they were hidden for longer periods of time due to the presence of conspecifics but in combination with dog feces and anthropic sounds did not induce variations in the response, as both by themselves already triggered an increase in the time they spent hiding. The vigilance model showed the effects of the same factors as the hiding model, but with antagonistic effects in the case of vigilance time which decreased during anthropic noises exposition. Finally, we want to highlight that European mink showed an innate response favorable to all three types of threats, but attention should be focused on human disturbances-as they trigger the most extreme responses-which may affect the rate of survival of this threatened species.

The Weekend Effect on Urban Bat Activity Suggests Fine Scale Human-Induced Bat Movements

Simple Summary

On weekends, people do things differently from weekdays, such as dining at a restaurant, going to a night club, attending a concert or a sporting event, or simply staying up late. These leisure activities in the city can change the environment people live in and can hurt wildlife that also lives in the same city. We recorded bats in the city center and in the city periphery and compared how active bats were. We found that in the city center, bats were less active on weekends than weekdays. The opposite pattern was found in the city periphery. It is possible that bats moved from the city center to the city periphery on weekends. Thus, continuous greenways are important to facilitate bat movements and avoid human–wildlife conflict. City planners can add new parks and/or preserve old-growth vegetation to form the center-to-periphery greenways.

Abstract

In the urban environment, wildlife faces novel human disturbances in unique temporal patterns. The weekend effect describes that human activities on weekends trigger changes in the environment and impact wildlife negatively. Reduced occurrence, altered behaviors, and/or reduced fitness have been found in birds, ungulates, and meso-carnivores due to the weekend effect. We aimed to investigate if urban bat activity would differ on weekends from weekdays. We analyzed year-round bat acoustic monitoring data collected from two sites near the city center and two sites in the residential area/park complex in the city periphery. We constructed generalized linear models and found that bat activity was significantly lower on weekends as compared to weekdays during spring and summer at the site in the open space near the city center. In contrast, during the same seasons, the sites in the city periphery showed increased bat activity on weekends. Hourly bat activity overnight suggested that bats might move from the city center to the periphery on weekends. We demonstrated the behavioral adaptability in urban wildlife for co-existing with human. We recommend that urban planning should implement practices such as adding new greenspaces and/or preserving old-growth vegetation to form continuous greenways from the city center to the city periphery as corridors to facilitate bat movements and reduce possible human-wildlife conflict.

Dynamics and determinants of glucocorticoid metabolite concentrations in wild Verreaux's sifakas

Glucocorticoids have wide-ranging effects on animals' behaviour, but many of these effects remain poorly understood because numerous confounding factors have often been neglected in previous studies. Here, we present data from a 2-year study of 7 groups of wild Verreaux's sifakas (Propithecus verreauxi), in which we examined concentrations of faecal glucocorticoid metabolites (fGCMs, n = 2350 samples) simultaneously in relation to ambient temperatures, food intake, rank, reproduction, adult sex ratios, social interactions, vigilance and self-scratching. Multi-variate analyses revealed that fGCM concentrations were positively correlated with increases in daily temperature fluctuations and tended to decrease with increasing fruit intake. fGCM concentrations increased when males were sexually mature and began to disperse, and dominant males had higher fGCM concentrations than subordinate males. In contrast to males, older females showed a non-significant trend to have lower fGCM levels, potentially reflecting differences in male and female life-history strategies. Reproducing females had the highest fGCM concentrations during late gestation and had higher fGCM levels than non-reproducing females, except during early lactation. Variation in fGCM concentrations was not associated with variation in social interactions, adult sex ratios, vigilance and self-scratching. Altogether, we show that measures of glucocorticoid output constitute appropriate tools for studying energetic burdens of ecological and reproductive challenges. However, they seem to be insufficient indicators for immediate endocrinological responses to social and nonsocial behaviours that are not directly linked to energy metabolism.

Ecological impacts of human-induced animal behaviour change

A growing body of literature has documented myriad effects of human activities on animal behaviour, yet the ultimate ecological consequences of these behavioural shifts remain largely uninvestigated. While it is understood that, in the absence of humans, variation in animal behaviour can have cascading effects on species interactions, community structure and ecosystem function, we know little about whether the type or magnitude of human-induced behavioural shifts translate into detectable ecological change. Here we synthesise empirical literature and theory to create a novel framework for examining the range of behaviourally mediated pathways through which human activities may affect different ecosystem functions. We highlight the few empirical studies that show the potential realisation of some of these pathways, but also identify numerous factors that can dampen or prevent ultimate ecosystem consequences. Without a deeper understanding of these pathways, we risk wasting valuable resources on mitigating behavioural effects with little ecological relevance, or conversely mismanaging situations in which behavioural effects do drive ecosystem change. The framework presented here can be used to anticipate the nature and likelihood of ecological outcomes and prioritise management among widespread human-induced behavioural shifts, while also suggesting key priorities for future research linking humans, animal behaviour and ecology.

On how risk and group size interact to influence vigilance

Vigilance allows animals to monitor their surroundings for signs of danger associated with predators or rivals. As vigilance is costly, models predict that it should increase when the risk posed by predators or rivals increases. In addition, vigilance is expected to decrease in larger groups that provide more safety against predators. Risk and group size are thus two key determinants of vigilance. Together, they could have additive or interactive effects. If risk and group size interacted, the magnitude of the group-size effect on vigilance would vary depending on the level of risk experienced, implying that the benefits of sociality in terms of vigilance vary with risk. Depending on the model, vigilance is predicted to decrease more rapidly with group size at low risk or at high risk. Little work has focused directly on the interaction between risk and group size, making it difficult to understand under which conditions particular interactive effects arise and whether interactive effects are common in natural systems. I review the vast literature on vigilance in birds and mammals to assess whether interactive effects between risk and group size are common, and if present, which pattern occurs more frequently. In studies involving predation risk, the greatest proportion reported no statistically significant interactive effects. In other cases, vigilance decreased with group size more rapidly at low or high risk in a similar proportion of studies. In studies involving risk posed by rivals (social risk), most documented a more rapid decrease in vigilance with group size at low than at high risk, as predicted if the need to monitor rivals increases in larger groups. Low statistical power to detect interactive effects might have been an issue in several studies. The absence of interactive effects, on the other hand, might suggest constraints or limits on the ability of animals to adjust vigilance to current risk or group sizes. Interactive effects on vigilance have implications for the evolution of sociality and for our understanding of the phenotypic plasticity of predator- and competitor-induced defences and deserve more attention in future studies.

Animals feel safer from humans in the dark

Mammals shift their activities to twilight and night hours in response to human disturbance

Experimental evidence of human recreational disturbance effects on bird-territory establishment

The worldwide increase in human outdoor activities raises concerns for wildlife. Human disturbances, even at low levels, are likely to impact species during sensitive periods of the annual cycle. However, experimental studies during the putative sensitive period of territory establishment of birds which not only investigate low disturbance levels, but which also exclude the effect of habitat modification (e.g. walking trails) are lacking. Here, we experimentally disturbed birds in forest plots by walking through twice a day during territory establishment. Later we compared the breeding bird community of experimentally disturbed plots with that of undisturbed control plots. We discovered that the number of territories (-15.0%) and species richness (-15.2%) in disturbed plots were substantially reduced compared with control plots. Species most affected included those sensitive to human presence (assessed by flight-initiation distances), open-cup nesters and above-ground foragers. Long-distance migrants, however, were unaffected due to their arrival after experimental disturbance took place. These findings highlight how territory establishment is a sensitive period for birds, when even low levels of human recreation may be perceived as threatening, and alter settlement decisions. This can have important implications for the conservation of species, which might go unnoticed when focusing only on already established birds.

Risk perception of vervet monkeys Chlorocebus pygerythrus to humans in urban and rural environments

Like other animals, primates respond to predation using behavioural adaptations. Hence, they should optimise their escape strategy under the risk of predation, and flee at a distance, referred to as flight initiation distance (FID), when the fitness-related benefits of staying are balanced against the costs of escape. However, there is an absence of FID studies in primates. In this study, we used vervet monkeys Chlorocebus pygerythrus, a medium-sized African cercopithecoid, as a model species to investigate the influence of environment type (urban and rural), group size (defined as the number of visible neighbours), sex and age on FID when approached by a human. We found significantly shorter FID among urban than rural monkeys; urban individuals delayed their escape compared to rural individuals. We found no relationship between FID and sex and age class, but FID was positively correlated with group size in both settings; urban monkeys live in smaller groups than monkeys in rural areas. As FID and group size are important predictors of predation risk perception in primates, results suggest that, despite probable effects of habituation, vervet monkeys in Uganda adjust their antipredator behaviour when coping with novel environments within human settlements. Our findings are consistent with some previous studies of risk perception in animals, and indicate that FID could be used as an alternative measure for predation risk in primates.

The influence of periodic increases of human activity on crepuscular and nocturnal mammals: Testing the weekend effect

Human recreation can negatively affect wildlife, particularly on weekends when human activity is highest (i.e., the weekend effect). Much of what we understand about the weekend effect is based on research conducted on diurnal species, which have greater temporal overlap with humans. Because nocturnal species generally avoid times when humans are active, they are likely less affected by anthropogenic activity on weekends. Our objective was to test the weekend effect in relation to the degree of nocturnality of mammals in a recreational area. We predicted that as nocturnality increased, the effect of human activity would decrease. To address our objective, we placed 50 remote cameras along the Diamond Fork River in Utah from January to June 2015. We found that three out of the four focal species supported our predictions. Mule deer (crepuscular) reduced activity throughout our entire study area during weekends and avoided campgrounds. Beavers and mountain lions (both nocturnal) did not negatively respond to increased human activity. Raccoons (nocturnal) reduced activity during weekends, but only within campground areas. Our findings indicate that as the temporal overlap increases between wildlife and humans, so does the influence that humans have on wildlife.

Emigration dynamics of cockroaches under different disturbance regimes do not depend on individual personalities

Group-level properties, such as collective movements or decisions, can be considered an outcome of the interplay between individual behavior and social interactions. However, the respective influences of individual preferences and social interactions are not evident. In this research, we study the implications of behavioral variability on the migration dynamics of a group of gregarious insects (Periplaneta americana) subjected to two different disturbance regimes (one without disturbances and another one with high frequency of disturbances). The results indicate that individuals presented consistent behavior during the nighttime (active phase of cockroaches) in both conditions. Moreover, we used a modeling approach to test the role of personality during the migration process. The model considers identical individuals (no personality) without memory and no direct inter-attraction between individuals. The agreement between theoretical and experimental results shows that behavioral variability play a secondary role during migration dynamics. Our results showing individual personality during the nighttime (spontaneous decision to forage) but not during the emigration process (induced by environmental disturbances) highlight the plasticity of personality traits.

Individual variation in behavioural responsiveness to humans leads to differences in breeding success and long-term population phenotypic changes

Whether human disturbance can lead to directional selection and phenotypic change in behaviour in species with limited behavioural plasticity is poorly understood in wild animal populations. Using a 19-year study on Montagu's harrier, we report a long-term increase in boldness towards humans during nest visits. The probability of females fleeing or being passive during nest visits decreased, while defence intensity steadily increased over the study period. These behavioural responses towards humans were significantly repeatable. The phenotypic composition of the breeding population changed throughout the study period (4-5 harrier generations), with a gradual disappearance of shy individuals, leading to a greater proportion of bolder ones and a more behaviourally homogeneous population. We further show that nest visit frequency increased nest failure probability and reduced productivity of shy females, but not of bold ones. Long-term research or conservation programmes needing nest visits can therefore lead to subtle but relevant population compositional changes that require further attention.