搜索结果：Folia primatologica; international journal of primatology

As human populations expand and modify landscapes, interactions between wild primates and domesticated animals have become increasingly frequent. This review synthesizes literature on primate-domestic animal interactions to assess patterns across these associations and set the context for the subsequent articles in the special issue on this topic. In our review, we sampled reports of directly observed interactions published in full-length manuscripts within the last 25 years. Dogs (Canis lupus familiaris) are the most frequently reported domestic species involved in agonistic encounters with primates, often acting as predators or human-directed deterrents in agricultural settings. In a sample of 100 search results for relevant key words, most interactions that were documented involved dogs (92% of 117 interactions recorded in 15 of 16 articles), most of which were free-ranging. Habitat type (agroforest, protected area, or town) showed an association dog type (free-ranging or with a known owner), where dogs with known owners in agroforest make up the largest proportion of interactions, followed by free-ranging dogs in agroforest. The nature of interactions (agonism or neutral) associated with taxonomic group, where no strepsirrhines were involved in neutral interactions with dogs, and all interactions with cattle were neutral. Despite the impact of domestic animals on wild primate populations, systematic studies on primates and domestic animals, especially beyond canines, are often limited. To better understand the nature of anthropogenically influenced interspecies interactions, we recommend that researchers distinguish between the degree of human control domesticated animals are under, document the behavioural responses of both primates and domestic animals, and include interactions with non-canine domestic species, such as livestock.

Our understanding of the viability of primates in anthropogenically fragmented habitats is undermined by the long timeframes for the effects of fragmentation to manifest. Studying primates in natural forest islands can better reveal the limits to habitat viability in the face of fragmentation. We present a study of a group of Azara's owl monkeys (Aotus azarae) occupying a 0.53 ha forest "island", the smallest such forest island and territory ever documented for the genus Aotus. We radio collared one individual and then, for ten months, collected ecological and behavioural data on the island and the group (123 scans, 44 observation days). We also collected forest structure data on the island. While the group did successfully establish itself on the island, the pair did not have an offspring during the birth season. The pair predominantly engaged in resting behaviour in close proximity to each other. Furthermore, the adult male of the group was characterised by eye deformities and bodily injuries, and eventually died nine months after we identified him. These results suggest that, while the forest island may be habitable in the short term, it may not have been sufficient for the long-term survival and reproduction. We propose that this forest island could act as a population sink, where individuals that are not competitive in the highly saturated gallery forest can reside temporarily. Our study shows the importance of considering not only presence/absence, but also behaviour and life history to consider the effects of forest island viability, especially in the face of future scenarios of anthropogenic fragmentation.

The Southern Lesser Bushbaby Galago moholi is a small, nocturnal, strepsirrhine primate, native to Sub-Saharan Africa. Previously considered a strict dietary specialist on tree exudates and insects, recent observations have revealed hitherto unappreciated plasticity in its feeding behaviour, encompassing fruits and even small vertebrates. While arthropods are an important seasonal component of the diet of this species, we still have little idea of the types of insect prey taken in nature, or the extent of any preferences among arthropod taxa. Here, I document behavioural observations made of G. moholi foraging at a moth trapping light on two occasions in November 2024 in Limpopo (Republic of South Africa), including details of feeding preferences and previously undocumented foraging vocalisations. To understand species-level preferences among potential insect prey, I presented an individual G. moholi with various prey types and recorded which were consumed. In addition, using male Driver Ants Dorylus helvolus, I experimentally manipulated prey items to gauge the relative importance of prey appearance, movement, and sound in determining their attractiveness to G. moholi. Lepidoptera were strongly favoured among available prey options, with increased discrimination applied to other groups such as Coleoptera and Hemiptera. Both sound and movement were important in determining predation from G. moholi. Although limited by low replication, these observations are the first to document species-level discrimination and preferences among a wide range of insect prey in wild G. moholi. Building a clearer picture of the dietary ecology of this species is vital for its conservation, and for better understanding its functional role in woodland food-webs. Future studies should seek to employ more systematic experimental approaches on captive and wild individuals (i) to clarify the traits that make different arthropod taxa suitable/attractive prey for this species, and (ii) to further explore the sensory ecology of G. moholi foraging, particularly the relative role of vision and audition.

Globally, the effective protected area network is one of the last resorts for conserving biodiversity. The nature of protected areas depends on the land ownership of the respective countries including India. The landholding in the northeastern states of India remains with native people, thus, 'Community Reserve' (CR) was introduced in 2003. Considering the high number of CR in Meghalaya that are home to many threatened primates, understanding their role in conserving the primates was crucial. We conducted day and night trail surveys in 32 CR of Meghalaya, and a questionnaire survey of local people for their perception of primates. We sampled basal area, tree density, canopy cover, canopy height, bamboo density, and human activity in each CR to test their influence on the occupancy of primates. We recorded the Western hoolock gibbon Hoolock hoolock, capped langur Trachypithecus pileatus, Northern pig-tailed macaque Macaca leonina, Assamese macaque Macaca assamensis, Rhesus macaque Macaca mulatta, and Bengal slow loris Nycticebus bengalensis. The primate richness and abundance were higher in the CR of Garo Hills than in the Khasi and Jaintia Hills. The gibbons had the highest patch occupancy, which was followed by capped langur, Assamese macaque, and pig-tailed macaque. Large-sized CR determined the occupancy of gibbons and Assamese macaques. Canopy cover positively influenced the occupancy of three primates except the Assamese macaque, whereas the canopy height had a positive association with three species of primates. The basal area, and tree density, negatively affected the occurrence of Assamese macaque, northern pig-tailed macaque, and capped langur. Macaques were the most hunted primates. The differential occurrence and abundance in different hill systems may be due to hunting and habitat size rather than habitat quality. Habitat restoration would improve the habitat quality with the involvement of communities to assist in retaining and avoiding the local extinction of primates.

Collecting observational data on nocturnal lemurs in the wild is challenging, resulting in limited information on their natural history, ecology, and evolution. Avahi laniger and Lepilemur mustelinus are two small, nocturnal lemurs that appear to defy the rules of folivory (being almost exclusively folivorous despite small body size) and are highly understudied. This research aimed to describe the nutritional ecology of these lemurs to better understand their adaptations to a folivorous diet. We collected eight weeks of behavioural data, including feeding behaviour, in October-December 2020 in Tsinjoarivo, Madagascar. Additionally, we collected thirty-three plant foods, which we observed the two species consuming, for nutritional analyses. Both species were mostly observed resting, a common behavioural adaptation for processing a folivorous diet, but differed in periods of peak feeding behaviour. A. laniger and L. mustelinus had very little dietary overlap: only five of 34 total plant species were consumed by both species and one of these shared foods was the same species, but different parts. The nutritional composition of A. laniger and L. mustelinus' foods were largely similar, but diverged in one nutritional variable: L. mustelinus consumed foods higher in available protein than A. laniger. Both species also approached plant secondary metabolites differently: A. laniger tolerated tannins while as L. mustelinus tended to avoid them. This research, the first nutritional ecology study of Avahi laniger and Lepilemur mustelinus in Tsinjoarivo, is consistent with previous suggestions of niche separation through food chemistry.

Madagascar's lemurs are globally unique primates, yet many nocturnal taxa remain poorly studied. Among them, the eastern woolly lemur (Avahi laniger) is widespread across the island's northern and central-eastern rainforests, but little is known about its ecology outside protected areas. We surveyed 18 unprotected forests, representing about one third of the species' range, to evaluate its occurrence, population density, habitat use, and interactions with local communities. Using 97 nocturnal line transects (291.8 km of survey effort) combined with vegetation assessments and 208 interviews, we found A. laniger at all study sites. Estimated population density was 41.3 individuals/km2, which is at the lower margin of reported values for the genus. Encounter rates did not differ significantly along a gradient of forest degradation (undisturbed to highly logged primary forest), suggesting some tolerance to structural degradation. However, use of fallow-derived habitats was restricted to sites with the early successional tree Harungana madagascariensis, highlighting the importance of vertical structures and specific food plants. Morphological measurements showed no evidence of reduced body condition compared to populations in protected areas. Interviews revealed broad local knowledge of the species (73% recognition), occasional and opportunistic hunting, and low prevalence of taboos against consumption. Notably, hunting could be linked to locally reduced abundances. We demonstrate that A. laniger persists across a gradient of human-modified landscapes, if vertical forest structures and food resources remain available. Conservation strategies should therefore include forested areas not generally considered suitable for lemurs (e.g., agroforests), while strictly preventing hunting to ensure population viability under ongoing habitat fragmentation.

Sleep behaviour has been recorded for only ten percent of primate species. Here, we contribute to this literature by using videography to collect novel sleep behaviour data on captive gorillas. We measured, to our knowledge, the first ever sleep architecture preliminary baseline estimate data in a population of captive western lowland gorillas (Gorilla gorilla gorilla) at the Basel Zoo (Switzerland) over three months (n = 90 nights of observation). The results of this study showed significant differences in levels of sleep fragmentation between the one dominant male of our gorilla community and the subordinate individuals (one young male and females ranging in age) of the same community. This perhaps suggests that dominant individuals may suffer in their overall sleep quality however, because dominance and sex are confounded in this population, these patterns should be interpreted cautiously. While this result could be interpreted to be tradeoff between the requirements of sleep and group protection by the dominant silver back, the results of this study are novel and the first of its kind. Thus, while these preliminary differences raise questions about how social roles may relate to sleep behaviour in gorillas, further research with larger samples is required to understand how biological sex, dominance rank, and the interaction between the two within gorilla populations, influences sleep within gorillas.

Brazil, a country with a rich diversity of primates, faces the challenge of preserving these species, since most are at some level of threat of extinction. Among Brazilian primates, the pygmy marmosets (Cebuella niveiventris and C. pygmaea) stand out as the smallest known species of monkey, with a wide distribution in the western Amazon. Faced with the need for quick and well-founded information to guide conservation, recent studies have used analyses of Species Distribution Models (SDMs) for primates. The present study aimed to investigate the genetic diversity in Cebuella, using the mitochondrial gene cytochrome b, and analyze the potential distribution (SDMs) of the two species. The phylogeny showed Cebuella divided into two clades, corresponding to the two species of the genus, corroborating previous findings. Herein, we applied species delimitation tests to the genus Cebuella for the first time, revealing significant divergences. The bPTP method identified six probable species within Cebuella, while the ABGD indicated 15 putative species. Both methods point to a high diversity within the genus. Species suitability modeling suggested that C. niveiventris seems to be more sensitive to seasonal variations in rainfall (BIO15) and the amount of rainfall during the wettest quarter (BIO8), while C. pygmaea appears more impacted by the intensity of the early rainy season (BIO15) and a period of lower rainfall variability throughout the rest of the year. The most pessimistic scenario for the future suggested that the more intense the environmental changes resulting from human activities, the greater the impact on future climates, increasing the probability of population decline.

Obtaining accurate data on occurrence, abundance, and population density of endangered species is of paramount importance. Accordingly, we need a continuous effort to improve current survey methodologies. One such possibility is the use of handheld thermal cameras to assist in playback-aided surveys. Here, we tested this possibility with our model species, Callithrix aurita, a small, endangered primate that inhabits the Atlantic Rainforest of southeastern Brazil. We hypothesized that the thermal camera would allow: (1) the identification of non-responsive groups or lone individuals; and (2) the detection of more individuals in cases where the groups approach the playback location. We surveyed four Atlantic rainforest fragments using the playback-aided active search methodology, complemented with scanning the surroundings with a handheld thermal camera. We did not identify any unresponsive groups/individuals, and were able to identify 51 individuals with the naked eye and 43 using the thermal camera, a non-significant difference, rejecting both hypotheses. We believe this result was due to the survey being carried out by a researcher highly trained on the study species. Therefore, on these grounds alone, our study does not support the use of thermal cameras in similar situations. However, on two occasions, we obtained more sightings of primates through the camera. Thus, the use of the device may result in an improvement in the quality of playback-aided surveys of Callithrix aurita populations, for which accurate data is crucial. We discuss the limitations and possibilities of use of thermal cameras with other primate species (e.g. fearful, living in large groups, nocturnal, unresponsive to playbacks, small-sized, cryptic or elusive, or that use hollows), and point directions where future research is needed.

Mother-Approved Infant Handling (MAIH), a behaviour characterized by non-maternal individuals carrying a mother's offspring with her consent following a process of behavioural negotiation, is a well-documented phenomenon in colobine species. This study systematically documented MAIH within a semi-provisioned breeding band of black-and-white snub-nosed monkeys (Rhinopithecus bieti) in Xiangguqing, Yunnan, P.R. China. The research aimed to test the learning-to-mother hypothesis, which posits that inexperienced females engage in infant handling to acquire maternal skills. Over the study periods in 2019 and 2022, we observed MAIH events across multiple one-male units (OMUs). Our findings revealed that MAIH was predominantly initiated by juvenile and adult females, particularly within the first two months after an infant's birth. A generalized linear mixed model analysis revealed that both handler age and the number of offspring significantly influenced the occurrence of MAIH. These results support and enrich the learning-to-mother hypothesis, suggesting that MAIH provides an opportunity for inexperienced females to gain caregiving skills. While older females exhibited higher MAIH occurrences, the negative quadratic effect indicates that it declines after peaking at a certain age. This study advances our understanding of the adaptive significance of allomaternal care in primate societies and offers insights into the evolutionary origins of cooperative breeding in humans.

Descriptions of the vocal repertoires of primates are essential to understanding aspects of behaviour and social ecology, and are increasingly useful in applied conservation. Sportive lemurs (Lepilemur spp.) are highly vocal but otherwise cryptic, making them promising candidates for bioacoustics research and monitoring; however, vocal repertoires have been described for only a handful of the 25 species, and the question of gradation within and between call types remains largely unexplored. Here we describe the call types and gradedness of the vocal repertoire of the Critically Endangered Nosy Be sportive lemur (Lepilemur tymerlachsoni). We recorded wild sportive lemur vocalisations over a six-week period in early 2023. From the spectrograms of these recordings, we manually classified 14 distinct call types, distinguishable both aurally and visually, representing the largest known repertoire for the genus and among the largest reported for any nocturnal primate. Depending on the call type, calls were produced singly, in sequences and combinations, or in extended bouts. We then used an unsupervised machine learning technique, fuzzy c-means clustering, to objectively classify the repertoire and quantify its graded structure using 25 acoustic measurements extracted from the spectrograms. Fuzzy clustering identified two acoustic clusters, revealing gradation both within call types and between clusters. These patterns were visualised with Uniform Manifold Approximation and Projection ('UMAP') dimensionality reduction. We present representative spectrograms for each call type, and compare our results with the published repertoires of other sportive lemur species. Our study provides a foundation for further behavioural research and acoustic-based conservation of L. tymerlachsoni.

Amongst the colobines (Colobinae subfamily), the douc langurs (Pygathrix) are known to use higher proportions of arm-swinging behavior in their locomotor repertoire. Previously, researchers have suggested the increased use of arm-swinging to be a result of habitat constraints. For example, suspensory locomotion allows animals to travel across unstable substrates, such as the terminal ends of branches, than would be possible in above branch locomotion. In this paper, we attempt to identify patterns of habitat use and arm-swinging amongst the doucs. Specifically, we predict arm-swinging will occur significantly more on horizontal substrates, in the main canopy, on branches (medium-sized substrates), and in old-growth forest. Data was recorded in the Son Tra Nature Reserve, Vietnam between November 2016 and April 2017. The monkeys were filmed and data was extracted continuously. Results indicate the red-shanked douc arm-swings more often when they are in the main part of the canopy compared to the top of the canopy, and possibly on substrates smaller than a bough. No differences were found in frequency of arm-swinging when individuals were in old versus new forest or on horizontal versus oblique substrates. The patterns of arm-swinging behavior follow patterns similar to that of spider monkeys, especially in substrate preferences. This information is critical for understanding and conserving the habitat of the critically-endangered red-shanked douc.

Characterizing activity budgets in response to seasonality and anthropogenic pressures provides insights into primate behavioral ecology. The Arsi geladas (T. gelada arsi) are a distinct and little-known subspecies of geladas living south of the Rift Valley in eastern Arsi, Ethiopia, where elevation and rainfall levels are low, temperatures are high, and habitat loss and degradation threaten the geladas. To better understand how Arsi geladas cope with the challenges of their highly disturbed and climatically challenging environment, we conducted 16 months of observational scan sampling on a focal band of approx. 35 individuals (consisting of two one-male units) at Goro-Jena to examine diurnal and seasonal variation in their activity budgets. Overall, Arsi geladas spent most of their time feeding (57.3 ± 5.0%), followed by socializing (18.7% ± 3.8), moving (12.5 ± 5.0), and resting (10.2 ± 3.1). Feeding peaked in the late morning and late afternoon and social behavior peaked in the early morning near sleeping sites. Resting also peaked in the early morning as well as around mid-day, when ambient temperatures were warmest, the latter peak potentially reflecting the thermoregulatory challenges of the hot climate in Arsi. Arsi geladas exhibited only minor seasonal shifts in their activity patterns with increases in feeding time corresponding with periods of lower resource availability and quality. Percentage of time devoted to feeding by geladas at Goro-Jena was comparable to that of some populations at high elevations which themselves must cope with cold climates. This finding suggests that Arsi geladas at Goro-Jena occupy a marginal environment that imposes substantial energetic stress on them. As such, priority conservation actions must include protecting and expanding natural gelada habitat at Goro-Jena - as well as elsewhere in Arsi - to ensure the persistence of this increasingly rare and threatened gelada subspecies.

The destruction of wildlife habitats due to the exponential growth of human population and its encroachment into wild areas is a major threat to many species around the world. In order to understand the effects of human disturbance on the Philippine tarsier (Carlito syrichta), we evaluated its population status by quantifying the species' population density in an agricultural habitat and assessed the degree of human disturbance in the area. We did the study in Subayon, Bilar, Bohol, where we surveyed 32 ha out of the total 115 ha of the village between April and June 2017. We predominantly used vocal activity to identify the presence and absence of tarsiers, supplementing the data with incidental sightings. In addition, human disturbances were assessed and described qualitatively. We estimated the population density on 75 individuals per square kilometer. The human disturbance was evidenced in 28 out of 32 plots, which indicates that the entire area has already been disturbed. This study showed that the Philippine tarsier could inhabit highly altered habitats such as agricultural landscapes and suggest that Subayon village might be important for the conservation of this species. We provided another example of the ecological flexibility of otherwise specialised nocturnal primates able to inhabit agricultural areas. To avoid conflicts with humans and to conserve such a species in the future, education, outreach and active involvement of local people are essential.

People play an important role in the welfare of nonhuman animals in zoos. The aim of this study is to find out if the behavior of squirrel monkeys maintained in Faunia, a zoological and botanical garden located in Madrid (Spain), and the height they occupy in their enclosure is associated with the flow of visitors and the keeper presence. Although the effects of visitors and keepers were difficult to separate, the response to increasing flow of visitors was not linear, being usually associated with greater individual variability in responses. In a more precise way, when the flow of visitors increased, feeding and locomotion decreased, while resting and interactions with people increased. Although decreasing of positive behaviors as feeding seems to indicate that monkeys perceive high numbers of visitors as a nuisance, interactions with people suggest that those could consider visitors as a kind of environmental enrichment.

Introduced species can negatively impact endemic flora and fauna. Studies have primarily utilized camera trap observations and occupancy modelling to better clarify the presence/absence and temporal overlap of endemic and exotic predators. Longitudinal data from field research sites are important as they can provide a finer understanding of predator dynamics and their effects on endemic species. One such site is the Bezà Mahafaly Special Reserve, in southern Madagascar. Protected since the 1970s, the local human population around Bezà Mahafaly Special Reserve has greatly expanded, leading to habitat disturbance in the surrounding forests and increased contact between local wildlife, people and their livestock and dogs. Here we use a combination of scat sampling, field observations of successful and attempted predations, locations of scat samples with identifiable lemur remains, and camera trap data to better assess the predator ecology at Bezà Mahafaly Special Reserve. Our results indicate that forest cats (Felis catus), are effective predators of both adult and infant lemurs and appear to be a constant mammalian predator, utilizing mammal prey more than dogs. Dogs are both predators and scavengers of lemurs. Civets focus on small prey, such as insects and rodents as well as plant material. The fosa, Cryptoprocta ferox, are also present but may not hunt in the area continuously. The killing of an adult ring-tailed lemur by two men from outside the area indicate culturally imposed taboos against lemur killing may no longer be effective given that new arrivals may not share the same local cultural restrictions. Scat sampling of exotic predators is one way to expand our understanding of exotic and endemic predator impact on lemur populations, and long-term studies with multiple assessments of predation can provide a clearer understanding of how non-endemic and endemic predators affect endangered species survival.

Mangrove forests are highly threatened ecosystems, regarded as important habitats for many non-human primates, including tarsiers. However, for Philippine tarsiers (Carlito syrichta; formerly Tarsius syrichta), our understanding of their relationship with mangroves remains poor. Here, we explored how Philippine tarsiers used mangrove habitats by locating their sleeping sites, describing their sleeping behaviours, and estimating their home ranges. We surveyed Philippine tarsiers from 24 June to 10 July 2025 in a mangrove forest within the Del Carmen Mangrove Reserve on Siargao Island. We were able to record 44 sleeping sites from six Philippine tarsiers that were radio-tracked. The tarsiers frequently slept on screw pines, non-mangrove trees, and thickets, although they also used true mangrove species (Rhizophora sp. and Nypa fruticans) within the flooded portions of the site. Adult males were skittish and consistently slept solitarily, whereas the adult females were often accompanied by their juvenile offspring. From the three adult males we fitted with GPS tags, we estimated minimum home range sizes (±SE) of 3.16 ± 0.59 ha based on minimum convex polygons and 4.22 ± 1.34 ha based on kernel density estimates, with percentages of mangrove overlap ranging from 17.56 to 72.99%. Our observations underscore the value of mangrove habitats as potential refugia for supporting insular primate populations against predators, disturbances, and stochastic events, and as evolutionarily significant ecosystems that, along with their behavioral flexibility, possibly contributed to their dispersal across open oceans. We recommend extending ecological research of tarsiers in mangroves and integrating mangrove protection in tarsier conservation.

Habitat degradation is a threat to primate species worldwide with agricultural practices chief among these. Livestock play prominent historical, economic, cultural and social roles in Madagascar, a biodiversity hotspot where one-fifth of the world's primates are endemic. In the arid regions of Madagascar, livestock and lemurs occupy the same forest habitats and understanding their co-existence is a conservation priority; however, lack of knowledge of livestock spatial and temporal movements in shared habitats limits our ability to manage impacts. This study aimed to detect livestock presence and characterize spatial and temporal patterns of livestock occurrence inside Beza Mahafaly Special Reserve. We analyzed five autonomous recording units with recording from one minute every 30 minutes in two forest types and protection zones (inside and outside fenced Parcel I) for one year. To gain a broader understanding of the potential impacts of livestock, we also looked at chopping sounds as a proxy for fodder collection and vocalizations of dogs that often accompany herders. We found that livestock were present in forests most often at dawn and dusk, suggesting a pattern of movements along well-traveled routes. Both livestock and chopping occurrences were greater outside of Parcel I, suggesting the fence may provide additional forest protection, but some nocturnal livestock activity was detected in Parcel I gallery forests. Livestock occurrence peaked in the wet season, but chopping was higher in the dry season (and in gallery forests) indicating herders may be supplementing livestock diets with fodder in the lean season. The presence of dog vocalizations were not consistent with livestock patterns of occurrence; instead, the dogs, an introduced predator, seemed to be free-roaming the reserve at night, which could pose a threat to the lemurs there. Our findings demonstrate that passive acoustic monitoring is an effective method of monitoring livestock related activities in protected areas.

Food transfer occurs when part or all of a food item is passed from one individual to another. Adult transfer of solid food to infants has been reported in 45 primate species. For aye-ayes, this behaviour was recorded in captivity where individuals were provisioned, but little is known about this behaviour in the wild. Wild aye-ayes consume hard-to-process foods that are inaccessible to infants such as wood-boring larvae embedded in trees and the endosperm of Canarium spp. seeds which are protected by a hard coat. Learning to process these food resources may be essential for aye-aye development. We used ad libitum sampling to record the social activities and behaviours of a mother and her male infant from January to December 2020 in Sangasanga Forest, Kianjavato, Madagascar. We collected in total 4 hours 57 minutes and 57 seconds of social behaviours. Over two days in December, we observed eight occurrences of the 11-month-old infant usurping Canarium sp. seeds from his mother. Our findings suggest that, due to physical limitations, the infant aye-aye primarily resorted to food transfer via theft to obtain hard-to-process food. Transfer of larvae, their main resource, was not observed, though it may occur until young aye-aye have the bite force needed to gouge holes in substrates and the coordination to retrieve and extract wood-boring larvae. Future research should explore if food transfer differs across individuals' sex, sites and type of food as well as the effects of anthropogenic disturbances on foraging.