Trail Cameras Research Articles

Trail cameras can greatly inflate nest predation rates

AbstractPhotographic monitoring currently provides the most accurate means for identifying nest predators and eventually their role in bird population declines worldwide. However, previous studies have found that commercially available trail cameras represent an artificial structure that tend to negatively bias predation rates, likely through predator neophobia. Based on an experiment in Arctic tundra, involving 50 artificial nests and 30 cameras in each of 2 breeding seasons, we demonstrated that trail cameras attracted corvids (in particular ravens [Corvus corax]), which caused an extreme and positively biased predation rate that was consistent over a range of experimental and environmental conditions. We call for new technologies that allow for photographic monitoring of bird nests with minimal visual footprints, in the form of smaller cameras and more efficient internal batteries to minimize novel and conspicuous external features detectable by predators. However, even such improved devices need to be assessed with respect to potential effects on nest predation in each case.

Taphonomic impact of vertebrate scavengers on degradation and dispersal of remains, southeastern British Columbia.

Vertebrate scavengers represent important taphonomic agents that can act on a body, particularly when in an outdoor environment. Understanding the effects of these agents will direct how and where to search for human remains and influence the likelihood of discovery in a particular region. The current study aimed to identify the taphonomic impact of scavenger guilds in the peri-urban and rural regions of southeastern British Columbia. Vertebrate scavenger activity on pig carcasses was recorded remotely using trail cameras and analyzed to determine temporal scavenging profiles. Both the peri-urban and rural environments produced comparable scavenger guilds, namely: turkey vultures, American crows/northern ravens (classified as "corvids"), American black bears, and coyotes. Although the two locations had different study lengths due to variable degrees of scavenging, for the period that was common to both locations (summer to early fall), the black bear was the most frequent scavenger followed by coyote. However, the dispersal of remains by the mammalian scavengers was distinctly different between sites. Only 12%-33% of skeletal elements were recovered at the rural sites compared to 80%-90% recovered at the peri-urban sites, even though the latter sites had a longer study timeframe. The extended timeframe of the peri-urban sites confirmed that certain scavengers (e.g., turkey vultures and black bears) are only seasonally active in this region. These findings demonstrate the variability of scavenger behavior and the need to assign caution and local ecological knowledge when predicting scavenger trends. Such taphonomic information is relevant for human remains searches in regions with comparable scavenger guilds.

Temperature Drives Summer Group Size Dynamics of Eastern Migratory Caribou in the Hudson Bay Lowlands of Manitoba

Aggregation behavior is pervasive across a broad range of animals and the outcome of this behaviour has both risks and rewards. Large aggregations of animals are a distinctive characteristic of Migratory Caribou (Rangifer tarandus Linnaeus, 1758), primarily in response to the environment factors such as predation, although caribou may also aggregate during high summer temperatures, likely in an effort to mitigate parasitic biting flies. To see if caribou in the Cape Churchill Caribou Herd of the Eastern Migratory caribou (Rangifer tarandus groenlandicus Borowski, 1780) Designatible Unit, also displayed aggregation behavior in relation to warmer summer temperatures, we collected trail camera photos with associated temperature readings during the summer period (May to September) from 2017 to 2020 in their summer range in Wapusk National Park, Manitoba, Canada. We found that summer caribou aggregation size was positively associated with ambient temperature, with aggregations increasing in size as temperature increased. The mechanism behind this behaviour should be investigated, as we predict more frequent and large caribou aggregations as summer temperatures continue to warm.

Predator-specific mortality of sage-grouse nests based on predator DNA on eggshells.

Greater sage-grouse (hereafter sage-grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage-grouse contend with a diverse suite of nest predators that vary in functional traits (e.g., search tactics or hunting mode) and abundance. Consequently, generalizing about factors influencing nest fate is challenging. Identifying the explicit predator species responsible for nest predation events is, therefore, critical to understanding causal mechanisms linking land use to patterns of sage-grouse nest success. Cattle grazing is often assumed to adversely affect sage-grouse recruitment by reducing grass height (and hence cover), thereby facilitating nest detection by predators. However, recent evidence found little support for the hypothesized effect of grazing on nest fate at the pasture scale. Rather, nest success appears to be similar on pastures grazed at varying intensities. One possible explanation for the lack of observed effect involves a localized response by one or more nest predators. The presence of cattle may cause a temporary reduction in predator density and/or use within a pasture (the cattle avoidance hypothesis). The cattle avoidance hypothesis predicts a decreased probability of at least one sage-grouse nest predator predating sage-grouse nests in pastures with livestock relative to pastures without livestock present during the nesting season. To test the cattle avoidance hypothesis, we collected predator DNA from eggshells from predated nests and used genetic methods to identify the sage-grouse nest predator(s) responsible for the predation event. We evaluated the influence of habitat and grazing on predator-specific nest predation. We evaluated the efficacy of our genetic method by deploying artificial nests with trail cameras and compared the results of our genetic method to the species captured via trail camera. Our molecular methods identified at least one nest predator captured predating artificial nests via trail camera for 33 of 35 (94%) artificial nests. We detected nest predators via our molecular analysis at 76 of 114 (67%) predated sage-grouse nests. The primary predators detected at sage-grouse nests were coyotes (Canis latrans) and corvids (Corvidea). Grazing did not influence the probability of nest predation by either coyotes or corvids. Sagebrush canopy cover was negatively associated with the probability a coyote predated a nest, distance to water was positively associated with the probability a corvid predated a nest, and average minimum temperature was negatively associated with the probability that either a coyote or a corvid predated a nest. Our study provides a framework for implementing an effective, non-invasive method for identifying sage-grouse nest predators that can be used to better understand how management actions at local and regional scales may impact an important component of sage-grouse recruitment.

COVID-19 Pandemic Effects on Angler Effort and a Brown Trout Population in a Driftless Area Stream in Southeast Minnesota

Abstract Early opinions of the COVID-19 pandemic included equivocal notions of whether the pandemic would result in more or less angler effort and harvest in recreational fisheries. Early papers also suggested using changes in angling license sales to infer changes in angler effort but expressed concern about adequate assessment of pandemic effects on fisheries because of interruptions to routine assessment programs. To assess pandemic effects on angler effort at a stream trout fishery, a trail camera was installed, immediately prior to implementation of a statewide stay-at-home order, at a representative stream trout angling site that is part of a long-term fish monitoring program. The trail camera was deployed through the trout harvest angling season from the peak pandemic year of 2020 through cessation of most restrictions in 2022. Statewide sales of angling licenses and trout stamps were assessed through this time to compare with angler effort measured with the trail camera. Annual trout population assessments were examined for pandemic effects in conjunction with angler effort. Anglers were present on 84% of days in 2020, 66% in 2021 and 69% in 2022. Following the pandemic peak of 603 angler-hours in 2020, angler-hours declined by -23% between 2020 and 2021, and by -16% between 2020 and 2022; whereas statewide sales of licenses and trout stamps only declined by -4% between 2020 and 2021 and -11% between 2020 and 2022, suggesting more angler pressure at the study site than could be inferred by changes in license or trout stamp sales. Higher pressure during the pandemic was due in part to more anglers younger than 20 years old. Despite higher angler pressure in 2020, there was no long-term effect on the Brown Trout population, as adult abundance in 2021 and 2022 exceeded abundance in every year from 2017 to 2020. These data add to a limited number of similar field-based pandemic studies coupling changes in angler use with fish population responses and should provide further insight into the broader assessment of COVID-19 pandemic effects.

Thin corridors limit wildlife: Variance of tropical carnivore distribution and habitat use in a critical rainforest corridor

AbstractMadagascar is acclaimed for its floral and faunal endemism and biodiversity. Among the island nation's most emblematic fauna are its native mammalian carnivores; they are members of the threatened and endemic Eupleridae family. The Corridor of Marojejy, Anjanaharibe‐Sud Special Reserve, Tsaratanana (COMATSA) is a newly protected corridor system that faces deforestation and lacks detailed assessments of its native carnivore community. We deployed 44 motion‐activated trail cameras to identify which terrestrial carnivores are found within the rainforest corridor landscape of COMATSA‐Sud and Marojejy National Park, and to examine carnivore occupancy, relative activity and the impacts of habitat edge. Our sampling array operated from October 20, 2021, to February 10, 2022 (113 days) and confirmed the presence of four species in Eupleridae: Cryptoprocta ferox, Fossa fossana, Galidia elegans, and Galidictis fasciata, as well as a non‐native carnivore species: Canis familiaris. We show that carnivore occurrences significantly increase with distance to forest edges. We discuss the negative impacts of forest loss on native carnivores and highlight the threats posed by the non‐native carnivore C. familiaris. Our findings spotlight faunal detections across the corridor and indicate that fewer native carnivores are found in the corridor compared to nearby protected areas, suggesting that deforestation correlates with a skewed distribution of carnivore detections. Based on our data, we provide management recommendations for the protection of the forest corridor and its endemic faunal community.

Advancements in monitoring: a comparison of traditional and application-based tools for measuring outdoor recreation.

Outdoor recreation has experienced a boom in recent years and continues to grow. While outdoor recreation provides wide-ranging benefits to human well-being, there are growing concerns about the sustainability of recreation with the increased pressures placed on ecological systems and visitor experiences. These concerns emphasize the need for managers to access accurate and timely recreation data at scales that match the growing extent of the recreation footprint. Here, we compare spatial and temporal patterns of winter and summer recreation using traditional (trail cameras, infrared counters, aerial surveys, participatory mapping) and application-based tools (Strava Metro, Strava Global Heatmap, Wikiloc) across the Columbia and Canadian Rocky Mountains of western Canada. We demonstrate how recreation use can be estimated using traditional and application-based tools, although their accuracy and utility varies across space, season and activity type. We found that trail cameras and infrared counters captured similar broad-scale patterns in count estimates of pedestrians and all recreation activities. Aerial surveys captured areas with low recreation intensity and participatory mapping captured coarser information on the intensity and extent of recreation across large spatial and temporal scales. Application-based data provided detailed spatiotemporal information on recreation use, but datasets were biased towards specific activities. Strava Metro data was more suited for capturing broad-scale spatial patterns in biking than pedestrian recreation. Application-based data should be supplemented with data from traditional tools to identify biases in data and fill in data gaps. We provide a comparison of each tool for measuring recreation use, highlight each tools' strengths and limitations and applications to address real-world monitoring and management scenarios. Our research contributes towards a better understanding of which tool, or combinations of tools, to use that can expand the rigor and scope of recreation research. These findings support decision-making to mitigate pressures on wildlife and their habitats while allowing for high-quality recreation experiences.

Icings as sentinels and modifiers of water flow through winter landscapes: An exploration of physico‐chemical processes on the lake‐dominated, discontinuous permafrost Taiga Shield

AbstractThe winter hydrological period is in transition across the Canadian subarctic, as climate warming is shifting precipitation regimes, thawing permafrost, and altering active layer dynamics, and thus increasing the overall amount, and variability, of winter streamflow. Effects of these changes are poorly understood on the Taiga Shield, which comprises ~20% of North America's permafrost‐covered area, and is characterized by a unique ‘fill‐and‐spill’ hydrology whereby runoff generation requires the exceedance of lake basin storage thresholds. Here, we assessed lake hydrostatic levels and used trail camera images of icings, which are sheet‐like masses of layered ice that are common manifestations of wintertime flow on the Taiga Shield, to understand landscape controls on winter water movement in this region. We further used paired geochemical measurements to explore how source water characteristics affect icing chemistry, and the degree to which icings may modify the chemical composition of active winter flow. We undertake this work over 2 years, and across watersheds of different sizes and lake basin characteristics. We show that icing growth is driven by hydroclimatic controls that include fill‐and‐spill hydrologic constraints and winter air temperatures, and that pre‐freshet pulses of water flow are common within this landscape. Across winters with variable antecedent precipitation levels, a larger catchment was able to support icing growth via continued runoff generation, while small catchments were not. Icings were often chemically dilute compared with source waters, indicating that solute exclusion may actively enrich geochemical concentrations in flowing water. Across icings, chemical variation appeared related to source water type (groundwater versus lake; lake size) and apparent redox conditions. These results highlight that streamwater hydrology and biogeochemistry can be dynamic during the understudied winter period, and illustrate that icings may alter the composition of wintertime flow as it moves through fluvial networks.

Leveraging camera traps and artificial intelligence to explore thermoregulation behaviour.

Behavioural thermoregulation has critical ecological and physiological consequences that profoundly influence individual fitness and species distributions, particularly in the context of climate change. However, field monitoring of this behaviour remains labour-intensive and time-consuming. With the rise of camera-based surveys and artificial intelligence (AI) approaches in computer vision, we should try to build better tools for characterizing animals' behavioural thermoregulation. In this study, we developed a deep learning framework to automate the detection and classification of thermoregulation behaviour. We used lizards, the Rough-tail rock agama (Laudakia vulgaris), as a model animal for thermoregulation. We colour-marked the lizards and curated a diverse dataset of images captured by trail cameras under semi-natural conditions. Subsequently, we trained an object-detection model to identify lizards and image classification models to determine their microclimate usage (activity in sun or shade), which may indicate thermoregulation preferences. We then evaluated the performance of each model and analysed how the classification of thermoregulating lizards performed under different solar conditions (sun or shade), times of day and marking colours. Our framework's models achieved high scores in several performance metrics. The behavioural thermoregulation classification model performed significantly better on sun-basking lizards, achieving the highest classification accuracy with white-marked lizards. Moreover, the hours of activity and the microclimate choices (sun vs shade-seeking behaviour) of lizards, generated by our framework, are closely aligned with manually annotated data. Our study underscores the potential of AI in effectively tracking behavioural thermoregulation, offering a promising new direction for camera trap studies. This approach can potentially reduce the labour and time associated with ecological data collection and analysis and help gain a deeper understanding of species' thermal preferences and risks of climate change on species behaviour.

Cross-boundary effects of human impacts on animal assemblages in the coastal zone

Human impacts on ecosystems often transcend ecosystem boundaries and environmental realms, complicating ecosystem assessment, conservation, and management. Whether and how different impacts affect ecosystems in distinct but adjacent domains remains untested in many settings, and is rarely tested concurrently at the same spatial scales. In this study, we quantified the effects of coastal urbanisation on the structure of terrestrial coastal vertebrate assemblages (including birds, reptiles and mammals using baited trail cameras) and marine surf zone fish assemblages (using baited underwater videography) at 100 sites along 50 km of beach in eastern Australia. Sites occurred along a gradient of intensities of urban land conversion in the hind dunes. While the effects of urbanisation on the species sampled were pervasive across both ecosystems, the area of urbanised land mattered more for the coastal vertebrates observed, while proximity to urbanised land was more important for the surf zone fish observed. Here, fewer individuals and species of coastal vertebrates were found at sites with a greater extent of urbanised land within 5 km. Conversely, fish assemblages were more diverse in the surf zones abutting urban areas and more abundant at sites approximately 150 m from urbanised land. The spatial properties of these landscapes, including proximity to headlands for coastal vertebrates and reefs for fish, modified the effects of urbanisation. Our findings suggest that urbanisation can have ecologically nuanced effects that are detectable across the land-sea boundary, and stress the importance of landscape context when assessing and conserving animal assemblages in and around coastal cities.

Factors influencing haulout behaviour of non-breeding weddell seals (Leptonychotes weddellii) at Cape Royds, Antarctica

The Weddell seal (Leptonychotes weddellii) is a fast-ice obligate species that plays an important role as both predator and prey within the high-latitude, coastal Southern Ocean. Weddell seals are affected by pressures of marine resource extraction and variation in sea-ice extent and characteristics that are affected by climate. Thus, monitoring their population dynamics provides an indicator of the effectiveness of fisheries management, and impacts of changing climate in the high latitude Southern Ocean ecosystem. Satellite imagery is increasingly being used to monitor the populations of this species, but assessment techniques require a better understanding of the environmental factors influencing the likelihood that individuals will be on the sea-ice and therefore visible in a satellite image. Addressing that goal, we captured 5054 trail camera photos during spring 2017 in the 24-h light at Cape Royds, Antarctica, and then counted seals on the fast ice every 30 min over 59 days. Using a generalised additive model (63% deviance explained) we described the haulout behaviour of non-breeding Weddell seals according to time of day, date, air temperature, pressure, solar radiation, and wind speed. We found that the seals’ haulout cycle is driven to a significant degree by weather variables, primarily temperature and wind speed. Quantifying these haulout patterns can be used to determine the time of day, and under what conditions, that most seals are hauled out. Integrating environmental parameters to correct time-of-day patterns would allow better cross-site abundance comparisons, leading to better Weddell seal population estimates for the Ross Sea region and the wider coastal Antarctica.

Effects of artificial light on foraging behavior of the Pacific Kangaroo Rat (Dipodomys agilis)

Abstract Artificial light at night is increasingly recognized as a cause of habitat degradation, and as a conservation threat to wildlife species. We studied the behavioral response of Pacific kangaroo rats (Dipodomys agilis) to natural and artificial light in coastal sage scrub in southern California, United States. We used digital trail cameras to monitor visits to seed trays in shrub and open, intershrub microhabitats. Under natural-light conditions, kangaroo rats were more active on full- than new-moon nights, and concentrated foraging beneath shrubs. Surprisingly, kangaroo rats frequently interacted with other rodents in seed trays. Near to an artificial light source, kangaroo rats removed fewer seeds, had fewer foraging bouts, and spent less time in trays—especially in brightly lit open microhabitats—compared to distances farther from the light. Differences between the first and second nights of trials during both experiments suggested that kangaroo rats learned locations of resource-rich seed trays and modified their behavior accordingly. Our results are similar to recent studies showing that artificial light depresses foraging activity of rodents in the areas of highest illumination, and adds to evidence of the need to mitigate impacts of urban lighting in fragments of coastal sage scrub, especially along the urban–wildland interface.

Cyclic dynamics drive summer movement ecology of snowshoe hares (Lepus americanus)

Animals exhibit dynamic movement and activity in response to environmental variation including changes in reproductive opportunities, predation risk, or food availability. Yet, it remains unclear which factors are primary in affecting animal movement, and whether the relative importance of these factors are consistent through time. We tracked snowshoe hares (Lepus americanus) using GPS telemetry during eight summers spanning a hare population cycle (2015–2022) in southwestern Yukon, Canada, to determine associations between environmental variation and hare movement and home range size. Hare density varied 25-fold during the study and home range size increased markedly during low hare density, especially for males. Both sexes retained similar core space use and linearity of movements, but at low densities males had greater and more variable movement rates and time spent travelling. Trail cameras revealed that annual changes in hare movement were also correlated with relative abundance of lynx (Lynx canadensis) and coyotes (Canis latrans). However, hare detection rates within a season were not closely associated with seasonal variation in predator detection. Observed differences between male and female hares in some metrics highlighted that different life histories and reproductive behavior are likely the main drivers of hare movement dynamics. Therefore, fitness rewards associated with successful mate search and reproduction appear to outweigh risks associated with increased movement, even in highly variable environments where costs of prioritizing reproduction-related activities are notably high and variable.

Activity responses of a mammal community to a 17-year cicada emergence event

Abstract During a limited period in the summer of 2021, 17-year cicada species (Magicicada cassini, M. septendecula, M. septendecim) represented a large pulse of easily accessible food unique to forest ecosystems in the eastern United States. Using trail cameras and acoustic recorders, we tested whether the activity levels of 8 mammal species in northwestern Indiana shifted in response to spatial and temporal variation in cicada densities from 18 May to 20 June 2021. Cicada densities varied temporally and spatially across all study sites. Most mammal species with sufficient data showed no response to cicada emergence, including 2 tree squirrel species, Peromyscus mice, Eastern Chipmunks (Tamias striatus), and 2 species of bats. Raccoons (Procyon lotor), likely cicada predators, showed a quadratic or more complex activity response to cicada abundance, indicating a potential saturation point at densities near 1 cicada per m2. Surprisingly, White-tailed Deer (Odocoileus virginianus) activity decreased to almost 0 at the same cicada densities when we expected no change in activity. While size or accessibility may exclude cicadas as prey for small and volant mammals, our results suggest predation and satiation by Raccoons. In contrast, deer may be avoiding areas of cicada abundance due to other stimuli, such as high noise output, which may decrease their ability to detect predators.

A Eurasian otter <i>Lutra lutra</i> (Linnaeus 1758) (Carnivora: Mustelidae) in the Tiber basin near Rome: relict or range expansion?

The Eurasian otter Lutra lutra faced a significant decline in Italy during the 20th century, leading to local extinctions. After fifty years of otter disappearance from the Tiber basin, this study documents a sighting near Rome, obtained during a long-term trail camera monitoring. The study area, Rio Moscio, offers a habitat rich in hygrophilous vegetation and diverse fauna, including other protected species such as the Italian wolf, the European wildcat, and the European polecat. The observed otter could either mark a potential range expansion or could challenge the presumed extinctions in this region, since it could be in dispersal from the closer known populations or an individual from a Tiber basin relict population. The study emphasises the need for continued monitoring and prompt future genetic analyses to obtain necessary insights for conserving otters in Central Italy.

Antarstick: Extracting Snow Height From Time‐Lapse Photography

AbstractThe evolution and accumulation of snow cover are among the most important characteristics influencing Antarctica's climate and biotopes. The changes in Antarctica are also substantially impacting global climate change. Therefore, detailed monitoring of snow evolution is key to understanding such changes. One way to conduct this monitoring is by installing trail cameras in a particular region and then processing the captured information. This option is affordable, but has some drawbacks, such as the fully automatic solution for the extraction of snow height from these images is not feasible. Therefore, it still requires human intervention, manually correcting the inaccurately extracted information. In this paper, we present Antarstick, a tool for visual guidance of the user to potentially wrong values extracted from poor‐quality images and support for their interactive correction. This tool allows for much quicker and semi‐automated processing of snow height from time‐lapse photography.

The trophic strategy of the European honey‐buzzard Pernis apivorus during breeding: extravagant specialization or ingenious solution?

This article provides insight into the trophic strategy of a little‐known top predator and allows for a better understanding of the selective pressures that shape its diet. We studied the diet of European honey‐buzzards, a raptor specialized in consuming social wasp brood. The ratio of predator to prey biomasses is one of the highest among raptors. Considering the prey size and ingestion rate hypothesis, we investigated the honey‐buzzard's preferences for native and exotic eusocial vespid species. We also described other prey items in the diet and how diet changes throughout the breeding season. We installed trail cameras in 24 honey‐buzzard nests in north‐western Spain in 2018–2021. We estimated the proportion and daily rate of delivery of native common‐wasps, invasive Asian‐hornets, reptiles, and birds and the honey‐buzzard's preferences for vespid species. We performed LMMs, GLMMs, and CLMMs to analyse relationships between response variables and predictors. Honey‐buzzards mainly consumed vespids (82% of prey). Common‐wasps and Asian‐hornets were almost the only two vespids consumed. The invasive hornet was the second most consumed prey, but common‐wasps were preferred. Vespids became more important as the age and number of nestlings increased. Our results suggest that this diet is the adaptive result of the conflict between being a median‐sized insect‐eating nidicolous raptor and collecting enough morsels for the growth of its nestlings. This would allow them to deliver a relatively large amount of biomass to the nest with a high ingestion rate. We discussed implications of our findings for the management of the invasive wasp.

Epidemiology of sarcoptic mange in a geographically constrained insular red fox population

Background Sarcoptic mange is a skin disease caused by the contagious ectoparasite Sarcoptes scabiei, capable of suppressing and extirpating wild canid populations. Starting in 2015, we observed a multi-year epizootic of sarcoptic mange affecting a red fox (Vulpes vulpes) population on Fire Island, NY, USA. We explored the ecological factors that contributed to the spread of sarcoptic mange and characterized the epizootic in a landscape where red foxes are geographically constrained.MethodsWe tested for the presence of S. scabiei DNA in skin samples collected from deceased red foxes with lesions visibly consistent with sarcoptic mange disease. We deployed 96–100 remote trail camera stations each year to capture red fox occurrences and used generalized linear mixed-effects models to assess the affects of red fox ecology, human and other wildlife activity, and island geography on the frequency of detecting diseased red foxes. We rated the extent of visual lesions in diseased individuals and mapped the severity and variability of the sarcoptic mange disease.ResultsSkin samples that we analyzed demonstrated 99.8% similarity to S. scabiei sequences in GenBank. Our top-ranked model (weight = 0.94) showed that diseased red foxes were detected more frequently close to roadways, close to territories of other diseased red foxes, away from human shelters, and in areas with more mammal activity. There was no evidence that detection rates in humans and their dogs or distance to the nearest red fox den explained the detection rates of diseased red foxes. Although detected infrequently, we observed the most severe signs of sarcoptic mange at the periphery of residential villages. The spread of visual signs of the disease was approximately 7.3 ha/week in 2015 and 12.1 ha/week in 2017.ConclusionsWe quantified two separate outbreaks of sarcoptic mange disease that occurred > 40 km apart and were separated by a year. Sarcoptic mange revealed an unfettered spread across the red fox population. The transmission of S. scabiei mites in this system was likely driven by red fox behaviors and contact between individuals, in line with previous studies. Sarcoptic mange is likely an important contributor to red fox population dynamics within barrier island systems.Graphical

Orchard management factors affecting rates of bud damage to kiwifruit orchards

Although bird damage to fruit crops is well documented, bird damage to flower and leaf buds is relatively understudied. In Aotearoa/New Zealand, bird damage to kiwifruit (Actinidia deliciosa and Actinidia chinensis) buds has been reported to be widespread. However, the responsible bird species and rates of damage have not been investigated, nor is it known if orchard management such as the presence of shelterbelts, and management of swards (grass) between vines or characteristics of the surrounding landscape affect patterns of bud damage. We aimed to identify the bird species responsible for damage to kiwifruit buds, the extent of damage across orchards, and factors correlated with bud damage. A combination of bird surveys, trail cameras, and bud damage surveys were employed across 18 kiwifruit orchards in the Bay of Plenty, Aotearoa/New Zealand. House sparrows (Passer domesticus), chaffinches (Fringilla coelebs), and silvereyes (Zosterops lateralis) were identified as the most frequent species damaging buds. On average, 10% of buds were damaged, but rates of damage varied widely across orchards. Increasing availability of sward seeds was associated with increasing bird abundance but decreasing bud damage levels, potentially because seeds from sward vegetation offer an alternative food source. Shelterbelt volume, block management type (conventional vs organic), and the proportion of vegetation in the surrounding landscape also influenced bird abundance and damage. Understanding which management and environmental factors influence bird abundance and damage may benefit bird management in orchards, such as leaving swards unmown to increase sward seed availability and to reduce bird damage levels to kiwifruit buds.

Urbanization does not affect red foxes' interest in anthropogenic food, but increases their initial cautiousness.

Human presence and activities have profoundly altered animals' habitats, exposing them to greater risks but also providing new opportunities and resources. The animals' capacity to effectively navigate and strike a balance between risks and benefits is crucial for their survival in the Anthropocene era. Red foxes (Vulpes vulpes), adept urban dwellers, exhibit behavioral plasticity in human-altered environments. We investigated variations in detection frequency on trail cameras and the behavioral responses (explorative, bold, and fearful) of wild red foxes living along an urbanization gradient when exposed to a metal bin initially presented clean and then filled with anthropogenic food. All fox populations displayed an increased interest and similar explorative behavioral responses toward the anthropogenic food source, irrespective of the urbanization gradient. Despite no impact on explorative behaviors, foxes in more urbanized areas initially showed heightened fear toward the empty bin, indicating increased apprehension toward novel objects. However, this fear diminished over time, and in the presence of food, urban foxes displayed slightly reduced fear compared with their less urban counterparts. Our results highlight foxes' potential for adaptability to human landscapes, additionally underscoring the nuanced interplay of fear and explorative behavioral response of populations living along the urbanization gradient.