Global Positioning System Tracking Research Articles

Habitat Selection and Specialisation of Herring Gulls During the Non-breeding Season

Understanding both the distribution and habitat use of populations through the annual cycle is vital to understanding how vulnerable species are to environmental change. However, distributions and habitat use can vary among individuals and populations, particularly in generalist species, with variation depending on external environmental factors, such as resource availability. Comprehensive information across multiple populations is important to guide spatial planning of protected areas and is increasingly available for breeding individuals, but it is still lacking for many species, particularly seabirds, during the non-breeding season, especially those with declining populations. We investigated within-species variation in migratory strategies, non-breeding habitat selection and habitat and spatial specialisation in a declining, opportunistic, generalist seabird, the European herring gullLarus argentatus, from multiple breeding colonies across northwest England and southwest Scotland using global positioning system (GPS) tracking during the non-breeding season of 2014/15. Although several individuals stayed within the area of the breeding colony, the majority of individuals migrated in a southerly direction and spent half of the annual cycle (on average 53%) away from the breeding area and kept moving through the non-breeding period. During non-breeding, herring gulls selected mainly marine intertidal, but also a range of anthropogenic terrestrial habitats. However, habitat selection differed between geographical regions, within a geographical region and among individuals. There was a generalist use of non-breeding habitats at the population level, but some habitat specialisation at the individual level that was repeatable through the non-breeding period despite individuals showing low spatial specialisation. The results highlight the importance of intertidal habitat and a mix of alternative foraging habitats in the wintering areas of herring gulls. The results also highlight that habitat selection in an opportunistic generalist can vary even between nearby regions and that appropriate conservation management plans may need to be tailored to regional differences in specific non-breeding areas.

RANCANG BANGUN KEAMANANAN KENDARAAN MENGGUNAKAN SIDIK JARI DAN GPS TRACKING BERBASIS ARDUINO PADA SEPEDA MOTOR

Innovation in motorcycle technology is increasingly visible from year to year. The increasing number of cases of motorcycle theft in Indonesia seems to be starting to cause significant unrest among motorcycle owners and drivers today. In response to this, Honda provides more security to its motorcycle products by adding a feature known as Secure Key Shutter (SKS). The risk of motorcycle theft is not only at night and in quiet places, during the day and in crowds, thieves can carry out theft of motorized vehicles easily. The theft ofmotor vehicles, especially motorcycles, is a daily problem that still needs to be solved. As for this study, we want to implement a security system in the form of a vehicle motorcycle alarm using fingerprints (Finger Print) and GPS (Global Positioning System) Arduino-based Tracking and this tool functions when a motorcycle vehicle wants to be turned on, the user puts his fingerprint on the finger print to turn it on. the electricity of the motorbike and if the motorbike is lost, it can be tracked using GPS (Global Positioning System) Tracking.

Niche dynamics suggest ecological factors influencing migration in an insectivorous owl.

Seasonal migration is a widespread phenomenon undertaken by myriad organisms, including birds. Competing hypotheses about ultimate drivers of seasonal migration in birds contrast relative resource abundances at high latitudes ("southern home hypothesis") against avoidance of winter resource scarcity ("dispersal-migration hypothesis"). However, direct tests of these competing hypotheses have been rare and to date limited to historical biogeographic reconstructions. Here we derive novel predictions about the dynamics of individual niches from each hypothesis and provide a framework for evaluating support for these competing hypotheses using contemporary environmental and behavioral data. Using flammulated owls (Psiloscops flammeolus) as a model, we characterized year-round occupied niche dynamics using high-resolution global positioning system tracking and remote-sensed environmental data. We also compared occupied niche dynamics to counterfactual niches using simulated alternative nonmigratory strategies. Owl occupied mean niche was conserved among seasons, whereas niche variance was generally higher during migratory periods. Simulated year-round residents in Mexico would have experienced putatively more productive niches than migrants. These findings provide ecological support for the "dispersal-migration" hypothesis in which winter resource scarcity is the primary driver of migration rather than summer resource abundances.

Distribution of Salers cows in contrasting rangeland pastures relative to established slope and water guidelines

Topographical constraints, particularly steep slopes and far distances to water, have persistently challenged livestock distribution globally. Information gained from global positioning system (GPS) tracking devices have accelerated knowledge of cattle (Bos taurus) use of complex topography to potentially challenge established guidelines. In northern Wyoming, USA, we deployed 5 GPS collars on multiparous Salers cows with calves from July to November 2018–2019. Cattle rotated between 2 contrasting rangeland pastures: the Basin pasture (Foothills Shrublands and Low Mountains ecoregion; mean slope of 17.7% (range: 0.87–111.01%)) and Mountain pasture (transitioning to Absaroka-Gallatin Volcanic Mountain ecoregion; mean slope of 24.4% (range: 0.26–125.11%)). We estimated mean and maximum slope use and distances from water, along with daily distances traveled for each GPS-collared cow per pasture per year. We also generated utilization distributions with Brownian bridge movement models to compare mean slope and distances to water among quartiles of predicted use, and compared stocking rate adjustments per pasture between standard and GPS location derived methods. Mean daily distance traveled was 5126.5 km and 5011.6 km in the Basin and Mountain pastures, respectively, and average distance to water was <1.65 km. Cattle use was concentrated on gentler slopes than the average slope of the pasture. Mean and maximum slope use was 17.5% (9.9°) and 68.2% (34.3°) respectively in the Basin pasture and 8.9% (5.1°) and 57.1% (29.7°) in the Basin pasture. Compared to standard methods, GPS-derived grazeable area calculations suggested that there was less grazeable area in the Basin pasture but more in the Mountain pasture. Our results indicate that cattle adapted to mountainous terrain may challenge established guidelines for slope use, but not for distance to water. Such information could influence grazeable area calculations, stocking rates, and water development.

Sensor-Based Detection of Predator Influence on Livestock: A Case Study Exploring the Impacts of Wild Dogs (Canis familiaris) on Rangeland Sheep.

Simple SummarySheep predation by wild dogs has serious production and animal welfare implications. By monitoring changes in the behaviour of sheep, on-animal sensors are an option for detecting wild dogs and alerting producers to their presence. This study identified differences in the daily distance travelled of sheep when in the presence and absence of a wild dog and highlights the potential for on-animal sensors to be used as a monitoring and management tool for wild dog detection.In Australia, wild dogs are one of the leading causes of sheep losses. A major problem with managing wild dogs in Australia’s rangeland environments is that sheep producers are often unaware of their presence until injuries or deaths are observed. One option for earlier detection of wild dogs is on-animal sensors, such as Global Positioning System (GPS) tracking collars, to detect changes in the behaviour of sheep due to the presence of wild dogs. The current study used spatio-temporal data, derived from GPS tracking collars, deployed on sheep from a single rangeland property to determine if there were differences in the behaviour of sheep when in the presence, or absence, of a wild dog. Results indicated that the presence of a wild dog influenced the daily behaviours of sheep by increasing the daily distance travelled. Differences in sheep diurnal activity were also observed during periods where a wild dog was present or absent on the property. These results highlight the potential for on-animal sensors to be used as a monitoring tool for sheep flocks directly impacted by wild dogs, although further work is needed to determine the applicability of these results to other sheep production regions of Australia.

COVID-19 Cluster Linked to Aerosol Transmission of SARS-CoV-2 via Floor Drains.

BackgroundRecently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through exposure to aerosols has been suggested. Therefore, we investigated the possibility of aerosol SARS-CoV-2 transmission within an apartment complex where residents reported testing positive for SARS-CoV-2 despite having no direct contact with other SARS-CoV-2–infected people.MethodsInformation on symptom onset and exposure history of the patients was collected by global positioning system (GPS) tracking to investigate possible points of contact or spread. Samples collected from patients and from various areas of the complex were analyzed using RNA sequencing. Phylogenetic analysis was also performed.ResultsOf 19 people with confirmed SARS-CoV-2 infection, 5 reported no direct contact with other residents and were from apartments in the same vertical line. Eight environmental samples tested positive for the virus. Phylogenetic analyses revealed that 3 of the positive cases and 1 environmental sample belonged to the B.1.497 lineage. Additionally, 3 clinical specimens and 1 environmental sample from each floor of the complex had the same amino acid substitution in the ORF1ab region.ConclusionsSARS-CoV-2 transmission possibly occurs between different floors of an apartment building through aerosol transmission via nonfunctioning drain traps.

An Ultraminiaturized Frequency Selective Surface With Angular and Polarization Stability

This letter presents the design and testing of a novel triple-layer frequency selective surface (FSS) with ultraminiaturization for electromagnetic shielding applications. The proposed unit cell is constructed using meandered lines running along the three layers and they are interconnected using metalized vias to increase the electrical length of FSS. The FSS is designed to offer band stop resonance at L-band frequency with a foot-print of 0.022 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> × 0.022 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> with a thickness of 0.006 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> and it provides at least 38% of miniaturization in comparison with similar literature. To validate the transmission performance, a prototype FSS with a periodicity of 6 mm is fabricated. The FSS consists of 2500 elements arranged in a 50 × 50 square lattice. The transmission performance of the proposed FSS is verified using simulation and experiment. The proposed FSS has rotational symmetry and hence it is polarization insensitive. Furthermore, the FSS offers excellent angular stability up to the maximum incidence angle of 60° under both transverse electric and transverse magnetic modes of operation. The proposed FSS can be used for shielding applications in global positioning systems tracking and aircraft surveillance systems.

Australian Magpies Gymnorhina tibicen cooperate to remove tracking devices

Recent advances in tracking technology have enabled devices such as Global Positioning Systems (GPS) loggers to be used on a wide variety of birds. Although there are established ethical considerations to these processes, different species may react differently to particular devices and attachments. Thus, pilot studies are still of utmost importance in this field. Here, we describe one such study trialling a novel harness design for GPS tracking devices on Australian Magpies Gymnorhina tibicen. Despite previous testing demonstrating the strength and durability of the harness, devices were removed within minutes to hours of initial fitting. Notably, removal was observed to involve one bird snapping another bird’s harness at the only weak point, such that the tracker was released. This behaviour demonstrates both cooperation and a moderate level of problem solving, providing potential further evidence of the cognitive abilities of this species. To our knowledge, this is the first study to report the conspecific removal of GPS trackers, and should be considered when planning future tracking studies especially on highly social species.

Decision rules for determining terrestrial movement and the consequences for filtering high-resolution global positioning system tracks: a case study using the African lion (Panthera leo).

The combined use of global positioning system (GPS) technology and motion sensors within the discipline of movement ecology has increased over recent years. This is particularly the case for instrumented wildlife, with many studies now opting to record parameters at high (infra-second) sampling frequencies. However, the detail with which GPS loggers can elucidate fine-scale movement depends on the precision and accuracy of fixes, with accuracy being affected by signal reception. We hypothesized that animal behaviour was the main factor affecting fix inaccuracy, with inherent GPS positional noise (jitter) being most apparent during GPS fixes for non-moving locations, thereby producing disproportionate error during rest periods. A movement-verified filtering (MVF) protocol was constructed to compare GPS-derived speed data with dynamic body acceleration, to provide a computationally quick method for identifying genuine travelling movement. This method was tested on 11 free-ranging lions (Panthera leo) fitted with collar-mounted GPS units and tri-axial motion sensors recording at 1 and 40 Hz, respectively. The findings support the hypothesis and show that distance moved estimates were, on average, overestimated by greater than 80% prior to GPS screening. We present the conceptual and mathematical protocols for screening fix inaccuracy within high-resolution GPS datasets and demonstrate the importance that MVF has for avoiding inaccurate and biased estimates of movement.

Tourists’ Behavioral Characteristics Regarding Island-Based Tourism Destinations through the Perspective of Spatial Constraints: A Case Study of Yangma Island in China

The factors affecting tourist behavior are complex and diverse, but research on its effect from a purely spatial perspective is still limited. The aim of this paper is to explore the dichotomous interaction between tourists and islands: the behavioral patterns of tourists in island destinations and the mechanisms by which island spaces constrain tourist behavior. This study uses fine-grained global positioning system (GPS) tracking data actively authorized and released by tourists. We empirically studied tourist behavior from a spatial constraint perspective and discovered the following: island space has a strong influence and constraining effect on tourist behavior; different spatial attributes have different constraining effects on tourist behavior; and people with different identities interact with different attributes of space to produce different spatial properties, resulting in a ‘harmony-contradiction’ model of spatial interaction. These findings are of great value in expanding the perspective of spatial constraints and exploring the interactions between people and land. They are also of great practical significance in promoting spatial planning synergy, facilitating the construction of high-quality island-based tourism destinations, and building a harmonious relationship between people and land.

The Cost of Gathering Among the Baka Forager-Horticulturalists From Southeastern Cameroon

What present-day foragers do for their living and what they eat have long been privileged areas for exploring human behavior, global health, and human evolution. While many studies have focused on hunting and meat acquisition, less attention has been given to gathering and plant foods. Despite evidence of variation in both nutritional quality and energetic costs of gathering different plants, the overall effort spent on gathering in relation to other subsistence tasks is still under explored. In the current context of economic, climate, and social changes, many forager societies also rely on other subsistence strategies, including agriculture and wage labor. In this study, we aim to explore the place of gathering in the livelihood of a mixed economy society, the Baka forager-horticulturalists of southeastern Cameroon, by comparing the involvement and the costs of activities related to food acquisition. From a pool of 153 adult participants (97 women and 56 men), we collected 246 daily records using a GPS (Global Positioning System) tracker combined with heart rate monitor and time allocation recalls. We compared the duration, distance traveled, and the intensity of work, measured by calculating the metabolic equivalent of task (MET), of subsistence activities related to food acquisition. Results from this work show that gathering activities, performed by both women and men, are energetically costly, with higher MET values than hunting and fishing activities. Furthermore, the MET values vary depending on the targeted plant foods. We discuss these insights in the overall framework of subsistence patterns, merging them with the socio-cultural and environmental factors that might explain Baka livelihood and subsistence strategy.

Validity of a Global Positioning System-Based Algorithm and Consumer Wearables for Classifying Active Trips in Children and Adults.

To investigate the convergent validity of a global positioning system (GPS)-based and two consumer-based measures with trip logs for classifying pedestrian, cycling, and vehicle trips in children and adults. Participants (N = 34) wore a Qstarz GPS tracker, Fitbit Alta, and Garmin vivosmart 3 on multiple days and logged their outdoor pedestrian, cycling, and vehicle trips. Logged trips were compared with device-measured trips using the Personal Activity Location Measurement System (PALMS) GPS-based algorithms, Fitbit's SmartTrack, and Garmin's Move IQ. Trip- and day-level agreement were tested. The PALMS identified and correctly classified the mode of 75.6%, 94.5%, and 96.9% of pedestrian, cycling, and vehicle trips (84.5% of active trips, F1 = 0.84 and 0.87) as compared with the log. Fitbit and Garmin identified and correctly classified the mode of 26.8% and 17.8% (22.6% of active trips, F1 = 0.40 and 0.30) and 46.3% and 43.8% (45.2% of active trips, F1 = 0.58 and 0.59) of pedestrian and cycling trips. Garmin was more prone to false positives (false trips not logged). Day-level agreement for PALMS and Garmin versus logs was favorable across trip modes, though PALMS performed best. Fitbit significantly underestimated daily cycling. Results were similar but slightly less favorable for children than adults. The PALMS showed good convergent validity in children and adults and were about 50% and 27% more accurate than Fitbit and Garmin (based on F1). Empirically-based recommendations for improving PALMS' pedestrian classification are provided. Since the consumer devices capture both indoor and outdoor walking/running and cycling, they are less appropriate for trip-based research.

Spatiotemporal risk assessment for avian influenza outbreak based on the dynamics of habitat suitability for wild birds.

Highly pathogenic avian influenza (HPAI) has predominantly damaged the poultry industry worldwide. The fundamental prevention and control strategy for HPAI includes early detection and timely intervention enforcement through a systematic surveillance system for wild birds based on the ecological understanding of the dynamics of wild birds' movements. Our study aimed to develop a spatiotemporal risk assessment model for avian influenza (AI) infection in wild birds to empower surveillance information for a contingency strategy. For this purpose, first, we predicted the monthly habitat suitability of seven waterfowl species, using 227,671 Global Positioning System (GPS) tracking records of 562 birds from 2014 to 2018 in the Republic of Korea (ROK). Then, that predicted habitat suitability and 421 coordinates of AI detection sites in wild birds were used to build the risk assessment model. Subsequently, we compared the monthly predicted risk of avian influenza virus (AIv) identification in wild birds between case and non-case poultry farms with HPAI H5N6 outbreak in the ROK between 2016 and 2017. The results reported considerable variation of monthly habitat suitability of seven waterfowls and the impact of predicting AI occurrences in wild birds. The high habitat suitability for spot-billed ducks (contribution rate in November=40.9%) and mallards (contribution rate in January=34.3%) significantly contributed to predicting the average risk of AIv identification in wild birds, with high predictive performance [the monthly mean of area under the curve (AUC)=0.978]. Moreover, our model showed that the averaged risk of identification AI in wild birds was significantly higher in HPAI infected premises, with infected domestic duck holdings exhibiting a significantly higher risk than the chicken farms in November. This study suggests that animal health authority establishes a risk-based HPAI surveillance system grounded on the ecological nature of wild birds to improve the effectiveness of prevention and preparedness of emerging epidemics.

SISTEM APLIKASI LOKASI KEAMANAN KENDARAAN MENGGUNAKAN GPS (GLOBAL POSITION SYSTEM) BERBASIS WEB

&#x0D; &#x0D; &#x0D; &#x0D; Parepare city is a developed city which requires its people to have high mobility for the sake of work demands or daily activities. The higher the need for transportation, the higher the motor theft crime. Since 2019 until now there have been around 69 cases of theft and only a few have been found by the police, it is because there is no Gps device on the vehicle so that it cannot track the location of the lost vehicle. GPS tracking is a system that allows users to track the position of motorized vehicles in real time. The type of research that will be carried out in this study is to create a vehicle security location application system using a web-based GPS (global position system). This application can monitor the location of the vehicle and can also control the engine and horn on the vehicle remotely. Testing the system that has been made Black Box, it is found that the functional application runs well in accordance with the design made. &#x0D; &#x0D; &#x0D; &#x0D;

Temporal Changes in Association Patterns of Cattle Grazing at Two Stocking Densities in a Central Arizona Rangeland

Simple SummaryMonitoring changes in the utilization of forages across rangelands can be time consuming and difficult with untrained personnel. The use of real time positioning for cattle is becoming commercially available with the improvements in technology. The objective of this case study was to identify the changes in livestock social associations and spatial location at two stocking densities throughout a six-week grazing period. Both pastures used similar sized herds with 35 and 29 animals tracked with global positioning systems set at 30-min intervals. A half-weight index value was calculated for each pair of tracked cattle to determine the proportion of time that cattle were within 75 m and 500 m of each other. Throughout the study, forage utilization increased from 5 to 24% and from 10% to 20% and forage mass decreased from 2601 kg ha−1 to 1828 kg ha−1 and 2343 kg ha−1 to 1904 kg ha−1, in the high stocking density pasture and low stocking density pasture, respectively. Utilization of forages throughout the trial forced cattle to disperse and travel further from water sources to find new feeds. Real-time GPS tracking has the potential to remotely detect changes in animal spatial association, identify when cows disperse, and improve recognition for the need of pasture rotation to avoid rangeland degradation.Proper grazing management of arid and semi-arid rangelands requires experienced personnel and monitoring. Applications of GPS tracking and sensor technologies could help ranchers identify livestock well-being and grazing management issues so that they can promptly respond. The objective of this case study was to evaluate temporal changes in cattle association patterns using global positioning system (GPS) tracking in pastures with different stocking densities (low stocking density [LSD] = 0.123 animals ha−1, high stocking density [HSD] = 0.417 animals ha−1) at a ranch near Prescott, Arizona. Both pastures contained similar herd sizes (135 and 130 cows, respectively). A total of 32 cows in the HSD herd and 29 cows in the LSD herd were tracked using GPS collars at location fixes of 30 min during a 6-week trial in the summer of 2019. A half-weight index (HWI) value was calculated for each pair of GPS-tracked cattle (i.e., dyads) to determine the proportion of time that cattle were within 75 m and 500 m of each other. Forage mass of both pastures were relatively similar at the beginning of the study and forage utilization increased from 5 to 24% in the HSD pasture and increased from 10 to 20% in the LSD pasture. Cattle in both pastures exhibited relatively low mean association values (HWI < 0.25) at both spatial scales. Near the end of the study, cattle began to disperse likely in search of forages (p < 0.01) and travelled farther (p < 0.01) from water than during earlier periods. Real-time GPS tracking has the potential to remotely detect changes in animal spatial association (e.g., HWI), and identify when cows disperse, likely searching for forage.

Review and evaluation of methods in transport mode detection based on GPS tracking data

Mobility data, based on global positioning system (GPS) tracking, have been widely used in many areas, such as analyzing travel patterns, investigating transport safety and efficiency, and evaluating travel impacts. Transport modes are essential factors in understanding mobility within the transport system. Therefore, in this study, a significant number of algorithms were tested for transport mode detection. However, no conclusive recommendations can be drawn regarding which method should be used. The evaluation of the performance of the algorithms was not discussed systematically either in current literature. This paper aims to provide an in-depth review of the methods applied in transport mode detection based on GPS tracking data. The performances of the reviewed methods are then compared and evaluated to provide guidance in choosing algorithms for transport mode detection based on GPS tracking data. The results indicate that the majority of current studies are based on a supervised learning method for transport mode detection. Many of the reviewed methods first require manual dataset labeling, which can produce major drawbacks, such as inefficiency and human errors. It was also found that deep learning approaches have the potential to deal with large amounts of unlabeled raw GPS datasets and increase the accuracy and efficiency of transport mode detection. • A systematic review of methods used to detect transport mode in GPS tracking data. • Compare and evaluate the performance of the reviewed methods. • Enhance knowledge for choosing algorithms to detect transport mode. • Investigate the usefulness of additional GIS information to detect transport mode. • Provide guidance for future research to develop transport mode detection.

When the Physician Becomes the Caregiver: A Review for Physicians Caring for Their Elder Relatives.

When the Physician Becomes the Caregiver: A Review for Physicians Caring for Their Elder Relatives.

Penggunaan Sistem GPS Untuk Keamanan Kendaraan Dengan Kontrol SMS Menggunakan Mikrokontroler Arduino

Motor vehicle theft cases still often occur around us, this happens because there is still a lack of security systems in motorized vehicles that only use ignition keys and key covers, where the weakness of standard security systems like this has been understood by perpetrators of motor vehicle theft. to perform the action. The need for additional security systems is felt to be very necessary, in order to avoid the occurrence of motor vehicle theft. To overcome all this, a motor vehicle security system was created using SMS with an Arduino-based GPS tracking method, to create a GPS Tracker that can control vehicles via SMS (short message service) that can track or assist the vehicle's position using the Arduino Uno GPS (global positioning system). , SIM 800L. If the vehicle is lost, the owner can be tracked only by SMS to the number that has been programmed on the Arduino uno to prevent and make it easier to get back a stolen motor vehicle.

Predicting the SARS-CoV-2 effective reproduction number using bulk contact data from mobile phones

Over the last months, cases of SARS-CoV-2 surged repeatedly in many countries but could often be controlled with nonpharmaceutical interventions including social distancing. We analyzed deidentified Global Positioning System (GPS) tracking data from 1.15 to 1.4 million cell phones in Germany per day between March and November 2020 to identify encounters between individuals and statistically evaluate contact behavior. Using graph sampling theory, we estimated the contact index (CX), a metric for number and heterogeneity of contacts. We found that CX, and not the total number of contacts, is an accurate predictor for the effective reproduction number R derived from case numbers. A high correlation between CX and R recorded more than 2 wk later allows assessment of social behavior well before changes in case numbers become detectable. By construction, the CX quantifies the role of superspreading and permits assigning risks to specific contact behavior. We provide a critical CX value beyond which R is expected to rise above 1 and propose to use that value to leverage the social-distancing interventions for the coming months.

Direct evidence of a prey depletion “halo” surrounding a pelagic predator colony

Colonially breeding birds and mammals form some of the largest gatherings of apex predators in the natural world and have provided model systems for studying mechanisms of population regulation in animals. According to one influential hypothesis, intense competition for food among large numbers of spatially constrained foragers should result in a zone of prey depletion surrounding such colonies, ultimately limiting their size. However, while indirect and theoretical support for this phenomenon, known as "Ashmole's halo," has steadily accumulated, direct evidence remains exceptionally scarce. Using a combination of vessel-based surveys and Global Positioning System tracking, we show that pelagic seabirds breeding at the tropical island that first inspired Ashmole's hypothesis do indeed deplete their primary prey species (flying fish; Exocoetidae spp.) over a considerable area, with reduced prey density detectable >150 km from the colony. The observed prey gradient was mirrored by an opposing trend in seabird foraging effort, could not be explained by confounding environmental variability, and can be approximated using a mechanistic consumption-dispersion model, incorporating realistic rates of seabird predation and random prey dispersal. Our results provide a rare view of the resource footprint of a pelagic seabird colony and reveal how aggregations of these central-place foraging, marine top predators profoundly influence the oceans that surround them.