Movements Of Birds Research Articles

Assessing individual movement, habitat use, and behavior of non-breeding marine birds in relation to prey availability in the US Atlantic

Resource availability is a key factor driving marine bird movements and distributions, but direct information on prey availability is difficult to obtain at relevant scales. We present novel methods for describing multi-scale trophic associations, combining movement analyses of marine birds with estimates of forage fish surface aggregations from digital aerial survey data and species occupancy from bottom trawl survey data. We analyzed satellite telemetry data from northern gannets Morus bassanus, red-throated loons Gavia stellata, and long-tailed ducks Clangula hyemalis in the US Atlantic during the non-breeding period. Using discrete-time hidden Markov models to distinguish area-restricted (i.e. putative foraging) from transit movements, we examined how environmental factors influence movement, and how forage fish species distributions and surface aggregations influence habitat use by gannets and loons that have greater dietary reliance. Our results suggest that chlorophyll a concentration significantly affected movement behavior across species, highlighting the importance of higher-productivity areas around estuaries during colder months when regional productivity is low. Though variable across species and seasons, spatial cross-correlation analysis revealed that herring species (Family Clupeidae), including Atlantic menhaden Brevoortia tyrannus, may be important resources; it also showed positive spatial correlations with forage fish aggregations. This suggests that prey patch dynamics and factors driving aggregation formation may be as important as species composition. However, spatial patterns were generally low (<0.3), suggesting a mismatch in spatiotemporal resolution, exemplifying the challenges in quantifying trophic relationships in marine systems. Disentangling predator-prey relationships is critical to understanding the mechanisms driving marine bird behavior in rapidly changing marine systems.

Seasonal altitudinal movements of birds in Brazil: a review

Birds’ seasonal altitudinal movements in Brazil are poorly understood. The main source of information and has fostered interest since the 1980s. However, most of the available information is anecdotal, sources are repeatedly cited, and the information provided is quite superficial and speculative. Through bibliographic searches, we found 107 studies, 83 (77%) of which we consider valid, and only 63 (59%) were peer-reviewed. Most studies were carried out in southern and southeastern Brazil. Only 11 studies explicitly addressed seasonal altitudinal movements. Surprisingly, none of the studies simultaneously comprised a full year of study, standardized sampling methods, and encompassed the entire altitudinal range through which the birds might have moved. As a consequence, the quality of the data is questionable, and the expression “altitudinal migration” is unlikely to be accurate and has never been unequivocally demonstrated for birds in Brazil. Mention of “altitudinal migration” was found for 68 bird species, but these must be more clearly defined and appropriately tested.

The relative sizes of nuclei in the oculomotor complex vary by order and behaviour in birds.

Eye movements are a critical component of visually guided behaviours, allowing organisms to scan the environment and bring stimuli of interest to regions of acuity in the retina. Although the control and modulation of eye movements by cranial nerve nuclei are highly conserved across vertebrates, species variation in visually guided behaviour and eye morphology could lead to variation in the size of oculomotor nuclei. Here, we test for differences in the size and neuron numbers of the oculomotor nuclei among birds that vary in behaviour and eye morphology. Using unbiased stereology, we measured the volumes and numbers of neurons of the oculomotor (nIII), trochlear (nIV), abducens (nVI), and Edinger-Westphal (EW) nuclei across 71 bird species and analysed these with phylogeny-informed statistics. Owls had relatively smaller nIII, nIV, nVI and EW nuclei than other birds, which reflects their limited degrees of eye movements. In contrast, nVI was relatively larger in falcons and hawks, likely reflecting how these predatory species must shift focus between the central and temporal foveae during foraging and prey capture. Unexpectedly, songbirds had an enlarged EW and relatively more nVI neurons, which might reflect accommodation and horizontal eye movements. Finally, the one merganser we measured also has an enlarged EW, which is associated with the high accommodative power needed for pursuit diving. Overall, these differences reflect species and clade level variation in behaviour, but more data are needed on eye movements in birds across species to better understand the relationships among behaviour, retinal anatomy, and brain anatomy.

WATLAS: high-throughput and real-time tracking of many small birds in the Dutch Wadden Sea

Tracking animal movement is important for understanding how animals interact with their (changing) environment, and crucial for predicting and explaining how animals are affected by anthropogenic activities. The Wadden Sea is a UNESCO World Heritage Site and a region of global importance for millions of shorebirds. Due to climate change and anthropogenic activity, understanding and predicting movement and space-use in areas like the Wadden Sea is increasingly important. Monitoring and predicting animal movement, however, requires high-resolution tracking of many individuals. While high-resolution tracking has been made possible through GPS, trade-offs between tag weight and battery life limit its use to larger species. Here, we introduce WATLAS (the Wadden Sea deployment of the ATLAS tracking system) capable of monitoring the movements of hundreds of (small) birds simultaneously in the Dutch Wadden Sea. WATLAS employs an array of receiver stations that can detect and localize small, low-cost tags at fine spatial (metres) and temporal resolution (seconds). From 2017 to 2021, we tracked red knots, sanderlings, bar-tailed godwits, and common terns. We use parts of these data to give four use-cases revealing its performance and demonstrating how WATLAS can be used to study numerous aspects of animal behaviour, such as, space-use (both intra- and inter-specific), among-individual variation, and social networks across levels of organization: from individuals, to species, to populations, and even communities. After describing the WATLAS system, we first illustrate space-use of red knots across the study area and how the tidal environment affects their movement. Secondly, we show large among-individual differences in distances travelled per day, and thirdly illustrate how high-throughput WATLAS data allows calculating a proximity-based social network. Finally, we demonstrate that using WATLAS to monitor multiple species can reveal differential space use. For example, despite sanderlings and red knots roosting together, they foraged in different areas of the mudflats. The high-resolution tracking data collected by WATLAS offers many possibilities for research into the drivers of bird movement in the Wadden Sea. WATLAS could provide a tool for impact assessment, and thus aid nature conservation and management of the globally important Wadden Sea ecosystem.

SEIR-Metapopulation model of potential spread of West Nile virus

In 2018, West Nile Virus (WNV) was detected for the first time in Germany. Since the first detection, 36 human cases and 175 cases in horses and birds are detected. The transmission cycle of West Nile Virus includes birds and mosquitoes and as dead-end hosts — humans and horses. Spatial dissemination of the disease is caused by the movements of birds and mosquitoes. It should be noted that the vector activity and the spread of WNV are not entirely intertwined but there is a greater scale of overlap between it. The dissemination process is rather complicated and it can not only be attributed to different weather driven factors like temperature but also other biological factors i.e. vector competency, habitat suitability etc. In our current study, we have restricted our modelling effort only to temperature dependent to simplify the modelling assumptions. While the activity and movement of mosquitoes are depending mainly on temperature, in the birds there is a complex movement pattern caused by local birds and long-range dispersal birds. To this end, we have developed a metapopulation-network model to delineate the potential spatial distribution and spread of WNV across Germany. Our model combines vector, local birds, and long-range dispersal birds contact networks. We have assumed different distance dispersal kernels models for the vector and avian populations with the intention to include short and long-range dispersal. The model includes spatial variation of mosquito abundance and the movements to resemble the reality.

Seasonality modulates habitat cover effects on avian cross‐boundary responses and spillover

Species cross‐boundary response is a key mechanism affecting species spillover into agricultural fields. However, temporal changes in edge permeability, which may depend on the seasonal availability of resources in both matrix and native habitats, remain poorly understood. Here we tested how edge crossing behavior and the associated spillover of birds into sun coffee plantations respond to landscape structure and seasonality. We monitored the movement of six insectivorous understory bird species (four forest specialists and two forest generalists) using an automated telemetry system along a gradient of forest cover (7–60%) during two seasons (dry versus wet) at nine sampling sites at the Brazilian Atlantic forest. We monitored 116 individuals and obtained a total of 15 129 bird detections across seasons. Bird resistance to crossing edges was strongly driven by an interaction between seasonality and forest cover in the surrounding landscape, with higher resistance to crossing edges along the dry season and in landscapes with lower amount of forest cover. Furthermore, spillover patterns in plantations were driven by an interaction between forest cover and distance from forest edges, but this was most pronounced for forest‐specialist bird species. Forest specialists moved more intensively and farther from edges in more forested landscapes, whereas forest generalists showed similar patterns of occupation regardless of forest cover and isolation. Our study contributes to a better understanding of avian cross‐boundary responses and spillover in response to landscape structure across seasons, and the factors driving bird movement decisions in anthropogenic landscapes. There are a myriad of possible mechanisms governing movement decisions, and these mechanisms may interact in complex ways and remain important foci for research within the fields of tropical ecology and evolution.

Prospects for monitoring bird migration along the East Asian‐Australasian Flyway using weather radar

AbstractEach year, billions of birds migrate across the globe, and interpretation of weather radar signals is increasingly being used to document the spatial and temporal migration patterns in Europe and America. Such approaches are yet to be applied in the East Asian‐Australasian Flyway (EAAF), one of the most species‐rich and threatened flyways in the world. Logistical challenges limit direct on‐ground monitoring of migratory birds in many parts of the EAAF, resulting in knowledge gaps on population status and site use that limit evidence‐based conservation planning. Weather radar data have great potential for achieving comprehensive migratory bird monitoring along the EAAF. In this study, we discuss the feasibility and challenges of using weather radar to complement on‐ground bird migration surveys in the flyway. We summarize the location, capacity and data availability of weather radars across EAAF countries, as well as the spatial coverage of the radars with respect to migrants' geographic distribution and migration hotspots along the flyway, with an exemplar analysis of biological movement patterns extracted from Chinese weather radars. There are more than 430 weather radars in EAAF countries, covering on average half of bird species' passage and non‐breeding distributions, as well as 70% of internationally important sites for migratory shorebirds. We conclude that the weather radar network could be a powerful resource for monitoring bird movements over the full annual cycle throughout much of the EAAF, providing estimates of migration traffic rates, site use, and long‐term population trends, especially in remote and less‐surveyed regions. Analyses of weather radar data would complement existing ornithological surveys and help understand the past and present status of the avian community in a highly threatened flyway.

The genetics of bird migration

Bird migration is one of the most amazing biological phenomena exhibited by organisms today, with birds as small as three grams travelling thousands of kilometers twice each year. Most people are familiar with this behaviour; they likely recognize the seasonal movements of birds each year and may have even witnessed specific migratory events (e.g., geese flying in their characteristic V-formations). What many people may not know is that bird migration has a strong genetic basis, especially in groups like songbirds who migrate alone and at night, preventing juveniles from following more experienced adult birds on their first migration. Successful migration also requires the coordinated function of many traits, not only behavioural traits like timing and orientation but also morphological and physiological traits to permit these long distance treks. Together, these traits comprise what has been called the 'migratory syndrome'. In this primer, we provide a broad overview of research on the genetics of migratory traits, from early experimental work to future functional assays and their importance for bird conservation. We focus primarily on songbirds as most work on the genetics of migration has been conducted with this group.

Direct and Indirect Role of Migratory Birds in Spreading CCHFV and WNV: A Multidisciplinary Study on Three Stop-Over Islands in Italy

The annual movements of migratory birds can contribute to the spread of African ticks and tick-borne pathogens of potential public health concern across Europe. The aim of the study was to investigate their role in the possible introduction of African ticks and tick-borne pathogens into European countries during spring migration. A total of 2344 ticks were collected during three spring seasons from 1079 birds captured on three Italian stop-over islands during their northbound migration. Once identified, each tick was tested by RT-PCR for the presence of Crimean-Congo hemorrhagic fever (CCHFV), West Nile (WNV), and Usutu (USUV) viruses. Moreover, carcasses of birds found dead were collected and tested for the possible presence of WNV and USUV. Results confirmed a higher contribution of trans-Saharan migrants compared to intra-Palearctic ones and the prevalence of African tick species in the sample. CCHFV was detected for the second time in Italy in a Hyalomma rufipes, and WNV was found in two ticks of the same genus, all carried by trans-Saharan birds. WNV lineage 1 was also found in the organs of a Garden warbler. These results confirm the role of migratory birds in carrying African ticks, as well as viruses of zoonotic importance, from Africa into Europe.

The Positive Effects of Covid-19 Lockdown on Environmental Attributes: A Review

The effect of covid 19 on human health was devastating and the fatality rate was high around the world. World Health Organization declared the outburst of this infectious disease a pandemic situation. To check the rapid dispersal of the COVID-19 virus, most countries of the world enforced quarantine and strict lockdown. The effects of COVID-19 lockdown on environmental health draw the attention of the scientific communities. Therefore, this research paper inspected and narratively reviewed the observed effects of COVID-19 lockdown on the changes in the environmental quality based on secondary research data. The work provides a distinct indication considering the impacts executed by COVID-19 lockdown on the air, water, soil, and noise as typical environment elements. It has been widely reported that the amount of pollution in the air, water, soil, and noise exhibited a significant decline during lockdown period. It has been noticed in different literature that global air quality improved because of less anthropogenic emissions of air contaminants and atmospheric particles. For instance, releases of carbon, nitrogen, sulfur and particulate matter are reduced and ozone layers were reported to being increased. Aquatic life and water ecosystem have also been restored in many countries due to less commercial fishing. Moreover, soil pollution was less due to a significant decrease in solid and water waste dumping. Because of less transportation of vehicles, industrial and other urban activities, sound pollution dropped to a significant level. Clean beaches, transparent seawater, wildlife sightings and free movement of animals and birds were also found in some counties during lockdown. However, these effects of lockdown were temporary, as the world again enters the pre-lockdown situation. Human attitudes must be changed to continue the positive impact on the environment. World policymakers should take the necessary steps to guarantee the steadiness of the positive environmental effects derived from the COVID-19 lockdown.

Animal Migration Studies with the Use of ICARUS Scientific Equipment in the URAGAN Space Experiment aboard the Russian Segment of the ISS

The major challenges of space research are monitoring and exploration of our planet, which are carried out through the use of remote sensing satellites (RSS) operating in near-Earth orbits. They provide invaluable information for assessing the environmental, epidemiological and other situations on our planet, including animal migration data. The ICARUS project (International Cooperation for Animal Research Using Space) implemented on the International Space Station (ISS) is an ideal laboratory for in-orbit testing of instrumentation and various space technologies aimed to refine methods for tracking movements of mammals and birds. The paper analyzes the experience in the operation of the animal migration monitoring system installed in the Russian segment (RS) of the ISS (ISS RS). The system has incorporated the latest accomplishments in space science, satellite navigation, control technology, and microelectronics. The scientific results on the study of animal and bird migrations obtained within the Russian research program are briefly discussed.

Movements and habitat connectivity of New Zealand forest birds: a review of available data

New Zealand’s original forested landscape has been greatly fragmented since human arrival, limiting connectivity and habitat quality for forest-dependent fauna. We review the limited available information about forest bird movement behaviour, especially whole-year sociality and movement, natal dispersal, and pasture- and water-gap crossing. Most small insectivores (17 species) and North Island kōkako are territorial year-round, but frugivore-nectivores (three species), raptors (two species), and volant parrots (four species) can be highly mobile, presumably to find scattered food.

Measurement and Analysis of Radar Signals Modulated by the Respiration Movement of Birds

Once, bird respiration was thought to be responsible for the 10 dB-level fluctuations in the radar signals of birds. Although, recently, many researchers provide evidence against this, there are almost no quantification measurements of the contribution of respiration to bird signals in microwave anechoic chambers. Here, we first measured the radar signals modulated by the respiration of birds in a microwave anechoic chamber. Theoretically, the simulated signal fluctuation caused by the respiration of a 1 kg standard avian target (SAT) duck is approximately 1.2 dB based on the water sphere model. Then, experimentally, in a microwave anechoic chamber, we measured the signal fluctuations produced by the respiration movement of ducks using a dynamic system composed of a network analyzer and a high-speed camera. We tracked continuous radar data of a living duck and a dead duck within the S-band, X-band, and Ku-band, and then presented them using low-resolution range profiles (LRRP) and high-resolution range profiles (HRRP). The results indicate that respiration movement causes periodic signal fluctuation with a respiration rate of approximately 0.7 Hz, but the amplitudes within S-band, X-band, and Ku-band are approximately 1 dB level, much less than the 10 dB level. Respiration is not responsible for the 10 dB-level periodic signal fluctuation in radar echoes from birds.

Rapid elevational shifts of Switzerland's avifauna and associated species traits

AbstractGlobal change in climate and land use has profound effects on species' geographic and elevational distributions. In European birds, while species are predicted to track their climatic niches upslope, lowland agricultural intensification and high‐elevation land abandonment can drive elevational shifts. Species traits that can predict response to change in climate and land use can inform conservation, but a thorough examination of their relationships with elevational shifts in European birds is lacking. We estimate the change in the elevational distributions of 71 species from 1996 to 2016 in a region of the western Palearctic with wide elevational gradients (approximately 3000 m) and large changes in temperature. We model the relationships between elevational shifts and species traits associated with resource preference and adaptive capacity at five reference points including the cool edge, warm edge, and the core of species' elevational distributions. When intermediate reference points were removed, changes to the results were negligible, indicating that three reference points are likely sufficient. We found significant upslope and downslope shifts in 56% and 23% of our study species, respectively. Asymmetric rates of shifts in the cool and warm edges caused significant contractions in elevational extent in 30% of our study species. The effect of elevational preference (i.e., midpoint elevation) was habitat dependent. Movement in alpine birds was unidirectionally upslope, with nearly half displaying significant or apparent elevational range contractions. In woodland birds, asymmetries of shifts in reference points led to expansions in extent in low‐elevation species and contractions in high‐elevation species. Generally, migrants, species with smaller mass, smaller relative brain size, smaller hand‐wing index, and generalists in diet, habitat, and elevation had greater upslope shifts. While elevational shifts in European birds were heterogenous and species‐specific, many were rapid, and species traits associated with resource preference and adaptive capacity were associated with common patterns of elevation.

No detectable effect of geolocator deployment on the short‐ or long‐term apparent survival of a tropical seabird

A wide range of biologging devices are now commonly deployed to study the movement ecology of birds, but deployment of these devices is not without its potential risks and negative impacts on the welfare, behaviour and fitness of tagged individuals. However, empirical evidence for the effects of tags is equivocal. Global location sensing (GLS) loggers are small, light level recording devices that are well suited to studying the large‐scale migratory movements of many birds. However, few published studies have examined their impact on adult survival, a key demographic rate for long‐lived species, such as seabirds. To address this, we have collated a long‐term mark–recapture dataset in conjunction with a 10‐year GLS tagging programme and examined the impact of tarsus‐mounted GLS loggers on the adult apparent survival probabilities of a medium‐sized tropical gadfly petrel. We found no evidence to indicate that deployment of GLS loggers affected apparent adult survival probabilities either in the short term, i.e. during deployment, or in the long term, i.e. from carrying a device at some point in the past. Annual adult apparent survival was estimated at 0.965 (95% CI 0.962–0.968) during 1993–2018. Our findings suggest that using GLS loggers to document the movements of medium‐sized gadfly petrels over multiple years is a viable technique without negatively impacting adult survival. This result has potential relevance to movement ecology studies of other ecologically and morphologically similar seabirds through GLS logger deployments.

Integrating data types to estimate spatial patterns of avian migration across the Western Hemisphere.

For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence probabilities to produce probabilistic least-cost path (LCP) indices. In a final step, we use generalized additive mixed models (GAMMs) both to evaluate the ability of LCP indices to accurately predict (i.e., as a covariate) observed locations derived from tracking and band re-encounter data sets versus pseudo-absence locations during migratory periods and to create a fully integrated (i.e., eBird occurrence, LCP, and tracking/band re-encounter data) spatial prediction index for mapping species-specific seasonal migrations. To illustrate this approach, we apply this framework to describe seasonal migrations of 12 bird species across the Western Hemisphere during pre- and postbreeding migratory periods (i.e., spring and fall, respectively). We found that including LCP indices with eBird occurrence in GAMMs generally improved the ability to accurately predict observed migratory locations compared to models with eBird occurrence alone. Using three performance metrics, the eBird + LCP model demonstrated equivalent or superior fit relative to the eBird-only model for 22 of 24 species-season GAMMs. In particular, the integrated index filled in spatial gaps for species with over-water movements and those that migrated over land where there were few eBird sightings and, thus, low predictive ability of eBird occurrence probabilities (e.g., Amazonian rainforest in South America). This methodology of combining individual-based seasonal movement data with temporally dynamic species distribution models provides a comprehensive approach to integrating multiple data types to describe broad-scale spatial patterns of animal movement. Further development and customization of this approach will continue to advance knowledge about the full annual cycle and conservation of migratory birds.

Animation of Bird Characters with Special Focus on Rio(2011)

This study analyzes the animation of bird characters based on real-world avian laws of motion in the 3D animated film, Rio (2011). The research focuses on three aspects—the primary movement, personification, and animation of facial expressions of birds. First, the primary movement of birds, including take-off and landing, are analyzed. Then, personification and animation of facial expressions are investigated based on some of the characters’ expressions in Rio (2011). Finally, different modes of animating avian characters’ expressions are discussed. This study is expected to contribute to future studies of similar topics in other films and lead to better understanding of the animation of avian characters.

Piling behaviour in British layer flocks: Observations and farmers` experiences

Smothering of laying hens, defined as death due to suffocation when hens tightly pile together in layer barns, is a well-known problem affecting the British loose-housed layer industry. However, knowledge about mechanisms contributing to piling in British layer flocks remains anecdotal. To understand piling behaviour mechanisms, the behaviour of 27 British loosed-house layer flocks from two farmer organisations (four brown hybrids, twenty large barns with a flock size of median ± SD, 10 175 ± 5721 birds, and seven small mobile barns, flock size: 2000 ± 0 birds) with a history of piling behaviour was observed. Video observations were taken along walls and in the centre of the floor area of the layer barns. The number of piles, pile sizes, pile durations, events preceding piles, and locations where piles started (wall/floor area) were described for one day (08:30–16:00 h) at three times of day (0–4 h, >4–8 h, >8–12 h after lights on) either around 20 weeks or around 30 weeks of flock age. Events preceding piling were analysed using descriptive statistics. The effects of time of day, flock age, laying hen hybrid, the area where piles started, and colony size on the number of piling events, pile sizes, and pile durations were assessed using univariate analysis and linear or generalised linear mixed-effects models in R. In addition, twelve British farmers, a subset of the investigated farms, were interviewed about their experiences with piling and smothering. Interviews were audio-recorded, transcribed, and analysed using qualitative content analysis. In total, 92 piles were detected in the videos, lasting on average 21.9 ± 29.3 min and involving 25 ± 39 hens. Piles were mostly preceded by the attraction of hens to other hen behaviours (63.0%) and bird movements through high animal densities on the floor area (23.0%). Piles occurred significantly more frequently at > 4–8 h compared to > 8–12 h and 0–4 h after lights on. Pile sizes were larger in the floor area centre than along walls and positively correlated with pile durations and the flock sizes. Interview analysis revealed that farmers considered multiple events to be triggers for piling and smothering, including the transfer from the rearing to the laying environment, flight responses, broken routines, gregarious nesting in nests or on the floor area, and other gregarious behaviours such as dustbathing in the centre of the floor area. They reported that the causes of piling and smothering change throughout the flock cycle and time of day.

Coot Algorithm for Optimal Carbon–Energy Combined Flow of Power Grid With Aluminum Plants

To achieve a low-carbon and economical operation for the power grid, this paper proposes a novel optimal carbon–energy combined flow (OCECF) by considering the influence of aluminum plants. It attempts to minimize the carbon emission of power grid, power loss, and the voltage deviation by taking the reactive power control of aluminum plants into account. Since the presented OCECF is a nonlinear and complex optimization problem, a new metaheuristic algorithm called Coot algorithm is employed to acquire a high-quality dispatch solution under various scenarios. The Coot algorithm is inspired by the movement of birds on the water surface, which can implement a wide exploration via the random movement and a deep exploitation via the chain movement with the group leaders. The performance of Coot algorithm for the presented OCECF is carried out on an IEEE 57-bus system with various power plants, in which the group search optimizer is introduced for performance comparison.

Monitoring Raptor Movements with Satellite Telemetry and Avian Radar Systems: An Evaluation for Synchronicity

Avian radar technologies have the potential to serve an important role in the quantification of bird movements and determining patterns of bird use in areas where human–wildlife conflicts might occur (e.g., airports, wind energy facilities). Ground-truthing studies are needed to help wildlife managers understand the biological meaning of radar information, as the capabilities and limitations of these technologies are relatively unknown. We conducted a study to evaluate the efficacy of three X-band marine radar sensors for tracking red-tailed hawks (Buteo jamaicensis) on or near the airfield at Chicago’s O’Hare International Airport from September 2010 to May 2014. Specific information regarding red-tailed hawk locations derived from satellite telemetry was used to determine how frequently the three radar sensors provided corresponding tracks of these avian targets (i.e., synchronized monitoring). We examined various factors (e.g., bird altitude and distance to the radar) to determine if they had any influence on the frequency of synchronicity between satellite telemetry locations and radar tracks. We found evidence that as the distance between a hawk and the radars increased, the radars’ ability to detect and track known avian targets decreased. Overall, the frequency of synchronization events for red-tailed hawks was low. Of the 1977 red-tailed hawk locations that should have been visible to the radar sensors, 51 of these bird movements were tracked by at least one of the radar sensors (2.6%). This study provides a new methodology for evaluating the performance of radar systems for tracking birds and determining what factors might influence overall performance.