Bird Collisions Research Articles

Assessment of the impact of technogenic monitoring sites on seasonal migration ornithocomplexes

Today, the Azov-Black Sea coast of Ukraine is one of the most important migration routes in Europe, which is used by up to 15 million birds every season. The development of a scientific and information system for monitoring, assessing and predicting the state of biodiversity on the territories of wind power plants (WPP) in the Azov-Black Sea region is extremely important, and the study of seasonal ornithocomplexes is a key moment in the creation of wind farm sites. Assessment of the impact on them is paramount in the development of management plans and risk minimization. The studies were carried out in the Azov-Black Sea region of Ukraine at 12 monitoring sites in the period from 2010 to 2021 using modern international methods adopted in the European Community, used for these technogenic territories, as well as author’s developments. The studies that were carried out using the WEBBIRDS WEB-application for monitoring seasonal ornithocomplexes and computer modeling of assessing the impact of the wind farm site based on the server accumulation of monitoring data (an author’s development), software for calculating the risk assessment of bird collisions with wind turbines (CRM), assessing the potential biological removals (PBR) showed no significant adverse impact of wind farms on birds observed at all 12 sites. These monitoring studies make it possible to assert that the main impact on the stability of migratory bird complexes in the project area is exerted by various biotic and abiotic factors such as landscape-biotopic, forage, weather factors, and the impact of wind farms is minimal.

Wind farm noise shifts vocalizations of a threatened shrub-steppe passerine

Wind energy has experienced a notable development during the last decades, driving new challenges for animal communities. Although bird collisions with wind turbines and spatial displacement due to disturbance have been widely described in the literature, other potential impacts remain unclear. In this study, we addressed the effect of turbine noise on the vocal behaviour of a threatened shrub-steppe passerine highly dependent on acoustic communication, the Dupont's lark Chersophilus duponti. Based on directional recordings of 49 calling and singing males exposed to a gradient of turbine noise level (from 15 up to 51 dBA), we tested for differences in signal diversity, redundancy, and complexity, as well as temporal and spectral characteristics of their vocalizations (particularly the characteristic whistle). Our results unveiled that Dupont's lark males varied the vocal structure when subject to turbine noise, by increasing the probability of emitting more complex whistles (with increased number of notes) and shifting the dominant note (emphasizing the longest and higher-pitched note). In addition, males increased duration and minimum frequency of specific notes of the whistle, while repertoire size and signal redundancy remain constant. To our knowledge, this is the first study reporting multiple and complex responses on the vocal repertoire of animals exposed to turbine noise and unveiling a shift of the dominant note in response to anthropogenic noise in general. These findings suggest that the Dupont's lark exhibits some level of phenotypic plasticity, which might enable the species to cope with noisy environments, although the vocal adjustments observed might have associated costs or alter the functionality of the signal. Future wind energy projects must include fine-scale noise assessments to quantify the consequences of chronic noise exposure.

A predictive flight-altitude model for avoiding future conflicts between an emblematic raptor and wind energy development in the Swiss Alps.

Deployment of wind energy is proposed as a mechanism to reduce greenhouse gas emissions. Yet, wind energy and large birds, notably soaring raptors, both depend on suitable wind conditions. Conflicts in airspace use may thus arise due to the risks of collisions of birds with the blades of wind turbines. Using locations of GPS-tagged bearded vultures, a rare scavenging raptor reintroduced into the Alps, we built a spatially explicit model to predict potential areas of conflict with future wind turbine deployments in the Swiss Alps. We modelled the probability of bearded vultures flying within or below the rotor-swept zone of wind turbines as a function of wind and environmental conditions, including food supply. Seventy-four per cent of the GPS positions were collected below 200 m above ground level, i.e. where collisions could occur if wind turbines were present. Flight activity at potential risk of collision is concentrated on south-exposed mountainsides, especially in areas where ibex carcasses have a high occurrence probability, with critical areas covering vast expanses throughout the Swiss Alps. Our model provides a spatially explicit decision tool that will guide authorities and energy companies for planning the deployment of wind farms in a proactive manner to reduce risk to emblematic Alpine wildlife.

Joint attention mechanism for the design of anti-bird collision accident detection system

<abstract> <p>Among various aviation accidents, bird collision is one of the most common accidents for civil passenger aircraft in recent years. With the significant breakthrough of deep convolutional neural networks in the field of target detection, this paper proposes a target detection method to prevent bird collision accidents. The algorithm in this paper integrates different attention mechanisms on the YOLOv5s network to solve the problems of small target detection miss, false detection and insufficient feature extraction capability. The trend-aware loss (TAL) and trend factor (W<sub>i</sub>) are used to solve the drift of the prediction frame. After comprehensive ablation experiments, the improved algorithm shows significant improvement on the detection accuracy and speed. Results indicate that mean average precision (mAP) value reaches 99.8%, which is 6.3 percentage points higher than the original algorithm.</p> </abstract>

Using citizen science to identify environmental correlates of bird-window collisions in Poland

Bird collisions with windows are among the highest sources of human caused mortality to this group of animals. However, environmental correlates of spatial patterns in collision risk are poorly understood, thus making mitigation measures difficult to implement. We took advantage of Covid-19 lockdown in the spring of 2020, when people were obligated to stay mainly at home, and performed a memory-recall questionnaire survey concerning bird-window collisions in Poland. We received information on bird-window collisions with 1800 buildings across the whole country accompanied by characteristics of each building, its vicinity and resident's behavior (time spent home, window cleaning). We supplemented these data with landscape description and performed statistical models to estimate importance of 13 explanatory variables as predictors of number of bird-window collisions. Reported number of collisions increased with the share of forests and arable land within 2 km of the building, and with proximity to rivers. Number of collisions also increased when single trees were close to buildings. More collisions were reported for houses than for flats and for new buildings than for old ones. Reported number of collisions increased with window cleaning which might suggest that cleaning reduces glass visibility for birds. As bird-window collision risk is highly variable among buildings but can be reduced with several measures improving glass visibility for birds, we recommend to use predictive models to identify collision hotspots for applying these measures. New houses located near rivers, in forests or agricultural landscapes have highest collision risk, and trees near buildings, often planted to benefit birds, can additionally elevate collision rate, thus potentially creating ecological traps. In such collision hotspots, reduction of window cleaning frequency can be considered as a mitigation measure unless the visual markers improving glass visibility for birds are installed on the panels.

Beyond BACI: Offsetting carcass numbers with flight intensity to improve risk assessments of bird collisions with power lines.

The continuing global expansion of electricity networks increases the risk of bird collisions with power lines. Several field studies have demonstrated that this risk can be reduced by marking lines with flight diverters. A before‐after control‐impact (BACI) design is currently the suggested approach for evaluating the effectiveness of these diverters and is generally assumed to give unbiased results.Using systematic flight survey data, we demonstrate that the assumptions underlying the BACI approach are frequently violated, leading to biased effectiveness estimates. We present an alternative field and statistical design in which the number of bird strike victims is directly related to bird flight intensity (“fusion design”), instead of estimating it indirectly using a control site. The presented design is validated based on simulations.We demonstrate that the presented method is unbiased and shows an approximately 3‐fold higher statistical power compared with BACI, even under ideal/unbiased data conditions, with similar field‐experimental effort. Moreover, this approach can provide a direct analysis of bird reactions/collisions, estimation of collision rates, and the possibility of conducting the required fieldwork within a single season.Our presented method can be used to standardize and improve future studies on diverter effectiveness, for example, by supporting the acquisition of a more detailed picture of species‐, diverter type‐, and habitat‐specific estimates.

Local bird densities and habitats are poor predictors of bird collision with glass bus shelters

Bird collisions with glass are a major source of avian mortality, killing billions of birds each year worldwide. Likely, the crucial step to prevent bird-glass collisions is understanding spatial and temporal bird-glass collision patterns. As more and more glass-made constructions appear in public spaces, it becomes essential to identify main drivers of bird collisions with these novel objects. In this study, we perform an attempt to identify local characteristics that may influence the risk of bird collisions with glass bus shelters. We monitored 58 bus shelters from March to July 2018 in urban and rural habitats of south-western Poland. We visited the shelters searching for bird carcasses and traces of collisions but also surveyed birds near shelters, considering the two scales (20 and 100 m of the shelter), and bird behavior (flying vs non-flying). We found 52 evidence of bird collisions and number of collisions per bus shelter ranged from 0 to 7 which substantially deviated from random distribution. Bird abundances recorded near bus shelters, recorded at both 20 m and 100 m scales, were poor predictors of bird-glass collisions and did not improve parsimony of models explaining collision risk. This refers to all recorded birds as well as to the subsets of flying individuals and species being collision victims. Similarly, habitat composition near bus shelters hardly predicted variation in bird-glass collision risk. As we did not manage to identify any important drivers explaining collision risk, we conclude that before we learn how to predict areas with high number of bird-glass collisions, we suggest that developers, urban planners and architects should be advised to design all public transportation shelters using nontransparent materials.

Nonrandom Bird-Glass Collision Pattern: Fewer Strikes Near Glass Edge

Collisions with glass or glass-covered objects are an important source of bird mortality worldwide. In this study, we investigate bird-glass collision pattern with the help of novel method using marks left by birds on glass surfaces. We surveyed 85 glass bus shelters every 12 days over a year to evaluate which parts of glass surfaces have the highest risk of collision. Among 178 bird-glass collisions recorded only 3% took place within 10 cm from glass edge, although this glass band (i.e. 0–10 cm from edge) covers over 30% of the whole glass area, on average. More inner parts of glass (10–70 cm from glass edge) had collision frequency slightly higher than expected by their coverage or proportional to their coverage. Different collisions recorded at one glass seemed independent suggesting no spatial aggregations within single glass. This study is the first to demonstrate the non-random risk of bird collision in relation to position on the glass surface and may suggest that there is no need to implement mitigating measures, like visible markers placed on the glass, closer than 10 cm from the glass edge.

Reducing Bird Collision Risk Per Megawatt by Introducing Longer Wind Turbine Blades

Renewable energy, including wind energy, remains one of the most effective options for controlling global warming. However, increasing wind turbine size (mainly blade size) implies expanding the blade swivel range (rotor sweep zone), and concerns have been raised about a possible increase in the number of bird collisions with the rotating blades. Conversely, an increase in turbine size, accompanied by a reduction in rotation speed might reduce the avian collision risk. The change in the number of collisions with increasing wind turbine size was analyzed using simple collision risk models. The results showed that with an increase in the length of the wind turbine blade, although the number of collisions per turbine increased monotonically, the number of collisions per megawatt generated decreased as a hyperbolic function. These models involved some assumptions for simplicity; therefore, their validity requires testing in wind-power replacement projects.

Bird-window collisions: Mitigation efficacy and risk factors across two years.

BackgroundResearch on bird-window collision mitigation is needed to prevent up to a billion bird fatalities yearly in the U.S. At the University of Utah campus (Salt Lake City, Utah, USA), past research documented collisions, especially for Cedar Waxwings (Bombycilla cedrorum) drawn to fruiting ornamental pears in winter. Mirrored windows, which have a metallic coating that turns window exteriors into mirrors, had frequent collisions, which were mitigated when Feather Friendly®bird deterrent markers were applied. Bird-friendly windows–ORNILUX®ultraviolet (UV) and fritted windows–also reduced collisions when data were collected across fall and winter. Extending this prior research, we evaluated additional mitigation and tested the replicability of effects for pear trees, mirrored windows, and bird-friendly windows across two years.MethodsUsing published data from eight buildings monitored for collisions in year 1 (Fall and Winter, 2019–2020), we added another year of monitoring, Fall and Winter, 2020–2021. Between years, Feather Friendly®mitigation markers were added to collision-prone areas of two buildings, including both mirrored and transparent windows.ResultsThe two buildings that received new Feather Friendly®mitigation had significantly fewer collisions post-mitigation. Control areas also had nonsignificant decline in collisions. The interaction of area (mitigation vs. control) by time (year 1 vs. 2) was significant, based on generalized estimating equations (GEE). The total yearly collisions across all eight buildings declined from 39 to 23. A second GEE analysis of all 8 buildings showed that mirrored windows, pear trees, and bird-friendly windows were each significant when analyzed separately. The best-fit model showed more collisions for mirrored windows and fewer collisions for bird-friendly windows. We found pear tree proximity to be related to more collisions in winter than fall. In addition, pear trees showed reduced collisions from year 1 to 2, consistent with new mitigation for two of three buildings near pear trees.DiscussionFeather Friendly® markers can mitigate collisions with transparent windows, not only mirrored windows, compared to unmitigated areas over 2 years. Results also underscore the dangers of pear tree proximity and mirrored windows and the efficacy of bird-friendly windows. Thus, bird collisions can be prevented by window mitigation, permanent bird-friendly windows, and landscape designs that avoid creating ecological traps.

Drivers of fatal bird collisions in an urban center

Millions of nocturnally migrating birds die each year from collisions with built structures, especially brightly illuminated buildings and communication towers. Reducing this source of mortality requires knowledge of important behavioral, meteorological, and anthropogenic factors, yet we lack an understanding of the interacting roles of migration, artificial lighting, and weather conditions in causing fatal bird collisions. Using two decades of collision surveys and concurrent weather and migration measures, we model numbers of collisions occurring at a large urban building in Chicago. We find that the magnitude of nocturnal bird migration, building light output, and wind conditions are the most important predictors of fatal collisions. The greatest mortality occurred when the building was brightly lit during large nocturnal migration events and when winds concentrated birds along the Chicago lakeshore. We estimate that halving lighted window area decreases collision counts by 11× in spring and 6× in fall. Bird mortality could be reduced by ∼60% at this site by decreasing lighted window area to minimum levels historically recorded. Our study provides strong support for a relationship between nocturnal migration magnitude and urban bird mortality, mediated by light pollution and local atmospheric conditions. Although our research focuses on a single site, our findings have global implications for reducing or eliminating a critically important cause of bird mortality.

Birds Strike – Impact on the Safety of Civil Aircraft Operations in Poland in 2008–2018

Abstract The authors assessed the real threat to civil aircraft traffic in Poland resulting from bird strikes. It was found that in the period 2013–2018, the probability of such events increased by four times. Data for this work were downloaded from the ECCAIRS database maintained by the Civil Aviation Authority. Air traffic events have been collected for several years in this database. An assessment of the energy of bird collision with the aircraft, resulting from the bird’s mass and relative speed of movement, was also presented. Ways to minimise the risk of collision were described by introducing crew warning systems and means to scare off birds from the airport grounds. The method of testing the resistance of turbine engines to the foreign body’s absorption was also shown, as well as design methods for increasing the engine resistance to bird strikes.

Computational and experimental study of bird failure at different speeds of collision with a flexible plate

This article presents an experimental and computational study of bird collision with a flexible plate at different impact speeds. Tests were carried out with the aid of a pneumatic gun. The bird mass in the study was about 300 g, and the speed range was 49-75 m/s. The actual mechanical properties of the plate were determined with tensile tests of flat specimen-witness. A video recording and strain gauging were performed during the strike. Some frames of high speed video recording for the highest bird’s velocity c = 75 m/s are presented in the article to demonstrate the process of bird rupturing. Different models of the bird material were examined to compare computational and measured strains.

A Review of Impact Tests of Light and Small UAV

Unmanned Aerial Vehicles are widely used in aerial photography, exploration, logistics and other fields for their low cost, low take-off and landing requirements and many other advantages. With the deep application of UAVs, their safety problems have become increasingly prominent. The frequent occurrences of collision events have attracted the public attention. This paper reviews the UAVs weight threshold estimation test, UAVs impact aircraft windshield test and aircraft horizontal stabilizer test, and compares the results with bird collision results, discusses the impact safety challenges of light and small UAVs. This paper puts forward what should focus on about UAVs designing.

A large-scale experiment demonstrates that line marking reduces power line collision mortality for large terrestrial birds, but not bustards, in the Karoo, South Africa

Abstract Line markers are widely used to mitigate bird collisions with power lines, but few studies have robustly tested their efficacy. Power line collisions are an escalating problem for several threatened bird species endemic to southern Africa, so it is critical to know whether or not marking works to adequately manage this problem. Over 8 yr, a large-scale experiment was set up on 72 of 117 km of monitored transmission power lines in the eastern Karoo, South Africa, to assess whether line markers reduce bird collision mortality, particularly for Blue Cranes (Grus paradisea) and Ludwig’s Bustards (Neotis ludwigii). We tested the 2 marking devices commonly used in South Africa: bird flappers and static bird flight diverters. Using a before-after-control-impact design, we show that line marking reduced collision rates for Blue Cranes by 92% (95% confidence interval [CI]: 77–97%) and all large birds by 51% (95% CI: 23–68%), but had no effect on bustards. Both marker types appeared similarly effective. Given that monitoring at this site also confirmed high levels of mortality of a range of species of conservation concern, we recommend that marking be widely installed on new power lines. However, other options need to be explored urgently to reduce collision mortality of bustards. Five bustard species were in the top 10 list of most frequently found carcasses, and high collision rates of Ludwig’s Bustards (0.68 birds km–1 yr–1 uncorrected for survey biases) add to wider concerns about population-level effects for this range-restricted and Endangered species.

Forecasting of the number of bird collisions with turbines in the territory of Pre-Azov region wind park using the route census method

The information system has been designed to ensure the analysis of information on the monitoring results of the wind power plant (WPP) territory using the route census method. The database contains 48 fields, reflecting the monitoring results of birds’ behavior in the territory of WPP and processing the initial data: year, month and day of observation, a number of birds of this species, flight altitude, flight speed, direction of flight, coordinates of the bird registration point on the Google-map, average number of birds flying over the territory of the wind park at a given time, coordinates of the points of intersection of the bird flight path with the perimeter of the wind park or observation site, the length of bird flight path over the observation site, and other parameters. The analysis of distribution of birds in the territory of the “Primorsk-1” WPP according to the types of migration (forage, transit, nesting, and ground), direction of flight and altitude characteristics has been carried out. The total number of registered birds was 8927 specimens of 72 species, of which 802 specimens of 11 species were referred to the transit type, 2511 specimens of 32 species – to the forage type, 5614 specimens of 60 species were on the ground (ground type). Most birds (63%) belong to the ground type. 28% of birds were registered in the forage group, 9.0% of birds were flying in transit. The greatest activity of birds is manifested in the autumn migration season, when the transit group accounts for 77% of all annual transit flights. The proportion of birds of forage and ground types, registered in autumn, is 68% and 74%, respectively, of the total number of birds registered in autumn. In the group of ground birds, the overwhelming majority of specimens belong to the period of autumn migration (4141 birds or 74%). The least number was observed in the winter season (317 birds or 5.6%). The author proposes a mathematical model for analyzing birds’ interaction with turbines using the results of monitoring the territory of wind power plants by means of route census method. The model makes it possible to obtain information on the probability of different species of bird collisions with wind wheels and the number of collisions with turbines, depending on the flight characteristics of birds, parameters of wind parks and observation conditions in different seasons. In the risk zone of birds’ interaction with turbines, only specimens of one species, Buteo buteo, were observed. The calculated probability of one bird collision when passing through the wind wheel is 0.19. The anticipated number of bird collisions with turbines during one year of the “Primorsk-1” wind park functioning is in the range of 5.6÷6.7 specimens.

Research on Aircraft Collisions with Birds according to Identification Examinations in 2002–2019

The results of research on identification of bird species involved in collisions mainly with aircraft of the Aeroflot–Russian Airlines Public Joint-Stock Company are presented. Identification examination as a complex study includes DNA analysis, as well as examination of the macro- and microstructure of a group of feathers, a single feather, or a fragment of one. The bird strike location is established. The reasons and factors leading to the appearance of a species at the airfield are considered, and brief recommendations are given to minimize bird strikes at the airfield. During this period, 32 species of ten bird orders involved in strikes were identified. It was found that most collisions occurred with the orders Charadriiformes (mostly with gulls), Falconiformes, and Apodiformes. It is noted that more than 90% of collisions occur at the airport or in its vicinity; there are half again as many more strikes during taking off than during landing. The largest number of collisions takes place in spring and summer time and during daylight hours. The engine, nose cone, and fuselage mainly suffer from bird collisions.

Evaluating bird collision risk of a high-speed railway for the crested ibis

We evaluate the bird-train collision risk associated with a recent high-speed railway project for the crested ibis (Nipponia nippon) and other local bird species in the Qinling Mountains, China. Using ground-walked line transect surveys, we surveyed the population abundance, distance to the railway bridge, and bridge-crossing behaviors of the birds in the study area. The results show that: (1) The crested ibis and the little egret (Egretta garzetta) were the two most abundant waterfowl species in the study area. The relative abundance index of these two species were about 43.33% and 42.75%, respectively; (2) 92.86% of the observed crested ibises were firstly detected within the range of 0 m to 25 m of the vicinity of the railway bridge; (3) The ratio between crossing over and under the railway bridge is about 7:3, which we found that crested ibises preferred flying over the bridge, but little egrets were more likely to cross the railway below the bridge. In the end, we recommend that, while the collision risk for the crested ibis could be low, protection structures, such as barrier poles or fences, should still be considered to avoid possible collisions of other co-habitants and promote conservation for multiple bird species in the area.

Correlates of bird collisions with buildings across three North American countries.

Collisions with buildings cause up to 1 billion bird fatalities annually in the United States and Canada. However, efforts to reduce collisions would benefit from studies conducted at large spatial scales across multiple study sites with standardized methods and consideration of species- and life-history-related variation and correlates of collisions. We addressed these research needs through coordinated collection of data on bird collisions with buildings at sites in the United States (35), Canada (3), and Mexico (2). We collected all carcasses and identified species. After removing records for unidentified carcasses, species lacking distribution-wide population estimates, and species with distributions overlapping fewer than 10 sites, we retained 269 carcasses of 64 species for analysis. We estimated collision vulnerability for 40 bird species with ≥2 fatalities based on their North American population abundance, distribution overlap in study sites, and sampling effort. Of 10 species we identified as most vulnerable to collisions, some have been identified previously (e.g., Black-throated Blue Warbler [Setophaga caerulescens]), whereas others emerged for the first time (e.g., White-breasted Nuthatch [Sitta carolinensis]), possibly because we used a more standardized sampling approach than past studies. Building size and glass area were positively associated with number of collisions for 5 of 8 species with enough observations to analyze independently. Vegetation around buildings influenced collisions for only 1 of those 8 species (Swainson's Thrush [Catharus ustulatus]). Life history predicted collisions; numbers of collisions were greatest for migratory, insectivorous, and woodland-inhabiting species. Our results provide new insight into the species most vulnerable to building collisions, making them potentially in greatest need of conservation attention to reduce collisions and into species- and life-history-related variation and correlates of building collisions, information that can help refine collision management.

Factors Affecting Differential Underestimates of Bird Collision Fatalities at Electric Lines: A Case Study in the Canary Islands

Carcass counts notably underestimate avian collision rates due to three main bias sources: imperfect detection, carcass removal by scavengers and carcass dispersion in unsearched areas. We assessed these sources of bias at electric lines of two Canary Islands, Lanzarote and Fuerteventura, quantifying the factors influencing them. We also carried out a cost-effectiveness assessment of carcass search done perpendicularly to electric line axis. We surveyed 230km of three types of electric lines (high-voltage, medium voltage and telephone lines) during three periods (July 2015, November-December 2015 and March 2016) searching for collision fatalities (N = 431), recording the species, the carcass distance from the electric line, mean cable height, carcass detection distance and decomposition state. In addition, we carried out a disappearance rate experiment to estimate carcass removal by scavengers. A generalised least squares model was used to analyse dispersion distance of carcass from electric lines, in relation to species body mass, mean cable height and line typology. Detection probability functions were fitted to estimate carcass detectability, incorporating body mass, decomposition state and habitat structure as covariates. A Generalised Mixed-Effects model was carried out to analyse carcass disappearance in relation to time elapsed since carcass placement, carcass size, season and island. Dispersion distance decreased with body mass and increased with cable height, being further at high-voltage lines. Overall, detection probability was 0.134, increasing with carcass size, decreasing with decomposition state and being lower in rocky areas which offered a significant challenge when walking through rough terrain. Disappearance rates differed between islands probably due to differences in avian scavenger abundance, increased with time elapsed and decreased with bird size. This study provides correction factors to obtain unbiased estimates of avian mortality rates within sparsely vegetated landscapes. Moreover, it identifies a 27m threshold distance at which the cost-effectiveness of searching for carcasses is optimised.—Gómez-Catasús, J., Carrascal, L.M., Moraleda, V., Colsa, J., Garcés, F. & Schuster, C. (2021). Factors affecting differential underestimates of bird collision fatalities at electric lines: a case study in the Canary Islands. Ardeola, 68: 71-94.