Bird Aircraft Collisions Research Articles

Using wedelia as ground cover on tropical airports to reduce bird activity

Bird-aircraft collisions (i.e., bird strikes) are a major problem at airports worldwide, often because birds are attracted to airfields to feed on seeds, insects, or rodents that abound in the grassy areas near runways and taxiways. We compared an alternative ground cover, wedelia (Wedelia trilobata), to existing vegetation (control plots) on the airfield at Lihue Airport, Kauai, Hawaii, to determine if bird populations on the airport could be reduced by eliminating their forage base. We studied wedalia because it is a low-growing plant that did not need mowing, was easily established in plots, and out-competed other plants, resulting in a significant decrease in plant diversity. Thus, wedelia indirectly results in a decreased seed base for granivorous birds. Total invertebrate biomass was 41% lower in wedelia plots than in other vegetation plots (control plots). Rodent populations were 67% lower in wedelia than in control plots. Zebra doves (Geopelia striata), spotted doves (Streptopelia chinensis), and mannikins (Lonchura spp.) used wedelia plots significantly less than control plots, whereas, the lesser Pacific golden-plover (Pluvialis fulva) was unaffected. By reducing seed production, insect densities, and rodant populations, wedalia should be a useful ground cover on tropical airports to reduce bird use and, ultimately, bird strikes on the airport.

An ecological approach to birdstrike risk analysis

Airports are peculiar developed habitats that, besides being extremely noisy and unappealing to some bird species, are highly attractive to others. Bird–aircraft collisions, or birdstrikes, cause losses in terms of human lives, direct monetary losses and associated costs for the civil aviation industry. In recent years, birdstrike risk assessment studies have focused on the economical aspects of the damage caused by wild animals and the hazards of wildlife–aircraft collisions, while an ecological approach, taking into account animal behaviour for the analysis of such events, has seldom been adopted. We conducted a risk analysis for birdstrikes at the Venice Marco Polo International Airport (VCE), Italy. We defined the key variables involved in these events and summarised their interactions in a single metric risk index we called the “Birdstrike Risk Index” (BRI). Our aim was to provide a tool for birdstrike risk analysis that described the risk on the basis of the actual presence of birds at airports. The application of the BRI at VCE allows relative risks across species to be defined, providing information for prioritising management actions. Furthermore, due to the seasonality of bird species presences, the application of the BRI to a long-term data series should give clues of birdstrike risk in future scenarios. This new ecological approach that we applied to a particular airport could easily be adapted for use at other airports worldwide and integrated into risk assessment procedures. The study results and the BRI tool are addressed to scientific consultants of airport safety managers.

Migratory Canada geese cause crash of US Airways Flight 1549

In the United States alone, over 7400 bird–aircraft collisions (birdstrikes) were reported in 2007. Most of these strikes occurred during takeoff or landing of the flight, and it is during these flight phases that aircraft experience their highest risk of substantial damage after colliding with birds. Birdstrikes carry enormous potential costs in terms of lives and money. Using feather remains and other tissue samples collected from the engines of US Airways Flight 1549, which crash landed in the Hudson River in New York City on 15 January 2009 after a birdstrike, we apply molecular tools and stable hydrogen isotopes to demonstrate that migratory Canada geese were responsible for the crash. Determining whether the geese involved in this birdstrike event were resident or migratory is essential to the development of management techniques that could reduce the risk of future collisions. Currently, the US civil aviation industry is not required to report birdstrikes, yet information on frequency, timing, and species involved, as well as the geographic origin of the birds, is critical to reducing the number of birdstrikes. Integrating this information with bird migration patterns, bird‐detecting radar, and bird dispersal programs at airports can minimize the risk of such collisions in the future.

Evaluation of two perch deterrents for starlings, blackbirds and pigeons

Bird–aircraft collisions are costly and potentially deadly to people and wildlife. From 1990 through 2004, 57 702 bird collisions with aircraft were reported within the USA to the US Federal Aviation Administration. Approximately 82% of the strikes occur below 305 m height above ground level; therefore bird deterrents on airfields that reduce the quality of the birds' habitat are critical to safe airport operation. One management approach is to reduce perching sites within the airport premises. We tested two anti-perching devices (Birdwire™ and BirdBlox™) in an aviary setting. As an ancillary test, we determined which wire in a standard three-strand security array was preferred by blackbirds and starlings. Red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), and European starlings (Sturnus vulgaris) were deterred from sitting on a perch when anti-perching wire was installed 5 cm above the perch. These same species preferred the top wire of the three-wire security array. Red-winged blackbirds, common grackles (Quiscalus quiscula), brown-headed cowbirds, European starlings, and rock pigeons (Columba livia) were deterred from perches protected by BirdBlox™. Because our tests were conducted in a captive situation, we recommend field testing the products to determine if bird use of airport structures may be reduced in an operational setting.

Evaluation of Bird Response to Propane Exploders in an Airport Environment

Bird-aircraft collisions (bird-strikes) cause serious safety hazards to aircraft, costing civilian aviation at least $496 million annually in the U.S. Non-lethal bird-frightening devices, such as propane exploders, are commonly used to deter birds from airport environments. We conducted a study during August - October 2004 to determine the efficacy of propane exploders utilized with and without concurrent lethal reinforcement activities for altering bird behavior at John F. Kennedy International Airport in Queens, New York. Two groups of 8 propane exploders each were deployed on the airfield. One group of propane exploders was set to “off” (control), whereas the other group was programmed to activate at 15-minute intervals (treatment). This pattern was reversed each week for a 12-week period. In addition, lethal control activities to reduce gull-aircraft collisions were conducted during August and September 2004. We conducted bird observations associated with propane exploders during the lethal control program (8-week period) and following the end of the program (4-week period). The number of bird flocks (≥1 birds) that were within 150 m of treatment (n = 432) and control (n = 442) propane exploders was similar. Simultaneous lethal control activities at the airport did not alter the effectiveness of the propane exploders. Birds responded (e.g., altered flight path) on 3 of 21 (14.3%) occasions when a bird flock was within 150 m of a treatment propane exploder that activated. Our findings suggest propane exploders used in this manner in this airport environment do not significantly alter birds behavior or reduce the threat of bird-strikes. Future research is needed to evaluate techniques such as motion-activated propane exploders to enhance the effectiveness of this tool to reduce wildlife hazards at airports.

A Comparative Analysis of the Influence of Weather on the Flight Altitudes of Birds

Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird-aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution of birds and how this is influenced by weather. This study focuses on the dynamics of flight altitudes of several species of birds during local flights over land in relation to meteorological conditions. We measured flight altitudes of several species in the southeastern Netherlands using tracking radar during spring and summer 2000. Representatives of different flight strategy groups included four species: a soaring species (buzzard Buteo buteo), an obligatory aerial forager (swift Apus apus), a flapping and gliding species (blackheaded gull Larus ridibundus), and a flapping species (starling Sturnus vulgaris). Maximum flight altitudes varied among species, during the day and among days. Weather significantly influenced the flight altitudes of all species studied. Factors such as temperature, relative humidity, atmospheric instability, cloud cover, and sea level pressure were related to flight altitudes. Different combinations of factors explained 40%-70% of the variance in maximum flight altitudes. Weather affected flight strategy groups differently. Compared to flapping species, buzzards and swifts showed stronger variations in maximum daily altitude and f lew higher under conditions reflecting stronger thermal convection. The dynamic vertical distributions of birds are important for risk assessment and mitigation measures in flight safety as well as wind turbine studies.

EFFICACY OF AIRCRAFT LANDING LIGHTS IN STIMULATING AVOIDANCE BEHAVIOR IN BIRDS

Abstract Aircraft collisions with wildlife (primarily birds) are costly in terms of injury or loss of human life, loss of the animals involved, damage to property and business, and the use of lethal control of wildlife at airports worldwide. One potential nonlethal technique to reduce bird–aircraft collisions—pulsed white and wavelength-specific aircraft-mounted light—has been considered for nearly 3 decades, but the efficacy of the technique has not been evaluated quantitatively. We tested the hypothesis that during daylight, captive birds exposed to an approaching ground-based vehicle exhibiting pulsing 250-W white aircraft landing lights would initiate avoidance behavior more quickly than birds experiencing an oncoming vehicle with nonpulsing (steady) or no lights (control). In experiments involving captive brown-headed cowbirds (Molothrus ater), Canada geese (Branta canadensis), European starlings (Sturnis vulgaris), herring gulls (Larus argentatus), and mourning doves (Zenaida macroura), only cow-bir...

Displays of Bird Movements on the WSR-88D: Patterns and Quantification*

Abstract The WSR-88D can readily detect birds in the atmosphere in both clear air and precipitation mode, and echo reflectivities of 30–35 dBZ may be realized during heavy migration events or when birds are departing a roosting site. This paper describes the appearance of birds on base reflectivity, base velocity, and velocity azimuth display wind profile products, and presents a calibration curve that relates decibel values of reflectivity to bird migration traffic rates. The recognition of bird displays in WSR-88D products is essential for the accurate interpretation of data gathered by the radar and its use in the development of forecasts. The findings also document the importance of the WSR-88D as a remote sensing tool for biological studies of birds and insects in the atmosphere and the application of such information in the avoidance of bird–aircraft collisions.

Bird and small mammal abundance at four types of waste-management facilities in northeast Ohio

Location of waste-management facilities in urban and suburban areas is increasingly controversial for a variety of reasons. Because traditional putrescible-waste landfills often attract large numbers of gulls ( Larus spp.) and other birds, they can present a significant risk to air-traffic safety when located near airports. The Federal Aviation Administration (FAA) provides recommendations for the location of putrescible-waste landfills and other waste-management facilities near airports because of the potential for bird—aircraft collisions. To extend the life of traditional putrescible-waste landfills, many communities are turning to non-traditional waste-management facilities such as yard-waste compost facilities, construction and demolition landfills, and trash-transfer stations. These types of facilities may present potential bird-strike risks, and may attract nuisance birds such as starlings ( Sturnus vulgaris) and rock doves ( Columba livia), and nuisance mammals such as Norway rats ( Rattus norvegicus). Objective data are needed on bird and mammal use of these facilities for wildlife biologists to advise regulatory agencies and local governments on the siting and management of these facilities. From May 1993 to April 1994, we compared bird species and numbers at five non-traditional waste-management facilities of three types in northeastern Ohio with species and numbers at a vacant lot (control site) and at a major putrescible-waste landfill. We also surveyed small mammal species and numbers at two compost facilities, a vacant lot, and a small wooded lot. Bird abundance at the five facilities was no different than, or less than, at the vacant lot. About 350 times more birds were seen per observation at the putrescible-waste landfill than at the other five waste-management facilities. Bird use of these non-traditional waste-management facilities appears to be influenced much more by the type of habitat or land-use surrounding the facility than by the waste itself. Fewer small mammals were caught at the compost facilities than at the vacant lot and wooded area. Thus, these non-traditional waste-management facilities do not appear to attract birds or small mammals at higher than background levels and would not pose a significant nuisance problem to the community or be a hazard to aircraft if located near airports.

Analysis of Bird Strikes at a Tropical Airport

Bird-aircraft collisions (bird strikes) are a major problem worldwide because they threaten passenger safety and result in costly repairs and lost revenue for the commercial air carrier. From 1990 to 1994, we conducted runway sweeps at Lihue Airport on Kauai, Hawaii searching for avian remains from bird-aircraft collisions. Three species of granivorous birds, 2 owl species, and the Pacific golden-plover (Pluvialis julva) composed >80% of the bird strikes. Ninety-one percent of the strikes involved solitary birds; 9% involved >1 bird. Bird strikes were positively correlated with mean monthly rainfall, perhaps due to increased seed production along runways during the rainy months, resulting in increased bird use in hazardous areas. Bird strike rates were also higher when winds were from a southwesterly direction and lower when cloud cover was 100%. Larger, faster commercial air carriers exhibited higher strike rates than military or general aviation types, with engine ingestions being most common, followed by strikes on the windshield and nose. Ingestions resulted in losses >$1.5 million in damage. Damage was caused by species ranging in mass from 13-1,300 g. More bird strikes occurred during landings than takeoffs with strikes unevenly distributed along the runway. During the landing phase, more bird strikes than expected occurred at the point of touchdown, whereas most strikes occurred in the mid-portion of the runway during takeoffs.

The use of very low and very high frequencies in the development of an acoustical deterrent for bird–aircraft collisions

Bird strikes have become an increasing problem at commercial and military airports. With the demand for reduced aircraft noise and increased speed, birds are presented with reduced auditory cues and less reaction time when confronted with planes. The major drawback to the use of acoustic deterrents is the rapid habituation. Caged sparrowhawks readily detected signals between 5 and 40 Hz with thresholds of detectability ranging from 76 to 64 dB SPL. No flying induced startles were noted, although the birds did try to localize the source. Habituation to low‐frequency stimuli occurred with as little as three presentations. Free‐ranging geese were presented with the same frequencies as substrate vibration along with sound pressure stimulation. In a limited sample (three geese) avoidance was noted. The application of low‐frequency sound as substrate vibration on runways is promising. Alternatively, microwaves produce an auditory stimulus to the ear that can be altered by changes in frequency, pulse width, and overall power. Pulsed microwaves or microwaves modulated by low‐frequency sound are potential sources alerting birds from a flying plane already carrying navigation radar.