Wildlife-aircraft Collisions Research Articles

Dublin Hareport: The movement ecology and airfield interactions of resident, airside hares, at an international airport.

Understanding how animals move and use space within an environment is vital for the development and implementation of effective management actions. Within airfield environments, animal movement can present a substantial risk to aircraft, resulting in wildlife-aircraft collisions (strikes) if animals enter into the manoeuvring areas of the airfield, namely the runways, taxiways and areas that connect the two (hereafter collectively referred to as 'tarmacked areas'). However, reliable ecological data to inform management decisions can be difficult to obtain in such environments, due to access restrictions. Here, we present the first GPS data describing the movement ecology and spatial use of mammals on an airfield - Irish hare (Lepus timidus hibernicus), at Dublin International Airport - through the deployment of five GPS collars. A total of 4571 tarmacked area interactions were recorded between December 2021 and August 2022, with all five hares engaging with tarmacked areas. Between December and August, the highest number of interactions were recorded for the month of April (n = 1073), followed by March (n = 703). There was a mean of 4.3 (range: 0-65) interactions with tarmacked areas, per hare, per day throughout the study period. Hares most frequently engaged with tarmacked areas between 05:00 and 07:59, with some seasonal variation. The greatest cumulative distance moved per month was observed in May (505 km) and April (503 km). We identified that the average home range size of collared hares was 2.8 km2 (±SD 0.1 km2), based on 95% Kernel Utilisation Distribution. Furthermore, we demonstrate that the hares incorporate tarmacked area habitat types into their home ranges with up to 13% of one individual's movements incorporating these areas. Our study demonstrates the suitability of GPS tracking devices for studying the movement ecology of high-risk mammal species at airfields in order to inform airside management practices.

Sex and Age Bias in Australian Magpies Struck by Aircraft

Wildlife–aircraft collisions represent a safety and financial challenge, necessitating site-specific hazard assessments, which are generally based on species’ attributes and collision frequencies. However, for many bird species, collision probability and risk may not be distributed equally among individuals, with sex and age differences possible but rarely examined. We examine Australian Magpies, a resident, grassland species of bird in southeastern Australia frequently involved in collisions with aircraft at airports, and which can be sexed (adults) and aged. We compared collision rates recorded at Melbourne Airport, Victoria, Australia, with airside counts of magpies, recording, when observable, the sex and age of the birds. Adult females and males were similarly abundant at the airport (46.6% female), but females were struck relatively more frequently than males (78.1% female). Juvenile (first-year) magpies were struck more frequently than expected based on their representation in bird counts. We show an example of where some demographic groups within species represent higher hazard potential to aircraft than others, and management which manipulates demography of magpies at and near the airport (such as discouraging local breeding and targeted harassment/dispersal) may be fruitful.

The impact of the COVID-19 pandemic on wildlife–aircraft collisions at US airports

Exploiting unprecedented reductions in aircraft movements caused by the COVID-19 pandemic, we investigated the relationship between air traffic volume and the frequency of wildlife-aircraft collisions, or wildlife strikes, at the 50 largest airports in the United States. During the COVID-19 months of 2020 (March–December), both air traffic volume and the absolute number of wildlife strikes were reduced. The net effect of these two movements, however, was an increase in the wildlife strike rate from May 2020–September 2020. This increase was found to be most pronounced at airports with larger relative declines in air traffic volume. We concluded that the observed increase in the wildlife strike rate was, at least in part, generated by risk-enhancing changes in wildlife abundance and behavior within the airport environment. That is, wildlife became more abundant and active at airports in response to declines in air traffic volume.

Mammal management: Strike mitigation measures and practices at European airports

Airfield environments can be attractive to a broad range of wildlife, including mammals, and rates of wildlife-aircraft collisions are generally increasing, globally. It is important, therefore, that the components of an airfield that may be attractive to wildlife and the effectiveness of current mammal-exclusion and strike mitigation measures, are understood. However, the suite of applied measures and the efficacy thereof differs between airfields. The collation of such information would represent a useful tool in potentially mitigating strike frequency or severity for airfield managers. To this end, an online survey was distributed to personnel responsible for wildlife management at airfields in Europe (Belgium, France, Greece, Ireland, Spain and the UK) between July 2020–March 2021. Mammals were recorded at all responding airfields (n = 22), while mammal strikes were recorded at 21 locations. A mammal sightings index scored foxes (91% of airfields) and rabbits (81% of airfields) as the most frequently recorded species. The presence of specific habitat (mainly heathland/peatland) airside was associated with a high mean mammal diversity at airfields in Ireland, the UK and Belgium which reported the presence of this habitat type. The erection of fencing and grassland management measures were the most frequently implemented mitigation measures, while managing water sources within the airfield environment was ranked as the most successful mitigation measure. Our study highlights the need for Wildlife Hazard Management Plans to consider an integrated management approach that not only mitigates general strike risk but is also adaptable to species of particular concern.

Use of a portable thermograph as a potential tool to identify nocturnal airport bird risks / Uso de um termógrafo portátil como uma ferramenta potencial para identificar riscos noturnos de aves em aeroportos

Worldwide, wildlife-aircraft collisions constitute a major human health and safety concern. About 98% of wildlife-aircraft strikes involve bird species (i.e., bird strikes) resulting in an annual loss of $1.2 billion to the aviation industry and costing 194 human lives. Thus, airport managers desire better tools to identify wildlife aircraft risks and management option to mitigate them. A number of variables have been identified that can attract the birds and other animals to the airport area. These variables include increased food availability, clear views of predators, and open water. Regular bird surveys can help managers to identify bird strike risks and prioritize management actions to reduce avian hazards. However, bird species detection efficiency at the airports can vary according to the applied methodology. We compared the efficiency of a portable thermograph to detect bird risk in a Brazilian airport using the transection methodology at night. Linear transects adjacent to the airstrip were traveled, by foot, at an average speed of 1 km/h, with and without the device, looking for birds. With the device, transects were traveled with the thermograph in mode on and at each bird visualization a photo was taken. Without the device transects were traveled with a flashlight looking for birds. A portable thermograph allows warm-blooded animals to become easily visible against the environment, both day and night, once it can detect and produce radiation images in the long infrared range of the electromagnetic spectrum (approximately 9,000 to 14,000 nanometers or 9 to 14 µm). Our evaluations were conducted in the Regional Airport of Itanhaém, São Paulo, Brazil, in September and October 2015. Our results show that the thermography detected 13 locations with 25 specimens of birds, while the same method applied without the device recorded three locations with three specimens, resulting in nine times more bird specimens per hour. We believe that the thermographs may be considered as a new method in nocturnal airport bird risks and even common nocturnal bird surveys, with benefits exceeding its U$ 20.000,00 costs.

Reducing whale-ship collisions by better estimating damages to ships

Collisions between ships and whales raise environmental, safety, and economic concerns. The management of whale-ship collisions, however, lacks a holistic approach, unlike the management of other types of wildlife-vehicle collisions, which have been more standardized for several years now. In particular, safety and economic factors are routinely omitted in the assessment of proposed mitigation solutions to ship strikes, possibly leading to under-compliance and a lack of acceptance from the stakeholders. In this study, we estimate the probability of ship damage due to a whale-ship collision. While the probability of damage is low, the costs could be important, suggesting that property damages are significant enough to be taken into consideration when assessing solutions. Lessons learned from other types of wildlife-vehicle collisions suggest that the whale-ship collision should be managed as wildlife-aircraft collisions. For several years, the International Civil Aviation Organization (ICAO) manages collisions between aircrafts and wildlife at the international level. We advocate that its United Nations counterpart, namely the International Maritime Organization (IMO), get more involved in the whale-ship collision management. Further research is needed to more precisely quantify the costs incurred to ships from damages caused by whale-ship collisions.

Estimating interspecific economic risk of bird strikes with aircraft

ABSTRACTThe International Civil Aviation Organization promotes prioritization of wildlife management on airports, among other safety issues, by emphasizing the risk of wildlife–aircraft collisions (strikes). In its basic form, strike risk comprises a frequency component (i.e., how often strikes occur) and a severity component reflecting the cost of the incident. However, there is no widely accepted formula for estimating strike risk. Our goal was to develop a probabilistic risk metric that is adaptable for airports to use. Our specific objectives were to 1) update species‐specific, relative hazard scores (i.e., the likelihood of aircraft damage or effect on flight when strikes occur) using recent U.S. Federal Aviation Administration (FAA) wildlife strike data (2010–2015); 2) develop 4 a priori risk models, reflecting species‐specific strike data and updated relative hazard scores; 3) test these models against independent data (monetary costs associated with strikes); and 4) apply our best model to strike data from 4 large, FAA‐certificated airports to illustrate its application at the local level. Our best‐fitting risk model included an independent variable that was an interaction of quadratic transformed relative hazard score and number of wildlife strikes (r2 = 0.74). Top species in terms of estimated risk nationally were red‐tailed hawk (Buteo jamaicensis), Canada goose (Branta canadensis), turkey vulture (Cathartes aura), rock pigeon (Columba livia), and mourning dove (Zenaida macroura). We found substantial overlap among the top 5 riskiest species locally across 3 of 4 airports considered, illustrating the degree of site‐specific differences that affect risk. Strike risk is dynamic; therefore, future work on risk estimation should allow for model adjustment to reflect ongoing wildlife management actions at airports that could influence future strike risk. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

To Live and Fly in LA: Using Bird Strike and Management Program Information to Improve Safety at Airports in the Los Angeles Basin (Abstract)

Author(s): Pitlik, Todd J.; Herrmann, Elizabeth; Peralta, Eric; Washburn, Brian E. | Abstract: Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Wildlife strikes can be evaluated at different levels, include efforts to examine these problems at the national, regional, or state level, or for an individual airport. Similarly, wildlife strikes involving individual wildlife species or guilds can be examined at varying scales. Although wildlife strike analyses at the national, regional, or species/guild level are valuable, airport-specific analyses are essential for the effective implementation and evaluation of integrated wildlife damage management programs as these actions are conducted at the airport level. The species that present hazards to safe aircraft operations varies among airports, even when considering airports that are very close to each other (spatially). We developed a strategic planning framework to increase the efficacy and appropriateness of wildlife hazard mitigation programs, using the three Los Angeles World Airports as examples. This framework is intended to be simple, adaptable, and useful to airport wildlife biologists and their co-operators (i.e., airport manager and operations personnel). First, we reviewed the airport-specific wildlife strike information to determine if trends or patterns exist. Second, we categorized the wildlife species (primarily birds) based on their direct mitigation potential, feeding behaviours, seasonality, and migration patterns. Lastly, we reviewed the graphs of direct mitigation actions that were conducted each year. Using each individual airport’s wildlife strike data, direct mitigation effort information, and the life history/ecological characteristics of individual wildlife species, we devised a matrix of four categories (i.e., I to IV) to simply the evaluations, thus allowing us to group wildlife species or guilds according to their behavioural patterns and direct mitigation potential. Species included in Category I are those species that are invasive, are resident (i.e., non-migratory), and have a moderate to high direct mitigation potential. Category II includes species that typically have a semi-resident or migratory life history and have moderate direct mitigation potential. Species that are migratory and are winter residents at the airports but have a low to moderate direct mitigation potential were included in Category III. Category IV species are typically summer residents at the airports or migratory oceanic waterbirds with minimal to low direct mitigation potential. For each wildlife species of interest, we graphed the number of reported wildlife strikes (for non-damaging, minor damage reported, and substantial damage reported) for each year using information extracted from the Federal Aviation Administration’s National Wildlife Strike Database. Risk values (i.e., low/medium/high) were assigned to each individual wildlife species of interest based on the frequency of damaging strikes that occurred at each airport. We graphed the available direct mitigation data involving each wildlife species of interest at each airport. Direct mitigation actions included lethal removal of problematic individuals, live-trapping and translocation of problematic individuals, and non-lethal hazing. Once each wildlife species or guild of interest was subjectively classified into one of the four categories, strategic planning efforts can be conducted to evaluate and modify an airport’s wildlife damage management plan and activities. Recommendations regarding the potentially most effective direct and indirect mitigation recommendations can then be made for each category based on the findings related to the wildlife strike information and direct mitigation activities previously conducted at the airport.Our efforts resulted in a simple, adaptable, and useful strategic planning framework to conduct airport-specific planning and evaluations of wildlife damage mitigation actions. However, because our approach is flexible, there is great potential for modification and improvement (depending on the wants and needs of a specific airport program). The use of standardized willdlife strike rates, incorporation of risk metrics, and considerations of hazardous wildlife abundance data are potential sources of information that could be used within our framework.

Sunshine, Beaches, and Birds: Managing Raptor-Aircraft Collisions at Airports in Southern California

Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Raptors (i.e., hawks and owls) are one of the most frequently struck guilds of birds within North America. Integrated wildlife damage management programs combine a variety of non-lethal and lethal management tools to reduce presence of raptors on airports. Live-capture and translocation away from an airport is a commonly used non-lethal method to reduce the risk of raptor-aircraft collisions. In southern California, USDA Wildlife Services airport biologists live-captured, marked with auxiliary markers (i.e., airport program-specific plastic leg band), and translocated approximately 1,232 raptors from seven airports and military bases located within the highly urbanized environment of the Los Angeles Basin during January of 2010-December of 2016. Ten different raptor species were marked and relocated during this effort. The composition of translocated raptors was red-tailed hawks (38.9%), Cooper’s hawks (27.5%), American kestrels (20.7%), barn owls (7.4%), and great horned owls (3.7%). Overall, the percentage of translocated raptors that returned to an airport was 11.1%. Although research is needed to better understand and increase the efficacy of such management efforts, this non-lethal method of reducing the presence of individual raptors at airports in southern California will be an important component of future wildlife management programs.

Commentary Using Dietary Analyses to Reduce the Risk of Wildlife–Aircraft Collisions

Commentary Using Dietary Analyses to Reduce the Risk of Wildlife–Aircraft Collisions

Using Bird Strike Information to Direct Effective Management Actions within Airport Environments

Author(s): Pitlik, Todd J.; Washburn, Brian E. | Abstract: Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Many bird species, especially gulls, are very difficult to manage within airport environments as many traditional methods (e.g., trap and remove from the airport) can be relatively ineffective due to the birds’ various activities on airports (e.g., feeding, loafing, and flying). Such challenges have greatly impacted the Los Angeles International Airport and the Van Nuys Airport, as documented through historical bird strike records collected since 1990. Using information contained in these bird strike records, USDA APHIS Wildlife Services personnel conducted strategic planning efforts to reduce the risk of bird strikes. Since 2009, efforts have been made to improve the quality of wildlife strike reporting at Los Angeles World Airports facilities through the distribution of bird strike collection kits to airline maintenance offices, subcontract aircraft maintenance companies, and Airside Operations personnel. These kits are intended to facilitate an increase in wildlife strike reporting and the number of wildlife strikes identified to the species level. Following intensive management efforts that included trapping and removal of doves (i.e., rock pigeons, mourning doves), bird strikes by these species have decreased significantly at these airports. Airport-specific integrated wildlife damage management programs at airports that use bird strike information to guide management activities toward problem species have great potential for reducing the risk of bird strikes.

Are Turf-type Tall Fescue Cultivars Useful for Reducing Wildlife Hazards in Airport Environments?

Wildlife-aircraft collisions pose a serious risk to aircraft and cost civil aviation over US$1 billion worldwide annually. Wildlife-aircraft collisions pose a serious risk to aircraft and cost civil aviation over US$1 billion worldwide annually. Habitat management within airport environments is the most important long-term component of an integrated approach to reduce the use of airfields by hazardous wildlife. Recent research has demonstrated that Canada geese avoid foraging on endophyte-infected tall fescue; consequently, this turfgrass might be useful in airfield revegetation and seeding projects. Although some research evaluating commercially available tall fescue cultivars on airfields has been conducted, additional information is needed to determine if tall fescue cultivars might be viable for airfields in various regions of the U.S. In 2007, a study was initiated to examine the establishment of currently available high-endophyte 'turf-type' tall fescue grasses at 9 airfields. The objectives were to: 1) determine if selected tall fescue cultivars establish on airfields across the U.S. and 2) provide airport-specific recommendations for tall fescue cultivar selection. At each airfield, 12 tall fescue cultivars were seeded into 3 replicate experimental plots in either fall of 2007 or spring of 2008. Although tall fescue cover varied among airports, most cultivars resulted in similar amounts of tall fescue cover after one or two growing seasons. This study demonstrates and identifies tall fescue cultivars that will grow successfully in the environmental conditions found on these airfields while providing airfield vegetation that is minimally attractive to wildlife hazardous to aviation.

Avian use of solid waste transfer stations

Transfer stations are an important component of modern solid waste management systems. Solid waste management facilities (e.g., landfills) are very attractive to and used by many birds, resulting in a variety of health and safety problems, including disease transmission to humans and increased risk of wildlife–aircraft collisions. In the United States, the Federal Aviation Administration recommends municipal solid waste management facilities (e.g., landfills, transfer stations) not be sited within 8 km of an airport. Little information is available regarding the attractiveness of transfer stations to birds or the factors that might influence avian use, particularly on a national scale. The objectives of my study were to: (1) quantify avian use of transfer stations, (2) determine if building design features influence their attractiveness to birds, and (3) determine if other factors (e.g., season, geographic location, operational procedures) influence bird use. Twenty-nine waste transfer facilities and 4 control sites, located in 7 states (representative of various U.S. geographical regions) were studied. Avian abundance and activity was quantified at each facility and control site twice per week for one year. Nuisance bird species commonly observed using transfer stations (e.g., feeding on refuse) included gulls, European starlings, and crows. Patterns of wildlife use at transfer stations varied by season, geographic location, transfer station building design, and on-site management characteristics. Overall, this study demonstrates that wildlife use of transfer stations, particularly by nuisance birds, can be substantial.

Wildlife Strike Risk Assessment in Several Italian Airports: Lessons from BRI and a New Methodology Implementation

The presence of wildlife in airport areas poses substantial hazards to aviation. Wildlife aircraft collisions (hereafter wildlife strikes) cause losses in terms of human lives and direct monetary losses for the aviation industry. In recent years, wildlife strikes have increased in parallel with air traffic increase and species habituation to anthropic areas. In this paper, we used an ecological approach to wildlife strike risk assessment to eight Italian international airports. The main achievement is a site-specific analysis that avoids flattening wildlife strike events on a large scale while maintaining comparable airport risk assessments. This second version of the Birdstrike Risk Index (BRI2) is a sensitive tool that provides different time scale results allowing appropriate management planning. The methodology applied has been developed in accordance with the Italian Civil Aviation Authority, which recognizes it as a national standard implemented in the advisory circular ENAC APT-01B.

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.

Habitat management approaches for reducing wildlife use of airfields

Wildlife-aircraft collisions (wildlife strikes) pose safety risks to aircraft and cost civil aviation over $390 million annually in the USA. We reviewed published studies to summarize findings on habitat management techniques that have shown potential for wildlife strike reduction. Habitat components that may attract wildlife to airports include food, cover, water, and loafing areas. Although maintaining tall herbaceous vegetation on airfields may reduce the attractiveness of loafing and feeding sites for some species of birds such as gulls, this strategy may also increase cover and food resources for other hazardous species. Thus, optimum vegetation height management strategies require further research and may be site-specific. Replacing attractive vegetation with less palatable vegetation has also been recommended, but studies with widespread application are lacking. Removal of ornamental trees and shrubs reduces cover for deer and small mammals and nesting sites for birds while also reducing availability of perches. However, exclusion techniques are also needed for reducing the availability of artificial perches and water. Despite more than 30 years of substantive discussion on the importance of these habitat management techniques, few reliable studies of the effectiveness of these techniques have been conducted under operational airport conditions.

Food habits of raptors using airports in north-central Kentucky

Author(s): Stucker, Keith P.; Dunlap, Brett G. | Abstract: As domestic air travel and wildlife populations have increased in recent years, wildlife-aircraft collisions (wildlife strikes) have increased, prompting concerns for human safety and the economic impacts of wildlife strikes. Most of these wildlife strikes occur in the immediate vicinity of airports. Therefore, removal of wildlife attractants from the airfields themselves is an important component of effective wildlife strike hazard management programs. In response to a such a wildlife strike problem, the U.S. Department of Agriculture’s Wildlife Services program initiated a wildlife hazard mitigation program at airports in north-central Kentucky which included direct control of raptors. To identify the food-based attractants that may be attracting raptors to these facilities, we salvaged digestive tracts from carcasses of raptors removed from these airports and identified food items contained within. These data will be used to focus prey-base management activities and help reduce the attractiveness of airfield habitats to foraging raptors in an effort to reduce wildlife strikes and the need for direct control of these birds.