Mastermark in collaboration with OMSI hosted the first ever “Mastering the Skies” event in Manila, Philippines this February. Your thoughtful inquiries were met with responses from our Airport Biologists as part of the engaging session. While the event generated a multitude of insightful questions, this article aims to tackle any unanswered queries from the session.
Didn't make it to the event? No problem! This article is the perfect place to meet your new best friend, Airportbiologist.com. We are a free resource and community hub for all things related to airport wildlife biology. It is open to anyone and everyone interested in the field of airport wildlife biology, welcome!
Question: What is the recommended timeframe for conducting surveys to obtain good data?
The intent of conducting wildlife surveys is to better understand the abundance, behaviour and movement patterns of wildlife specific to your aerodrome. With this in mind, it is better to schedule surveys during periods of higher wildlife activity, to more efficiently capture as much of the wildlife presence at the aerodrome using the resources available. Peak wildlife activity may vary depending on the species of wildlife present at your airport. Throughout the day, wildlife is most active during two periods: dawn and dusk. However, depending on your aerodrome’s strike history or high-risk species, targeted surveys may be arranged at specific hours of the day corresponding to when strike frequency is highest or when a particular species is likely to be active.
Ideally, the frequency of each dawn and dusk survey should be conducted daily. The datasets from regularly frequent surveys would allow for accurate identification of patterns and trends. These trends are particularly useful in determining when birds arrive or leave for the migratory season, when the start of breeding seasons are, or if there are any sudden increases in wildlife due to changes in the surrounding environment.
If frequent surveys are not feasible, the surveys may be reduced to one a week for a total of two dawns and two dusks a month. This will allow for a general sense of the wildlife in the aerodrome from week to week.
The intent of conducting wildlife surveys is to better understand the abundance, behaviour, and movement patterns of wildlife specific to your aerodrome. With this in mind, recommended timeframes for conducting surveys should be able to target both daily peaks in wildlife activity as well as capture seasonal fluctuations in species diversity and abundances.
A duration for this initial wildlife study should minimally be one year in order to properly capture abundance and diversity data related to seasonal fluctuations in the year. Beyond this, year-on-year changes in species abundance and diversity within the aerodrome could also be present and a extended study period of 3-5 years would provide greater insight on the yearly trends of wildlife within the aerodrome.
Question: Are certain plane colours more attractive than others towards birds?
Theoretically, brighter colour schemes have higher RGB values and would contrast more against the background of the sky compared to darker colour schemes, allowing birds to better detect and avoid aircraft in flight.
A 2011 study found a correlation between brighter coloured fuselages and lower strike rates. However, as the study assessed the relationship based on publicly available bird strike data, it was acknowledged that multiple confounding factors such as altitude and temperature and bias in data collection (e.g. not reporting less significant strikes) may have affected the validity of the cause-effect relationship between colours and strike rates.
Question: At what altitude does a bird strike usually occur?
Globally, 95% of bird strikes occur below 2000 ft. Based on ICAO’s Doc 9137 on Wildlife Hazard Management, typically these strikes occur during take-off, approach, or landing phases of flight. Do note that strike rates may vary between aerodromes depending on local environments and behaviour of wildlife in the area. Aerodromes that lie along migratory flyways (i.e. the primary routes used by birds when travelling south or north at the start and end of their migratory seasons) have a higher rate of strikes at higher altitudes. This is caused when migratory birds such as ducks or geese may travel long distances at altitudes up to 7000 ft above ground level.
Question: Is there a difference between dispersing native birds vs. dispersing pest birds?
Dispersing native birds and pest birds requires distinct approaches based on their conservation status, legal protections, and ecological roles. Do note that distinctions between native and pest birds will vary widely from country to county. Native bird dispersal will usually prioritize conservation concerns, which may restrict the use of lethal mitigation methods. In contrast, dispersal of pest birds, which are often non-native species, is driven by concerns for public health, safety, and nuisance mitigation.
In Singapore, several pest bird species have less legal protection under local legislation. Consequentially, approval for the trapping and population control of these birds are more easily obtained. However, pay attention to your own country’s legal regulations, which may have different definitions on what and how species are protected, as well as the kind of measures which can be deployed against them.
Question: What is the most effective way to disperse both birds and bats in an airport? What equipment should I use to disperse egrets?
There is no silver bullet as to the MOST effective way or equipment to disperse birds, egrets included, and bats. It should first be noted that there are many bird and bat species, each having their own unique physical and behavioural characteristics. The same dispersal tool may produce different reactions from different species.
In Singapore, the medium egret (Ardea intermedia) has been known to be dispersible by bird scaring lasers, the crack of a stock whip, the presence of a vehicle and even the waving of a red flag. Regardless of the species, it is necessary to consider the following factors when choosing the appropriate tools for dispersal:
· Behaviour of the species
· Dispersal history
· Environmental conditions during dispersal
· Local legislations protecting target species
· Resources available to the airport operator
What are the egrets doing in the aerodrome? It is important to determine what the particular species is doing in the aerodrome as this may affect how easy or difficult it is to disperse them. A group of egrets on a tree will be harder to disperse than egrets simply foraging in an open field.
Wildlife behaviour may vary depending on whether the species is resident or migratory. A migratory bird that just arrived in your aerodrome at the start of the migratory season will usually be more skittish and easily dispersed. In such cases, simply the approach of a vehicle may be enough to disperse them.
Dispersal history affects what tools you would use to disperse the wildlife. All wildlife may get used to or "habituate" to dispersal tools which are used repeatedly over a prolonged period. This habituation will cause tools to lose effectiveness on the target species. Habituation is resolved by having a toolbox of several different dispersal tools or systems which allow you to alternate or cycle through your methods and approach, thus preventing the wildlife from habituating to the dispersal systems.
Environmental conditions such as ambient light or sound affect the effectiveness of dispersal tools used. Wildlife lasers used for bird dispersal work well during low-light times of day such as dusk and dawn, but have a reduced dispersal range in bright daylight conditions causing the laser to be less visible to the bird.
Legislation involving the protection of wildlife plays a role in the choice of dispersal equipment. Lethally shooting birds can be used in conjunction with the use of pyrotechnics. As the birds come to associate the sound of the pyrotechnics with the sound of a gunshot, it can reduce habituation. This approach would not be possible if the targeted species is protected from culling.
Airport operators must balance their manpower availability and budget for wildlife dispersals, how they do so will affect what tools would be recommended. Using automated wildlife dispersal systems may reduce manpower requirements for dispersal patrols, but these systems tend to have a higher upfront cost.
Ultimately, airport operators will benefit from comprehensive wildlife behaviour data, historical wildlife dispersal effectiveness data, and knowledge on the environment and legislation you are dispersing within. Beyond that, remember that habitat management plays an important role in wildlife strike mitigation. Reducing the attractiveness of your aerodrome to a particular species will reduce the amount of effort needed to disperse them.
Question: Is there a fast and easy solution that can assist in improving a database for trend and data analysis?
When starting the process of collecting wildlife data, developing a comprehensive data collection protocol and conducting personalized airport wildlife training is the perfect combination. The protocol should clearly dictate how each data field should be filled in or sorted. The training should equip staff with the skills to identify species of local wildlife and determine the kinds of behaviour they are displaying.
A fast and easy solution can be the onboarding of a sophisticated data collection system. These systems could include an avian radar or a tablet with accompanying software specialised for wildlife data collection on the field. A radar system’s ability to track wildlife movements in real time will allow for much greater resolution in spatial patterns and the timing of wildlife movements in the aerodrome. A tablet with specialised software can help to streamline the data collection process, making it not only easier to collect data out in the field, but also easier to transfer that data into a digitalised database.
Question: Is there data on the maximum bird mass that engines of different aircraft types can withstand without causing damage?
Various aircraft models will naturally exhibit different levels of tolerance concerning their engines and bird strikes. While there isn't a direct dataset involving different aircraft/engine types and the maximum bird mass they can safely ingest without causing damage, we can make estimates based on the specific aircraft or engine type.
Commercial fixed-wing aircraft turbine engines are tested and certified under FAA’s 14 CFR Part 33-77 (USA) and EASA’s Airworthiness Code CS-E 800 (EU). However, aircraft are given different classifications based on size (e.g. CS-23 covers airplanes with 19 seats or less or a Maximum Take Off Weight of 8618 kg). Planes under CS-23 classification do not have any bird strike certification requirements. Only those classified as large turbine-powered airplanes, with Maximum Take-Off Weight (MTOW) of more than 5670 kg, have such requirements. These certification processes only test whether ingestion damage is possible under specific conditions. One certification criteria example would be “an ingestion of a single bird at 200 knots of weight between 1.8kg and 3.65kg, depending on the engine inlet area, shall not cause the engine to catch fire, suffer uncontained failure or become impossible to shut down, and shall still allow at least 50% thrust to be obtained for at least 14 minutes after ingestion”. It is important to keep in mind that these are specific conditions tested for certification. In reality, there are many different situations that do not fall within these conditions. For example, the US Airways flight 1549 struck and ingested a flock of Canada geese, which weighed about 2.5kg per adult, subsequently losing all engine power.
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