“During a bird watching visit overseas, while at transit at an airport, I observed the airport staff using a double barrel shotgun to disperse raptors (above). As the flights from this transit airport were limited, regulated and fixed, the staff would periodically enter the airfield on a motorbike to chase away the raptors just before take-off or landing. The raptors at this site were predominantly Black Kites (Milvus migrans) (below). Once the airport staff spotted me using my camera I was politely asked to stop recording the activity. There were two staff members with shotguns monitoring the 7-8 Black Kites circling the airport. Black Kites are well known urban scavengers and the environment around this airport was resources-rich from their perspective (lots of open garbage).
“Airports have increasingly ‘struggled’ with animal ‘incursions’ and especially with birds striking aircraft. Wikipedia calls these bird strike risks as BASH (bird aircraft strike hazard) (Reference 1). A ‘nice’ acronym as long as we realise that the birds are not intentionally striking an airplane and have an equal right to the air and land space they/we inhabit.
Why do Bird Strike Events Happen at Airports?
“In the USA the number of documented bird strike events has steadily risen, partly due to better reporting. The USA Federal Aviation Administration has documented a 7.4 fold increase in annual bird strikes from 1,847 in 1990 to 13,795 in 2015 (Reference 2 & 3). This is possibly due to the rapid increase in airplane and flight numbers but also due to a shrinking habitat for birds. Birds are also attracted to airports for a number of other reasons. Airports offer a large, open, green space where birds can feed, nest and often be free of predators. Some airports are located near wetlands or water bodes which attracts migratory or resident water-birds. How birds endure the noise levels from planes landing and taking off is an enigma.
“At airports in Malaysia I have often seen Cattle Egrets (Bubulcus ibis), Little Egrets (Egretta garzetta), Paddyfield Pipits (Anthus rufulus) and Common Mynas (Acridotheres tristis). In my home town (Ipoh) Red-wattled Lapwings (Vanellus indicus) nest on the grass verge of the airport runway, Cattle Egrets and Brahminy Kites (Haliastur indus) hunt for prey on the runway. Numerous other birds fly past or visit the airport grounds daily.
Methods to Reduce/Prevent Bird Strike Events
“I performed a limited internet search for methods used to prevent bird aircraft strike hazards at airports. I used three key search phrases. A general open ‘airport bird’ search followed by targeted ‘airport bird control methods’ and ‘bird strike prevention at airports’ searches. There are numerous methods utilised by various airports. The problem is so important that it has become commercially viable for businesses. I have discussed these methods from older mechanism to newer, more humane, technologies which involve chasing away the birds or deterring their presence.
1. Flash & Bang Method (Acoustic or Visual Repellents)
In the past birds were shot with shotguns or pistols, but most airports that use them now employ them for the sound effect. Some use ‘screamers’ or explosions that emit sparks to frighten away the birds. In recent years propane and sonic cannons have been deployed. Not all birds respond to these and tolerance or habituation can develop. (Reference 3)
At Mexico’s international Airport Peregrine Falcons are deployed to keep birds away. In the past they would feed on these birds but currently, due to lobbying by environmental agencies, they are trained to frighten birds away by their ‘threatening silhouette in the sky‘. Other raptors are also used by various airports (Reference 4).
Some airport staff have used Border Collies to chase birds away. Dogs apparently work better for birds that become tolerant to pyrotechnics, especially Egrets and Herons (Reference 5 & 2).
4. Modifying Habitat
Environmental control of food sources and habitat is used to make the airport grounds less appealing to birds. This involves removing potential nesting sites, keeping grass mowed short, reducing insect volumes and seed plants, and ensuring no open rubbish adjacent to airports. Covering sources of water is also important (Reference 6).
5. Relocating Birds
Some airports resort to capturing and relocating birds when other measures fail, especially for raptors. Occasionally, but less often today, birds are culled (Reference 6 & 2).
A number of airports have begun to use green lasers to scare away birds. Airports in Dundee, Frankfurt and Amsterdam are among many that employ a long range laser light to temporarily frighten birds off the airport grounds. The lasers are claimed to be safe to both the human and avian eye. Lasers work best at dawn and dusk (Reference 7 & 8).
7. Playbacks of Distress, Alarm or Predator Calls
Apart from the crude loud noises utilised (see No. 1) newer acoustic repellents include using call play back of distress, alarm or predator calls. These have to be used judiciously to prevent habituation and only calls of local bird species and predators are effective.
8. Physical/Visual Deterrents
A number of commercial firms are offering physical/visual deterrents to keep birds away from airports (Reference 9). These include:
a. Electric deterrent systems (safe, low shock electric fencing on ledges, parapets, etc).
b. Bird netting installation (on roofs/car parks to reduce roosting/nesting).
c. Bird Spiking Installations (upward pointing wires/spikes to prevent landing).
d. Bird Gel Deterrent (long-lasting, waterproof, natural products installed on roofs that give off ultra-violet light, appearing as flames and act as visual deterrents).
9. Robotic Birds
Drones designed as birds of prey, robotic falcons, are being tested and described as ‘indistinguishable from its natural counterpar’. These might serve to keep smaller birds away (Reference 10).
10. Modifying Aircraft Behaviour
One last method to minimise bird strikes is to adapt aircraft flight schedules to bird behaviour. One example would be to reduce aircraft arrivals and departures near dusk and dawn, i.e. at peak bird movement times, especially for Starlings flocks (Reference 11). Many airports also now monitor mass bird movements via radar to alert pilots.
“While researching this issue I came across an excellent resource and discussion on the subject by Piotr Matyjasiak – ‘Methods of bird control at airports’ a chapter in a book on modern ecology (see Reference 11) – really worth the read. Matyjasiak states that there are ‘three general ways to minimise airplane bird strikes: modifying the birds’ habitat, controlling the birds’ behavior and modifying the aircrafts’ behavior. Airports that have had the most success with minimizing bird strikes have employed all three methods through various techniques.’ He also says that ‘Scaring techniques should be used selectively and in rotation in order to avoid habituatio’. His paper has a nice table summarising most methods and their efficacy but there have been some advancements since he wrote it.
“Mankind has overrun the planet and often can only see issues from their perspective. Hence birds are viewed as threats to aircraft in the airport vicinity and a danger to man. It is vital that, while we protect aircraft from ‘bird strikes’, that we also work to support birds and prevent their harm from airplanes. In these present times perhaps drones piloted by humans may pose a greater risk to aircraft than wildlife.”
Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
11th May 2018
1. Bird strike. Wikipedia LINK (accessed May 2018).
2. Tom Geoghegan. 10 ways to prevent plane bird strikes. BBC News, Washington. Nov 2013 LINK.
3. Dolbeer, Weller, Anderson, Begier. Wildlife Strikes to Civil Aircraft in the United States, 1990–2015. Federal Aviation Administration and National Wildlife Strike Database, Serial Report Number 22. Nov 2016 PDF.
4. Mexico’s airport falcons keep nuisance birds away. AFP, February 1, 2018 LINK.
5. Alexander-Adams. Fact Sheet – The Federal Aviation Administration’s (FAA) Wildlife Hazard Mitigation Program. Sept 2016 LINK.
6. Melissa Mayntz. Airport Bird Control Methods: How Do Airports Prevent Bird Strikes? April 2017 LINK.
7. Aerolaser Handheld at Frankfurt Airport, Germany. Bird Control Group LINK.
8. Patrick Murphy. Worldwide: Handheld laser being used by airports to disrupt birds. LaserPointerSafety LINK.
9. Airport Bird Strike Hazards & Airfield Bird Management (UK commercial site) LINK.
10. Robotic falcons to scare away real birds at Edmonton airport. CBC News. May 2017 LINK.
11. Piotr Matyjasiak. Methods of bird control at airports. Chapter of a book in: Theoretical and applied aspects of modern ecology. J. Uchmański (ed.), Cardinal Stefan Wyszyński University Press, Warsaw, pp. 171-203, 2008. Available HERE.
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