From broken windscreens, shattered helmet visors, holes in rotor blades, to complete loss of engine power and having to ditch into the Hudson: Bird strikes have been a threat since the start of aviation.
The stats show trends that suggest a significant increase in amount of bird strikes as time goes on 📈
There is a lot of misinformation related to bird behaviour and bird strikes. On top of this, training for flight crew rarely features bird strike related exercises.
So what are the most common bird strike myths that need debunking? What are the main threats of bird strikes, how can we mitigate them, and what can be done to safely get an aircraft on the ground after a bird strike? 💡
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What are Bird Strikes and how Common are They?
Bird strikes are defined as:
On average, about 95% of animals that are involved in strikes with aircraft are birds. The remaining 5% are land-based animals and happen near airports and runways.
According to the data (our sources are in the resources section below), over 270,000 bird strikes were reported between 2016 and 2021!
Between 2% and 8% of all recorded bird strikes resulted in aircraft damage.
On top of this, between 6% and 7% of all recorded bird strikes resulted in a negative operational effect on the flight.
Doesn’t sound like a huge percentage, right?
Well no, but if you consider that the average amount of yearly reported bird strikes is about 45,000, that’s a lot of operational impact!
Bird strike accidents are also becoming a lot more common for a few reasons we’ll cover later. Have a look at this graph based on bird strike related accident data from EASA:
From the start of the aviation industry until 2019, bird strikes have caused 618 hull losses and 534 fatalities.
The type of operation and aircraft heavily influences the risk of bird strikes. Have a look at what type of aircraft experiences the most amount:
The first ever recorded bird strike happened to the Wright Flyer III in 1905, so you could say we didn’t last very long before the first bird strike happened.
8 Common Myths about Bird Strikes
There’s a lot of bird strike misinformation floating around amongst pilots and the aviation industry in general. Let’s go over the top myths that are still quite common.
None of these have any scientific backing, and most are actually proven to be untrue:
1) Birds don’t fly at night
Birds absolutely fly at night. In fact, 19% of all bird strikes happen at night! Not only this, but bird strikes above 500 feet AGL are about 7 times more frequent at night than during the day, during the spring and fall migration seasons.
2) Birds don’t fly in poor visibility
Birds can fly in poor visibility and even fog!
3) Landing lights repel birds
There is no conclusive evidence that birds see and avoid white aircraft lighting. However, there is evidence to suggest that certain types of light can help repel birds, which we’ll get into more later.
4) Bright aircraft colours protect against bird strikes
It’s true that there is some research on bright vs dark paint and bird strikes. However, the effects of brighter colours still needs further research to reach a definite conclusion.
5) Birds will actively take avoiding action
While birds have demonstrated they can avoid aircraft, they aren’t perfect. It’s best not to assume they will take corrective action when there is a possible impending collision.
6) Birds only fly at lower altitudes
Birds do not only fly at lower altitudes. In fact, bird strikes have been reported between 30,000 and 40,000 feet! An aircraft over the ivory coast collided with a bird flying at 37,000 feet, which is one of the highest ever recorded.
We will cover the correlation between bird strikes and altitudes later in the article, as the higher you are does make bird strikes less common.
7) Bird are easily spotted and avoided
While big birds can be easier to spot, depending on the background from a pilot’s perspective, many are very hard to see. White birds can often blend in with the clouds, if they fly above the horizon from a pilot’s perspective.
For all the non-white birds out there (and there are many), these can also be hard to spot if they’re below the horizon, depending on the colour of the environment.
8) Bird strikes are a nuisance, but not a safety concern
Bird strikes have caused many accidents, fatalities and complete hull losses. As mentioned before, 2% to 8% of all bird strikes resulted in aircraft damage.
What are the Threats of Bird Strikes?
Bird strikes can cause flight safety issues in a lot of different ways, depending on quite a few variables. While they pose a threat to both large and small aircraft, the consequences tend to be more severe for smaller general aviation aircraft.
This is because of lots of factors such as single pilot operations, single engine aircraft, more fragile airframes, and less overall redundancy.
Bigger aircraft are definitely not exempt from these consequences though. Let’s go over the main threats to flight safety that are directly or indirectly caused by bird strikes:
Windshield Damage
Depending on the aircraft type and weight of the bird, windshields are not designed to withstand the force that comes with certain types of bird strike.
To give you an idea of what passenger plane windows are certified for, the FAA requires windows to withdstand a strike with a bird of up to 2 lbs at cruise speed, which is pretty significant but still doesn’t account for all birds (FAR 14 CFR Part 25).
On the helicopter side in Europe, we can look at CS-29 (certification requirements for large helicopters), which states:
So again, a bird of up to about 2 lbs. Although for helicopters the velocity requirement is up to Vne, rather than cruise speed. This is for large rotorcraft though, for smaller helicopters the requirements aren’t as strict.
The windshield is one of the parts of an aircraft that collide with birds the most, have a look:
An example of a fairly recent bird strike that caused windshield damage to a helicopter is this accident in 2018, that featured a Bell 429 in the UK, where the AAIB concluded:
Crew Safety
There have been numerous accidents where the windshield broke due to a bird strike, and caused harm to the flight crew in both helicopters and planes.
An example of this is a an accident that happened to a Bell 407 (N620PA).
The air ambulance flight was in the en-route phase to pick up a patient, when satellite tracking was lost at an altitude of roughly 1250 feet AMSL.
Then, the report states:
However:
And:
“While the helicopter flight controls were continuous, it could not be determined if the bird strikes jammed the pilot’s controls and/or incapacitated the pilot.”
On the fixed wing side, here’s another example:
DCH8-400 near Medford, USA in 2003.
“The crew sustained multiple bird strikes during a night visual circuit, resulting in loss of flight displays, multiple false warnings, and a broken left hand side wind screen.
The captain sustained significant facial injuries and temporary incapacitation with a successful approach and landing being completed by the co-pilot.”
Damage to Avionics
Pitot tubes, sensors, antennas and wiring can also be damaged by bird strikes. This is taken into account during certification as well. The fact that most pitot tubes are widely separated from each other on larger planes and helicopters, isn’t just to achieve overall redundancy. For instance, certification requirements on the FAA side state:
It’s commonly understood that even insects or foreign object debris can cause pitot tube blockages, not to mention birds that weigh the same as a bag of potatoes!
Structural damage
Structural damage is one of the most common consequences of a bird strike. Out of all the areas you could collide with a bird, the fuselage is often the least safety critical compared to engines and avionics, but it should not be overlooked.
One example is this bird strike that caused an emergency due to structural damage to an airliner:
“On 19 November 2022 an Airbus A320 was descending below 13,000 feet towards its destination Omaha clear of cloud at night and at 290 knots when an explosive decompression occurred as a result of bird strike damage.
An emergency was declared and once on the ground, three locations where the fuselage skin had been broken open were discovered. The structural damage was assessed as substantial and the aircraft was withdrawn from service for major repairs.
The birds involved were identified by DNA analysis as migrating Snow or Ross’s Geese, the former of which can weigh up to 2.6kg.”
Main or tail rotor damage
An additional risk for helicopters is a bird entering the main or tail rotor discs. At tip speeds that are close to the speed of sound, a collision with a bird can often result in even more damage than an airliner flying at Mach 0.8.
Holes, broken blades, and everything in between are not uncommon. A recent example of blade damage due to a bird strike was this accident in the UK:
An AW109SP, G-TAAS was flying at about 1,000 ft AGL at 140 kts.
“As the helicopter was descending and turning towards East Midlands Airport on return from a HEMS mission, a bird struck the left windshield.
The windshield shattered, and the bird entered the cockpit striking the technical crew member (TCM) on the left side of their helmet.
The TCM and pilot were unhurt. The debris from the windshield also hit the main rotor disk. This created a hole in the trailing edge of one of the main rotor blades.”
Flight Control Issues
Bird strikes that happen on or near control surfaces, linkages or any other component linked to flight controls can partially or fully block the controls.
For airplanes, the main ones are flaps, slats, rudders, and ailerons and their control linkages. If a bird gets stuck in the mechanism, it’s possible that the flight crew won’t be able to retract certain control surfaces.
For helicopters, it’s the swashplate assembly and the control rods that can be exposed to bird strikes, and if damaged can cause a lot of problems with controlling the disc.
Startle Effect
Bird strikes can be very unsettling, depending on where and how they hit the aircraft. Startle effects can lead us away from dealing with what should be the main priority: flying the aircraft. An example of this is this accident:
“On the morning of 9 July 2022, a Bell 206 L-1, registered VH-ZMF departed a private helipad at Cattai, NSW for a private flight. About 9 minutes later, the helicopter impacted terrain about 10 km to the north of the departure point. The helicopter was destroyed, and the pilot, who was the sole occupant, was fatally injured.”
What did the ATSB find?
Shortly after crossing Dargle Ridge at about 500 ft above the ground and while approaching the Richmond airspace control boundary, a wedgetail eagle impacted the helicopter just below the front left windscreen.
It was unlikely that the pilot saw or had time to avoid the wedgetail eagle due to sun glare and a required radio frequency change.
The pilot was likely startled and initiated abrupt control inputs leading to the main rotor severing the tail boom. This led to an inflight break-up of the airframe and collision with terrain.
Obstruction of Vision
You can probably imagine just how much impact a collision with larger birds can have on windshield visibility. Even without windshield damage, it can completely block the vision from a pilot’s perspective.
A recent example is this video from a pilot in Los Rios, Ecuador. It shows how much mess can be created from a bird strike (viewer discretion advised, it’s not great to look at):
Loss of Engine Power
Especially for planes, the threat of losing engine power due to a bird strike is one of the most critical threats during take-off.
The most notable and fairly recent bird strike accident that caused a complete loss of engine power was US Airways flight 1549, which ditched into the Hudson after taking off from LaGuardia Airport in New York.
This happened after both engines lost power due to a strike with multiple geese!
Another example is a bird strike that happened to an A320 neo in 2021 trom Atlantic City:
“The plane ingested a large bird into its right engine during takeoff, and a high speed rejected takeoff followed. When leaked fuel pooling within the engine cowling subsequently ignited, an emergency evacuation was completed on the runway.
The investigation identified the ingested bird as a bald eagle with a mass above the applicable certification standard and the fuel leak a secondary consequence of a fan blade broken by bird impact.”
EASA requires manufacturers to conduct engine ingestion tests. Basically, they fire birds with certain weights into the engine to prove there are no ‘hazardous engine effects’. These effects mainly include things like an uncontrolled fire, engine separation, and engine containment.
What Factors can Cause Bird Strikes?
So what are the main causes and factors that correlate with a higher risk of bird strikes? There are quite a few, with quite a lot of research that is trying to zoom in on what exactly can be used as predictors. Here are the main ones:
Bird habitats
Probably the most obvious one is flying through areas that are known to have a more dense bird population. The main one being bird habitats, as well as other areas that are known to have more birds. These are usually marked on aviation charts, and often reported by various flight information services.
Coastal Airports
Airports near coastal areas tend to have a higher density of birds around them, and therefore have a higher correlation with bird strikes.
Coastal areas typically offer a wide range of habitats and environments for birds that create food abundance. They can also serve as stopover points for bird migration, where rest and food after long travel distances are no longer a problem.
Ridge soaring and cliffs
Ridge lines and cliffs usually have a higher density of birds than their surrounding environment. This has a few reasons:
- Cliffs create updrafts based on the wind direction. Birds often like to use these to soar, or gain altitude without spending much energy.
- Cliffs and ridges provide bird nests protection from predators.
- Cliffs often provide micro-climates and vegetation that attract specific bird species.
Day vs night
While birds do fly at night, there are definitely more birds in the sky during the daytime. Bird strikes above 500 ft during bird migration periods however, are more common at night than during the day. For most of the year though, the amount of birds flying at one time is lower during the night than during the day. This graph shows the overall ratio based on ICAO data:
Bird Migrations
In Europe, the most amount of bird strikes happen during the migrations in spring and autumn. ICAO data based on worldwide reports shows that during July and August, bird strikes are the most common:
Bird behaviour and migration tendency depends on a lot of different things like availability of food, and regional weather conditions.
They tend to use altitudes between 300 and 9000 ft AGL, and they prefer a tailwind over a headwind.
Relative Velocity
The kinetic energy that comes with a bird strike can be explained with this equation:
As you can see, if your airspeed doubles, the kinetic energy quadruples! This means that reducing speed in an area where you consider a bird strike risk to be high, can be helpful to mitigate the effects of one occurring.
Let’s fill in the equation for some context. A bird that weights roughly 5 kg (like a goose) that collides with an aircraft at 130 kts (which is roughly 67 m/s), generates a kinetic energy of 11222 Joules. If we decide to reduce our speed to 65 kts, the same bird strike would only generate 2805 Joules!
Flight altitude
The threat of bird strikes, while still present, reduces massively the higher your cruising altitude is.
How much?
Well, there’s quite a bit of data on during what phase of flight bird strikes tend to occur, have a look:
The 3 phases with the highest risk are the take-off, approach, and landing. While not only related to altitude, it is one of the main influences here.
Bird numbers in specific regions
National Geographic estimated in 2021 that the total bird population across the globe was between 50 billion and 430 billion. This is obviously a huge range, and is due to the fact it’s hard to acquire accurate data on this.
In terms of trends, the USA’s Environmental Protection Agency reported steady increases in bird numbers, especially in the 1990s and 2000s. Data is still being analysed for more recent years. Bird population varies widely across different regions in the world, which also ties into migration cycles.
As time goes on, 3 factors will likely increase the amount of reported bird strikes, that aren’t just related to bird population as a number:
- An increased emphasis on reporting
- More accurate data collection and analysis
- An increase in global aviation traffic
How to Mitigate the Threats of Bird Strikes
As flight crew, we have quite a few ways to mitigate the threats of bird strikes. Here are the most effective safety barriers, which all come down to effective Threat and Error Management:
Use Helmets / Visors
For aircraft flying at lower altitudes, wear a helmet, and keep your visor down as much as possible. Flying on Night Vision Goggles might make this trickier or even impossible, but flying with your visor down will significantly reduce the chances of lasting physical injury.
Pre-Flight briefing
Discuss known local bird habitats during your pre-flight briefing. Check your aeronautical charts for indications for bird activity and habitats, and revise the what-ifs and action in the event of a bird strike.
NOTAM and BIRDTAM
NOTAMS can give lots of information on bird activity, and can also include a BIRDTAM, which gives specific information on what to be aware about to reduce the risks of a bird strike.
A BIRDTAM will provide a scale of risk level from 5 to 8, where 5 is ‘fairly great’, and 8 is ‘extremely great’. Only levels higher than 5 are reported in these. It will also show the general area and the affected altitude.
Check the ATIS
Airports have a responsibility to report significant local bird activity, and often have collected data on when higher bird activity is expected. Whether that is specific times during the day, or certain months in the year.
Use of Lights
Studies have shown that birds can avoid LED lights with peaks at 470 and 630 nanometers, which appear blue and red to humans.
Ultraviolet, green, and white light did not produce any noticeable patterns in these studies though.
Manufacturers are starting to come up with ways to incorporate this into aircraft designs. Lighting systems like Pulselite have been demonstrated to reduce the risk bird strikes as well.
Windshield Heating
Windshield heating will make the windshield more shatter-resistant. This reduces the risk of a windscreen breaking up in flight due to a bird strike, and therefore mitigates the threat of pieces of windscreen flying around the cockpit and negatively affecting crew safety.
Increase Cruise Altitude
For every 1000 feet increase in your cruise altitude, there is a significant reduction in risk for a bird strike.
On top of this, only 1% of bird strikes happen above 2,500 feet, according to the FAA. EASA also recommends flying at a minimum of 2500 feet where possible.
Airport Bird Management
Airports have a number of tools to reduce the amount of bird activity, mainly:
1) Bird deterrents such as pyrotechnics, lasers, noise, and specific lighting
2) Ultrasonic devices
3) Making the environment less bird friendly by removing standing water and minimising vegetation
4) Falconry: yep, using trained birds to reduce the bird problem!
5) Monitoring activity to collect data and understand trends
Bird Strike Awareness and Training
Pilots should receive training on bird awareness, understanding the threats, and how to mitigate them. Think back to your training, how much emphasis was put on the risks and threats of bird strikes?
Reduce Airspeed
As we’ve shown with the equation for kinetic energy earlier, reducing speed has a massive impact on the kinetic energy affecting the aircraft during a collision. Consider reviewing your cruise speed if flying through high risk areas.
Signs of a Bird Strike
Look out for these:
Visual: birds seen in close proximity, remains on the windshield or other visible aircraft parts
Tactile: Unusual vibrations from the airframe, the engine, power loss, asymmetric power, or abnormal handling of the aircraft
Auditory: Noise of a strike, engine surge or stall, aerodynamic noise
Smell: Smoke or odor
Engine Indications: A rise, reduction, or fluctuation in parameters
Avionics: A loss of data or indications that make no sense
System Malfunctions: Damaged antennas or other impacted systems can result in malfunctions that can be explained by external damage
What to do if you Suspect a Bird Strike
- Immediate Action: Fly The Aircraft, don’t get distracted, cross-check your instruments, and reduce speed if your windshield is damaged
- Assess the damage: If you suspect airframe or engine damage, maintain or reduce speed to keep aerodynamic disturbances low
- Consider your options: Have a plan A, and a plan B, whether that’s to continue, divert, or land immediately.
- Make a decision and carry out your plan: Choose the most appropriate option based on the variables you’re having to deal with
- Share the event on frequency: If workload allows, inform ATC and request assistance if required
- Assess the damage once landed: Carry out a post-flight inspection to verify what happened, and include an engineer in this process
- ASR and consider MOR post flight Once things have settled down, file a bird strike report at your relevant aviation authority.
Bird Strike Accidents
AW169 Bird Strike, Texas, USA
AW109 Bird Strike, UK
Most Notable Bird Strike Incidents and Accidents
Resources
Bird Strike Damage and Windscreens
Rotorcraft Bird Strikes by EASA
Rotorcraft Occupant Safety during Bird Strikes
Conclusion
Bird strikes can have a significant negative impact on flight safety, from structural damage, harm to flight crew, to complete loss of engine power.
There are a lot of different variables that go into determining how much risk for bird strikes there are in your specific circumstances. Understanding these is a great starting point to becoming more conscious of the impact they have on flight safety.
We hope this article can aid overall awareness on bird strikes for flight crew, and help with understanding the ways to mitigate the threats!
We don’t publish all our Notes from the Cockpit (like this one) publicly, some are shared only by email. Get the next one sent straight to your inbox ⤵️
4 Comments
Anonymous · April 14, 2025 at 12:03 PM
Thank you for the article. Requesting increased font size in the animations.
Jop Dingemans · April 14, 2025 at 12:04 PM
Thank you. We’ll look into this!
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