A bird strike is the collision between an aircraft and an animal, with birds being the most common perpetrators. While this phenomenon has existed since the earliest days of powered flight, it became a serious safety concern with the advent of high-speed jet aircraft. Although most encounters cause little damage, the potential for a catastrophic accident makes wildlife management a high-priority safety activity for the global aviation industry. Risk is managed through stringent aircraft design standards and proactive control measures at airports.
Tracking the Frequency of Strikes
Bird strikes occur frequently, though few result in a serious incident. The Federal Aviation Administration (FAA) in the United States recorded approximately 17,200 wildlife strikes in 2023, with birds involved in about 97% of these incidents. This volume translates to dozens of reported strikes daily across the US, a number trending upward due to increased air traffic and growing populations of larger bird species.
The majority of collisions happen at low altitudes, specifically during the departure and arrival phases of flight. About 70% of all reported strikes occur below 500 feet above ground level, with the highest concentration during takeoff or landing. This is because aircraft operate in the same airspace as the highest density of bird activity, which is concentrated around airports.
Despite the high frequency of strikes, only a small percentage result in significant damage. Historically, only about 2% to 8% of reported strikes lead to structural damage requiring repair or causing a flight interruption. The most hazardous birds are large-bodied species like Canada geese, raptors, and vultures, whose greater mass carries substantially more kinetic energy upon impact. Data collection relies heavily on voluntary reporting, meaning the actual number of minor, non-damaging strikes is likely much higher than official figures suggest.
Consequences of a Strike
The outcome of a strike is determined by the bird’s size and speed, and the specific part of the aircraft struck. The most serious consequence involves ingesting a bird into a jet engine, which can lead to a sudden loss of thrust. When a bird enters a high-speed engine, it can damage the fan blades, leading to an imbalance that propagates through the compressor and turbine sections in a cascading failure.
To mitigate this risk, aviation authorities mandate rigorous engine certification testing using artificial birds, typically gelatin projectiles fired from a pneumatic cannon. Large transport aircraft engines must demonstrate they can ingest a single large bird (1.8 kg to 3.65 kg) without fire or uncontained failure. They must also maintain at least 50% thrust for 14 minutes post-impact. Smaller birds are tested in multiples, requiring the engine to maintain minimum thrust for 20 minutes after ingesting up to 16 medium-sized birds.
Beyond the engines, the airframe’s forward-facing components are the most susceptible to damage. Commercial aircraft windshields are designed with multiple layers of materials like glass and vinyl to withstand the impact of a 1.8 kg bird at cruise speed without penetration. Other common impact points include the nose cone, which often houses the radar equipment, and the leading edges of the wings and tail. Damage to the airframe can necessitate an immediate diversion or emergency landing, particularly if the integrity of the flight controls or pressurized cabin is compromised.
Reducing Wildlife Risk at Airports
Airport operators actively manage the risk of bird strikes through comprehensive Wildlife Hazard Management Plans (WHMP) that address local ecological factors. A primary strategy is habitat modification, which aims to make the airport environment unattractive to hazardous species by eliminating food, water, and shelter. This includes ensuring proper drainage to remove standing water, which attracts waterfowl, and implementing specific turf management practices.
Many airports maintain grass at a height of 6 to 14 inches to deter small, flocking birds that prefer short grass for foraging. This simultaneously discourages raptors by reducing the small mammal population that tall grass can harbor. Physical exclusion techniques are also utilized, such as installing netting over water retention ponds and using perimeter fencing to prevent terrestrial animals like deer and coyotes from entering the operational area.
Active dispersal techniques are used when birds enter the airfield despite passive habitat management. These methods range from bio-acoustics (broadcasting species-specific distress calls) to pyrotechnics like cracker shells that produce loud noises to scare birds away. Some airports employ specialized staff using lasers, trained working dogs, and falconry to actively haze and disperse bird populations. Advanced avian radar systems are increasingly used to track real-time bird movements, providing air traffic controllers with data to warn pilots and allow wildlife control teams to intercept flocks.