Unintentional Aerial Encounters
Avoiding Costly Clashes with Wildlife
By James Williams, FAA Safety Briefing Magazine
“Always keep your eye on your opponent, and never let yourself be deceived by ruses.”
— The Dicta Boelcke, Oswald Boelcke, 1916
Surprises can be good when discussing a birthday party, but not when just hoping for a peaceful flight. The Dicta Boelcke cited above was a simple list of eight rules for air combat developed by Oswald Boelcke in the infancy of air combat. Boelcke, along with Max Immelmann, for whom the aerial maneuver is named, and others, formed the original cadre of fighter pilots with aircraft developed as fighters. The Dicta Boelcke which was distributed around the nascent German Fighter Corps, served as one of the earliest tactical guides and influenced virtually every air combat manual up to today.
Our dealings with wildlife in general aviation (GA) are not inherently adversarial, but potential conflict exists. Oftentimes, pilots and birds find themselves occupying the very same airspace; it is an encounter where no one truly wins. Denying the enemy’s use of the sky was the first purpose of fighter aircraft — to deny the sky to bomber aircraft. More importantly, reconnaissance aircraft helped the high commands aim artillery and plan offensives. Our ambitions as GA pilots aren’t so grand, but the individual consequences of these unintentional wildlife conflicts can range from deadly, to simply inconvenient. So, what do we do about it?
In 2023, there were 19,367 strikes logged, with 701 classified as damaging strikes.
Securing Our Advantages
The first step in approaching any problem is to define the problem and make sure it actually exists and that you are not chasing ghosts. Regarding wildlife strikes, we have data to consider. In cooperation with the U.S. Department of Agriculture Wildlife Services, the FAA produces an annual report of the Wildlife Strike Database. While there is some discussion around the completeness of that data, the question is generally around to what degree the official tally undercounts actual wildlife strikes since many minor strikes are not reported. So, we can consider the total reported strikes to be a lower boundary for the scale of the problem and the real number may be much higher. The total damage and injury count is probably closer to reality since it’s more likely that someone will report a strike that results in significant damage or injury. However, even the “low impact” strikes are essential to report because they can inform mitigation strategies.
Wildlife strikes dipped in 2020 due to lower aviation activity but have been steadily rising ever since. In 2023, the last year with complete data, there were 19,367 strikes logged, with 701 classified as damaging strikes. The data for 2024 is still being vetted and analyzed and should be available in the next couple of months. Total costs for the same period had a similar trend but didn’t set any records with a high of $461 million versus a high of $589 million in 1995. Total cost includes repairs, aircraft downtime, and other expenses. However, it is hopeful that despite a significant increase in reports, the damage bill isn’t climbing in strong correlation. This may mean we are capturing a more complete picture.
Making Preparations
How can we prepare to avoid these unintended clashes? The Dicta Boelcke emphasizes working in groups, and that’s an important point here because what we can do directly is limited. But together with airports, government agencies, and others, we can work to reduce the dangers. As individual pilots, we can improve our situational awareness. Many factors can increase or decrease our likelihood of a too-close encounter with the wild kind.
First, seasonal migration patterns bring extra avian visitors to, or throughout the country. During those times, extra vigilance should be applied. But this is really just ramping up some common-sense concepts that can help avoid collisions. Knowing the area surrounding airports for our flight route can help. Avoid flying over attractive environments like lakes, ponds, wetlands, water treatment facilities, and garbage dumps to the extent practical. Also, increasing altitude can reduce your chances of a bird strike. Most reported strikes — a whopping 92% — happened at 3,500 feet above ground level (AGL) or below, and 71% occurred at 500 feet AGL or below. Altitude isn’t a complete savior, but it dramatically improves your odds; about 1% of strikes occur at 9,500 AGL or higher. Unfortunately, these tactics won’t work as we approach the airport so we’ll need to lean on our airport partners.
Fire Only at Close Range
The Dicta Boelcke emphasizes the need to engage only at close range to ensure success, and close range, in terms of the airport environment, is where our danger is greatest. It’s where we’re low and slow and may not have any avoidance options. Airport operators know this and work with government and research organizations to enhance their defensive and offensive wildlife weapons.
The most effective solutions involve an ounce of prevention. By working with communities and municipalities, airports seek to avoid placing wildlife attractants like the aforementioned landfills, retention ponds, wastewater treatment plants, etc., in the immediate surroundings. This can go a long way toward reducing the wildlife populations in the immediate airport area, but it isn’t a complete solution. Airports also work to make their grounds less habitable for birds and other animals. While small rodents like mice aren’t usually a problem for aircraft directly, they can draw potential problems in the form of predators. Habitat modification may include removing water, food sources, and nesting locations from the airport area to the extent possible.
Many factors can increase or decrease our likelihood of a too-close encounter with the wild kind.
To illustrate this with a personal story, we once had neighbors living in the U.S. as embassy staff and they were unfamiliar with the local wildlife common in suburban America. They would put out “food” for the squirrels in the middle of their backyard. But with the placement in the open area surrounded by tall trees, their intended squirrel feeder quickly became a hawk feeder. Allowing attractive habitats on airport property can create similar circumstances where an inconsequential species attracts a problematic one for pilots. Good perimeter fencing is also a must. While we think of this in terms of security, it is also a barrier for animals like deer and coyotes. These strikes are far rarer than bird strikes, but the larger size of these animals can make any contact more dangerous.
While passive measures are great, they often require supplementation with more active approaches. These can vary greatly depending on each airport’s budget and needs. Simple solutions include techniques like propane cannons that startle animals periodically. But like the classic scarecrow used for centuries on farms, there may be a need to reinforce this faux threat with something more tangible. This is where “dog fights” come in multiple ways. Using trained predators like dogs and raptors can make your airport environment seem less hospitable to concerning species. Using these predators to chase off wildlife can affect local populations beyond the short time the predators are active.
As you can see, it’s not about a single approach to solving all your wildlife problems. The layering of these approaches delivers the best results. Just like in the early air war, it wasn’t just the Fokker Eindecker that led to the period of German air superiority that the British would call the Fokker Scourge. In fact, French pilot Roland Garros (for whom the tennis stadium is named to show you how big a deal it was) had equipped his airplane with a crude system of metal reinforcements on the propellor that allowed him to fire through the propellor arc before the Germans developed the proper equipment. The combination of the right airplane, equipment, pilots, and tactics/doctrine created that success. But nothing lasts forever, and the Entente air forces would catch up after several months. By the end of 1916, Boelcke and Immelmann would be lost in combat. Continued evolution of tactics and equipment is vital. This is why research is so important.
Adding more approaches to wildlife management can provide airport operators with more options and greater variety. This can be useful for some species that habituate to more established tactics and might otherwise require culling. A recent example is using drones instead of predators to drive off wildlife. You can read more about that in the Drone Debrief department.
But adding more tools to the toolbox isn’t without complications. Using drones at an airport requires careful coordination and well-defined procedures — it’s not as simple as grabbing a drone and heading out to the airport. Wildlife management is an evolving process requiring teamwork from the aviation community. The environment isn’t static, and we must continue to help however we can. For most of us, that means reporting any strike we experience, even when it’s inconsequential. For some, that means helping maintain a clean airport environment to avoid attracting airborne and terrestrial scavengers. For others, it’s working on research that may bring the next great tool to help keep airplanes and wildlife separate. For civil pilots, the greatest air combat victory possible is to avoid it entirely.
A Personal Perspective
On Halloween a few years ago, I was with a relatively new student pilot whom I just met that afternoon. We decided we were going to do one pattern at Bay Bridge airport. We got off the departure end of Runway 29, and to the left side of my eye, I saw three large birds come across the front of the aircraft. The trailing bird, which I found out was a cormorant, made a hard right turn and immediately entered the aircraft by busting through the plexiglass windshield of the Cessna 172, hitting me in the face and making its way to the back of the aircraft.
At that point, I realized the plane was still flying, but we needed a lot of extra power because of all the drag from the smashed windshield. We made it around, and on final, I actually had to apply full power because of the drag and a 10-knot headwind. Fortunately, we had enough power and landed safely. I’ve been flying small airplanes for 24 years and instructing for 12 years. The majority of my 4,000 hours is instructing in smaller airplanes, and I never had a close encounter with a bird in all that time.
Typically, the birds will dive under you or just avoid you, but in this case, I think it was just such a low level, with the wetlands being so close to the end of Runway 29, that I think we were both just taking off. Now, I definitely look at the environment around an airport and incorporate a scan for wildlife prior to taking off.
Watch the FAA Wildlife video that features Chris’ account at bit.ly/FAAbird.
— Chris Criswell, FAA Airport Data and Airspace Branch manager
Learn More
- FAA Wildlife Hazard Mitigation
- Things That Go Bump in the Flight, FAA Safety Briefing, Jan/Feb 2009, Page 28
Report a Wildlife Strike
James Williams is FAA Safety Briefing’s associate editor and photo editor. He is also a pilot and ground instructor.
