By Robert N. Rossier, EAA 472091
This piece originally ran in Robert’s Stick and Rudder column in the October 2023 issue of EAA Sport Aviation magazine.
It’s that time of year again: fall migration season. The “snowbirds” — myself included — are heading south to escape the chill of winter. I’ve planned my route and will time my departure with the onset of favorable weather.
Unfortunately, snowbirds aren’t the only ones heading south. Each spring and fall, madness prevails as thousands upon thousands of birds migrate along well-known routes. It’s a good time for all of us who fly to take precautions to help ensure our paths don’t cross. The last thing we need is to run into “fowl” weather.
Bird Strike Incidents and Accidents
Each year, the United States alone sees roughly 9,000 bird strikes. While many of these result in relatively minor damage, others wreak havoc, causing serious damage, injury, and even fatal accidents.
In March 2020, the pilot of a Beech Bonanza (BE36) suffered a “fowl” weather day. He was 7 miles west of Orlando Sanford International Airport (KSFB) in Florida at 1,600 feet AGL when the aircraft suffered a bird strike from an anhinga — a migratory waterfowl weighing nearly 3 pounds with a wingspan of almost 4 feet. The bird penetrated the center of the passenger side of the windshield, striking the interior dashboard and slamming into the pilot’s right arm.
According to the bird strike report, the pilot had difficulty communicating, and a light gun was used to clear the aircraft for a precautionary landing. Damage to the aircraft included a broken windshield and instrument panel, a hole in the tail, and a dent in the wing surface, totaling $40,000 in repair costs.
In September 2021, a student pilot in a Cessna 152 on approach to landing at Olive Branch Airport (OLV) in Mississippi was at 300 feet AGL when an American kestrel crashed through the windscreen. After landing, the pilot was taken to the hospital for a head injury caused by the strike.
Clearly the danger of bird strikes is real. The most dangerous time for bird strikes is between July and November, which is when about 53 percent of bird strikes occur. Although we are nearing the end of this fall’s higher-risk season, danger still lurks.
Where Birds Fly
To better understand the phenomenon of bird strikes, we need a sense of birds’ habits — where they live, where and when they hunt or feed, where they nest, and where they fly. We should understand what they will likely do when threatened, either in the air or on the ground.
Different species of birds prefer different environments, and may nest and feed in different areas. We typically encounter birds such as seagulls near municipal landfills, transfer stations, and fish packing plants, all of which are often near airports.
Open grassy areas — common to airports — are another favored habitat. Many birds prefer open grassy areas where seeds and insects are fed upon. Other birds prefer tall, unmowed grass where they can remain hidden from predators. Hawks and other raptors frequent open grassy areas to hunt for mice, rabbits, and other small mammals.
Peak feeding times are typically in the early morning and before sunset, but can occur at any time of day. Those birds near the coast that eat shellfish may adjust their feeding times to coincide with low tides.
And of course, another important consideration involves migration. All of us who take to the air must find ways of navigating effectively. When flying VFR, we might take advantage of natural features such as shorelines, rivers, mountain ranges, and so on. We might also use manmade features to navigate highways, cities, railroads, and other features.
Birds also seem to rely on natural navigation, so we need to be aware of the routes they typically follow. Four major migration routes that birds follow across the United States include:
- The Atlantic Flyway, which follows the Atlantic Coast.
- The Mississippi Flyway, which extends from the area surrounding the Great Lakes down the Mississippi River.
- The Central Flyway, which navigates along the eastern side of the Rocky Mountains.
- The Pacific Flyway, which follows the Pacific Coast.
The Danger Zone
Bird strike accident data gives us a good idea of where bird strikes are most likely to occur. Roughly 90 percent of bird strikes occur at or near airports. While 32 percent occur when a pilot is on departure, nearly double that number (62 percent) occur when a pilot is on approach for landing.
Seventy-one percent of bird strikes occur below 500 feet AGL, and that number declines 43 percent for each additional 1,000 feet of altitude. But some strikes do occur in cruise flight, and there are outliers in terms of altitude; the highest recorded bird strike was at 31,300 feet.
Higher bird body mass correlates to greater damage, but so does speed. When we’re close to the ground — particularly pattern altitude and below — it serves us well to be at reduced airspeed. Lower speed means reduced impact energy — and corresponding lower risk of serious damage. At slower speeds, we can better maneuver out of a bird’s flight path, and the birds are more likely able to avoid us.
Beware of the Shell Game
Any time we operate at airports near the shore, we need to understand the peculiar bird-related hazards that we might face. Besides a direct bird strike, there’s the potential for being shelled, both in the air and on the ground. Birds that feed on shellfish have a clever way of opening those shells — they drop them from altitude onto the pavement!
Not only does that pose a risk of getting hit by a skydiving clam or oyster, but the shell fragments on the runway can play havoc with our tires. To add to the excitement, some birds pick up shellfish such as oysters that may still be attached to rocks, adding to the mass and damage-causing potential of their clever feeding habits.
Avoidance Strategies
Several strategies can be applied to help us avoid bird strikes:
- Check for NOTAMs regarding bird activity at airports we’ll be visiting.
- When planning a flight, consider where the bird strike hazards may be greater. Expect to see birds when flying near environments where they live, hunt, and feed.
- Beware of migratory birds, especially along flyways such as rivers, shorelines, and along mountain ranges.
- If encountering birds in the air, pull up and climb over them; their natural reaction is to dive.
- If encountering birds near or on the ground, expect them to fly up to escape the perceived threat.
- Use lights (especially flashing landing lights) in the traffic pattern — although not 100 percent effective in alerting birds to our presence, this practice may help.
- Reduce speeds when at low altitudes and in the pattern. This allows both birds and pilots to maneuver out of the way more easily, and the kinetic energy of an impact is reduced.
- Make pilot reports to airport management and other nearby aircraft when bird strike hazards are noted.
- If a bird strike occurs, land promptly and carefully examine the aircraft for damage.
- Report bird strikes through the FAA at WildLife.FAA.gov/Add.
What Else Can Go Wrong?
We all know that birds aren’t the only wildlife that can foul up a flight. Twenty-nine percent of deer strikes occur from October through November, so watch carefully, especially in the early morning and evening hours.
The more we know about birds and migration, the more we can adjust our operations to mitigate the risks.
Robert N. Rossier, EAA 472091, has been flying for more than 40 years and has worked as a flight instructor, commercial pilot, chief pilot, and FAA flight check airman.