Open versioned aggregates of the FAA National Wildlife Strike Database (1990-2026): conditional damage rates by animal family, airframe, and airport

The Sky's Hidden Traffic Jam

Imagine the sky above our airports as a busy highway, but instead of cars, it's filled with airplanes and, occasionally, a few uninvited guests: birds, bats, and even deer. This paper lives in the corner of science called aviation safety, specifically focusing on "wildlife strikes." Think of a wildlife strike like a fender-bender in the sky. Sometimes, a plane just bumps into a bird and keeps going; other times, the impact is hard enough to break a window, dent an engine, or force the pilot to turn back. The big question researchers ask is: Which animals are the most dangerous, and where do these bumps happen most often?

To answer this, we need to understand two tricky ideas. First, reporting bias. In the real world, if you scratch your car, you might not call the police. But if you crash it, you definitely will. The same goes for planes: pilots are much more likely to report a strike if it causes damage than if it's just a harmless "boop." Second, conditional rates. This is a fancy way of saying, "Out of the accidents we know about, how many were actually bad?" It's different from asking, "How many accidents happen per hour of flying?" because we don't have a perfect count of every single bird that ever flew near a plane, only the ones someone wrote down.

Why does this matter? Because if we want to keep planes safe, we need to know where the real dangers hide. If we only look at the most common animals, we might miss the ones that cause the most trouble. This paper acts like a giant, organized detective board, sorting through decades of messy reports to find the true patterns behind the chaos.

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The Paper's Big Discovery: The "Volume vs. Danger" Twist

This paper is a massive data cleanup project. The author, Denys Kolomiiets, took the U.S. Federal Aviation Administration's (FAA) National Wildlife Strike Database—a huge, messy pile of reports from 1990 to 2026—and turned it into a clean, easy-to-read set of tables. The goal was to stop researchers from having to dig through raw, confusing files every time they wanted to know something about bird strikes. Instead, this paper gives everyone a pre-sorted "menu" of facts.

Here is the most surprising thing the paper found: The most common animals are not the most dangerous ones.

Imagine a party where 41% of the guests are tiny, chatty sparrows (perching songbirds). They are everywhere! But if you ask, "Who caused the most broken dishes?" the answer isn't the sparrows. They only break dishes in about 1.5% of their visits. On the other hand, imagine a few giant, heavy guests like deer. They show up very rarely (only 0.7% of the time), but when they crash into a plane, they smash it 81.8% of the time.

The paper shows that if you just count how many times an animal hits a plane, you get a list led by small birds. But if you count how often they actually cause damage, the list flips completely. Deer and waterfowl (like geese and ducks) are the heavy hitters. They are rare, but when they show up, they are a serious threat. This suggests that if airports want to stop damage, they shouldn't just try to scare away the most common birds; they need to focus on keeping the heavy, dangerous ones away.

The Airport Mystery: Busy Doesn't Mean Dangerous

The paper also looked at airports, and here, too, the numbers tell a weird story. You might think the busiest airport with the most bird hits would be the most dangerous. But the data says otherwise.

Denver International Airport has the most reported strikes of any airport in the U.S.—over 11,000 reports. However, only about 2.2% of those were damaging. It's like a busy intersection with thousands of minor bumps but very few crashes.

On the other hand, Sacramento International Airport is only eighth on the list for total hits, but it has the most damaging strikes of any airport (491 of them). Its damage rate is 11.3%, which is five times higher than Denver's.

The author explains this with a simple idea: Big airports report everything. At huge hubs like Denver, pilots and staff are very careful to write down even the tiniest, harmless bumps. This floods the data with "safe" reports, making the damage rate look low. At smaller airports, people might only bother to write a report if something actually broke. So, a high damage rate at a smaller airport doesn't necessarily mean it's more dangerous; it might just mean they are only reporting the bad stuff. The paper found a clear pattern: the busier the airport, the lower the percentage of damaging strikes. This means you can't just look at a list of "most strikes" to find the "most dangerous" places.

What About the Planes?

The paper also checked which planes get hit the hardest. It turns out, small, light planes (like the Piper PA-28 and Cessna 172) get damaged much more often than big jets. About 26.7% of reported hits on the Piper PA-28 caused damage, compared to only 6.0% for the massive Airbus A320.

This makes sense if you think about physics: a bird is a huge obstacle for a light plane, but just a tiny speck for a heavy jet. However, the paper warns us not to call this a "risk" in the strict sense. We don't know how many hours these planes fly, so we can't say for sure if small planes are more likely to get hit, only that when they are hit, they are more likely to get hurt.

The 2025 Record Breaker

The paper also notes that 2025 was a record-breaking year for reports. There were 24,458 total strikes and 901 damaging ones—the highest numbers ever recorded in the database. But the author is careful to say this doesn't mean the sky got more dangerous. It likely means people got better at reporting the small, harmless bumps. The number of damaging events is still rising, but the percentage of reports that are damaging is actually going down, which suggests we are just seeing more of the "minor" stuff that used to go unreported.

The Bottom Line

This paper doesn't discover a new type of bird or a secret crash. Instead, it organizes the past 35 years of data to show us a clear truth: Don't judge a book by its cover, and don't judge a bird strike by its frequency.

The animals that show up the most (songbirds) are mostly harmless. The animals that show up the least (deer, waterfowl) are the ones that cause the most trouble. And the busiest airports aren't necessarily the most dangerous; they just have the best record-keeping. By sorting the data this way, the paper gives airports and pilots a better map for where to focus their safety efforts, moving away from just counting birds and toward understanding which ones actually matter.