Fall Bird Migration Is Almost Here: How Seattle Windows Can Stop Being a Hidden Hazard

More than one billion birds fly into glass in the United States every year, according to the U.S. Fish & Wildlife Service. Most people picture a tall glass tower downtown when they hear that number. The government numbers point much closer to home.

Federal data puts 56% of these bird deaths at buildings of one to four floors. Another 44% happen at houses. Less than 1% happens at tall buildings. Fall migration runs from mid-August through early November, so the risk is here right now.

Why Birds Can’t See Glass the Way We Do

Birds do not stop for glass, because nothing about it looks solid to them. The U.S. Fish & Wildlife Service explains that glass reflects plants and open sky, so birds fly toward what looks like a real place to land. They also look straight through glass at plants on the other side and aim for those. Both mistakes end the same way.

The harm is worse than the sound of the hit suggests. The Cornell Lab of Ornithology reports that birds often die later from bleeding inside the body or bruising on the brain, even when they fly off right after. A bird that flies away has not always survived.

Timing matters too. Most hits happen in daylight, when birds see clouds, sky, trees, and the ground in the glass. At night, lit buildings pull migrating birds off course. Those birds often hit windows the next morning instead.

Why Fall in Seattle Is Peak Risk Season

Birds hit windows in every month, but the count goes up in spring and fall. Cornell reports that hits happen most at dawn and dusk during migration. Many birds fly at night, drop into trees at dawn to rest and feed, then take off again at dusk. Moving in and out of those trees is exactly when a reflection of trees turns deadly.

Seattle sits on the Pacific Flyway, so a lot of that traffic passes over our buildings. Birds Connect Seattle runs a volunteer project that counts bird strikes at real local buildings. Their fall 2026 counting season runs from September 15 through October 29, with routes at Seattle University, the Seattle Asian Art Museum, and downtown Seattle. Past routes have also covered Columbia City and Tukwila International Blvd Station.

One local point is worth knowing before you plan around the calendar. Birds Connect Seattle points to a 2021 study from Vancouver, B.C. It found that winter risk in the Pacific Northwest is as high as spring risk, which does not match what other regions see. Researchers think our evergreen trees keep birds near buildings all winter, so we treat bird strike film here as a year-round fix.

Most Bird Strikes Happen at Homes and Low Buildings

That 56% figure changes who this topic is for. A two-story dental office in Ballard is riskier than most people think. So is a house with one big window facing a garden. Glass towers get the headlines, and the government numbers put them under 1% of the total.

Height also tells you where to spend money. The U.S. Fish & Wildlife Service says to treat glass up to the third floor, or up to the height of the plants next to the building. Doing only the ground floor windows still helps a lot. So does doing only the glass where birds keep hitting, and that is usually where we start on commercial jobs.

Some building features raise the risk more than others. Birds Connect Seattle studies buildings with big glass walls, clear balcony panels, roof gardens, and mirror-like glass. Outside shades and awnings do the opposite and cut reflections. If your building has a green roof above a glass wall, that pair is worth a closer look.

What Bird-Safe Window Film Actually Looks Like

Bird strike film puts a pattern on the glass so birds can see something solid. The gaps between the marks decide whether it works. Federal guidance calls for up-and-down stripes at least ¼ inch wide, with no more than 4 inches between them. Side-to-side stripes need the same width and a tighter 2-inch gap. Dots need to sit closer together than stripes, because small dots break up the reflection less.

A few more rules decide the result, and they are easy to get wrong:

• Put it on the outside. Film on the outside of the glass works best. Film on the inside only works if the outer surface is not too shiny to see the pattern through.
• Cover the whole pane. Cornell is clear on this: one or two stickers on a big window will not stop anything.
• Skip the hawk shape. Cornell says hawk cut-outs do almost nothing to scare birds off.
• Watch the contrast. White stripes can work better than black ones when the glass reflects something dark.
• Think about the smallest birds. A 2-inch by 2-inch grid protects hummingbirds and other tiny birds.

Get the spacing right, and the film does its job quietly for years. Get it wrong, and you have a decorated window that birds still fly into.

Two products cover most of what we install. Solar Gard byDESIGN Bird Strike film comes in up-and-down, side-to-side, and dot patterns. It lets in 88% of the light and bounces back only 9% on either side. For 3M work, one detail matters: most 3M FASARA glass finishes are made for inside glass only. Four designs are approved for outside use, and 3M says those four scatter sunlight and cut the glare bouncing off the window.

Protecting Birds Without Losing Your View

The worry we hear most is that bird film will make the glass look frosted or busy. Modern patterned films do not work that way. The byDESIGN Bird Strike line cuts glare by only 1% and barely blocks the view at all. You notice the pattern up close and stop noticing it from across the room.

There is one honest downside worth naming. Cornell describes one-way films that let people see out while the glass looks blocked from the street. Those films work well, and they also cut incoming light and cooling costs. They do change how the building looks from outside, so they fit some walls and not others.

Patterned film is not the only tool. Federal guidance notes that frosted and etched glass cuts both bird strikes and heat from the sun. Outside shades and awnings cut the reflections that cause daytime hits. On mixed jobs we sometimes put bird strike film on the worst glass and decorative film elsewhere, so the building still looks like one design.

A Simple Seasonal Checklist for Homeowners and Building Owners

You can work through most of this in an afternoon, before you call anyone. The goal is to find the glass that matters and skip the glass that does not. Cornell suggests looking at your windows the way a bird would, and that one step usually answers the question.

1. Walk outside and look at each window. If you see trees or sky in the glass, birds see the same thing.
2. Note where birds have already hit. The same panes tend to get hit again.
3. Start with glass up to the third floor, or up to the height of nearby trees and bushes.
4. Check any pattern you like against the ¼ inch and 2-inch spacing rules.
5. Plan to put the film on the outside, and check that the film is made for outside use.
6. Turn off lights you do not need at night during migration. Motion sensors and downward-facing lights help and cut power bills.
7. Report bird strikes to Birds Connect Seattle, or sign up to count as a volunteer.

Work down that list, and you will know which windows need film and which ones do not. That is the same order we follow when we walk a property.

Get Your Windows Checked Before Peak Season

Fall migration has already started, and the counting season begins September 15. We offer a free on-site check for homes and businesses across Seattle, Bellevue, Tukwila, and the greater Puget Sound. We will find your riskiest glass and confirm spacing that meets federal guidance. You get a written quote for commercial bird strike film or residential bird strike film.

If you want more background first, our earlier guide covers why birds hit windows and how bird strike film prevents it. When you are ready, contact us, and we will set up a visit.