How to stop birds hitting your windows

A feeder makes your windows more dangerous. That is not a reason to take the feeder down, but it is the reason this page exists: you have concentrated birds in a small area and given them a reason to make sudden, panicked, low-altitude flights — usually away from a hawk or a cat — and a pane of glass reflecting trees and sky reads to a bird as somewhere to fly.

The scale is worth stating once. American Bird Conservancy puts it at more than 1 billion birds dying from collisions with glass every year in the U.S. alone. Most of that is not skyscrapers. It is houses.

The good news is that this is one of the few bird problems with a genuinely reliable solution, and it costs about twenty dollars a window.

The rule that decides whether anything works

ABC's guidance for homeowners is specific in a way product packaging almost never is. Three things:

• Spacing. Patterns with vertical, horizontal or diagonal spaces of two inches or less prevent most collisions, provided the markers meet the size rules. Patterns should also be visible from about ten feet away.
• Marker size. Dots should be at least a quarter of an inch in diameter. Decals at least that size, spaced two to four inches apart, should prevent most collisions.
• Which side of the glass. Treatments go on the outside. ABC says placing products inside should be avoided whenever possible.

That third point is the one that quietly ruins most attempts. Markers on the inside of the glass are behind the reflection — the bird sees sky and trees mirrored on the outer surface, and your decals are on the wrong side of the mirror. The treatment has to interrupt the reflection itself.

How we chose these

On published manufacturer specifications and ABC's published guidance, checked against live listings in October 2026 so every pick is currently purchasable. No testing claim: we have not run collision trials, and nobody should trust a site that says it has without showing the method.

Ranking went: can the product be applied at two-inch spacing over a whole pane without costing more than the window; does it go on the exterior; how long does it survive weather; and how visually intrusive is the result. Our full criteria are here.

Tape is the right first purchase

A roll of translucent bird tape is unglamorous and it is what we would buy. The reason is that it makes the two-inch rule easy: you measure, you cut strips, you apply them in a grid, and you can see immediately whether the spacing is right. Dots require more judgment; screens require hardware.

Measure before you order. A 40-foot roll three-quarters of an inch wide covers two to three panes at normal spacing — but “normal” depends on your pane. A large picture window at two-inch spacing eats tape quickly, so work out the number of strips first (window width divided by two inches, plus the verticals if you are doing a grid) rather than discovering it half way up the glass.

The honest downside: you will see it. A grid of white strips on the outside of a window is a visible change to your house, and anyone who tells you a working treatment is invisible is selling you a treatment that does not work. If a window is killing birds, the trade is worth it. If it has never had a strike, you do not need to treat it.

Dots, and the one published number in this category

The dot-marker systems used on commercial glazing are now sold in DIY rolls, and they are the permanent version of the same idea: a carrier tape goes onto the exterior glass, you squeegee it, and peel the tape away leaving a grid of dots behind.

Feather Friendly publishes the figure that everybody else in this category is implicitly relying on: 95% collision reduction using 2” x 2” spacing of visual markers. Treat it as a maker's claim for a marker system at a stated spacing rather than as an independent test of one particular roll — but note that the number is tied to a spacing, which is the right way to make that claim.

It costs more per window than tape and the application is unforgiving: the carrier goes on once, and crooked rows stay crooked. For a window you are not going to re-treat in three years, it is the better buy.

Decals: fine, if you use them the way the rule says

The supermarket answer — a packet of UV-reflective decals — gets a bad reputation it half deserves. The product is not the problem. The problem is that people put up four of them.

A thirty-pack applied at ABC's two-to-four-inch spacing covers a much smaller area than people expect: a small casement, not a patio door. Used properly on a small pane, decals work and are the least visually intrusive option. Used as decoration on a big window, they are a placebo.

One note on the UV claim. Several decal products are sold on being visible to birds in ultraviolet while nearly invisible to us. That is the part of the pitch we would lean on least — ABC's guidance is written in terms of the size and spacing of markers visible from about ten feet, and a pattern you can see is a pattern you can check. If you buy UV decals, space them as if they were ordinary ones.

The free half: where the feeder goes

Before buying anything, move the feeder. The counter-intuitive rule is that there are two safe places for a feeder and the dangerous zone is in between:

• Within three feet of the glass. A bird leaving the feeder cannot build up enough speed to injure itself. This is why window feeders stuck to the pane are safe rather than dangerous.
• More than thirty feet away. Far enough that the window is not part of the bird's immediate flight path when something spooks the flock.

A feeder ten or fifteen feet from a big window is the worst of both: enough runway to hit the glass hard. Our feeder-safety guide covers the distances and the cat half of this problem, and window feeders are compared here.

ABC's advice on triage is also worth following: treat the windows across from feeders, baths and fruiting plants first. You almost always know which pane the problem is.

Doing one window properly, start to finish

1. Identify the pane. Strikes cluster. Look for smudges, feather dust or a faint print on the outside of the glass.
2. Move the feeder to within three feet or beyond thirty. Free, and it may be enough on its own.
3. Measure the pane and work out the strips or dots needed at two-inch spacing. Buy accordingly; one roll is often not enough for a large window.
4. Clean the outside of the glass and let it dry. Nothing adheres to a dusty window through a winter.
5. Apply to the exterior surface, working to marked spacing rather than by eye. Step back at ten feet: if the pattern reads as a pattern, it is right.
6. Check it each spring. Tape lifts, decals shed. A half-failed grid has bird-sized gaps in it again.

What we would buy

• One problem window, sensible money: a roll of bird tape, applied outside in a two-inch grid.
• A window you want fixed for good: the DIY dot-marker roll, at the 2 x 2 spacing the maker publishes its figure for.
• A small pane, or a first try: a thirty-pack of decals, all thirty of them, two to four inches apart.
• Birds at the glass on purpose: a window feeder mounted on the pane, which puts the birds in the zone where a strike cannot do damage.

The thing to take away is that this problem is solved, and the solution is a spacing rather than a product. Two inches, on the outside, across the whole pane. Everything else on this page is a way of achieving that.