How to Stop Birds From Hitting Your Windows: Fixes That Work

A soft thud on the glass, a puff of feathers, a bird sitting dazed on the patio: it is one of the more upsetting things that can happen in a yard you set up to help birds. The good news is that the fixes are cheap, most take an afternoon, and the guidance from wildlife agencies is specific enough to follow with a ruler. This guide walks through it in order, starting with the windows that matter most.

Why birds fly into glass

Birds do not read glass the way people do. The US Fish & Wildlife Service explains that they do not treat it as a barrier, and that reflections of sky and plants can actually draw them closer (US Fish & Wildlife Service). A window that mirrors your maple tree looks, to a chickadee, like more maple tree.

The scale is larger than most people guess. The same agency says more than one billion birds collide with glass in the United States every year, and that most fatal collisions happen at homes and buildings shorter than four stories. Put plainly, this is mostly a house problem, not a skyscraper problem, which also means homeowners can do a lot about it.

One more thing worth knowing before you start: the agency notes that most birds that seem fine after a strike later die from their injuries. A bird that flies off is not proof your windows are safe.

Step 1: Find your problem windows

You do not have to treat every pane on day one. Start by working out where the strikes happen. The Fish & Wildlife Service's home toolkit lists three signs: a sudden thud, a powdery outline of a bird left on the glass, and stunned or injured birds on the ground below (Bird-Friendly Home Toolkit).

Then walk outside and look at each window from a few yards back. Put these at the top of your list:

• Windows that reflect trees, shrubs or open sky
• Windows closest to feeders and birdbaths, which the toolkit says to treat first
• Any pane where you have already heard a thud or found a feather print

Step 2: Mark the outside of the glass

This is the step that does the heavy lifting. The federal guidance is short: put patterns on the outside of the window, make each mark at least 1/4 inch across, and space the marks no more than 2 inches apart. A 2-inch by 2-inch grid matters most for small birds such as hummingbirds. Because dark marks can vanish against a dark reflection, medium to light colors show up better.

Cornell Lab's Project FeederWatch gives the same number, recommending repeating patterns no more than 2 inches apart (Project FeederWatch).

The spacing rule that makes or breaks decals

Decals have a mixed reputation, and spacing is the reason. Audubon is blunt about it: decals may help, but only when they sit no more than 2 to 4 inches apart, and a large window can need a lot of them (Audubon). A separate Audubon Magazine piece says a lone silhouette does little, and that the pattern should cover most of the window (Audubon Magazine).

So the honest answer is that the decal is not the fix. The spacing is. Follow the tighter 2-inch figure and you satisfy every source above.

Pick a treatment that fits your budget

The Fish & Wildlife Service publishes rough costs per square foot, which makes comparing options easy:

These are the agency's estimates, not store prices, so use them to rank options, not to budget to the dollar. If your windows already take exterior insect screens, leaving them on is the least effort of all: the agency says they cut reflections and signal that the window is a barrier.

Step 3: Move your feeders

Here is the part that surprises people: closer is safer. The Fish & Wildlife Service toolkit says to keep feeders within 3 feet of windows so a bird cannot build up enough momentum for a fatal collision. Audubon gives the same advice and adds a second option, mounting the feeder directly on the glass with suction cups.

The danger is the middle distance. Audubon Magazine, citing research by ornithologist Daniel Klem Jr., reports that feeders placed 3 to 30 feet from a window are especially dangerous. Get out a tape measure and check where yours sit.

Moving a feeder can change other things, so check two details afterward. A feeder near the house may sit closer to a launch point for squirrels; our guide to keeping squirrels off your bird feeder covers the clearances. And a feeder by the window still needs the same upkeep, so keep following a regular feeder cleaning routine.

Step 4: Dim the lights and tidy the view

Collisions happen most during spring and fall migration, when most birds travel at night, according to the Fish & Wildlife Service. Its suggestions cost nothing: turn off lights you are not using, put fixtures on timers or motion sensors, and close blinds or curtains after dark so light does not spill out.

Two small indoor habits from Audubon help during the day as well. Keep drapes or blinds partly closed when you can, and move houseplants back from the glass.

When a bird attacks the window instead

A bird that pecks or flutters at the same pane again and again is a different situation. Audubon Magazine explains that repeated strikes in spring and early summer usually mean the bird is battling its own reflection. The suggested remedy is to hang something that moves on the outside of that window, such as a mobile, wind chimes or Mylar streamers. Items hung inside do little.

If a bird hits anyway

Even a well-marked house can have a strike. Audubon's advice is worth keeping handy (Audubon Magazine):

1. Approach slowly and pick the bird up gently, with gloves or clean hands.
2. Place it in a paper bag or a lined shoebox with nothing it could tangle its legs in.
3. Contact a wildlife rehabilitator first. That is the best option, because the bird can get expert care.
4. If none is available, set the container in a dark, quiet room away from pets and people for about an hour.
5. Do not offer food or water. Liquid can end up in the bird's airway.
6. If you hear it moving around after the hour, take it outside and let it go.

Frequently asked questions

Do window decals stop bird strikes?

They can help, but only in a dense pattern. Audubon says decals must be no more than 2 to 4 inches apart, and the Fish & Wildlife Service sets the bar at 2 inches. One silhouette in the middle of a pane does little.

How far should bird feeders be from windows?

Within 3 feet, or attached to the glass itself. Both the Fish & Wildlife Service and Audubon recommend that range, because a bird leaving the feeder cannot build much momentum over such a short distance. Audubon Magazine describes 3 to 30 feet as especially dangerous.

Should markings go on the inside or the outside of the glass?

Outside. The Fish & Wildlife Service guidance calls for patterns on the exterior surface. If you cannot reach the outside of a window, Audubon's tip to keep blinds or drapes partly closed is a stopgap, not an equal substitute.

Sources

• Threats to Birds: Collisions (Buildings & Glass) — US Fish & Wildlife Service
• Bird-Friendly Home Toolkit — US Fish & Wildlife Service
• Help Birds Avoid a Deadly Collision — Audubon
• How to Deal with Backyard Mishaps — Audubon Magazine
• You Found a Bird That Crashed Into a Window. Now What? — Audubon Magazine
• Feeding Birds — Project FeederWatch, Cornell Lab of Ornithology