An Affordable DIY Option to Prevent Birds From Hitting Windows

Homeowners may be shocked and disheartened when a bird hits their window, but the sad truth is that this happens much more frequently than people think. In Canada, an estimated 25 million birds perish every year due to collisions with glass. 90% of these collisions are thought to happen at single family homes.

There is no shortage of proposed ‘solutions’ on the market that allegedly prevent birds from flying into windows. Unfortunately, many are simply not effective. For example, some homeowners may choose to apply one or two hawk silhouettes on a large window to deter birds. However, birds are not scared by the silhouettes, and they will likely try to fly around the silhouette, colliding with another untreated portion of glass.

To effectively prevent birds from hitting windows, we need to provide birds with visual cues that will help them identify the entire glass surface as a barrier they cannot fly through. The Acopian BirdSaver (or Zen curtain) is one method that is effective in reducing bird collisions with glass. The BirdSaver is essentially strands of thin cord hung in front of the window, spaced closely enough that birds will not try to fly through the gaps between the cords. Custom-made Acopian BirdSavers can be purchased, or you can use readily accessible materials to make your own.

This post will walk you through one method to make your own Acopian BirdSavers.

Tip: Take the Homeowner Assessment or download the FLAP App to determine which windows at your home present the greatest risk to birds. Treat these windows first.

Materials to construct the BirdSavers

  • Paracord or other 1/8” diameter cord*
  • Aluminum J channel

Other materials needed

  • Tin snips
  • Measuring tape
  • Pencil
  • Drill
  • Scissors
  • Lighter
  • Appropriate screws for mounting
  • Ladder

*Acopian BirdSavers recommends using dark olive-green parachute cord (550 paracord; 1/8” diameter) to construct the BirdSavers. However, you can also use another 1/8” diameter cord. The important thing is that it is heavy enough to stay straight while hanging, and also that is has a tight weave to avoid nails or toes getting stuck if a curious bird decides to land on the cord (this happens). Acopian BirdSavers also recommends pre-shrinking the cord to avoid risking an exposed area of glass at the bottom of the window.

How much will it cost?

Let’s say you have a standard patio door (82” tall and 70” wide). According to the Acopian BirdSaver cord spacing guide, if you space cords 4 inches apart, you will need 17 pieces of cord for a window with a width of 70”. Add an additional 2 inches to the length of the cord (82”) to account for the knots you will tie at each end, and you will need 17 84” pieces of cord, or 119 feet.

A 10-foot piece of J channel is less than $7.00 CAD at a hardware store such as Home Depot or Home Hardware, and a 50-foot roll of paracord is also around $7.00 CAD (available at many hardware and craft stores). Therefore, your cost to treat your patio door would be $28.00 CAD, with supplies left over to potentially cover another small window. By shopping around, or using supplies you already have lying around, you could easily lower that cost.

Before you get started

First, measure the width of the window to determine what length of J channel you will need. Based on that measurement, check the cord spacing guide (choose 4 inch or smaller spacing) to determine the number of cords you will need to cover your window. Then, measure the height of the window, considering how high above the glass you will need to mount the J channel, to determine the length of each cord. Add 2 inches to this number to account for the length you will use to tie knots. Lastly, multiply the number of cords you need with the length of each cord to make sure you have enough paracord for your project.

Step 1: Cut the J channel to length

Using tin snips, cut the J channel to match the width of your window.

Step 2: Drill holes in J channel

With a measuring tape and pencil, mark out the desired spacing of holes on the J channel (4 inches or closer). After marking the location of the holes, you may choose to use an awl or similar tool to start the holes. Then, use a drill to finish making the holes along the length of J channel. Ensure that the holes are large enough that the cord will fit through snugly.

Step 3: Prepare the cord

Cut the needed number of strands to the desired length. If you are using paracord or another synthetic cord, using a lighter to singe both ends of each strand will help to reduce fraying.

Step 4: Feed cord through holes

Feed a strand of cord through each hole, and secure by tying a knot at the top. Then, tie another knot at the very bottom to reduce fraying.

Step 5: Mount on window

Drill holes for mounting on each side of the J channel. Then, centre the BirdSaver in front of the window, and affix to the outer window frame by drilling in the screws.

You’ll notice in this example, there is a small gap between the ends of the cords and the bottom of the glass. Ideally, there should not be a gap greater than an inch or two. This is the result of a miscalculation of how high above the glass the BirdSaver would be mounted, so remember to account for this in your calculation of the length of each cord!

Take it a step further

Do you have bird baths or bird feeders on your property? Help birds stay safe by moving these bird attractants to within 1.5 feet or closer to your window. Should a bird still accidentally collide with your window, they will be less likely to become injured over this short distance.

Thank you for helping birds!

Photo: Carol Edwards

Disclaimer:  BirdSafe and FLAP Canada do not endorse or recommend any commercial glass product or manufacturer; therefore, mention of commercial products on this website cannot be construed as an endorsement or recommendation. Results may vary depending on conditions such as landscaping, topography, building design, lighting, local bird populations and the condition of the product itself. No window solution can guarantee elimination of bird-window collisions.