Thunk. That’s the sound a bird makes when it collides with a window. It’s a terrible, unmistakable sound.

Recently, I heard that thunk, and I never want to hear that thunk again. I ran downstairs, hoping the bird that had hit one of our large, modern windows had flown away. Instead, I saw what I’d feared: a dead songbird lying on the deck below. Above, some of its feathers remained stuck to the window, a grey-blue shadow of what had happened seconds before.

I picked up the bird, hoping it might still shake off the collision, but it was truly dead, eyes frozen open. I burst into tears.

I berated myself, because it shouldn’t have happened. Just a month before I’d found a dead woodpecker in the city we recently moved from—it had collided with one of the plate glass windows in a tall building. And I’d once found a stunned bird outside this very house. It eventually flew off, thankfully. Those were my warnings—if only I’d heeded them. I follow multiple wildlife rescue organizations on social media and I know what windows can do to birds. I’d even researched how to prevent strikes, but I confess I got daunted. The best solutions also seemed the most complicated and so I put off dealing with the situation. I’d get to it eventually, I told myself. We had so much else to do, after all.

And then that thunk.

That’s how I found myself on a ladder outside our house in below-freezing weather drawing closely-placed circles with a bar of soap. Waxy white polka dots now decorate the offending windows. My partner pointed at the lower left corner of one of the windows and said, “Right about there is where you started to lose it.” The polka dots had become downright frenetic. Those windows communicate a silent, panicked plea to our birds— the birds I so lovingly feed massive quantities of sunflower hearts: Please, please don’t fly into me.

It’s ironic that I’d spent so much time researching the right feeders, the right feed, how far from the house to place them, etc., when it arguably would have been far more important for me to bird-safe our windows. Birds are adept at feeding themselves with no help from us. But the buildings we erect in their homes, directly in their flight paths— our homes’ windows like mirrors reflecting only trees and sky—birds aren’t equipped to handle those.

We’re losing them…

Hundreds of millions of birds are killed each year by colliding with windows. Some estimates place the actual number at a billion. If you’re like me you probably assume the leading culprit is tall buildings, but in fact our homes account for the greatest number of window collision fatalities. And while I might have hoped that the bird that flew away after colliding with our home was ultimately fine, it’s highly likely that it wasn’t. It could easily have died from its injuries or been killed by a predator in its weakened state. There is no happy ending when it comes to bird strikes. This is why we have to prevent them in the first place.

We’re in the middle of a bird crisis. According to an exhaustive, shocking study published in the journal Science in 2019, in the past fifty years, nearly 3 billion birds have vanished from the United States and Canada. As noted by the non-profit organization 3 Billion Birds, “Of the nearly 3 billion birds lost, 90% came from just 12 bird families, including sparrows, warblers, finches, and swallows. These common, widespread species play influential roles in ecosystems. If they’re in trouble, the wider web of life, including us, is in trouble.” To understand the long-term implication of this decline, consider that every breeding bird that’s lost is a loss of its progeny as well—and so on. We can’t keep losing birds at this rate without serious environmental consequences.

There are multiple causes for this steep decline, and we humans are at the center of all of them: Habitat loss on a massive scale. Free-roaming cats (Cat owners: Please keep your cats indoors, it is safer for the cat, and safer for wildlife!). Pesticides used in industrial farming as well as home gardening that kill birds and the insects they eat. Poisons used by homeowners to kill mice and rats, and which also kill the birds that prey on them (Home owners: never put out poison for mice and rats; instead, find out where they’re entering your home and fill the holes. There are also multiple options for

humane trapping while you figure out where they’re entering.). Also topping the list of causes for the decimation of wild birds? Collisions.

It’s our individual and collective responsibility to mitigate this situation that we’ve created. While the issues of habitat loss and widespread use of pesticides may seem bigger than we can tackle individually, we can control how we operate in our little corners of the world. It bears repeating: keep your cats indoors; don’t use pesticides or poisons; and please, please bird-safe your windows.

Search “bird collisions” on your web browser and you’ll come up with a lot of advice and a dizzying variety of choices, some expensive and seemingly time-consuming. The American Bird Conservancy is an excellent resource and compiles lists of approved products—many more than I can summarize here. They also list specialized products for sliding glass doors, office buildings, etc. And they have a great guide to DIY options. As helpful a resource as their website is, even their cogent advice can feel like a lot to wade through when you’re just getting started (especially if you’re still sobbing after a bird hit your window, as I was). To make your initial foray a bit less confusing than mine was, here’s a very generalized menu of options that you will come across:

Stickers and window tape: The key with stickers and tape is placement. They must be placed on the outside of the window. And they should be placed no more than 2” apart (any wider spacing is too wide for smaller songbirds). If you’re like me, then the first thing you’re going to think is: yikes, that’s a lot of stickers and tape. There are also liquid products that you can use to create dots between the stickers. And yes, that is also a lot of dots.

DIY: Any opaque or translucent tape, when applied to the outside of a window, will deter birds. Tempera paint will also do the trick.

Screens: Regular insect screens that you likely already have on many windows help to reduce reflection and also cushion the blow if a bird should collide.

Bird Crash Preventers: These are strings that hang vertically in front of windows, away from the glass, spaced 4” apart. The strings don’t interfere (much) with our view of the outdoors, but signal to birds that there is a barrier in their flight paths.

Where to start?

A few words of reassurance: Do not be alarmed at the thought that after retrofitting, your house will look like a kindergarten classroom at holiday time, with artsy-craftsy snowflake stickers stuck on every surface. No one wants that. This is all about focus and efficacy.

The American Bird Conservancy recommends paying close attention to the problem areas on your particular home. The best place to start your retrofitting is with any window that you know a bird has crashed into. You may find that after fixing that window, you can stop right there. If you discover other problem areas, you can then address those. In our home, I will start with the two windows where I know I’ve had bird strikes—neither of which has a screen on the outside. For the time being I’m going to figure that my windows with screens are reasonably safe. And if we decide to replace windows and remove any screens elsewhere in the house, then I will retrofit those as needed.

What method is best?

Now that you know what windows are problems, which method is best for you? In my opinion, here are the pros and cons of stickers, DIY methods, screens, and bird crash preventers:

Stickers and Tape

After I finished crying over the dead songbird on our deck and covered the offending window with soap, I went online and ordered enough square stickers to cover it and another problematic window (truthfully I was so upset that I over-ordered and could probably do several neighbors’ windows as well). I also ordered UV liquid to create dots between the stickers. In order to place them properly, I will have to get on a ladder, clean the exterior of the window, and then measure as I go to be sure that the stickers and UV dots are at the right distance from each other. The stickers will be somewhat visible to our eyes—more translucent than transparent—but should signal to birds to keep away. This is going to be a project and I’m guessing that at some point the strain will show. Is the effort worth it to save birds? Certainly. That said, I am physically able to climb a ladder and if I weren’t able to do so, this would not work for me. You can hire folks to do this for you, but that is an expense—and the stickers themselves were an expense. Pros: Effective if placed correctly; easy to order. Cons: Labor intensive; potentially costly; not permanent (you can order a UV flashlight to show you when the stickers are starting to wear off and need to be replaced—depending on the product, UV liquid can last 3 months, stickers can last 4 months). And again, they only work if you use a lot of them and place them correctly.

DIY

Remember what I said about the kindergarten classroom? Some of the DIY methods can look a little like that. But if you have kids and a window you don’t mind letting them loose on, this could be a fun project. Pros: Cheap and not at all time-consuming. Cons: DIY is gonna look DIY. It’s only as effective as its execution—as with stickers, any gaps larger than 2-4” could create a strike risk.

Screens

Ideally, you already have screens in most of your windows. Depending on the configuration, you may still have half your window exposed. If you like to remove your screens in the winter, then you are unfortunately also eliminating them as a protective device at a time (late winter/early spring) when birds are migrating and many collisions occur. Pros: You probably already have them. Cons: Only work when they’re in the windows; you’ll still need to use stickers or bird crash preventers where you don’t have screens.

Bird Crash Preventers

Why oh why didn’t I get bird crash preventers when I heard my first thunk? Possibly because they seemed labor intensive and they involve a level of craft and installation skill that I don’t personally feel that I possess. However, the kits are actually considerably less expensive than the stickers I ordered, and I know some folks I could probably convince to help me install them. These preventers are also called “Zen curtains” which might give you a sense of how they look—long cords attached to brackets that are screwed into your home above your windows (almost like a curtain rod) and fall in even vertical lines over your windows. Acopian Bird Savers has kits you can purchase and install, or if you are handy they also offer directions for how to make your own. There are other brands (this is one tested by the Conservancy) that use monofilament, which is less visible to the human eye, but it is also less visible to birds; it’s still a good product, but not as protective as cords. For comparison, the Conservancy rated Acopian Bird Savers a 5 in prevention (the lower the number the better), and the monofilament product a 27 (their upper limit for recommending a product is 30, which means the product prevents 50 percent of bird strikes). Bottom line: the best method is the one you use, so if you know the cords will bug you, then go for the monofilament. Honestly I find the cords lovely, and the whole set-up feels like good karma. Pros: The cord version is highly effective and the kits are reasonably priced. Once installed, there is no upkeep. Cons: You have to be willing to attach something to your house and there is some initial labor to pay for, or to do yourself.

It’s up to us…

As someone who has some rather unhinged-looking soap circles covering two large windows in my home, I can attest to the fact that you’d be surprised what your eye will become used to. My plan now is to install bird crash preventers—they feel like the best method for me. They’re the most effective and most permanent solution, and I can get help in installing them. You may love the idea of stickers (there are some pretty ones) especially if you only have one or two windows of concern. You may even like the idea of painting an offending window. (One important reminder: For any method to be effective, it must be on the outside of the window.)

Whatever you do: Do something. Learn from my mistake—don’t wait for the thunk. Making our windows safe for birds may require some work and initial adjustment, but I’m confident that once we do the work in our home, the sight of those cords will become as natural to us as the big blue recycling bin in the corner of the kitchen or the compost bucket on the counter. When I think about the number of times in any given day that I pause in front of the window to watch the birds cavorting around our feeders, when I think about the joy I feel that my offering of seed is so graciously (and gluttonously) accepted by them, I am certain that it is the very least I can do.Update:
We successfully installed bird crash preventers on our two problematic windows, and so far they’re working like a dream: not a single bird crash that we are aware of, and it’s been weeks. My partner, who is both kind and handy, decided to DIY the installation of strips of 3⁄4” wood molding (painted to match the house) at the exterior tops and bottoms of the two windows. Then he inserted small wood screws 4” apart, top and bottom (measure so that you can line up the top and bottom screws). Then we made loops in one end of long strings of paracord, attached those to each of the top screws, and tied them as tautly as possible to the bottom screws. The results are as visually pleasing as they are effective, and it’s such a relief to know that we’ve done all that we can.

Paracord: https://www.paracordplanet.com/black-nano-cord-300-feet/