Dear #bird Mastodon,

I just recently moved, and our new place has very large plate glass windows that look out onto a wooded area. Very nice view, but obviously a death trap for birds... We've unfortunately already had two fatal collisions since we moved in.

I can't change the windows in the short term, so I'm searching for a quick solution. I could do an array of stick on reflectors, but I wanted to check with you on this "bird pen" (see photo).

The idea is that you draw lines with a marker that absorbs in the UV but not in the visible, so the birds see it but people don't. That's a cool idea... but does it really work?

UPDATE: For everyone sharing this or seeing it now, there is a clear answer in a post below: this is not an effective solution.

Also based on some replies already received: if you want to do something to help birds, make sure you do it on the OUTSIDE of the window, because a big problem is the reflection of the sky and trees (the birds don't necessarily see what is inside of the window).

@skyglowberlin @CoopSciScoop @travislongcore
I scribble on the windows (outside) with a bar of soap during the season. Doesn't cost, washes off, works. You don't have to cover the entire window.

@penpencilbrush Thanks for the tip, we could potentially try that quickly (after it stops raining 😂).

How visible is it from inside? And do you really just do it once per year?

@skyglowberlin @CoopSciScoop @travislongcore

schau mal Seite 16
http://vogelschutzwarten.de/downloads/LAG%20VSW%2021-01_Bewertungsverfahren%20Vogelschlag%20Glas.pdf

@skyglowberlin we have silhouettes of birds of pray hanging on the inside of the windows. It seems to be very effective without actually scaring them away.

@skyglowberlin @CoopSciScoop @travislongcore i have black flyscreens on all my windows. They work too, i think.

Thanks to @tinoeberl for a clear answer. His link is in German, so I'm posting a translation for everyone else who is interested:

Such products therefore cannot be recommended as a measure to reduce the risk of bird collisions, despite being marketed as “bird-protection glass.”

...

At best, the UV-light markings tested to date are only marginally effective. They are apparently barely noticeable under real-world lighting conditions and therefore reduce the risk of collision only slightly, if at all. UV-light markings are therefore insufficient to adequately reduce a high risk of collision. To date, they have not proven effective in protecting birds.

@skyglowberlin During migration mostly.

If you get a rainstorm hitting those windows, it has to be redone. It doesn't take long, unless you want to get creative.

Otherwise, a big scribble in the middle of the window most likely to be hit by birds. Takes seconds.

It is visible from the inside, but we don't notice it after a bit.

@Eorlingur The problem with large windows is that under many lighting conditions, the birds can't see inside, they just see a reflection from the glass that looks like trees and sky. So it's important to have a treatment on the outside of the window.

@fuersi Are they on the inside or the outside? If they're on the inside, it won't stop the problem of the bird seeing a reflection from the window that looks like sky and trees.

@penpencilbrush Thanks for the tip. I will probably go with an array of reflectors.

@skyglowberlin @CoopSciScoop @travislongcore temporary and long-term solutions including the soap and tempera paint from Canadian resource FLAP
https://www.flap.org/stop-birds-from-hitting-windows

@skyglowberlin Here's another brochure with samples of effective and ineffective bird safety measures. Unfortunately, that pen is ineffective.
Personally, I've found that birds seem to be able to spot dirty windows quite well.
https://wua-wien.at/images/stories/publikationen/wua-vogelanprall-muster-2022.pdf

@CoopSciScoop @travislongcore

@skyglowberlin I cannot find the original article or paper I once read, but those informations come close to it:

https://featherfriendly.com/blogs/feather-friendly-blog/why-birds-collide-with-windows-and-how-can-we-prevent-it

I once applied dots of sunscreen on my windows. It’s a mess to get it off but it was a cheap and fast solution.

(Edit: Typo)

@skyglowberlin

Hang something like sparse tinsel? So it moves in a breeze?

@skyglowberlin We have similar stickers to these, definitely not perfect (I wonder if we should add more), but they do seem to reduce strikes.
https://shopping.rspb.org.uk/bird-feeders-boxes-tables/bird-care-accessories/bird-safety-hygiene/swift-and-swallow-window-stickers.html

@skyglowberlin If you see strange little markings accompanied by exclamation points and talon marks, I would definitely start worrying at that point. Doubly so if you get a formal letter in the mail on proper stationery. Little law firms are no joke, especially ones run by larger birds. They can be real vultures!

@skyglowberlin @tinoeberl @sundogplanets

McCormick Place in Chicago applied white dots to their huge windows, which appears to have massively decreased the number of bird strikes.

https://www.allaboutbirds.org/news/bird-collisions-window-safety-mccormick-place-chicago/

@skyglowberlin @fuersi On the outside, in our case.

And the usual plastic flyscreens don't last more than 2 years in the sun's UV light, which for bigger windows might become costly (and also, make them easily replaceable; those velcro tapes that come with them work fine on small windows, but the glue doesn't last either. I have wooden frames for the flyscreen and just staple the velcro strips down).

@skyglowberlin There are small plastic siluette stickers of flying eagles and other birds of prey to put on the window.

@skyglowberlin Outside the window, attached inside the frame.

@skyglowberlin

Birds, accustomed to slipping through small openings between dense branches, boldly fly into the “empty” space, not expecting an invisible wall there, and perish. What can be done? It’s often recommended to put up stickers with silhouettes of birds of prey. In reality, you might as well stick snowflake patterns on the window, because they don’t so much scare the birds away as make them wary of a space that is no longer empty.

You can also stretch fishing line strings outside the window—they’ll be almost invisible to humans, but birds will see them in the UV spectrum. Or draw patterns on the outside of the window with a UV marker that’s invisible to us. A marker (Centropen Security UV Pen; Edding 8280) is the simplest method, but it’s not very long-lasting. It washes away in the rain, so you’ll need to redraw the pattern regularly.

@skyglowberlin it works if the silhouette is up against the glass. We have reflective film on our windows but you can still see it from the outside. It probably helps that it is white. We just cut it out from some printer paper.

@skyglowberlin good luck! Thank you for thinking of the birds.

@skyglowberlin I ended up DIYing this https://www.birdsavers.com/make-your-own/. I had read that interior bird deterrents were ineffective and I can't really reach the outside of my windows to apply something like stickers directly, but was able to hang something that covers most of the window. it's not unobtrusive, but I personally don't mind it—and no collisions that I know of since!

@skyglowberlin best solution for us has been to not clean the windows. Enough grime keeps the birds safe.

@skyglowberlin @meraord I used the birdpen this spring on the glass around our pooldeck. Vertical lines. No collisions. Previous summer we found at least 3-4 dead birds, when the stickers in the picture was there. The lines are visible in some light or damp conditions. No picture on this though.

@ReCyclist The maximum spacing between elements for the birds to see is supposed to be 5 cm, so I don't really like that approach because then a huge fraction of the whole window would need to be covered in the stickers. I think the dots will work better for us.

@sarahjelm Yes, but you have to keep the spacing 5 cm or less between them for them to be effective, and I don't want to block so much of the window. The little rows of dots will work better for us, I think.

@skyglowberlin @CoopSciScoop @travislongcore
Do what I do, never clean your windows. Less effort no bird deaths.

@saxicola Our windows are very old and no longer fully opaque, but the problem is the reflection at certain times of day and sunlight conditions - from outside you see trees and sky, not a dirty window.

@skyglowberlin

And most importantly: the stickers, fishing line, and marker patterns must all be on the outside of the window; otherwise, they won’t affect the mirror reflection in the glass at all.

(all this info is taken from a real field ornithologist and wildlife rehabilitation specialist)

@dravyptak I talked with a friend who is a visual ecologist - the problem with UV is that while songbirds can see it, many other birds can't. They also tend to have problems under overcast conditions (which is about 2/3 of the time in Germany).

@znoteer 5 cm. That's why I don't like the "bird" stickers, you need way too many of them to be effective.