Saturday, November 15, 2014

Easy, inexpensive, do-it-yourself bird safe windows

100% bird safe windows  

(re-posted from bigredaglaia because it is a popular essay)

"Bird Window Trampolines":  an invisible,  cheap, easy and 100% effective way to make windows bird-safe
We all know that sickening "thunk" when a bird hits a window.  Often the dead bird can be found beneath the window, more often it flies off and likely dies of internal hemorrhaging later.  The estimates of birds killed by window strikes range in the hundreds of millions per year in the USA.  If you live somewhere with birds near your house, and your house has windows, you are probably killing birds.
But I hate to be indoors and the one thing that can make indoor living tolerable is a nice picture window, and the more and bigger the better.  For a bird enthusiast like me, this poses a conundrum.   Go insane indoors without windows, or stay (somewhat) sane and accept collateral damage to the many birds simply going about their business and suddenly dying in a collision they literally couldn't see coming.
I found a solution.
View looking out a window that is protected with netting from bird strikes.  The mesh is barely visible.
There are simple and inexpensive steps anyone can take to make their windows bird-safe.  Here I describe what I've done to the big picture windows in my living room that were real bird killers.  Before I did this, bird strikes occurred often, especially in the spring during migration, as fledglings left the nest in summer, and again in the fall, with a few through the winter.  Any time a Sharp-shinned Hawk burst out of the woods into the yard, birds were likely to hit the glass. 
The solution costs about $15/window and it takes about 30 minutes per window.   Here are simple instructions and a few photos of the result.  All you need are: two round curtain rods, six curtain rod brackets, and some netting for each window.
Buy the plastic mesh that you use to keep birds off fruit bushes and trees.  Any garden supply store has it.   A 7 X 21 foot net cost me $9, enough for 3-4 windows.  (I first used old mist nets, but these lose their integrity and tore more easily).
Example of the netting available to keep birds off fruit trees.

Outside the window, above and below attach the brackets that hold the curtain rods.  These should stand away from the glass at least 6 inches.  If the windows are recessed the brackets can be shorter than windows that are flush with the wall.  Put three brackets for each rod-- left, right and center above and below the window (maybe more for a window longer than 4-5 feet.  The upper three brackets have the "U" that cradles the rod facing up, while the lower three brackets are upside down with the "U" facing down.
Lower curtain rod holding mesh.  I used a larger, stronger rod on this double window.
Cut a piece of the mesh about 8 inches larger than the span from curtain rod to curtain rod and wider than the window.
While comfortably seated thread the top curtain rod through the net, through every-other cell of the mesh.  Then hang this on the upper brackets-- in the corner brackets but outside the middle bracket so it sags slightly below the bracket.  This is so when you put the rod into the middle bracket it helps draw the net tight.
Pull the net down tight to where the lower curtain rod will rest.  Measure or count meshes down to where the rod is when moderately tight, then go up two or three cells, about 2-3 inches. 
Thread the lower curtain rod through the mesh through the mesh 2-3 inches above the line of the lower brackets.  As with the top rod, be careful to thread straight through so the two rods are parallel.  If not parallel the mesh will not pull tight evenly.
When it is through the lower curtain rod should hang in the net a couple inches above the brackets below. 
Pull the mesh outward to the sides so the net is taut left to right and fully covers the window.
Then pull the lower curtain rod down and snap it into the three brackets.   It should be pretty tight and the upper curtain rod should be bowing down more in the middle.
Push the middle of the upper curtain rod up and snap it into the middle bracket.  This should pull the net really tight.
Upper curtain rods holding mesh on two windows with a few tacks in between to pull the mesh tight horizontally.
If it is not tight, you can simply release the lower curtain rod from the brackets, pull the rod out of the mesh, and thread it through a little higher, and then re-seat it in the brackets.
The finished net should be firm against your push and require substantial pressure to push as far as the glass.  A "trampoline."
On a large window I put a few tacks along the sides and pull the mesh on to them to add tension side-to-side.  This also brings the edges to the wall and reduces the chance a bird would ever get between the mesh and the glass.  This has never happened for me.
When the net is up and in place, you can trim some of the excess mesh off the sides, but leave a few cells outside the edges.   This helps retain the integrity of the net and stops it from becoming too slack if a mesh tears at a tack or on the curtain rod. 
Now and then you can check the tension on the net and pull it a little tighter on the edges if needed.
Sitting inside and looking out I barely see the mesh against a dark background.  On sunny days sometimes it is more evident.  But it really is not very apparent and a lot less noticeable than typical screened windows.  From the outside the mesh is invisible.  One could paint or conceal the curtain rods, but I hardly notice these either.
Birds still fly "into" the windows.  The mesh, like the glass, is invisible to them.  But instead of instant deacceleration when they hit glass, the net stretches and slows them without hitting the solid glass.  Airbags in cars work on the same principle-- instead of slapping your head on the windshield with 60 to 0 deacceleration in a fraction of a millimeter, your momentum is absorbed by the airbag, not your skull.  Same for the birds only it is the net instead of the airbag.
Three large picture windows protected with mesh.
On windows where I have put these nets I never hear that "thunk" and I have never found a dead bird below.   The first window where I used fruit tree netting (rather than old mist nets) is still in good shape after two years.  There are a few meshes torn where possibly big birds hit, and I sometime see bird droppings on the window to indicate a bird bounced and defecated. 
I enjoy my large windows guilt-free.  I can put bird feeders right up beside them and never have strikes, even when a Sharp-shinned hawk passes and all the birds freak out.
I like this method.  It works.  It does not cost much.  It is easy to do.  It requires little maintenance (you can easily remove, wash the windows and replace).  It does not obscure the view at all.   Note added- we just did spring cleaning and washed the windows.  It only took a minute to release the lower rod holding the net, fold it to the top rod, clean the window, and put it back in place.   This really works.  Even when a Cooper's hawk comes by and birds dive for cover, none hit the window anymore.  This used to happen often.

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