One possible explanation for why birds fly into windows is that they see a reflection of the outdoors, thinking they can fly right through. (When looking at the window reflections in these pictures, it's pretty obvious to see how this could happen.)
Another explanation is that, during mating season, birds see their reflection as a competitor that has to be fought off.
And if you're considering putting up bird feeders, waterers or bird houses, you're increasing the chances of bird-window collisions.
At our house, we'd had several casualties from birds flying into our window, so something had to be done. The challenges were that we have very limited carpentry skills, couldn't invest a lot of money, and didn't want to obstruct our view from inside the home.
Since most of our windows don't open, they can't accommodate screens. So, here's a photo of what we decided on:
At Lowes, we purchased 1 roll of 7'x100' wildlife netting ($13), 2 10-packs of 6' long by 1 1/2" wide lath strips ($9/pack), a pack of 9/16" wood staples ($3), and 6 1" spring clamps ($11) and a tube of liquid nails (optional).
Since this row of windows measures 16' wide by 6' high, we cut an 18' strip of the 7' wide netting and spread it out on the deck. To add just a little weight to the bottom of the netting (but not so much that it might compromise the gutters) -- and to add stability to the top of the netting, we aligned 3 pairs of lathing along both the top and bottom of the netting, with the netting sandwiched between. The lath strips were then stapled together.
Below: Dabs of Liquid Nails were added to help keep the slats together, in case the wood staples fail.
Above: Lastly, we clamped the top of the netting onto our gutters with the spring clamps.
So far, we've had no more bird collisions. And the netting is virtually invisible from inside our house.
If you have suggestions on how we could improve upon our efforts to prevent birds from flying into the windows, please share them in the feedback section below.