I drill a hole at the edge of old CDs and hang them from black sewing
thread in my windows... they move with the slightest air currents and
birds don't try to fly through the glass. Also don't keep house
plants on window sills or anything that looks like vegetation or a
perch. And since I have window shades I tape silhouettes of raptors
on the backs facing out so even when only half way down the raptors
are visible. There are web sites where you can print them. Millions
of migrating birds meet their demise every year from slamming into
windows, especially windows in tall buildings in big sities. There
are wildlife organizations tying to get those buildings to comply with
installing bird safe glass.
There are double and triple glazed windows now that have images
embedded between the panes that are only visable from the outside,
windows can also be automaticaly tinted like eyeglasses, and the
visable images can be changed too.
When a bird strikes a first floor window most times it will be okay,
birds at that altitude aren't flying very fast. They may get knocked
out for a couple of minutes but if left alone they will revive and be
fine. But at second story windows and higher birds will hit windows
at greater veloscity and most will die on impact.
It costs nothing, PROTECT YOUR WINDOWS FROM BIRD STRIKES.