Recently, research has shown that window strikes can be prevented.
In 1993 the organization, FLAP (Fatal Light Awareness Program), started helping birds, injured or killed by collisions with the windows, during their nocturnal migration. Their focus was on high rise buildings, in downtown Toronto, that left their lights on all night, confusing birds. They then discovered that daytime collisions with glass on all buildings, commercial and residential, is an even greater problem and is responsible for the deaths of billions of birds worldwide.
FLAP: “Ornithological studies have determined that we can reduce or even eliminate bird/window collisions.” It is important to have the correct “ DENSITY and COVERAGE: Separate visual markers by spaces no more than 10 cm (4 inches) apart vertically or 5 cm (2 inches) horizontally that cover the entire window “
There are many products sold to prevent window strikes, but most do not meet these standards and give a false sense of security to the homeowner.
For methods that meet the FLAP Canada Standards check out their page on their site.
Feather Friendly is an excellent product for residential use and is Flap approved.