There are a variety of simple actions you can take at your home or workplace to effectively reduce the number of birds killed by collisions with windows or with lighted, tall buildings.
 
At Home

• Hang streamers or strings of old compact disks (CDs) in front of a window, or apply static window clings like Whispering Windows, WindowAlerts, or homemade appliqués to the outside of your window to help divert birds away from the glass.  To be most effective, such deterrents should be spaced no more than 10" apart.  If collisions continue, it may be necessary to reduce the spacing to 4" apart.
• Apply an antireflective plastic film like CollidEscape to the outside of a window to reduce reflections and prevent collisions
• Install BirdScreens or plastic netting in front of your window.  These act like a safety-barrier to prevent serious injury to birds that would have otherwise hit the glass
• If you feed birds, place your feeders either within 3 feet of your window, or more than 30 feet away from your window to minimize the risk of window collisions for your feeder patrons.
• For windows that are aligned with each other, allowing birds to see all the way through your home or a corner of your home, close the draperies or blinds on one of the windows.
• If you live in a high-rise building or along the Lake Michigan or Mississippi River shorelines, turn out exterior lights and interior lighting visible from outside your building between about 11 p.m. and 6 a.m. from mid-April through early June, and September-October.
• Join the WIngs program's BirdSafe Homes initiative: http://www.wihumane.org/wildlife/wings/homecollisions.aspx

(reprinted from the WBCI website