Winged window whackers

Injuries caused from flying into windows are one of the most common reasons for birds being brought to wildlife rehabilitators. Over the years, WERC, the Wildlife Education and Rehabilitation Center in Morgan Hill, has received countless window-bangers ranging in size from tiny hummingbirds to a huge turkey vulture. 
Injuries can range from simple concussions to horribly broken beaks and wings. Birds may fly into the window because they see a reflection in the glass as the real thing, such as a tree branch or another bird.  Or their little bird brains just can’t tell that see-through doesn’t mean fly-through. 
One method of prevention is to make the invisible visible. Close the curtains or attach silhouettes to the glass.  Putting decals on the window can not only help prevent bird accidents but can keep people from walking into sliding glass doors, too. 
Hang up “distractions” outside of the window such as streamers, wind chimes, or windsocks.  You can “bounce” the birds off the window by tautly stretching fine mesh or screening over the window.  Sometimes birds hit the window because they’re fleeing a predator, i.e. an outdoor cat, so it’s safer to locate your bird feeders away from windows. 
What to do if preventative measures fail and you hear that sickening thump against the panes?  Gently pick up the bird and quickly examine it for dire injuries such as a broken wing or bleeding wounds. 
A bird with such injuries should be brought immediately to a licensed wildlife rehabilitator.  Otherwise, place the bird in a covered container, such as a cardboard box punched with breathing holes and with toweling laid on the bottom.  Keep the box in a quiet, warm, and safe area.  Don’t give the bird any food or water. 
Check the bird after a few hours.  If it can “self-release”—fly away on its own—congratulations.  You can breathe a sigh of relief and give yourself a pat on the back.  If the bird is nocturnal/nighttime (most owls) wait until early evening to release. If the bird is diurnal/daytime (hawks and songbirds such as this cedar waxwing that got “drunk” on fermented toyon berries and crashed into a window) you may need to keep it overnight and release it in the morning.  However, if the bird isn’t able to fly away, bring it to your wildlife rehabilitator ASAP.
By the way, that turkey vulture mentioned above recovered just fine from its concussion.  It had flown into—but not through—a heavy plate glass window and knocked itself unconscious.  When eventually released in Morgan Hill, the vulture headed north to San Jose, back to where it had been found.