Bird-Proof Your Panes
Nearly half of all window strikes happen at residential houses, which is why it’s so important for renters and homeowners to take steps to make their homes bird safe. Birds collide into glass typically because the window is reflecting the surrounding habitat or sky and birds can’t tell the difference. And because the sheer number of windows is so great, their toll on birds is huge. Up to about 1 billion birds die from window strikes in the U.S. each year, according to a 2014 study.
There are a few easy solutions that will help birds avoid your home’s windows.
During the Day
Go outside and look at your windows from a bird’s point of view. If you see branches or sky reflected in or visible through the glass, that’s what the birds will see, too. Adhere UV reflecting decals on the outside of the window close together—the space between them should not exceed 2 inches by 4 inches. UV reflecting decals or UV ink makes no difference to the human eye, but they make all the difference to birds. Stickers, sun catchers, mylar strips, masking tape, or other objects (even sticky notes) also work on the outside surface of the window. Remember, these are only effective when spaced very closely (see above). What you’re trying to do is break up the reflectivity. Note that hawk silhouettes do little to deter birds.
Remember: placing just one or two window stickers on a large window is not going to prevent collisions—they must cover most of the glass with the spaces between too narrow for birds to fly through.
Why Birds See Ultraviolet Light
There are two types of light-sensitive cells, called photoreceptors, in the eye: rods and cones. Cone photoreceptors are responsible for color vision. While humans have blue, green, and red-sensitive cones only, birds have a fourth cone type which is either violet or UV-sensitive, depending on the species.
Here is a fascinating article on how birds see the world.
Resources
How To Help A Window Collision Victim
If you find a bird dazed from a window collision, examine it for external injuries. If the wings are both held properly, neither dangling, and the eyes seem normal, see if it can perch in a branch unassisted. If so, leave it to recover on its own.
If the bird has a noticeable injury, get it to a wildlife rehabilitator as quickly as possible. Broken bones usually need proper attention within minutes or hours to heal properly without surgery. Use this directory to find a rehabber near you.
Meanwhile, place it in a dark container such as a shoebox, and leave it somewhere quiet, out of reach of pets and other predators, for 15 minutes. If the weather is extremely cold, you may need to take it inside, but don’t keep the bird too warm. Do not try to give it food and water, and resist handling it. The darkness will calm the bird while it revives, which should occur within a few minutes unless it is seriously injured. Do not open the box indoors to check on it or it might escape into your house and be hard to get back out!
Take the box outside every 15 minutes or so and open it—if the bird flies off, that’s that! If it doesn’t recover in a couple of hours, take it to a wildlife rehabilitator. Remember that, technically, it is illegal to handle a migratory bird without a permit, and medically helping an injured bird requires training, so your job is just to transport the bird to a rehabilitator.
