american goldfinch killed by window strike
Photo by Susan Spear/Cornell Lab.

For birds, glass windows are worse than invisible. By reflecting foliage or sky, they squint like inviting places to fly into. And considering the sheer number of windows is so great, their toll on birds is huge. Up to well-nigh 1 billion birds die from window strikes in the U.S. each year, according to a 2014 study.

The good news is that you can profoundly reduce the danger your home’s windows pose to birds with some simple remedies, equal to Christine Sheppard, who directs the Bird Collisions Program of the American Bird Conservancy. The group offers extensive information on preventing collisions on its website. The Fatal Light Awareness Program moreover offers unconfined information on preventing bird collisions.

What happens to birds that hit windows? Sadly, the bird often dies, plane when it is only temporarily stunned and manages to fly away. Many times these birds die later from internal gory or bruising, expressly on the brain. Daniel Klem of Muhlenberg College has researched this issue since the 1970s. He writes, Glass is an indiscriminate killer that takes the fit as well as the unfit of a species’ population.

Why Birds Collide With Windows

imprint of dove on plate glass window
The window imprint left by a Mourning Dove. Photo by Priscilla Bradley/PFW.

There are two main types of window collisions: daytime and nighttime. In daylight, birds crash into windows because they see reflections of vegetation or see through the glass to potted plants or vegetation on the other side. At night, nocturnal migrants (including most songbirds) crash because they fly into lighted windows.

For reasons not entirely understood, lights divert nocturnal migrants from their original path, expressly in low-ceiling or foggy conditions. In the lighted area, they mill about, sometimes colliding with one flipside or the lighted structure. As a subsequent hazard, migrants drawn off undertow by urban lighting may roost safely nearby, only to wilt vulnerable to daytime reflections in windows the pursuit day. The BirdCast project and the Fatal Light Awareness Program have increasingly well-nigh this problem.

There’s one additional reason: birds sometimes see their reflection in a window and wade it. This happens most commonly in the spring when territoriality is high. Although it can be worrying to the homeowner, it’s seldom a threat to the bird’s survival. Most of the remedies suggested unelevated for window strikes will moreover help solve the problem of a bird attacking its reflection.

How to Safeguard Your Windows For Birds

reflection of foliage in window - hazard to birds
Reflected landscapes can misplace birds and rationalization mortiferous window strikes. Photo by Susan Spear/Cornell Lab.

Start by identifying dangerous windows, including large picture windows, paired windows at right angles to each other, or windows with feeders outside. Go outside and squint at your windows from a bird’s point of view. If you see branches or sky reflected in or visible through the glass, thats what the birds will see, too. Past recommendations well-nigh unscratched distances for feeders outside windows are no longer thought to be valid, Sheppard says. “If you’ve got windows near a bird feeder, you should make them bird friendly and don’t worry well-nigh how far yonder they are.”

Treatments for Existing Windows

To deter small birds, vertical markings on windows need to be spaced no increasingly than 4 inches untied and horizontal markings no increasingly than 2 inches untied wideness the unshortened window. (If hummingbirds are a problem, the spacing should be reduced to a 2-inch by 2-inch grid.) All marking techniques should be unromantic to the outside of the window.

  • Tempera paint or soap. Mark the outside of the window with soap or tempera paint, which is inexpensive and long lasting. You can use either a grid pattern no increasingly than 4 inches by 2 inches (see above), or get creative and paint patterns or artwork on your window.
  • Decals. Put decals, stickers, sun catchers, mylar strips, masking tape, or other objects (even sticky notes) on the outside surface of the window. These are only constructive when spaced very closely (see above). Note that hawk silhouettes do little to deter birds. Remember: placing just one or two window stickers on a lare window is not going to prevent collisionsthey must imbricate most of the glass with the spaces between too narrow for birds to fly through.
  • Dot Patterns and Tape. Long-lasting tape products offer an easier way to wield the correct spacing of dots wideness your window. More well-nigh bird tape.
  • Acopian Bird Savers. Also known as “zen curtains,” these closely spaced ropes hang lanugo over windows. They do the work of tape or decals but are easier to install and can be aesthetically pleasing. You can order them to fit your windows or make your own.
  • Screens. Installing mosquito screens over your windows is very effective, as long as they are on the outside of the window and imbricate the unshortened surface.
  • Netting. Imbricate the glass on the outside with netting at least 3 inches from the glass, taut unbearable to vellicate birds off surpassing they hit. Small-mesh netting (around 5/8″ or 1.6 cm)  is best, so that birds don’t get their heads or persons entangled but will vellicate off unharmed. You can mount the netting on a frame, such as a storm-window frame, for easy installation and removal.
  • One-way transparent film. Products such as Collidescape permit people on the inside to see out, but makes the window towards opaque on the outside. They can reduce the value of light that comes in your window (this can moreover reduce your cooling costs), equal to Sheppard.

New Homes and Remodels

  • Install external shutters and alimony them sealed when youre not in the room or taking wholesomeness of the light or view. (These can be huge energy savers, too!)
  • Install external sun shades or awnings on windows, to woodcut the reflection of sunlight. Remote controlled shades are available.
  • On new construction or when putting in new windows, consider windows that have the screen on the unshortened outside of the glass.
  • Add interior vertical blinds and alimony the slats only half open.
  • Avoid visual paths to sky and greenery. Bright windows on the opposite wall from your picture window may requite the illusion of an unshut path to the other side. Closing a window shade or a door between rooms can sometimes solve this situation.

Lights Out

Lights Out initiatives are gaining ground in U.S. cities including Dallas, Houston, Philadelphia, and New York. The all-night glow of office buildings and streetlights in cities is expressly dangerous for drawing migrating birds off course, delaying their migrations and making them vulnerable to window collisions. Turning off nonessential lights and installing downward-facing lighting are relatively simple ways to reduce the problem of strained light at night. It’s still wise to take precautions versus window collisions using any of the whilom methods, expressly for homeowners.

How to Help a Window Standoff Victim

If you find a bird tranced from a window collision, examine it for external injuries. If the wings are both held properly, neither dangling, and the vision seem normal, see if it can perch in a workshop 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 wreck usually need proper sustentation within minutes or hours to heal properly without surgery. Use this online directory to find a rehabber near you.

Meanwhile, place it in a visionless 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 dont alimony the bird too warm. Do not try to requite it supplies and water, and resist handling it. The darkness will wifely the bird while it revives, which should occur within a few minutes unless it is seriously injured. Do not unshut the box indoors to trammels on it or it might escape into your house and be nonflexible to get when out!

Take the box outside every 15 minutes or so and unshut itif the bird flies off, thats 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.