If you’ve ever heard the sickening thud of a bird hitting your window, you know you’ll do anything to prevent another occurrence. Sadly, it’s estimated that more than 100 million to one billion birds die every year in collisions with manmade structures. “Bird-window collisions are a significant threat to avian populations,” says Chloe Saucedo Crumley, public affairs and engagement manager with Audubon Texas. “Understanding the causes, seasonal variations, and appropriate responses can mitigate these incidents.”

Birds that fly away often suffer concussions and internal injuries, so they die slowly over several days. Tragically, a collision which kills a parent bird may lead to the deaths of babies in the nest, too. It’s also estimated that up to 50 percent of bird-window collisions leave no evidence, so you may not even know a bird has hit your window.

Read on to learn the simple steps you can take to help prevent neighborhood and migrating birds from hitting your windows:

Why Birds Hit Windows

Birds can’t see glass. Collisions occur due to reflections on windows and because the mirror-like surface looks like a clear passageway to birds. “Daytime crashes occur due to the reflectivity of glass showing trees, sky, or vegetation, and transparency, where birds see through the glass to potted plants or vegetation on the other side,” says Crumley.

 At night, nocturnal migrants, which includes most songbirds, crash because they fly into lighted windows. Researchers aren’t sure why, but artificial lights at night also divert and disorient migrating birds, drawing them to urban areas, which leaves them vulnerable to threats such as building collisions. This is a huge risk for birds because about 80 percent of migratory birds in North America migrate at night, says Crumley.

How To Prevent Birds From Hitting Your Windows

Believe it or not, skyscrapers aren’t as much of a threat of bird collisions as our houses: It’s estimated that 44 percent of annual collision fatalities occur at residences that are one to three stories tall. In order to keep birds safe and away from your windows, National Audubon Society and Crumley suggest these tips:

• Move bird feeders less than three feet from the nearest window, which prevents birds from gaining deadly speed as they take off. Window bird feeders also are okay. Or place feeders more than 30 feet away from the house.
• Install screens on windows or glass doors. This keeps out bugs for you and eliminates reflections for the birds.
• Use vertical cords, which dangle in the breeze, on the outside of windows to break up reflections. They should be closely spaced to prevent bird strikes. You can buy or DIY these cords with paracord.
• Place films or dots, spaced 2 x 2 inches apart both vertically or horizontally, on windows. These can be adhesive tape or painted dots in a grid form. This spacing preserves your view but also protects even little birds. Be aware that a single sticker of any shape or size won’t work to prevent strikes.
• Turn off non-essential outside lights at night from 11pm to 6am, especially during migration periods in spring and fall. If you can’t shut lights, direct lighting downwards, or use motion sensors that only activate when needed. Also, use warm white, not bright white light, and don’t install landscape lighting that shines into the sky or up into trees.
• Close curtains and blinds at night to reduce illumination that can disorient birds.

What To Do If A Bird Hits Your Window

Despite your best efforts, birds may still collide with windows. If you find or hear a bird that has collided, Crumley suggests these steps:

• Assess the situation. If the bird is alive, wear gloves and gently place it in a small box lined with soft fabric or tissue.
• Contact a wildlife rehabilitator. They can provide medical care to injured birds. Find one by searching “wildlife rehabilitator near me.” Your state’s department of environmental conservation or state fish and wildlife agencies also may have a list of local rehabbers.
• If the bird is deceased, wear gloves to handle and bury them in your yard. Or call your town or municipality to see if they can assist with wildlife removal.