For the Birds
Designing Solutions
Simulate a bird–window collision, then design, test, and refine a screen solution to reduce the force of impact and prevent bird mortality.
Windows, Birds, and the Search for Solutions
Glass windows are one of the largest human-caused threats to birds. In the United States alone, scientists estimate that collisions with windows kill as many as 988 million birds every year. The problem comes from how birds see glass. A clear window can look like an open space to fly through, while a reflective window can mirror the sky, trees, or clouds — making the glass appear to be open habitat. Indoor plants near a window can also lure birds straight toward the glass. At night, birds that migrate are drawn to the bright lights of cities, where they can become disoriented and strike buildings.
These deaths matter beyond the individual bird. Birds fill important roles in their ecosystems: they spread seeds, pollinate plants, and help control insect populations, and they serve as both predator and prey. When many birds are lost, biodiversity decreases and the ecosystem can become less stable, which can ripple outward to affect other species — including humans, who depend on healthy ecosystems for food and other resources.
People are working on solutions. Some buildings now use patterned or specially treated glass that birds can see and avoid, and homeowners can add tape, decals, or screens to break up reflections. Many cities run “lights out” programs that dim building lights during migration season. But no single fix prevents every collision. Another approach is to reduce the force of impact, so that a bird that does hit the glass is more likely to survive. Designing any of these solutions means weighing trade-offs such as cost, appearance, safety, and reliability. In this investigation, you will design and test a screen meant to soften that impact — using a clay model to stand in for a real bird.
Check your understanding
Choose the best answer for each question. You’ll get instant feedback so you can learn before starting — your first answer is recorded for your report.
Step 1–2 · The unprotected window
The clay ball models a chickadee in flight. The drop height is calibrated so the falling clay reaches the bird's real flight speed. Dropping onto the bare floor models a bird hitting an unprotected window.
Step 2c · Baseline deformation (no screen)
Drop the model chickadee onto the bare floor and measure the diameter of the deformation. Any deformation = bird mortality.
Step 3 · Design your solution
Your apparatus: a fiberglass screen on a wooden embroidery hoop, raised off the floor on stackable spacers. You control the gap height between the screen and the floor. The screen flexes on impact — a larger gap gives it more room to slow the clay before it bottoms out.
Step 4a · Components of the simulation
Identify the real-world component each part of the simulation represents. The first is done for you.
Step 4c–5 · Run the simulation
Set a gap height, then drop the clay three times for that value. Record several gap heights — including at least one that causes mortality — so you can find the threshold.
| Gap height (cm) | Trial 1 (cm) | Trial 2 (cm) | Trial 3 (cm) | Average (cm) | Result |
|---|
Reveal your graph
Step 6 · Minimum value
6.Using quantitative evidence from your data, identify the minimum gap height that prevents chickadee mortality.
Step 7 · Choose a new bird
Pick a different bird and refine your solution to prevent its mortality. Keep the minimum value you found for the chickadee in mind — a heavier or faster bird carries more impact energy.