Birds do not perceive glass the same way that humans do. At a young age, we develop visual cues from repeated interactions with the clear surface, this helps us to detect the glass and avoid bumping into it, well, most of the time. To birds, glass is not detectable and they perceive the reflection as habitat to explore, or mistake themselves as an intruder in their territory. Unfortunately, these interactions often result in fatal collisions with windows. Bird strikes are also an issue in the evening, when lighted windows divert nocturnal migrants from their original path. Window collisions are an annual occurrence but are more common in the summer as young birds explore spaces and visit nearby feeders and bird baths. Glass collisions are one of the highest human-influenced sources of bird mortality in the United States, topped only by domestic cat predation. To truly address the issue, reduction measures need to be applied to a large number of buildings and of all different structure types, from residential homes to high rises. However, you can make a difference by starting with problem windows on your property. Read on to learn how minor changes can help!
Simple steps to make your windows bird friendly
Screens on the outside of a window eliminate reflection issues and soften the impact if a bird does collide with a window. Options vary from inserting an insect screen tailored to the dimensions of your windows or hanging a bird screen or Zen curtain on hooks. You can also make your own Acopian BirdSaver (aka Zen Curtain) by following this step-by-step guides.
Apply decorative paint
Tempera paint can be found at most art supply stores and can be applied with a brush or sponge. You can use stencils to make creative designs. The paint will not wash away with the rain but can easily be removed with a damp rag. Be mindful if using acrylic or oil-based paints, these can be difficult to remove.
Install window tape or films
The American Bird Conservancy (ABC) notes several studies that found patterns on glass can reduce bird strikes. Vertical stripes should be no more than 4 inches apart and horizontal stripes should be no more than two inches apart. The stripes themselves should be a minimum of 1/8” wide so that they are easy to see. Here are some ABC recommended materials:
Films are another alternative to consider:
With small and manageable changes we can collectively make a difference in protecting birds from window collisions and create safe spaces for birds at our own homes.