Make risky windows visible to birds
Why this can help
External markings can make glass more visible to birds and reduce collision risk. Research and conservation guidance support patterns covering the hazardous area rather than a few isolated decals.
One possible next step
Identify a window reflecting vegetation and follow a tested external marking or screen method.
What changes the outcome
Use an effective pattern with close spacing, generally about 5 cm, on the outside surface. Glass, surroundings and species affect outcomes. Do not infer birds saved from the area treated.
The action
One possibility
Leaving reflective glass unmarked
Another possibility
Applying a close-spaced pattern outside the glass
External markings can make glass more visible to birds and reduce collision risk. Research and conservation guidance support patterns covering the hazardous area rather than a few isolated decals.
Identify a window reflecting vegetation and follow a tested external marking or screen method.
Sources and calculation references
- Window markers reduce bird–window collisions, Ornithological Applications (2026)Ornithological Applications — authors listed in the linked publication · 2026
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