Bird Window Collision Deaths 3.5 Times Higher than Previous Estimates
Each Home Can Save 80 birds, Each Low-Rise 900 Birds
Dr. Daniel Klem, Jr. Director. Acopian Center for Ornithology
Interview with Dr. Daniel Klem, Jr. `The World’s Leading Bird Window Collision Expert * May 14, 2026
`The World’s Leading Bird Window Collision Expert * May 14, 2026
- Question: What does your new study published in the Wilson Journal tell us about the seriousness of the threats to birds of window collisions?
Answer: Dr. Klem On the US country-wide level, it shows that collisions are one of the top leading causes of bird mortality nationwide.
On a building-by-building basis, deaths from window collisions are about 3.5 times higher than previous estimates. For example, previous research estimated 2.1 collision deaths per residence per year and 20 at low-rise (four-stories or less). The new research shows that bird window collisions will cause about 7 collisions deaths per residence per year. The estimate of annual deaths at low-rise buildings increases from 21.7 to 916. Of course, the exact numbers are not the point. The point is that my study shows that the previous estimates of 2 and 21annual deaths are far below the actual mortality. I would use “over 80” and “over 900” respectively.(see table below)