Expert: Roger Lederer - 2/23/2011

Question
Hello, we recently moved into a house and we have a cardinal that day after day flys into windows of our house, 3 separate windows at different areas of our house. I would think that this would hurt, you can hear him across the house smacking into the windows. They are not large plate glass windows, they are just regular sized windows...any insight would be great.

Answer
This is very common behavior this time of year. Cardinals and many other birds are territorial and when they establish territories in the spring they become aggressive and chase off intruders. Unfortunately, they don't distinguish between their own reflection in a window (or car mirror) and try to chase that off. The solution to the problem is to eliminate the reflection. Misting the outside of the window with a very weak detergent or soda solution will eliminate the reflection but will also impair visibility for you. Awnings, eave extensions, and window screens will eliminate all reflection and stop the collision problem. Hanging ornaments such as wind chimes, wind socks, and potted plants also help. The behavior will stop when nesting begins.