Expert: Roger Lederer - 4/22/2010

Question
For several years during the Spring, a Robin flies onto some of our windowsills and pecks at the glass making grayish/white marks on the glass, and messing up the sill with excrement. In spite of deterrents such as rubber snakes and fake cats, the Robin or Robins continue with this behaviour many times waking us up at daybreak, and throughout the morning. Our windows are UV protected and act like a mirror from the outside. We live in Southern Ontario. Can you please suggest a suitable deterrent as it is very annoying.

Answer
Robins 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.