Expert: Roger Lederer - 4/24/2009

Question
I live on the 2nd floor of an apt. Bldg. with no terrace, only a narrow sill. For
the last week, this robin pecks at the glass, flaps his wings, hops along the
half screen rim. He chooses different windows. I see a nest at the top of a
pillar nearby, but can 't see into it. Is this robin acting neutiticslly as so e
suggest, is he seeing his own reflection as others have said, is he just
hanging out? This has never occurred before. How lonCg is he apt to repeat
this behavior?  

Answer
Robins, 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.