Expert: Roger Lederer - 11/27/2010

Question
For about 6 weeks a Western Scrub Jay has been "attacking"
the house. For the first 4 weeks, it stayed in a nearby tree
through the night and attacked a front window all through
the day. It also pooped on one specific car in the driveway
despite my sister's car being parked next to it.
A few weeks ago, it started attacking the back sliding door
which is on the opposite side of the house. At one point my
sister left her bags by the sliding door and when she came
back a few minutes later they were pooped on. From then on
the bird has been pooping on her car and not the first one.
We really don't want it to hurt itself, and we are very
curious as to why it's doing all this. Any ideas?

Answer
Jays, cardinals and many other birds are territorial and when they establish territories in the spring or winter they become aggressive and chase off intruders. Unfortunately, they don't distinguish between their own reflection in a window (or car mirror or bumper) 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 around the area the jay attacks will also help.