Back in the Cardinal Wild Bird Profile two readers asked similar questions about some irritating cardinal behavior. Diane has a cardinal constantly flying into her windows. Ozzie’s truck is getting some unwelcome attention from a red bird too.

Both behaviors may have a common origin. As I noted in the profile, cardinals are territorial birds. And like virtually every other bird, a cardinal can’t distinguish its reflection from a real bird.

So what happens when a cardinal looks at a reflective surface (like a window or mirror) and sees what it thinks is another cardinal budging into its territory? Well, it gets pretty mad . . . .

To answer both questions then, the issue probably isn’t nearby fruit, but reflections. The male cardinal sees what he thinks is another male who’s probably big enough to give him a hard time (who looks exactly the same size, in fact!) and tries to chase him away. The little red bird flies forward and either hits the window (not too hard, fortunately; cardinals aren’t power fliers) or lets loose some . . . displeasure, leaving you with a bit of a mess.

This article explains the phenomenon in a bit more depth. Fortunately, it’s pretty easy to deal with. First of all, place your feeders some distance away from a reflective surface so that the cardinal doesn’t see a "competitor" when it visits to eat. Next, keep your hedges cleared and your brush trimmed, especially around your car, so that you don’t accidentally put windows and mirrors too close to a prime roosting location. If the behavior presists, see what you can do to reduce or break up the reflection. Cornell University’s All About Birds site has some suggestions — and a nice picture of cardinals at a window!

I hope this answers your questions. Let me know if you have more!