Bird Brained Behavior: Why is that bird flying into my window over and over?

While dressing today, I wondered what that bonk, bonk, bonking was. It sounded like someone throwing a ball over and over against the side of the house. Then, I look toward the window and what did I see? Poor Robin Red-breast looking at me. Actually, he probably wasn't looking at me at all: the bird was seeing his shadow and defending his turf.

As a traumatic brain injury survivor, I get a little anxious whenever I see brains being bashed about, human or bird brains. So I looked it up on the Cornell Lab site, and here's what I found under the frequently asked questions:

Q. A bird keeps flying into my window, on purpose! Why is it doing this? I'm afraid it will hurt itself. What should I do?


A. The behavior you mention often occurs in spring and early summer. This is the time of year when most birds establish their territories, find a mate, lay eggs, and raise young. To ensure success, they defend their territory aggressively, and will attack and try to drive away any bird they view as a possible competitor or a threat to their young. When they see their own reflection in your window, they assume they're seeing a competitor and attack the image. The species most likely to do this are those that nest close to houses, such as American Robins, Northern Cardinals, bluebirds, California Towhees, Chipping Sparrows, and Song Sparrows. Both males and females engage in this.

Fortunately, this behavior usually dissipates within a few days or, at most, weeks. But while it lasts, the bird may exhaust or even hurt itself, and it distracts the bird from far more important activities. And this behavior can be extremely annoying for the people witnessing it.

To get rid of the reflection, you must alter the outside of the window. You can cover it with netting, fabric, or newspaper, or smear soap streaks on the glass. When you're no longer seeing the bird nearby you can remove this. Often, rubber snakes frighten birds away, at least temporarily—although like any object that doesn't move, the birds get used to seeing them. Helium-filled Mylar balloons on 3–4 foot strings make movements and cast glaring light that birds find confusing and even alarming. Setting a few near a window will frighten away most birds.

We have more information about protecting your birds from windows here.