Q: A bird keeps flying into my window. 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. This is the time of year when most birds are busy establishing their territories, finding a mate, laying eggs, and raising their young. They are very protective of their territory 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 so they attack their own image. Both males and females may do this, especially species that often nest close to houses, such as American Robins, Northern Cardinals, Chipping Sparrows, and Song Sparrows.
This territorial reaction may be so strong that the bird may exhaust itself, but it usually doesn't result in fatal injury. Try covering the outside of the window with netting or fabric so the reflection is no longer visible. You can also try drawing soap streaks across the window to break up the reflection. You will probably be able to take down the netting and remove the soap several weeks later, when passions aren't running quite so high.
Other kinds of window collisions can be much more serious. Visit our Window Collisions page for ways to avoid this potentially lethal problem.