There is a male cardinal that repeatedly flies into my windows. How can I make the bird stop this annoying behavior?
Male cardinals are very territorial and will scare away other male cardinals in their territory. Your cardinal is seeing its reflection in the window and thinks it is another male bird, so it repeatedly attacks its own reflection. There are a few ways to deter the cardinal from this behavior. Tape 2 to 3 metallic streamers to the top of your windows. Tape the other end of the streamer to the bottom of the window. It should hang loosely to wave in the breeze. You can also try sticking several stickers to the outside of the window. The streamers and stickers will break up the reflection in the window and hopefully your cardinal will stop attacking its reflection.