Decals can help prevent birds flying into windows
QUESTION: Two years or so ago you answered a question about birds seeing their reflections in windows, and mentioned that sometimes they fly into the windows and kill themselves. While visiting friends in Denmark, I noticed on their windows black decals of hawks diving. They explained that most birds are afraid of hawks and that decals of their image kept smaller birds from flying into windows. You can also make them out of black contact paper and put them on the outside of the window. It’s worked so well I thought I should write to you. I don’t mind the decals on the windows; in fact, I enjoy looking at them. You can wash the windows without harming them, and they are easily replaced.
S.S., Huntington Beach, CA
ANSWER: You're right about the decals working, but it's not because the bird sees the hawk as a predator. What it sees instead is something in its path rather than the thorouighfare the glass once appeared to be. In the case of a bird pecking at its reflection in a window, the hawk decal helps minimize the area of reflection.
Any shape will work, but the hawks have been a popular way to market and explain the presence of decals on windows.
I’ll be happy to send a copy of the hawk pattern you’ve so kindly included in your letter to readers. Please send a self-addressed stamped envelope to Andrea Kitay, P.O. Box 2489, Camarillo, CA 93011.