Thom Smith | NatureWatch: Reader question: Why do birds smack into windows repeatedly?

Q We have this robin that for the last week has sat on a little tree 10 feet from our three-paned north window. He flies at the window, hitting it with his chest, then flutters to the ground and flies up and at it again, then back to the tree. This starts at daybreak and ends at dark. He or she does this constantly all day long with less than three minutes between "lunges" and then sits on the tree and chirps. He started on our large sliding glass doors facing south, so I closed the shades and he went to the other window. What can we do short of living with all the window shades closed all day long?

— Barbara

A This aggression is not to be confused with accidental flying into windows (especially office buildings), causing around 100 million bird injuries and deaths every year, but the result of territorial instinct. I wish just one spring would come and go with robins, cardinals and song sparrows acting polite!

Trying to be good neighbors would make many a home owner/renter so happy, but birds are programmed to stake out a territory, find a mate, raise a family. You would not readily welcome an interloper camping out on your front porch. Neither do nesting birds. Other birds respond the same way, but the three mentioned here seem to be the most determined. I have heard of mockingbirds repeatedly attacking the "mail carrier" or a pet in addition to windows.

I get similar questions every spring, sometimes quite a few almost the same, word for word. If the launching site is not a tree, it is a shrub or bush, with the target a window or something else reflective, such as an automobile side mirror or shiny bumper. A friend, I'll call Randy Johnson, once had a song sparrow repeatedly attacking a side-view mirror on his car when parked in the driveway. The simple answer would have been to park the car elsewhere or cover the mirrors with a shower cap, small plastic shopping bag or sock. In these cases, we must be creative.

For years, I suggested Glass Wax be applied to inside glass and could almost hear my readers mumbling and imagining them shaking their heads. It does work, as will a black nylon window screening hung from the outside the window. In some cases, if only one window is the target, stop the reflection and eliminate the problem. The object is to stop the reflection. The bird sees itself in the window and thinks it is a rival, an intruder. It may be easier to remove the "little tree," or block the bird's view of your house from its perch or nest tree. The result is at first a smudge, but usually results in the window bloodied, with the bird unable to give in to the "intruder." This aggression may last for a month or so and, in the case of a robin that has two broods a season, into August, if it chooses to relocate to another part of your yard. Some birds have much larger areas to protect, amounting to a dozen or so acres.

Don't get the idea that fake snakes or owls will chase off the annoying bird or birds; spend your money and effort hanging light-weight plastic painter's drop cloth over the window. It is less noticeable and will let light into the house. Full window screens, although expensive, will stop reflections, as well as mosquitoes. White curtains or shades may also lessen reflection. Streamers hanging from windows sometimes help, as do larger photographs of faces hung in the window. Again, plastic owls and rubber snakes will not work (for more than a day).

Massachusetts Audubon has a suggestion, "Usually, however, the best course of action is to do nothing and wait."

Most birds are protected by federal law and state laws. Hope that the current administration in Washington doesn't abolish the Migratory Bird Treaty Act of 1918. And finally, be happy your home isn't within a wild turkey's territory!

Suggestions from readers welcome!

Thom Smith welcomes readers' questions and comments. Email him at Naturewatch @ or write him care of The Berkshire Eagle, 75 S. Church St., Pittsfield, MA 01201.     


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