Bird Window Attacks: Why Do They Happen?

Apr 27, 2021

Goose Window Attack

Spring migration is the high season for birds crashing into windows. Deaths number in the hundreds of millions every year. While many of these crashes are the result of birds’ inability to recognize the glass barrier, some are deliberate attacks, with birds striking over and over, sometimes for hours at a time. During the spring season, we get many calls about birds of all species, including robins, sandhill cranes, Canada geese, and Northern cardinals, pecking at, attacking, and actively trying to fly into windows.

Why Birds Exhibit This Strange Behavior

Many people assume the bird is attempting to enter the building. But the reason is a bit more complex: supply and demand! Most bird species are incredibly territorial in spring. They are nesting, and raising offspring is no small task. Baby birds must grow quickly and be ready to fly and fend for themselves before the weather turns. They eat ravenously and resources are at a premium, especially food. To make sure their chicks are well fed, males must provide protection against interlopers for their mate, their nests, and their territory.

Not all birds get the chance to nest every year. If he can’t find and defend a territory, a male bird may miss the chance to raise a family. Males without territories are constantly looking to take over territories, steal other males’ mates, and snag the resources needed to raise chicks of their own.

Why Birds Attack Windows

For the same reason that millions of birds are killed in window collisions every year: reflections. When a male bird patrolling his territory sees his reflection in a window, he sees a rival, coming to take everything he holds dear. With hormones raging, he tries to drive the intruder off. His reflection of course, doesn’t back down, and the fight is protracted, sometimes to the point of injury and exhaustion.

Window Reflection
Birds see their reflection in these windows and think it is an intruder onto their turf!

How to Stop Them from Attacking Windows

  • What Doesn’t Work. Bird of prey or other predator decals. Shaped decals that do not cover the majority of the window. Coyote or owl decoys. While these may give a bird pause, raging nesting hormones will often override fear of a potential predator, especially one that doesn’t move.
  • What May Work. Temporarily removing the reflectivity of the targeted windows until nesting season is over and the hormonal territorial drive has subsided. For a house, this can be as simple as closing the blinds, hanging some white construction paper, or using chalk paint to eliminate room for a reflection of the bird. These options are easy and inexpensive and may help prevent unintentional window collisions as well. For larger buildings, options include removing staging areas near windows where the birds rest between attacks, or covering windows with a film designed to eliminate reflectivity. The important thing to remember is that these are wild animals with an intense drive to protect their turf, and as long as a bird can see its reflection, the window is a potential threat.

Bird on Window Ledge
This bird is resting before attacking the “intruder” in this mirrored window again!

How Migratory Bird Management Can Help

Our team of biologists and bird experts can survey your property to design customized solutions based on the bird species involved, property features, and other details of your situation. Contact us today for a consult!

Contact us to learn more about our bird management services