Nearly 1 billion birds die each year from impact with windows, says K-State’s Ricketts

By Pat Melgares, K-State Research and Extension news service

MANHATTAN, Kan. – Homeowners who plan to make shiny windows part of spring cleaning chores may want to re-think how that’s done.

That is, at least, if they also enjoy the variety of backyard birds that populate many urban, suburban and even rural areas. Kansas State University wildlife specialist Drew Ricketts said an estimated 1 billion birds die each year as a result of impact with windows.

“There are two types of bird strikes,” Ricketts said. “One is where the bird doesn’t know the window is there and just runs into it. The other is when birds see their reflection in the window and sort of beat their beak on it because they’re trying to get at a competitor.”

Ricketts cited a study in which researchers tested window films to determine the best way to ward off danger for homeowner’s fine-feathered friends.

“A lot of times when I’m helping homeowners, I will suggest films that have a character of an animal or some sort of picture that allows the bird to see that the surface is not open,” he said. “Or, sometimes we think of putting newspaper or other object, but a lot of people don’t want to obstruct their windows.”

A pair of industrial products could be a better solution, he said. A bird shield is a film that has a pinstripe design that is barely visible to humans, but more easily seen by birds. Another product, a bird shade, is a film that uses a wavelength of light that humans can’t see, but birds can.

“If you want your window to look clear, these sorts of films could be very effective,” Ricketts said. “They’re generally made for industrial applications, but you could purchase them for a house.”

Researchers also report that where you place the films matters.

When the films were applied to the outside of the window, “the bird shades increased window avoidance by about 50% and the bird shield increased avoidance by about 40%,” Ricketts said.

“Fifty percent may not sound like all that much, but when you think that half a billion birds could avoid dying, then that’s a lot.”

When films are applied to the inside of windows, “researchers saw a drastic reduction in effectiveness,” Ricketts said.

“And so even though it may not be convenient when we’re thinking about applying something to a window to keep a bird from hitting it, it’s going to be important to apply that to the outside – rather than the inside – of the window.”

More information on managing wildlife in Kansas is available online from K-State Research and Extension.