Instincts can drive bird strikes against windows
It’s one of the signs of spring: That unnerving “thunk” when a bird flies into your picture window or storm door. It can be an upsetting experience, but the outcome isn’t necessarily going to be as bad as it might look, and there are steps you can take to help prevent those collisions.
Becky McPeake, a professor and Extension wildlife specialist for the University of Arkansas System Division of Agriculture, said there could be different reasons why a bird is flying into glass at your home or business.
“One reason it happens is because glass is invisible to birds,” she said. “When they’re in flight, they may see a reflection of the sky and trees and grass, or they may even be looking through two windows to the other side. They may perceive a flyway through your home.”
There’s another reason you might see a bird flying into your window: territorial instinct.
“Around nesting time, some species like the northern cardinal perceive another bird in the reflection and will fight to protect their nesting territory,” said McPeake. “It’s not like a bird colliding into a window, but it can be annoying to you, plus the bird can become exhausted from its flailing.”
In either case, there are several options if you want to find a way to help prevent these incidents. The simplest is to shut your blinds or curtains part or all of the way to break the reflection, but that’s not always practical, and one of the benefits of having a big window, of course, is to get a view of songbirds and other flying fauna from the comfort of your favorite chair. So a better option may be to put something on or in front of the window that will help the birds realize there’s something there.
McPeake said placing something in front of the window such as hanging reflective tape, aluminum strips, or old CDs can detract birds from windows. Adding a decorative or one-way window glass film can have little or no effect on the view from inside but which give birds a visual clue from the outside. A common remedy is to print out silhouettes of birds and attach them to glass, which can be effective if many of them are used with small spaces in between. Another method McPeake has seen used stretching very fine netting—the kind you purchase at garden stores to keep birds off your fruit plants—in front of the window.
“It needs to be a five-eighths of an inch fine mesh so birds can’t get their heads into it and cause injury,” she said. “You can attach the netting to an old window or screen frame, for example, about 3 inches from the glass so they bounce off the netting. The Lab of Ornithology at Cornell University did this outside their bird-feeding garden and their mortality rate went to zero.”
Another reason birds may fly into windows is tied to the fact that people frequently try to attract birds to their yards with feeders and birdbaths, said Lynn Sciumbato, a state and federally permitted wildlife rehabilitator who operates the Morning Star Wildlife Rehabilitation Center in Gravette.
“If a birdbath or feeder is close to the windows, they explode off the feeder when they’re startled and they can hit the window,” said Sciumbato. “If you set it a little further away from the house, that gives them a chance to navigate.”
However, placing feeders or birdbaths too far from a window can also be a problem. According to the Lab of Ornithology, feeders and other attractants placed away from a window allows fleeing birds to reach top speed before impact. They advise placing feeders within three feet of window glass. Birds may still fly into the glass but with not enough force to cause injury.
Protecting injured birds
If a bird hits your window and you find it on your front porch or the ground in front of your house, don’t pick it up. Birds don’t take well to handling. Instead, she suggested, get a laundry basket or something similar and set it over the bird.
“When they lie there knocked out, they’re fair game to every cat,” Sciumbato said. “That gives them a chance to come to without the stress of being picked up and carried around. Give them an hour, lift up the laundry basket, and probably half the time they’ll just fly off.”
While it’s most common to see songbirds fly into windows, Sciumbato says she’s even had hawks and owls at her rehabilitation center for the same reason.
“Hawks will run into the window when they are chasing a bird, especially Cooper’s hawks that are chasing songbirds,” she said. “They’re going 100 miles per hour after this bird, and the bird zigs or zags at the last second and the hawk doesn’t, and they’ll go right into the window.”
Whether it’s a warbler or a raptor, if the bird is injured you should contact a permitted rehabilitator to take over its care.
“Every native bird is federally protected, not just the raptors,” said Sciumbato. “You can’t kill them, you can’t keep them.”