Do Fake Owls and Other Decoys Work?

Maybe you've seen a scarecrow perched in a field or a plastic owl standing guard over a garden. The idea is that the decoy will scare away birds and small mammals from feasting on whatever goodies lie below. But do the fake people and pseudo-avian predators really do the trick?

Sort of, and here's why.

Scarecrows have long been the method of choice to dissuade birds from feasting on seeds and growing crops. They're often stick-like mannequins dressed in old clothes and placed in fields and gardens to ward off crows, sparrows, and other hungry birds.

But one of the problems with scarecrows is that they just stand there. Sooner or later, the birds figure out that the stick guy is not a real person because he just doesn't budge. Once they realize that, fear flies away.

"Many times they will turn scarecrows into a comfortable perch," writes Avian Enterprises, makers of a bird repellent.

Wising Up to Owls

Realizing that scare-people aren't all that scary, inventors came up with new and improved decoys. They tried owls because so many birds and small mammals, like rabbits, are frightened of the winged predator—and a frightened rabbit should be, in theory, less inclined to nibble on lettuce in a garden overshadowed by an owl.

Farmers, backyard gardeners, building managers, and homeowners hang plastic owls in hopes that hungry animals will recognize the owl shape and stay away. And that works, at least for a time.

A study by Linfield College found that songbirds are afraid of owl decoys. Researchers swapped out owl decoys for a cardboard box of the same size in an oak woodland within Oregon's Willamette Valley. Then they measured how often birds visited feeders in the vicinity of the objects and found they were much less likely to go near the feeder when the owl decoy was stationed nearby; however, they weren't scared one bit by the cardboard box. The birds did wise up over time, though. After a few days, they realized the owl was fake and returned to the feeder.

So it's the scarecrow problem all over again. If something just sits there—no matter how frightening it appears at first glance—birds are smart enough to figure out it's not all that scary.

Movement Is Key

Fake owls might work if you need to keep birds or animals away from somewhere for just a day or two. Or you could move your plastic owl around your house or garden so it looks like it's real. Some people also tie it to a rope so it sways and moves, almost like it's flying.

There are also special products that move and bounce constantly to convince hungry visitors they are keeping guard.

Terror Eyes, manufactured by Bird-X, are an effective alternative to fake owls. These brightly colored balloons have fierce eyes that follow their prey. They bounce on a spring and move constantly so birds don't get used to them.

Some large farms have also turned to those inflatable tube men that you often see outside car dealerships. They dance and shimmy and whip their appendages all around. No bird would dare go near them.

California farmers use shimmering aluminum PET ribbons. They're tied directly to the plants, reflecting the sun and scaring off any animal looking for a snack. You could do something similar with old CDs or garden spinners, though they should still be moved around occasionally to prevent birds from becoming accustomed to them. You could get a specialized version of a spinner, such as the Reflect-A-Bird Deterrent that uses wind power and reflective surfaces to scare birds.

On the non-object front, people have turned to gas-powered propane cannons or flash powder to make loud noises that scare birds away from everything. But birds get used to these sounds, too, particularly if they're emitted at steady intervals. Metal wind chimes can work, but they need to be right in the garden where the plants are, not on a nearby porch. Move them around, too.

Deterrents in the Water

It isn't just birds that are sometimes fooled by pretend predators. Surfers are finding their own decoys to try to deter sharks—at least at the very initial stage of an attack.

A company named Shark Eyes offers huge eye-shaped stickers that can be attached to surfboards, clothing, and diving gear. The company says it "aims to trick the shark into thinking it's been spotted, thereby removing the element of surprise and deterring an attack."

Richard Pierce, conservationist and founder of the Shark Conservation Society, tells Insider that the eyes make sense as a deterrent. "Great Whites are primarily ambush predators, and so it could be that if they were convinced their prey was observing them, they make look for an easier opportunity elsewhere."