Gardening Articles: Edibles :: Vegetables
When Birds are Pests (page 2 of 3)
by Michael E. Trunko
A whimsical scarecrow is fun, but only a modestly effective bird deterrent.
A benign deterrent is planting alternate food sources, such as mulberries or wild cherries, to lure birds away from your garden. Other approaches to bird problems require more sophisticated products and procedures.
"There are hundreds of products on the market that promise to protect your garden from birds," says Jack Wagner of Birdbusters, a supplier of bird deterrents in Washington, DC. "They include electronic sound devices, reflective tape, bird wire, inflatable owls, netting and balloons, just to mention a few. But many factors -- including the season, region, crop, the amount of money you're willing to spend, and the amount of time you're able to devote to your bird-control program -- need to be considered. And it's important to identify the species invading your garden -- you'll need different control measures for crows than for sparrows."
There are three kinds of bird-control techniques: scare devices, physical barriers and chemical repellents. I don't recommend the use of chemicals in home gardens, so I focus here on the first two.
Scare devices range from homemade deterrents to high-tech electronic repellers. They can work extremely well or hardly at all, depending on the methods used and the feeding pressure on the birds. The location of the device is important: Effective mounting sites are unobstructed places, about one to three feet above the plants. "The key to making a scare tactic useful is its element of surprise," Wagner explains. "Frequently change the device's location, elevation and frequency. Otherwise, it simply becomes part of the landscape's sights and sounds."
"A single scare device might initially provide good levels of bird control," says Zemsky. "For a superior and long-lasting scaring effect, however, choose products with differing scare techniques and position them in such a way that they effectively complement each other."
Visual devices, which run the gamut from toy pinwheels to aluminum pie plates suspended from strings to vinyl balloons, could be used along with a sound-generating device, for example. Brightly colored reflective ribbon (or surveyor's tape) can be effective. String rolls of the ribbon from pole to pole across a garden, twisting the strands to show off both sides. On sunny, windy days, the ribbon produces a low roaring noise as it undulates and flashes the sun's reflection, scaring by both sight and sound.
Scare-eye balloons, 18 to 24 inches in diameter and with a large eye to imitate a predator, are effective for flocking birds such as starlings, blackbirds and cedar waxwings. To make the balloons scarier, dangle long strips of silver and red reflective ribbon from them. Four or five balloons per acre are usually enough, but you should move them around frequently.
"One year we lost an entire corn crop to birds," says Billie Sees of Copley, Ohio. "We tried to chase them away, and even used a noisemaking device, but nothing worked." The following season, Sees purchased three scare-eye balloons and hung them at various locations in the garden. "The balloons worked! We had a great harvest, and no bird damage."
"Some newer sound repellers are species specific," Zemsky says. Sound devices are loud and disturb people in the area, however, so take your neighbors' proximity into consideration when choosing an acoustical scarer.
Though some bird-control devices seem to be high-tech, it's important to remember that limiting bird damage in your garden is not an exact science.
To increase the effectiveness of your scare tactics:
- Use a variety of products.
- Relocate scare devices every one to three days, changing them in the evening so the scene is new in the morning.
- Change the duration of their use and the time of day they are used.
- When the devices aren't in use, hide them to keep the birds from getting accustomed to them.
Physical barriers are anything placed between your garden and the birds. For example, if crows eat your seeds, lay chicken wire on top of the newly planted seedbed. When seedlings appear, raise the wire slightly by using boards or bricks to keep it above the tops of the plants. As the seedlings continue to grow, keep raising the wire, removing it when the plants are no longer vulnerable. Chicken wire also works well for protecting strawberries. You will need to make a boxlike enclosure. Use rods along the sides and through the top of the chicken wire for support. Be sure to leave no openings.
Other barriers include inverted crates or disposable cups (with the bottoms cut out) placed over seedlings. Or, cut out a 12- by 12-inch square of window screen cloth and staple it together to form a cone-shaped cover to place over your plants. An approach similar to the ribbon strategy involves stringing fishing line or wire across your garden or bushes.
"More and more growers -- from backyard gardeners to large operations -- are using netting," says Vincent de Bellis, a winegrower in Tenino, Washington. "Properly installed netting is 99 to 100 percent effective."
During the last few years, de Bellis lost between 50 and 90 percent of each harvest. All of his previous bird-control attempts failed. As a result, he installed a netting system that covers his entire growing area. Now, he has virtually no bird damage.
Netting, however, can sometimes be impractical. It can snag or tear on twigs or thorns, which often causes broken plants. One solution is to build an inexpensive framework or cage that completely covers the bushes or plants. Then buy a net that reaches to the ground on all sides. If wind blows the netting around, anchor it into the ground with bent wire.