Bird control in the field is much like getting your hair cut, changing the oil in your car, and cutting your grass, according to University of Georgia Professor Michael Mengak.
“There’s no such thing as one and done. This is not an event. Wildlife damage management is a process that goes on over and over and over again,” Mengak, a Wildlife Specialist with the Warnell School of Forestry and Natural Resources, says. “There’s no such thing as magic bullets or magic powder or any magic at all. It’s hard, hard work, and it’s going to be expensive.”
Unfortunately, complacency can be costly, too.
Although numbers are typically difficult to pin down, according to Mengak, he notes one 2013 study that concluded that bird damage to four crops over five states in one season totaled $189 million.
Specific to blueberries, a 100% crop loss with unnetted ‘Bluecrop’ plants could potentially result in $7,223 lost per acre, Mengak says. With ‘Tifblue’, a 60% crop loss with unnetted bushes could result in $8,668 lost per acre.
Considering those amounts of annual loss, the issue turns to the feasibility of a large up-front expense of a long-term solution, such as netting for birds and fencing for other animals.
“It can be justified in terms of these losses, but it’s not a simple economic decision to invest, perhaps, tens of thousands of dollars in a fence,” Mengak says. “Sometimes we can’t incur that large of an economic outlay up front, and we have to apply less expensive and perhaps more temporary methods.”
In any case, bird control requires diligence and perseverance, Mengak says. “There are going to be a lot of frustrations and failures along the way,” he notes, “but there are ways that we can improve our chances of success.”
Steps to Mitigate
Frequent winged pests include starlings, robins, blackbirds, crows, ravens, blue jays, mockingbirds, and wax wings, according to Mengak and David Lockwood, a Fruit and Nut Crops Extension Specialist with the University of Tennessee. Modes of bird control include:
Habitat Modification: Isolated plantings and smaller blocks are more vulnerable because they allow birds to concentrate their damage. Instead, plants fare better when nearer to other blocks and orchards. “It’s an odd way of thinking about things, but if you spread the damage around, then no one producer or one field or one crop or one plant has the majority of the loss,” Mengak says.
That said, losses, in general, are never spread evenly among different growers, Mengak says.
“Sometimes one producer suffers the majority of the loss, and the producer down the street suffers nothing. And the next year it may be reversed,” he says. “We don’t know why this happens, so we have to be vigilant with this and work on a long-term scale.”
Habitats that are near areas where birds can hide, roost or rest before they eat, such as power lines and tree snags, may increase damage; ditto for nearby woodlands and brushy fields. Mengak recommends removing isolated trees while avoiding power lines and established bird habitats when launching a planting.
Visual Scare Devices: Anything that moves ― streamers, spinners, aluminum pans ― will deter birds, Mengak says, but not for long. “Birds are not dumb. They get used to it very quickly,” he says. “Moving things around, changing the scare tactic is better. Of course, that requires time and energy on the producer’s part. Combining such devices is better than using one alone.”
Auditory scare devices: Legal shooting, pyrotechnics, carbide cannons, and distress calls can effectively repel by scaring or disorienting birds, Mengak says. “They have to be applied when the birds are coming to the area to feed, so maybe in the evening. Pyrotechnic cannons can be put on timers that go off at regular intervals.” Meanwhile, game birds that are regularly shot at, such as turkeys, are less susceptible to loud noises, he adds. Smaller birds that come in flocks are more susceptible to these loud noises.
Methyl Anthranilate: This derivative of ‘Concord’ grapes is sold as a taste repellent for birds. Golf courses use it to deter geese. At $100 per gallon, it is “kind of expensive,” Mengak says, “but it may be a short-term alternative in some situations. It irritates (the birds’) sense of taste.”
Netting: Although expensive, netting may be the most effective control practice, Mengak says, ranging from individual row coverage to total field enclosure. “Depending on the type of crop and format of harvesting, you may put them over the crop right before harvest. I’ve seen that done in vineyards,” Mengak says. “It’s an expensive up-front investment, but if done properly and applied, removed after the season is over, and stored properly, it can be used for several years, so the cost can be spread out over time.”