Growing Magazine - August, 2014

FEATURES

Bird Control

What's right for your operation?
By Tamara Scully


"Bird Gard is species-specific and only affects the target birds," said Rick Willis, marketing manager.
PHOTO COURTESY OF RICK WILLIS, BIRD GARD. CROW PHOTO BY ANAGRAMM/THINKSTOCK.COM.

Between the stealing and direct damage to crops, and the health concerns caused by their droppings, birds can cause damage in one way or another in just about any agricultural operation," said Rick Willis, marketing manager for Bird Gard. "Soft fruits, like grapes, cherries and blueberries, can suffer 30 to 50 percent crop loss. Damage to sweet corn can run $1,500 per acre or more. A single crow in an almond, pistachio or pecan orchard will destroy as much as a pound and a half of nuts per day."

In order to choose the best approach to controlling problem birds, you need to assess your particular situation, understand bird behavior, and explore different control strategies.

Bird behavior

Birds aren't all the same. Some are migratory and may simply be passing through, while others reside on the farm for at least a season or two. Some are sedentary and resist being uprooted from their territory, while others are highly mobile once nesting is completed. Preference in nesting and roosting environments, response to bird control methods, and distance traveled to forage for food differ between species.

Environmental factors also play a role in bird damage. When insect populations are high or other noncrop feeding alternatives are available, damage may be minimal or very localized.

Blackbirds, European starlings, robins, cedar waxwings, crows, ravens, magpies, house finches, house sparrows and common grackles are some of the bird pests plaguing growers, depending on crop and location. Properly identifying the birds of concern on your farm is essential for implementing control strategies. Conducting regular bird counts and noting signs of damage can help you plan and track the effectiveness of any bird control methods.

Willis said, "In soft fruits, the most common pest birds are starlings, robins and cedar waxwings. In apple and nut orchards, the biggest culprits are crows, ravens and magpies. Leafy greens are affected by many different species."

Regardless of species, birds do share some common traits. Breaking birds of established feeding patterns is difficult. Crops near roosting or nesting areas, woodlands or ponds are more vulnerable than those in the open. Birds often follow the same flight patterns to feed, and feeding is most common in the early morning and at sunset. Birds like to drink water while feeding, and they tend to be opportunistic feeders. They readily acclimate to uniform movement or noise. Feeding birds attract more feeding birds. Small flocks are harder to scare than large ones.



Bird Gard units can be positioned around the perimeter of the field, rather than covering every square foot.
PHOTO COURTESY OF RICK WILLIS, BIRD GARD.

"Once the nuisance birds have established a field as a feeding ground, and they have risen in numbers, it is much more difficult to eradicate them," said Justin Robertson of Advanced Avian Abatement. "An established flock is also more inviting to migrating birds."

Strategies for prevention

Use general as well as species-specific information to develop a bird mitigation strategy tailored to your needs. Ideally, bird control strategies would begin before crops are planted. Fields that are isolated, near the woods or a water source, and in the path of migratory flight patterns are most susceptible. Power lines often have suitable bird habitat, making nearby fields susceptible to damage.

When choosing cultivars, be mindful that birds often target early-ripening as well as sweeter varieties. Early-ripening cherries and grapes are typically under increased bird pressure, possibly due to a lack of other food crops at that time in the season. Early-ripening apples, as well as varieties that ripen later but turn red first, are more susceptible than other cultivars.



Using falcons for bird control may add value to the crop, since they are considered a "green" method and can also be seen as consumer-friendly.
PHOTO COURTESY OF JUSTIN ROBERTSON, ADVANCED AVIAN ABATEMENT.

"Recently, we have been hearing from growers complaining that birds were stealing blossoms to get at the sweet nectar inside and preventing the fruit from even forming," Willis said. "Crows and geese are notorious for pulling shoots out of the ground as soon as they emerge."

Depending on the crop, damage will occur just as it is coloring, softening or sweetening. Controlling birds before they find the crop is the key to success.

"The period of time a falconer usually flies a single cultivar of cherries, for instance, is four to six weeks, veraison through to harvest. A falconer is on-site all day, seven days per week. It is most effective to establish a presence with the trained raptors just prior to the start of ripening. This way, the nuisance bird problem can be stopped before it even starts," Robertson explained.

Discourage birds from nesting near fields by planting in an environment less suitable for supporting bird populations or using scaring equipment. Mowing down weeds and grasses and keeping the field and perimeters free from seeds that may attract birds can help. In some cases, a plot of sacrificial, readily available, alternative food, timed to lure birds away from the ripening cash crop, may be helpful.

"For low crops, such as berries and grapes, the elimination of trees around and inside the blocks helps to keep the birds out. Small birds, such as starlings, robins and cedar waxwings, need the seclusion of trees to stage their raids. If there are no trees around, they must fly further and are less likely to cause as much damage," Willis said.

Implementing bird control

Many growers may suffer minimal bird damage and opt not to incur the cost of mitigation programs, accepting any loss as part of the business. At some point, however, the cost of prevention will be minimal compared to the cost of crop damage if the birds remain uncontrolled.



This vineyard in Oregon's Willamette Valley is using Bird Gard for bird control.
PHOTO COURTESY OF RICK WILLIS, BIRD GARD.

"Every situation is different. General cost/benefit assessments can be made using simple equations, including average prices of fruit, ton per acre, and estimated bird damage in any one particular field," Robertson said.

The Bird Damage Project is an ongoing, multistate field research project on the impact of bird damage in blueberries, cherries, wine grapes and Honeycrisp apples. The purpose is to identify which birds are fruit pests, the best way to control the damage, and to determine if control methods influence consumer buying behaviors. Researchers in various regions of the U.S. are participating in this multiyear study, which is coordinated through Michigan State University.

Researchers looked at preliminary data from the studies to find the bird damage patterns in various crops. Crop damage was found to be greater on field perimeters than in the interior. Damage rates varied across crops and states. Researchers are also studying the efficacy of various control techniques and devices.



Justin Robertson of Advanced Avian Abatement.
PHOTOS COURTESY OF JUSTIN ROBERTSON, ADVANCED AVIAN ABATEMENT.

Types of control

Combining bird control methods is the most effective approach; select those tailored to your problem species and crop. It's crucial to get control strategies in place before birds are established in the area. Once they taste the crop, all methods become less effective.

  • Exclusionary: Prevents birds from accessing crops. This can be accomplished by netting the crop directly or by building an enclosure of netting, typically by erecting a "roof" over the top of the crop. Netting can also be strategically placed in the field, perhaps in outer rows, to reduce costs.
  • Noise deterrents: Crop cannons, electronic scarers, pyrotechnic pistols, etc. Crop cannons emit a loud bang as a scare method. Birds, however, can become accustomed to the noise, and eventually it can signal that food is available. Pyrotechnic pistols emit a whistling sound and are used to deter flocks of birds from landing in the crop area. Neighbors and domestic or farm animals can be disturbed, particularly by cannons and pistols. Some products may require a federal license to use, and may also fall under state and local regulations. Randomizing the noise interval, as well as moving the equipment weekly, can increase effectiveness. Electronic scarers can emit random noises or mimic distinct distress calls.
  • Visual deterrents: Flash tapes, scare-eye balloons, kites, flashing lights, mirrors, and replicas of hawks, owls or snakes. These can be species-specific, such as using flashing lights to deter starlings or yellow flash tape for blackbirds. Kites in the shape of predators can be filled with helium or put on flexible stakes and moved throughout the season. Combining stationary predator models with noise emitters can have an additive effect. Small windmills with reflective tape are also available.
  • Chemical repellents: These are applied to the crop to make them unpalatable to birds. A variety of food-grade sprays, either naturally occurring or synthetic, have been found to deter some birds. Fogging is another possibility.
  • Predators: Using trained falcons to deter birds or encouraging natural predator populations of hawks, kestrels and owls.
  • Shooting: Lethal bird control is possible, but take protected species and safety issues into consideration. When using a firearm to kill birds, you're required to follow federal, state and local regulations. In addition, you may need to obtain a wildlife nuisance and damage permit.
  • Trapping: Bird species are typically protected by federal law, so permits must be obtained and regulations followed. Older birds tend to avoid traps. Trapped birds typically must be released unharmed.

Field size can affect the degree of protection a control method provides. Some methods are effective when placed only in perimeter rows, while others must be placed throughout the field. The radius of effectiveness varies by method and product.



The presence of raptors keeps flocks of pest birds migrating.

"On crops of several hundred acres, it is extremely positive to position the Bird Gard units around the perimeter of the crops. This creates a sonic wall the birds will not cross, and does not require that every square foot of crop is covered," Willis explained.

Some tactics target species indiscriminately, while others target nuisance birds without affecting beneficial birds. Attracting predator birds can be a bonus when using certain methods.

"Bird Gard is species-specific and only affects the target birds. Beneficial birds, such as flycatchers and larks, are not affected," Willis noted. "Hawks, falcons, eagles and other raptors are not bothered, and they are actually attracted to the sounds of distressed birds. We also incorporate the sound made by raptors in the area to convince the target bird they are under attack. The raptors in the area hear our recordings and presumably believe there are other 'unauthorized' raptors in their territory. This causes them to circle overhead, which helps keep the pest birds out too."



Bird damage to cherries.
PHOTOS COURTESY OF RICK WILLIS, BIRD GARD.

Falconry

While devices such as Bird Gard can mimic the presence of predator birds and potentially attract them, using live predator birds is another control method. Robert Payne, founder of Advanced Avian Abatement, advocates the use of trained falcons, particularly for high-value crops.

The use of trained falcons can attract wild raptors in the area; it's essential to keep the two populations separate.



Bird Gard being used in a blueberry crop in Washington.

"Wild raptors are present everywhere we fly. Trained raptors are not just released on the land," Robertson said. "A falconer is with the birds at all times to help focus their presence on the problem area of crops."

Falcons are a relatively new control technique for agricultural crops, at least in the U.S. Training and caring for the falcons is a year-round endeavor. Falconers must also transport the birds to remote locations, providing housing for the falcons, as well as themselves, while on the job.

According to Robertson, the cost of a falconer is about $600 per day. This method eliminates the need for other equipment and infrastructure, such as netting, and eliminates the labor involved in using other control methods. It may also add value to the crop, since falcons are considered a "green" way to control pest birds and can be seen as consumer-friendly as well, he said.

"The benefits of the service are huge, and if done correctly [it's] very effective," Robertson said. "With falconry abatement, bird damage can be reduced to less than 1 percent. If the grower was experiencing anything over 4 or 5 percent damage, having a falconer present can save them thousands of dollars. Generally, one falconer with three to five birds can cover 40 to 100 acres effectively."



An American robin stealing a cherry.

Robertson added, "Falconry abatement is also a green alternative to using firearms, traps and poisons. It's nature, a natural solution to nuisance birds. There is an ever-increasing demand for green production when it comes to people's dinner tables."

Tailoring the wide variety of bird control options to fit your crop, the bird species and your budget can be the difference between success and the crop literally going to the birds. l

Tamara Scully is a freelance contributor based in New Jersey. Comment or question? Visit http://www.farmingforumsite.com and join in the discussions.