The sweet, ripe fruit of a blueberry bush appeals to a variety of wild birds, including robins, starlings, and cedar waxwings. These birds can quickly strip a bush of its harvest, leading to significant crop loss for the home gardener. Protecting developing berries requires deploying effective and humane control methods. The most successful approach combines strategies that physically exclude, visually deter, and chemically repel birds from your patch.
Establishing Physical Barriers
Exclusion netting is the most reliable method for protecting blueberry bushes, providing a physical barrier that birds cannot breach. Durable, UV-resistant netting materials are recommended for multiple seasons of use. A mesh size of \(3/4\) inch (19 mm) is often sufficient for common birds, but a tighter \(1/2\)-inch mesh is safer if smaller birds like sparrows are present.
Draping the net directly over the bushes is discouraged because birds can peck berries through the mesh, and removal can damage the plants. Instead, constructing a support frame is necessary to keep the netting elevated and taut above the plants. Simple, temporary structures can be built using inexpensive PVC pipe, preventing the netting from resting on the foliage.
The frame must be tall enough to accommodate the mature bushes and allow for easy access during harvesting. Sealing the entire perimeter of the netting is necessary, as birds are adept at finding even the smallest opening. Secure the bottom edges of the net firmly to the ground using sod staples, bricks, or heavy lumber to prevent birds from crawling underneath the barrier.
Utilizing Visual and Motion-Based Distractions
Visual deterrents work by creating an illusion of danger or constant motion, making the area appear unsafe to birds. Reflective materials, such as Mylar flash tape, are effective because the intense, unpredictable flashes of light disorient and startle approaching birds. Hang these items just above the bushes, allowing them to spin and move freely in the breeze for maximum effect.
Predator decoys, such as plastic owls or hawks, exploit the birds’ natural fear response. To be effective, their placement must be rotated every few days, or the birds will quickly realize the stationary figure is not a genuine threat. Some decoys incorporate motion, such as a wind-powered rotating head, which helps delay the habituation process.
The primary limitation of visual and motion-based tactics is that birds rapidly learn to ignore static or predictable threats. These methods are best used in short bursts or as part of a multi-faceted approach, rather than as a standalone solution. Pairing a reflective ribbon with a temporary decoy creates a more complex, confusing environment that is less likely to be dismissed quickly.
Sound and Taste Repellents
Auditory deterrents trigger an innate fear or avoidance response in birds by utilizing sounds they associate with danger. Specialized sound devices can broadcast distress calls of the pest species or the calls of their natural predators. For these sounds to maintain their effectiveness, they must be deployed intermittently and irregularly, as birds will become accustomed to a consistent pattern or volume.
Another effective approach involves applying a taste repellent directly to the fruit, which makes the berries unpalatable without causing harm. The most common active ingredient is methyl anthranilate (MA), a food-grade compound derived from grape extract. MA is an avian aversive agent that birds find extremely distasteful, even in small concentrations.
Commercial applications of MA have been shown to significantly reduce blueberry depredation. Because this compound is biodegradable and dissipates quickly, especially when exposed to sunlight, it requires reapplication. A fresh coat of the repellent must be sprayed onto the bushes after heavy rain or approximately every seven to ten days to maintain a protective concentration.
Maximizing Effectiveness Through Strategic Application
Successful bird control relies on timing and preventing the birds from becoming comfortable. The most common mistake is waiting to deploy deterrents until the berries are blue, which is too late because birds will have already established the location as a food source. All protective measures, particularly netting and taste repellents, should be in place before the fruit begins to show its first blush of color.
To overcome the problem of habituation, a dynamic strategy of rotation and combination is necessary for all non-exclusion methods. If using visual deterrents, switch their type or location frequently, perhaps every three to five days. This prevents the birds from learning that a specific object or sound is harmless, keeping them constantly unsettled.
For netting, proactive maintenance is required throughout the ripening season. Regularly inspect the barrier for tears, gaps, or areas where the net has sagged and contacted the berries, which invites pecking. The integrity of the seal at the base of the frame is important, as a small ground gap allows birds to slip inside the protected area.