Blueberries are a highly sought-after crop, prized for their sweet flavor and nutritional benefits. The ripening process attracts hungry birds, which can quickly decimate a bush and consume berries before they are fully mature. Protecting a blueberry patch requires proactive steps and an understanding of bird behavior. This guide details practical methods to secure your berries from avian competitors.
Physical Exclusion Methods
The most reliable method for protecting blueberries involves establishing a physical barrier between the fruit and the birds. Exclusion netting, often made from durable, UV-resistant high-density polyethylene (HDPE) or polypropylene (PP), is the primary material for this defense. Nets with a mesh size of approximately 3/4 inch (20mm) are sufficient to block most birds while still permitting beneficial pollinators to access any remaining flowers. Smaller mesh sizes, down to 1/4 inch, can be used if birds are reaching through the net to poke at the fruit.
Simply draping the netting over the bushes is common, but this allows birds to press against the mesh and reach berries near the surface. It can also lead to birds becoming tangled. A far more effective solution is constructing a rigid support system, often called a fruit cage or aviary. Frames are typically built using materials like PVC piping, wooden posts, or metal conduit to keep the net elevated above the foliage.
For taller highbush varieties, the supporting structure should be tall enough to allow for easy harvesting and prevent the netting from touching the plants. Posts should be set securely into the ground, spaced widely, and connected at the top to create a sturdy perimeter. This cage design ensures the netting remains taut and fully separates the birds from the fruit, offering complete crop protection.
Visual and Auditory Deterrents
While physical netting offers the best protection, visual and auditory deterrents can be used as supplementary measures or for temporary defense. Visual deterrents exploit a bird’s keen eyesight and sensitivity to light and erratic movement. Holographic flash tape, a highly reflective, iridescent film, is a popular tool that flutters and shines in the breeze.
Birds possess tetrachromatic vision, meaning they can perceive ultraviolet (UV) light, which makes the flashes from the tape particularly disruptive and disorienting. The tape works by creating a visual distraction zone that mimics motion and instability, signaling danger to foraging birds. For maximum effectiveness, the tape should be installed under tension so that it shimmers and vibrates, amplifying the visual and subtle auditory effect.
Auditory deterrents, such as electronic devices that broadcast predator calls or avian distress signals, can also be employed to frighten birds away. However, both visual and auditory methods share a significant limitation: birds are highly intelligent and adapt quickly to non-threatening stimuli. Once birds recognize that the flashing tape or repeated sounds pose no actual danger, they will often ignore the deterrent and return to feeding. These scare tactics are less reliable than physical exclusion and are best used in conjunction with other methods or only for short periods.
Strategic Deployment and Maintenance
The success of any protection strategy depends heavily on precise timing and thorough installation. Protection must be deployed before the blueberries begin to change color, which is the point birds become attracted to the ripening fruit. Applying netting or setting up deterrents while the berries are still green ensures birds do not establish a feeding pattern before the crop is vulnerable. Waiting until the berries are already blue often means birds have discovered the patch, making exclusion more difficult.
Ensuring complete coverage is critical, especially when using netting. Any gaps or openings, particularly where the net meets the ground, can be exploited by birds. The netting must be secured tightly to the frame and anchored at the base, often by burying the edges or using stakes to prevent entry. This thorough sealing prevents avian access from below and secures the barrier against strong winds.
If visual and auditory deterrents are used, habituation must be actively prevented through regular maintenance. Moving flash tape, decoys, or sonic devices to new locations every few days is necessary to maintain the illusion of a dynamic threat. Regular inspection of physical barriers is also important to repair small tears or holes that could allow birds to enter or damage the fruit.