It takes a truly philanthropic spirit to grow apple trees strictly to feed the birds. Several strategies may be needed to prevent this kind of unintended generosity. Homemade strategies share the element of surprise. Startling, confusing and redirecting your avian apple-eaters can be achieved with simple materials and small expense, leaving your planned harvest intact for your enjoyment.
Use the natural sensitivity to motion common to all species of birds to deflect them from apple trees. Reflective objects hung from tree branches will move in the breeze, sending light signals that warn birds away. Among easy household choices are aluminum pie pans or other disposable containers, old CDs and DVDs, and Mylar-printed gift-wrap and ribbon. Hang reflective objects with fishing line from tree branches, or tie strips of reflective ribbon, old gift bags and even old Mylar balloons to tall bamboo stakes around trees. One ambitious bird-battler even suggests wrapping trees in the fishing line itself; it will catch light and confuse birds about whether they have spotted a tree or something else. You may also have found a final use for tired Christmas balls and limp tinsel garlands.
Add sound effects to keep birds away. Hang pie pans in pairs, so the breeze will make them clink together. Dig out old Christmas decorations or mine local craft stores for inexpensive bells and other noise-makers that can be hung on fishing line from branches and activated by the wind. If it rattles, clacks or chimes, it will scare birds away.
Post predators to defend your trees. Most birds fear larger ones. Inexpensive inflatable owls or other raptors can be attached to tree branches or hung from bamboo poles. Both their shape and what smaller birds know about those larger birds' aggressive real-life qualities will help keep birds away from trees.
Install motion detectors to outside lights near apple trees. Birds often start and end their days at dawn and dusk, when there is little enough light to trigger motion-detector lights. A sudden startling flash will send birds back into the air and away from your apple trees.
Use water to scare birds. While you cannot spend every day in the yard defending your tree, a sudden blast from the garden hose or the periodic use of a sprinkler aimed high through your tree branches deters hungry birds. Consider programming sprinklers to go off close to your tree for more surprises.
Attract birds away from fruit trees. Redirect attention with bird feeders and plantings whose berries and seeds are bird favorites. Sunflowers, rudbeckias, coneflowers and barberry also attract birds away from fruit trees.
Deter insects that may draw birds to your trees as much as your apples do. The bugs, fruit worms and other insects attracted by your growing fruit may be attracting birds as well. Whether you clean your tree of insects periodically with blasts from the hose or consider chemical pesticides is a personal decision, but you may lessen the interest of birds in your fruit by taking measures to control apple-loving insects.