Preventing Birds on Cherry Trees
Birds are much more of a problem on sweet cherries than on tarts. Clear yellow-fruited varieties may escape much bird damage because birds can't pick them out easily unless the cherries develop red spots from worm infestation or injury. Yellow-red types will be attacked as soon as the red blush begins to show. Birds cause the greatest amount of damage to early ripening varieties but are less destructive to the latest ripening, when more food sources are available.
Distracting objects, such as white strips of cloth and aluminum pie plates hung in the trees, will scare most birds away from tart cherries, but they don't work as well for sweet cherries. You can also throw a spool of black thread through alt the branches in a tart cherry tree: the birds don't like to get their feet entangled, and stay away. Nylon mesh netting can be draped over dwarf trees and secured beneath the lowest branches.
Unfortunately, mature standard-size sweet cherries are too big to cover with netting. Growing mulberries nearby can protect sweet cherries if the mulberries start ripening before the cherries and continue producing fruit throughout the cherry ripening season. Plant a seedling (female) mulberry that ripens early. Do not plant 'Illinois Everbearing' mulberry (the best-tasting to humans) because it ripens too late. The fruit are too big for many birds, and it ripens over the entire summer rather than yielding a large crop just before cherry season. If there's no room for a mulberry tree, noisemaking devices and repellent sprays may work, though commercial growers find that the birds get used to them after awhile.