Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
Cherries, blueberries and some grape varieties are susceptible to bird damage. Cherry season is over for this year; however, blueberry harvest is under way and grapes will be harvested later this summer. Netting is effective, particularly in grapes where it can be mechanically applied. However it can be expensive in dwarf cherries and blueberries where structures will be needed to support the nets.
The following are some other methods to consider in managing birds in fruit crops:
Methyl anthranilate – this product is chemically similar to the major flavor component of Concord grapes, and is manufactured in large quantities by food processors. Birds are repelled by its taste, and it is regarded as safe for human consumption. There are many bird repellent products available containing this chemical. It needs to be applied multiple times during the season.
Sugar – Applications of sucrose sugar syrup have been shown to repel birds from blueberry plantings. Many bird species cannot digest disaccharides. The sugar is applied when the fruits begin to turn blue, and reapplied after episodes of rain.
Audio scare devices – Devices such as “Bird-Gard” with digitized, species specific bird distress calls can be effective. There are several types available with different species recorded such as crows, robins and starlings that sound every minute during daylight hours. Other types use calls of birds of prey such as hawks or owls.
Visual scare devices – Reflective tapes, balloons, waving air man devices, predatory bird models, and other visual devices can help to scare birds but may not work as stand-alone methods for long periods.