Preliminary estimates of bird damage to fruit crops made during 2012 show what fruit growers already know: Fruit production can be for the birds—at least a good part of it.

The estimates were made in the Pacific Northwest, New York, and Michigan as part of a $2 million project funded under the Specialty Crop Research Initiative.

The grant was made to Michigan State University in the fall of 2011. The principle investigator Dr. Catherine Lindell, an associate professor of zoology at MSU, heads a team of 21 researchers across North America who are studying the economic costs of bird damage and consumer responses to potential management techniques. Their ultimate goal is to provide robust information to growers on cost-effective, efficacious bird management strategies that are also environmentally sustainable.

While having a consumer component may seem odd, remember that fruit damage is often caused by birds that are not considered pests—birds like robins, the state bird in three states; cedar waxwings; red-winged blackbirds; even prized game species like Michigan’s and Massachusetts’s newly reestablished wild turkeys. It’s not all starlings, grackles, and crows.

“Fruit loss to birds is a long-standing and costly problem that has received little coordinated attention from researchers, leaving producers with few effective management options,” Lindell said in her report of the first year’s efforts. “U.S. producers lose tens of millions of dollars each year through direct losses and often ineffective efforts to deter birds.”

In addition to outright consumption, birds damage and contaminate fruit, leading to increased susceptibility to other pests and pathogens and reduced product quality.

Studies this year were hampered by low fruit crop production in Michigan and New York, but preliminary data show that birds damage more than 25 percent of the sweet cherries in New York, more than 12 percent in Michigan, and about 3 percent in the Pacific Northwest. For grapes, the percentages were 10 percent for Michigan, about 4 percent for New York, and about 7 percent in the Pacific Northwest.

The attractiveness of those sweet Honeycrisp apples to birds led to their inclusion in the study, where almost 2 percent were damaged by birds in the Pacific Northwest and higher levels suffered damage in Michigan and New York.

“Our goals for the first year were to determine damage levels in four fruit crops across three regions of the country and to assess the best methods of sampling birds to determine the species that cause the most damage and their relative abundance,” said Lindell, who made reports at two horticulture shows in Michigan this winter.

Field studies

The field studies are designed to determine which bird species do damage and differences in damage levels between interiors and edges of blocks. During 546 hours of observation using motion-sensitive video cameras in a Michigan sweet cherry orchard, 58 kinds of birds were detected—including wild turkeys caught jumping in the air to reach cherries on low limbs.

Most sampled blocks in Michigan tart and sweet cherries had no bird management this year because of the very low yields.

For tart cherries, north edges showed nearly 20 percent damage while other edges showed 3 to 7 percent damage. Interiors had about 6 percent damage. Overall damage in the 10 blocks was about 6 percent.

“The results suggest significant damage to sweet cherries from birds and lower levels to tart cherries, although damage on some tart cherry edges is high,” Lindell reported. “The results must be taken within the context of the very low cherry yields this year. We will repeat some of the damage sampling next year to check whether damage levels this year are representative of more typical years.”

“Growers told us that damage was high in 2012 because of the lack of both wild and cultivated fruit,” she said. In an effort to see how well their data conformed to grower experience, 1,590 fruit growers were surveyed and asked to estimate the bird damage levels in their crops. “We were pleased to see that our results and grower opinion matched pretty well,” she said.

Growers surveyed

Growers also report that of all the methods they use to deter birds—including sound and visual scare devices, predator nest boxes, trapping, and chemical repellents—the surest methods were netting the fruit and shooting to kill.

The project includes numerous orchardists in Washington, Oregon, Michigan, and New York, and several organizations.

Fruit farms include Seven Hills Vineyard, Broetje Orchards, Enfield Farms, Sakuma Brothers, Curt Maberry Farm, C & S Orchards, Sugar Shack, New Royal Orchards, Cherry Bay Orchards, King Orchards, Blueberry Ridge, Brookside Farms, Valley View Farms, Standing Stone, Blue Ribbon Packing Company, and Harvest Ridge Vineyards.

Organizations include the Cherry Marketing Institute, the Michigan Grape and Wine Industry Council, the Washington Blueberry Commission, the Michigan Apple Committee, Northwest Cherry Growers, and Washington ­Growers Clearing House Association.

Future project-related work will involve testing of various bird management strategies. Demonstrations are planned for this year.

For more information, go to http://birddamagetofruit