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In late summer, large flocks of blackbirds gather in the northern Great Plains to prepare for their strenuous migration to southern wintering grounds in the United States and Mexico. The birds acquire energy for their trip by feasting on energy-rich seeds and berries. Unfortunately for farmers, many of those seeds come from agricultural crops. Red-winged blackbirds, common grackles, and yellow-headed blackbirds cause most of the damage to commercial crops. Sunflower producers in North Dakota, South Dakota, and Minnesota suffer millions of dollars’ worth of losses annually due to blackbirds.
Reducing blackbird damage to sunflower crops continues to be a challenge for researchers and farmers. Farmers can suffer losses ranging from slight to devastating (total crop loss). Blackbirds tend to eat a portion of the grain in a field, which lowers the overall yield, but their depredation is not often enough to trigger an insurance claim.
Birds that congregate in fields in mid-August are not easily harassed because they are in the process of molting their flight feathers and tend to stay in nearby wetlands. It is these birds that can cause the most damage.