Cattail Management Symposium
Magnitude and Potential Solutions of Blackbird-Sunflower Problem
Louis E. Huffman
Animal Damage Control
Bismarck, ND
North Dakota Sunflower growers account for approximately 69% of the sunflowers grown in the United States. In North Dakota, most of the sunflower crop is produced in the area of the state that provides favorable conditions for local blackbirds estimated at 2.8 million breeding pairs. This area also corresponds to the late summer migration path of an estimated 30 to 50 million blackbirds.
Ripening sunflower fields provide an excellent high energy food source for migrating flocks of blackbirds. Dense stands of cattails growing in prairie pot hole wetlands offer water, loafing, and roosting habitat that all combine to make an ideal situation for south bound blackbirds.
The U.S. Congress made money available beginning in 1986 for a hazing program to provide sunflower farmers with assistance to reduce blackbird caused sunflower damage. Hazing is conducted with supercub type aircraft and a crew of pilot and observer/gunner. Persistent low-level flying near the bird flocks with shooting as reinforcement, is used to move damaging blackbirds out of problem areas. Eleven aircraft logged 2483 hours hazing blackbirds in 23 ND counties from August 12, 1991, through October 4, 1991. During 1991, 800 requests were received from sunflower growers, the most requests since hazing began in 1986.
A total of 12,912 hours have been flown during 6 years of hazing blackbirds in response to 3,882 grower requests. Sunflower damage recorded for the first 5 years of hazing was estimated at $10.1 million.
Avitrol on cracked corn was distributed 2 years, 1986 and 1990. Avitrol was not used in 1991 and no future use is planned. Scientific data does not support Avitrol as a viable tool for controlling sunflower damage.
Frightening devices, including pyrotechnics and propane exploders to a lesser extent, were provided to farmers outside the hazing area in 1990 and 1991.
Until the blackbirds are ready to fly south, the primary benefit of hazing and other frightening methods may be that damage is spread across a broader area.
With the realization that something else is needed that will have a longer term benefit, USDA/DWRC began cattail management research in 1989. Subsequently, Congress directed money in 1991 for a pilot cattail management project. The goal of cattail management is to remove a percentage of cattails from heavily infested wetlands to reduce the potential for formation of large concentrations of blackbirds, thereby reducing sunflower damage.
Cattail management began in 1991 using DWRC research data for glyphosate (Rodeo) application rate (2.5 qt/A), optimum time for application (August), and recommended percentage of cattail reduction (70%).
For the first year operational project 905 acres were aerially treated in North Dakota and 152 acres in South Dakota.
The cattail management effort is viewed as an operational demonstration project to help research to find if cattail management is an environmentally safe and biologically prudent method for reducing sunflower damage.
Initial plans for 1992 are to treat marshes in North and South Dakota that were identified in 1991 as roost sites holding more than 5,000 birds.
Approximately 2500 acres of dense cattail stands will be aerially sprayed in the operational demonstration project, and 500 acres will be treated in cooperation with the research project being conducted by Dr. George Linz.
Cooperation and communication between agencies and organizations that have a state in North Dakota wetlands is imperative to the success of cattail management.
We should bear in mind that there is no single technique or method that will provide an answer. If cattail management is successful, it will continue to be necessary to maintain alternative techniques that will provide integrated sunflower damage management.
With this in mind, hopefully cattail management can move forward while maintaining hazing at a reduced level, continuing to utilize other frightenting tools, and working toward developing an effective avicide registration.
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