Decoy plantings for reducing blackbird damage to nearby commercial sunflower fields |
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| Institution: | 1. Urika Pathology, Mukilteo, WA 98275 USA;2. Zoo/Exotic Pathology Service, 6020 Rutland Drive #14, Carmichael, CA 95608, USA;3. Department of Animal Science, Michigan State University, 474 South Shaw Lane, East Lansing, MI 48824, USA;4. Abt Associates, 1881 Ninth St., Ste 201, Boulder, CO 80302-5148, USA;5. USDA WS National Wildlife Research Center, P.O. Box 6099, Mississippi State University, Starkville, MS 39762, USA;6. DWH NRDAR Field Office, USFWS, 341 Greeno Road North, Suite A, Fairhope, AL 36532, USA;7. USDA WS National Wildlife Research Center, Fort Collins, CO 80521 USA;1. URIKA, LLC. Mukilteo, WA, USA;2. Veterinary Information Network, Davis, CA, USA;3. Abt Associates, Boulder, CO, USA;4. USDA/APHIS/Wildlife Services/National Wildlife Research Center, Mississippi Field Station Center, Mississippi State, MS, USA;5. US Fish and Wildlife Service, Deepwater Horizon NRDAR Field Office, Fairhope, AL, USA;6. USDA/APHIS/Wildlife Services/National Wildlife Research Center, Mississippi Field Station Center, Fort Collins, CO, USA;7. Michigan State University, East Lansing, MI, USA;8. Zoo/Exotic Pathology Service, Carmichael, CA, USA;1. Agricultural Ecology Laboratory, Forest and Wildlife Research Center, Mississippi State University, Box 9690, Mississippi State, MS 39762, USA;2. Carnivore Ecology Laboratory, Forest and Wildlife Research Center, Mississippi State University, Box 9690, Mississippi State, MS 39762, USA;3. United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Sandusky, OH 44870, USA;4. Warnell School of Forestry and Natural Resources, Savannah River Ecology Lab, University of Georgia, Athens, GA 30602, USA;1. Department of Agriculture, Nutrition, and Veterinary Sciences, University of Nevada, Reno, United States;2. Abt Associates, United States;3. US Department of Agriculture, APHIS/Wildlife Services’ National Wildlife Research Center, MS, United States;4. Department of Animal Science, Michigan State University, East Lansing, MI, United States;5. US Department of Agriculture, APHIS/Wildlife Services, National Wildlife Research Center, Fort Collins, CO, United States;1. Department of Radiology, NYU Langone Medical Center, New York, New York;2. Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia |
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| Abstract: | Field tests were conducted in North Dakota in August, September and October 1981 to 1983 inclusive, to determine if decoy plantings of nine sunflower fields and one interplanted corn/sunflower field would reduce blackbird (Icterinae) damage to nearby commercial sunflower fields. Total seed consumption by blackbirds of sunflower (90 ha) and corn (7 ha) was 87860 kg, worth US$26533·72 based on the average 3-year market price of $0·302/kg. The average cost of planting a decoy field was $74/ha for a total cost of $7178. The yearly cost-benefit ratio varied from 1:2 · 1 to 1:4·7 with an overall study average of 1:3·7. From 1981 to 1983, the annual median seed consumption in decoy fields was 917, 1210, and 1121 kg/ha compared with surrounding commercial fields within 11 km of the decoy fields which had losses of 4,99 and 115 kg/ha, respectively. In 1981, a comparison of losses between sunflower fields in Bottineau County and commercial sunflower fields within 11 km of decoy fields provided statistical evidence (P =0·0651) that there was less damage to commercial fields surrounding the decoy crops; this difference in losses was attributed to the presence of the decoy fields. Average blackbird numbers observed entering decoy fields per minute per hectare were 69 (1981), 49 (1982) and 91 (1983). Peak roost populations associated with decoy fields ranged from 72000 to 215000 blackbirds. Overall, redwings constituted about 83% of all blackbirds observed in decoy fields. |
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