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Location
Ithaca, New York
Start Date
6-10-1991 12:00 AM
Description
Under a Special Local Needs (Section 24[c]) registration, the effectiveness of a 2% DRC-1339-treated brown rice baiting program to reduce bird damage to sprouting rice was evaluated during 1989 and 1990 at the Millers Lake blackbird roost, Evangeline Parish, Louisiana. After prebaiting with untreated rice, treated bait diluted with untreated rice at a ratio of 1:50 or 1:25 in 1989, and 1:10 in 1990, was applied at a rate of 112 kg/ha at sites strategically located under blackbird flightlines. Total treated bait mixtures applied to these sites were 3,487 kg in 1989 and 3,071 kg in 1990, of which an estimated 70% was consumed by primarily red-winged blackbirds (Agelaius phoeniceus) and brown-headed cowbirds (Molothrus ater) each year. Based on bait consumption data, blackbird kills were roughly estimated between 1.3 and 2.7 million birds annually. Following these baiting programs, roosting populations prior to the time of rice planting during both years were the lowest ever recorded for this roost (6 previous years without baiting). Compared with baseline data from 2 previous years, roadside censuses within an 8-km radius of the roost also indicated significant reductions in foraging blackbirds during the bird damage period of both baiting years. Questionnaires were sent to rice growers within a 16-km radius of the roost each year, asking them to compare sprouting rice damage at their farms in 1989 and 1990 with that during the 1986, 1987, and 1988 baseline years. An analysis of the responses indicated an estimated average reduction in losses of 81 and 85% in 1989 and 1990, respectively. No detectable impact on nontarget bird populations was observed during these baiting programs and more recent detailed hazard studies of these appear to confirm these observations. Based on grower estimates of costs of bird damage with and without baiting, and the estimated costs of these programs, we conclude that these baiting programs are cost-effective for reducing bird damage to sprouting rice.
Recommended Citation
Glahn, J. F., & Wilson, E. A. (1991). Effectiveness of DRC-1339 baiting for reducing blackbird damage to sprouting rice. In Curtis, P. D., Fargione, M. J., & Caslick, J. E. (Eds.), The Fifth Eastern Wildlife Damage Control Conference (pp. 117-123). Ithaca, NY: Cornell University.
Included in
Effectiveness of DRC-1339 Baiting for Reducing Blackbird Damage to Sprouting Rice
Ithaca, New York
Under a Special Local Needs (Section 24[c]) registration, the effectiveness of a 2% DRC-1339-treated brown rice baiting program to reduce bird damage to sprouting rice was evaluated during 1989 and 1990 at the Millers Lake blackbird roost, Evangeline Parish, Louisiana. After prebaiting with untreated rice, treated bait diluted with untreated rice at a ratio of 1:50 or 1:25 in 1989, and 1:10 in 1990, was applied at a rate of 112 kg/ha at sites strategically located under blackbird flightlines. Total treated bait mixtures applied to these sites were 3,487 kg in 1989 and 3,071 kg in 1990, of which an estimated 70% was consumed by primarily red-winged blackbirds (Agelaius phoeniceus) and brown-headed cowbirds (Molothrus ater) each year. Based on bait consumption data, blackbird kills were roughly estimated between 1.3 and 2.7 million birds annually. Following these baiting programs, roosting populations prior to the time of rice planting during both years were the lowest ever recorded for this roost (6 previous years without baiting). Compared with baseline data from 2 previous years, roadside censuses within an 8-km radius of the roost also indicated significant reductions in foraging blackbirds during the bird damage period of both baiting years. Questionnaires were sent to rice growers within a 16-km radius of the roost each year, asking them to compare sprouting rice damage at their farms in 1989 and 1990 with that during the 1986, 1987, and 1988 baseline years. An analysis of the responses indicated an estimated average reduction in losses of 81 and 85% in 1989 and 1990, respectively. No detectable impact on nontarget bird populations was observed during these baiting programs and more recent detailed hazard studies of these appear to confirm these observations. Based on grower estimates of costs of bird damage with and without baiting, and the estimated costs of these programs, we conclude that these baiting programs are cost-effective for reducing bird damage to sprouting rice.