U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

October 2004


Published by Proc. 16th International Sunflower Conference, Fargo, ND


Crop damage attributed to foraging red-winged blackbirds continues to be a problem in localized areas of the United States. Therefore, new methods that are both environmentally and public friendly need to be developed for repelling blackbirds. One such method that is more humane and less hazardous than the chemical control is the use of aerial lines to repel birds. The purpose of this study was to evaluate the effect of aerial lines on the reproductive effort of nesting red-winged blackbirds and to determine the spacing, type, and size of aerial lines that are most effective. Maximum likelihood estimates for the probability of daily nest survival were obtained for 6 experimental groups: (1) sham, (2) control, (3) 15-cm spaced monofilament, (4) 30-cm spaced monofilament, (5) 15-cm spaced FireLine, and (6) 30-cm spaced FireLine. Three models were created for the data collected. Of the models, only one was significantly different (Model 1) from the others (Model 2 and 3), and for this reason we can conclude that aerial lines (0.878) have an significantly different probability of daily nest survival then the controls (0.931). Because the other two models (Model 2 and 3) did not differ fiom one another, we concluded there seems to be no difference between line spacing and no decision could be made on line type.