Vertebrate Pest Conference Proceedings collection


Date of this Version

February 1994


The California wild rice (Zizania aquatica) industry considers red-winged blackbirds (Agelaius phoeniceus) their most important pest problem. Farmers often have asked if crop-damaging blackbirds can be killed by mixing dry Portland cement or plaster-of-Paris with grain bait. We conducted a series of tests to determine the effect of cement or plaster mixed with wild rice fed to captive redwings and to determine feeding preferences of redwings for wild rice in relation to other grains. Birds would not eat cement- or plaster-treated rice when untreated rice was available and no mortality occurred when birds were offered only treated rice over a four-day period. Thus, treating grain with cement or plaster will not kill redwings but cement or plaster might serve as useful bird repellents for seed grain. Proso millet was strongly preferred over wild rice by redwings, indicating millet would be an excellent candidate as a lure crop and as a bait for trapping or for delivering a chemical. Sunflower would perhaps not be a preferred bait or lure crop in wild rice areas and cracked corn would not be a preferred bait.