Proceedings of the Vertebrate Pest Conference

Blackbirds in Ohio and other areas of the Midwest have diets of which 90% is composed of soft seeds, primarily the milk and dough stages of corn, during the late summer and early fall. Presently, economic loss of $15 million bird depredation to crops is estimated for Ohio, while other states report similar losses. Increasing losses, primarily to redwing blackbirds, were noted by farmers following World War II. Formal studies of this growing problem were initiated in 1957, with work focusing on poisoning blackbirds, testing scaring devices, trials of bird-resistant crop varieties, and studies of the basic biology of blackbirds. Studies on bird movement and nesting revealed that the largest number of locally raised redwings were produced in alfalfa fields: 5 times as many nests per acre than in cattail marshes. Roost surveys indicated an explosion in the redwing population. Among corn farmers in norther Ohio, organizations emerged to press for increased research and assistance to combat the growing losses. As a result, better loss assessment estimates were achieved, educational efforts were increased, and federal assistance is now more readily available.