Wildlife Damage Management, Internet Center for


Date of this Version

November 1976


Goodhue and Baumgartner (1965) described a chemical, 4-aminopyridine (hereafter referred to as "4-AP"), that causes certain flocking birds [e.g., Red-winged Blackbirds (Agelaius phoeniceus), Grackles (Quiscalus guiscula), House Sparrows (passer domesticus), and Starlings (stnrnus vulgaris)] ingesting it to act before death in a manner (squawking, erratic flight, tremors, convulsions) that repels other birds. The 4-AP was found to be effective as a treatment on cracked corn when applied to the ground in cornfields at the rate of 1 lb per acre [1.1 kg per ha (De Grazio, et al., 1972; Stickley, et al., 1972)] and 1.3 lb per acre [1.4 kg per ha (Stickley, et al., 1976)] in the ratio of 1 treated particle for 99 untreated ones. As a result, 4-AP was registered for use on field corn by Avitrol, Inc. in April 1972 as Avitrol FC Corn Chops-99 at 1 lb per acre and at a ratio of 1 treated to 99 untreated particles. (This formulation applied at this rate and in this ratio is hereafter referred to as "FC-99.") Since its registration in 1972, FC-99 has been used by some Ohio farmers to protect their field corn from bird damage. But dissatisfaction with the effectiveness of FC-99 has grown; some farmers claim that fields treated with FC-99 receive as much bird damage as untreated fields. Thus, we conducted a survey of field-corn fields in north-central Ohio in September 1975 to re-evaluate the efficacy of FC-99 as a bird repellent. The survey was conducted in three areas containing most of the FC-99-treated fields in north-central Ohio (Fig. 1). These areas, Sandusky, Ottawa, and Lucas Counties, have a history of heavy blackbird damage.