Hazards to animals feeding on blackbirds killed with 4-aminopyridine baits

Red-winged blackbirds (Agelaius phoeniceus) killed by ingesting cracked corn baits treated with 3 percent 4-aminopyridine, or by oral doses of 4-aminopyridine, were fed to canines, laboratory rats (Rattus norvegicus), black-billed magpies (Pica pica), and three species of hawks. The test animals consumed the equivalent of up to 3.4 LD₅₀ doses of 4-aminopyridine in single feedings and up to 3.2 LD₅₀ doses a day for 20 days in repeated feedings. None showed any symptoms of intoxication or gross abnormalities at necropsy.