A joint research program was initiated in 1979 to investigate the potential avian repellency and toxicity of 55 selected insect repellents originating from or related to naturally occurring chemicals. Seven of the chemicals or extracts tested exhibited avian repellency and two of these were considered to be moderately active, with R50’s (analogous to LD50) of 0.237 (trans‐asarone) and 0.240% (safrole). None of the 55 chemicals or extracts exhibited acute oral toxicity at 100 mg/kg or less to the red‐winged blackbird (Agelaius phoeniceus).