COMPARISON OF D-PULEGONE AND MANGONE AS COWBIRD FEEDING REPELLENTS

We compared the effectiveness of d-pulegone and mangone as feeding rep ellents to captive adult male brown-headed cowbirds (Molothrus ater Bo ddaert) during October-November 1995. For each repellent, we conducted 4-day, one-and two-choice cage tests using concentrations (w/w) of 0. 1%, 0.10%, and 0.001% with millet. During one-and two-choice tests, 0. 1% d-pulegone( reduced (P<0.01) cowbird feeding but lower concentratio ns did not. In contrast, concentrations of mangone as low as 0.001% re duced (P<0.05) food consumption during two-choice tests. Consumption o f mangone-treated millet, however, was similar (P>0.05) among one-choi ce tests and similar to total food consumption observed during two-cho ice tests. We conclude that mangone is less effective than d-pulegone and would be likely to be ineffective as a repellent for seed treatmen t. We recommend field tests to further assess the effectiveness of d-p ulegone or comparable isomers as avian feeding repellents.