Prediction of avian repellency from chemical structure: The aversiveness of vanillin, vanillyl alcohol, and veratryl alcohol

Abstract

The effectiveness of bird repellents is associated with the presence of an electron-withdrawing group (carbonyl or carboxyl) and an electron-donating group in resonance on a phenyl ring. The present experiments were designed to examine the relative importance of these structural features. European starlings ( Sturnus vulgaris) were presented with vanillin, vanillyl alcohol, and veratryl alcohol in two-cup and one-cup feeding trials and in one-bottle drinking tests. In feeding trials, veratryl alcohol was significantly more aversive than the other two chemicals. In drinking tests, veratryl alcohol was repellent only at the highest concentration (0.5% ml/ml), and was lethal at that concentration and at 0.1 and 0.05% ml/ml. Together, the findings have several implications. From a basic perspective, the data emphasize the importance of electron-donating groups on the phenyl ring of repellent chemicals. From the practical perspective, the data suggest veratryl alcohol as an avian toxicant, and warn against generalization from feeding to drinking tests. We propose that avian repellents must be tailored to the specialized settings in which they are used.