Interaction Between Sensory and Postingestional Repellents in Starlings: Methyl Anthranilate and Sucrose

Ingestion of concentrated sucrose solutions causes sickness in sucrase-deficient birds. As a result, some suggest that sucrose may represent an environmentally safe avian repellent. In the present experiments, we compared the repellency of sucrose to that of methyl anthranilate (MA), a known avian repellent. We also tested mixtures of sucrose and MA to investigate whether repellency could be enhanced, relative to sucrose or MA presented alone. The results showed that the MA was strongly avoided in both drinking and feeding trials. Conversely, only high sucrose concentrations were avoided, and only in drinking trials. No combination of MA and sucrose was as effective as MA alone. We conclude that sucrose is not sufficiently aversive to serve as an avian repellent in the field.