NONLETHAL BIRD REPELLENTS - IN SEARCH OF A GENERAL-MODEL RELATING REPELLENCY AND CHEMICAL-STRUCTURE

Identification of potential repellents through molecular modeling has implications for the development of commercially viable, ecologically sound, nonlethal bird repellents. We tested isomers (ortho, meta, para) and moieties (amino, hydroxy, methoxy) of acetophenones for their effectiveness as bird repellents to better understand the nature of repellency in birds. Chemically, basicity of a substituted phenyl ring, as defined by the electron-donating substituent, probably is an important feature influencing repellency; i.e., more basic substituents result in more potent repellents. Isomeric position of the electron-donating substituent, which leads to resonance of lone pairs of electrons, is also an important feature of repellency; i.e., repellency is enhanced when electron-donating substituents are in the ortho and para positions. An ancillary contributory factor enhancing repellency is the presence of intramolecular hydrogen bonds. Combining these features improves repellency. Thus, the most potent repellent, ortho-aminoacetophenone (OAAP), effective at concentrations less-than-or-equal-to 0.0003 vol/vol, is the most basic of the series tested. It has the amino group in the ortho position which enables this group to form a hydrogen bond with the carbonyl electron-withdrawing group.