Bird repellents: development of avian-specific tear gases for resolution of human–wildlife conflicts

The use of bird repellents may be required when human activities place birds in danger, e.g., hazardous waste sites, or when birds cause damage to crops, architectural structures, or are a source of zoonotic disease. Typical protective measures to keep birds away from areas include exclusion by use of netting, hazing (i.e., scaring tactics) and chemical repellents. Birds can rapidly habituate to visual and auditory hazing if the use of these tactics falls into a predictable pattern, or if the sign stimuli are not coupled with a salient aversive reinforcing stimulus. Chemical repellents are typically used to render a resource unpalatable and, as a consequence, create a disincentive for a bird to visit a particular area. Methyl anthranilate (MA) is a potent avian chemosensory irritant. In this paper, we explore the possibility of employing MA aerosols as a bird deterrent strategy. We determine the behavioral response of starlings (Sturnus vulgaris) to each of three aerosols: water or yucca extract (controls) and ReJeX-iT TP-40TM (a 40% MA solution), and found that starlings were irritated by exposure to the MA aerosol. Moreover, starlings did not habituate to repeated exposure to MA aerosols. We determined in the laboratory that the starlings threshold for irritation to a formulated aerosol was 8% MA.