Evaluating Bird Repellents
The basic objective for using repellents, be they mechanical or chemical, is to change the behavior of the targeted species. In general, the mechanics of the process are known, and have often been extensively studied, but less is understood about the response of the targeted species from exposure to the stimulant. When a stimulant is introduced into an operational environment in which a targeted species is to be studied, the goal becomes one of measuring the effect the stimulus has on the species. In controlled environments, such as cages or enclosures, the stimulant's effect on the targeted species can be carefully monitored, recorded and repeated. In natural environments the evaluation process is not as straight-forward because of the multitude of external factors impacting on the evaluation protocol. The objective of the research design, then, is to quantify the effect of these variables, exclude them from the equation, or account for their presence or absence. Current methods used for evaluating bird repellents are grossly inadequate particularly when evaluating imitation products. In general they rely on visual sightings developed to derive population estimates, sizes or densities, and to track changes and establish baseline information, all of which have little or no bearing on the immediate effect of changing the behavior of the targeted species in response to the stimulant. The paper will present alternative, supportable evaluation strategies and techniques
