Reducing bird repellent application rates by the addition of sensory stimuli

Red-winged Blackbirds ( Agelaius phoeniceus ) cause substantial damage to a variety of crops throughout North America. Nonlethal methods for controlling damage are generally ineffective, and environmental and cost concerns have limited the availability of chemical repellents such as methiocarb. One means of potentially lowering the effective application rate of methiocarb and similar aversive compounds is by combining the treatment with sensory cues. We tested groups ( n = 4) of male Red-winged Blackbirds in a series of 4-day feeding trials using brown rice treated with 0.025% (g/g) methiocarb, five times less than the previously established effective bird repellent rate. Each methiocarb treatment suppressed rice consumption, whether the repellent was alone or combined with a visual (red dye) and/or volatile (methylpyrazine) cue. When rice treated with just the sensory cues was subsequently presented, the red dye, but not the methylpyrazine, continued to deter feeding on rice. These results show that post...