Designer repellents: combining olfactory, visual or taste cues with a secondary repellent to deter free-ranging house sparrows from feeding

BACKGROUND: Repellents may prevent bird pests from eating crops or protect non-target birds from eating harmful substances. The feeding behaviour of free-ranging house sparrows (Passer domesticus) presented with wheat treated with the secondary repellent anthraquinone (AQ), paired with visual and/or olfactory and taste cues, was recorded in a series of trials. The aim was to determine the suitability of repellent combinations for preventing birds from consuming pest baits. RESULTS: Anthraquinone significantly reduced wheat consumption. The addition of cinnamon oil did not reduce consumption further, but the addition of either a blue colour or d-pulegone enhanced repellency. Green wheat was consumed more than blue wheat. In a multichoice test, the sparrows did not differentiate between low and high concentrations of AQ on blue-dyed wheat. With treatments on separate tables, the higher concentration was more repellent. Additional olfactory/gustatory cues palatable to pest mammals did not make the AQ-treated wheat more or less acceptable to sparrows. AQ-treated blue wheat with/without cinnamon oil was more repellent than green wheat with cinnamon oil, a colour/odour combination typically used for pest baits in New Zealand. CONCLUSIONS: These data demonstrate the potential of combining the secondary repellent AQ with additional salient cues for modifying the feeding behaviour of sparrows. Copyright (C) 2011 Society of Chemical Industry