Threat assessment by domestic ducklings using visual signals: implications for animal-machine interactions.

There are increasing opportunities for robots to work amongst animals in agricultural systems. One potential application is in herding animals prior to catching or transportation. An effective herding robot must be able to interrupt ongoing animal behaviour without causing panic or flight reactions. The extent to which different approaching stimuli interrupted the feeding behaviour of pairs of domestic ducklings was examined to assess their suitability as herding stimuli. Experiment 1 assessed the responses of ducklings to an approaching human (the most likely current herding stimulus), a vertical cylinder (a stimulus with the minimum features of a simple robot) and a model fox (simulating the more natural features of a predator). Interruption of feeding was greatest in response to the human and least to the cylinder. Experiment 2 found no significant difference in the extent to which feeding was interrupted when facial appearance and head orientation of the model fox were manipulated. Experiment 3 examined whether biologically realistic features of the model fox affected duckling response. At a distance of 7 m, photographs of the model fox interrupted feeding behaviour as much as the model itself. However, at a distance of 1 m, the model fox caused significantly more feeding interruption than an intact photograph. A fragmented photograph caused the least interruption of feeding behaviour.