Foraging innovation in an artificial environment: a case of little egret luring prey goldfish through beak dipping: supplementary material

Behavioural innovations play an important role in animal ecology and evolution. We report a case of little egret using its beak dips as a tool to lure and catch prey goldfish in an artificial environment designed to test predator-prey behavioural foraging games. The egret mimicked the food pellets falling into the pool from a mechanical feeder that fed the goldfish at regular intervals. The falling pellets created ripples in the water that acted as a cue for the prey goldfish to come out of the cover and feed on the floating pellets. The egret learned this phenomenon through time and used its beak dips to create ripples and attract the prey outside. The egret preferably used the location of the feeder in the pool to carry out its beak dipping attempts and maximize its fish capture success. The egret attempted this behaviour more in the largest cover that provided the best refuge to the prey goldfish. The egret beak dipping attempts to lure the prey goldfish out of the cover declined through experimental time as well as with increasing prey kills. As the beak dipping behaviour did not result in a high capture rate of fish, the egret subsequently reduced its attempts through time. This case study illustrates that foraging innovations can occur through learning in laboratory conditions containing a novel but artificial environment.