Social learning in common ravens, Corvus corax

We conducted an experiment to investigate whether the presence of a conspecific model can promote the acquisition of a motor task in common ravens. For this purpose, dyads, either of control birds or of model-observer pairings, were allowed to operate together in an arena with a set of identical boxes. Each box consisted of two compartments each containing a reward of three pieces of meat.:The compartments were closed by gliding lids with red flaps on their front, opening horizontally in opposite directions. Naive control individuals opened the lids exclusively by levering, that is, jumping on top of the box, inserting the beak at the posterior rim of the lid and pushing it open. Models were trained to demonstrate an alternative opening technique, pulling at the front flap, then jumping on top of;the box to get at the reward. In contrast to the control birds, observers initially opened boxes both ways, by pulling and levering. Furthermore, observers approached the boxes more quickly and showed less fearful behaviour than the control birds, which we attribute to the enhancing effect of the model. We discuss both stimulus enhancement and motor imitation as possible learning mechanisms. Even though observers initially obtained a considerable amount of reward produced by the models, scrounging evidently did not inhibit learning. (C) 1999 The Association for the Study of Animal Behaviour.