Table 1. Behavioral responses of crows and ravens during the exchange experiment.

success	exchange	individual took the initial item with the beak and upon request gave it back into the hand of the experimenter
	refuses reward	individual successfully exchanged but refuses to take the reward
failure	refuses initial item	individual refuses to take the initial item
	drop	individual drops initial item but not into the hand of the experimenter
	does not give back	individual does not give back the initial item upon request