OBSERVATIONAL LEARNING BY FORK-TAILED FLYCATCHERS (MUSCIVORA-TYRANNUS)

Summaryo1.Fork-tailed flycatchers, Muscivora tyrannus, were tested to see if they would avoid on first presentation and on the two succeeding presentations a distasteful aposematic butterfly, Heliconius erato2.If a bird did avoid altogether the three butterflies, it was placed with a conspecific 'trainer' bird which either, in the case of the experimental group, ate two imperfect mimics of Heliconius (Anartia amalthea) or, in the case of the controls, ignored the two presentations of the mimic in the presence of the observer bird.3.The observer birds, control and experimental, were removed from the trainer bird's cage and isolated visually from the trainer at which time they were presented with the imperfect mimic, Anartia amalthea. The experimental birds were significantly more likely to attack the mimic butterfly than was the control group4.It thus appears that fork-tailed flycatchers are capable of learning that aposematic prey they might otherwise avoid is edible, if they observe a companion bird eating that prey.5.That they can act on their observation in the absence of the bird they had watched shows that, in order for observational learning to occur, it need not be directly dependent on some form of social facilitation. © 1969.