The "false head" hypothesis states that due to the posterior ventral wing markings of certain butterflies which resemble a "false head," visually hunting predators, such as birds, are deceived into attacking the hind wing area rather than the true head of the butterfly. In the laboratory, six groups of artificially marked dead cabbage butterflies, Pieris rapae, were presented to Blue Jays, Cyanocitta cristata. Of the six "false head" markings, only the eyespot significantly influenced the point of attack. All of the "false head" markings, however, led to a greater proportion of attacks to the hind wing area of the butterfly. In the course of prey handling following an initial attack, each of the six "false head" markings significantly directed predator handling strikes away from the true head of captive butterflies to the anal angle of the hind wing. In a second experiment, live P. rapae with "false head" markings were mishandled and thus escaped, significantly more frequently than controls. Therefore, "false head" markings may confer a selective advantage by increasing the probability of escape, particularly during handling.

The "false head" hypothesis states that due to the posterior ventral wing markings of certain butterflies which resemble a "false head," visually hunting predators, such as birds, are deceived into attacking the hind wing area rather than the true head of the butterfly. In the laboratory, six groups of artificially marked dead cabbage butterflies, Pieris rapae, were presented to Blue Jays, Cyanocitta cristata. Of the six "false head" markings, only the eyespot significantly influenced the point of attack. All of the "false head" markings, however, led to a greater proportion of attacks to the hind wing area of the butterfly. In the course of prey handling following an initial attack, each of the six "false head" markings significantly directed predator handling strikes away from the true head of captive butterflies to the anal angle of the hind wing. In a second experiment, live P. rapae with "false head" markings were mishandled and thus escaped, significantly more frequently than controls. Therefore, "false head" markings may confer a selective advantage by increasing the probability of escape, particularly during handling.

Movement patterns of prey animals may be used by aerial predators to distinguish noxious from palatable, injured and sick from healthy, or difficult to capture from easy to capture prey. This was investigated in the laboratory by presenting Blue Jays with mealworms on a chain and pulley flight pattern simulation device. Palatable prey were presented in one movement pattern, while noxious (quinine-soaked) prey were presented in a second pattern. All birds learned to attack and eat palatable prey and to sit, watch, and avoid noxious prey. The ability to distinguish prey types at a distance by movement patterns may also allow a predator to conserve energy and increase hunting efficiency by attacking only palatable prey that it is highly likely to capture.

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