News Release

How Eurasian jays respond to illusions

Peer-Reviewed Publication

Proceedings of the National Academy of Sciences

Eurasian jay making a choice

image: Eurasian jay making a choice after having observed a sleight-of-hand illusion. view more 

Credit: Elias Garcia-Pelegrin.

A study examines Eurasian jays' reactions to illusions. To protect food from potential pilferers, large-brained birds, such as corvids, often manipulate food items within their beak in a manner reminiscent of sleight-of-hand techniques used by magicians. Elias Garcia-Pelegrin and colleagues examined whether sleight-of-hand illusions could deceive Eurasian jays. The authors trained six jays to peck at a fist to retrieve an edible reward hidden inside. During each experimental session, a reward was shown to the jay with one hand and either transferred to the opposite hand or retained in the same hand. If the jay pecked at the fist holding the reward, the jay was allowed to consume the reward. Jays observed three illusionary techniques: palming, which involves concealing an object in the palm; the French drop, which involves mimicking the grab of an object from one hand to the other; and the fast pass, which involves passing an object from one hand to the other quickly enough so that the transfer is unnoticed. Eighty human participants recruited online also observed the illusions via recorded videos. The authors report that jays were significantly less likely than humans to be deceived by French drops and palming, but both groups were equally deceived by fast passes. The findings suggest that humans and Eurasian jays are susceptible to illusions using fast movements, but jays are more influenced by observable motions than expected motions, according to the authors.

Article #20-26106: "Exploring the perceptual inabilities of Eurasian jays (Garrulus glandarius) using magic effects," by Elias Garcia-Pelegrin, Alexandra K. Schnell, Clive Wilkins, and Nicola S. Clayton.

MEDIA CONTACT: Elias Garcia-Pelegrin, University of Cambridge, UNITED KINGDOM; email:


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