カササギ
The Eurasian magpie is believed not only to be among the most intelligent of birds but among the most intelligent of all animals. Along with the western jackdaw, the Eurasian magpie's nidopallium is approximately the same relative size as those in chimpanzees and humans and significantly larger than the gibbons. Like other corvids, such as ravens and crows, their total brain-to-body mass ratio is equal to most great apes and cetaceans. A 2004 review suggests that the intelligence of the corvid family to which the Eurasian magpie belongs is equivalent to that of the great apes (chimpanzees, orangutans and gorillas) in terms of social cognition, causal reasoning, flexibility, imagination and prospection.