For centuries, researchers thought that self-recognition was limited to a few primates, elephants, bottlenose dolphins, and orca whales. But there's a new animal in town...with feathers. German psychologist Helmut Prior and his colleagues added European magpies to the exclusive list of animals with advanced cognitive abilities after a 2008 study published in the journal PLOS Biology.
They performed the classic mirror-mark test by sticking colored dots onto the birds' necks, placing them outside of their line of vision. The magpies didn't react to the dots when they couldn't see them, but they started to scratch at them once placed in front of a mirror. The birds with black dots, however, had zero reaction. That means the birds recognize their reflections as themselves and not another animal. From this research, we now know that self-recognition isn't limited to mammals (and more recently, ants). Pretty cool, huh?