Along with chimps, orangutans, elephants, and dolphins, some birds are smart enough to recognize themselves in the mirror. We're naturally inclined to think of mammals as the creatures most likely to have a developed sense of self, but it turns out that magpies are also quite self-aware. How do you know when an animal recognizes itself in the mirror? You need some way to tell whether an animal thinks a mirror image is another animal, or whether the animal recognizes itself. Researchers get at this problem by marking the animal in some way and watching how it behaves. In this case, a group of German researchers stuck a yellow sticker on the bird, in a place where the bird would only notice the sticker when looking in a mirror:
Image from Prior, et. al, PLoS Biology 6(8): e202
The test birds, seeing the sticker in the mirror image, frequently started searching their own bodies for the mark - a sign that these birds knew they were looking at an image of themselves. These results add to the evidence that, like some mammals, certain bird species have brains that can carry out more complex cognitive functions. Most animals don't have much use for the kind of self-awareness exhibited in this mirror test. But self-awareness can be useful, the German researchers argue: in the social environment of these birds, more self-aware individuals might be better at using past experience to predict the behavior of other birds in their social group.