The Bluejay (Cyanocitta cristata) is actually grey but light refraction causes the light to make it appear blue – the distortion is actually caused by the specific structure of their feathers. It can be aggressive and will raid other birds' nests, steal eggs, young birds, and even the nests. It is bright blue on top and whitish grey on the belly and chin. It has a grey-blue, feather crested head which they can raise and lower – the crest may be fully raise if it feels aggressive or excited or if it is frightened their crest will bristle outward kind of brush like. The blue jay's "Jay! Jay!" call is only one of a wide variety of sounds the bird employs — including excellent imitations of several hawk calls. It is pictured in southern Canada and in the United States where it is common.