A bluejay (also written blue jay) is a fairly large, noisy bird of eastern and central North America, with bright blue wings and back, a white face and chest, and a pointed crest on its head. It belongs with the jays: clever, loud birds that shout and scold. People in the US and Canada know it well; it visits gardens and steals peanuts. It is not a Taiwan bird, and it is not just “any bird that is blue.” In writing you will see both bluejay and blue jay; the two-word form is very common. Neutral, everyday English when you are talking about nature in North America.