"bluebird"的定义和意义

What is a "bluebird"?

A bluebird is a small, colorful passerine bird found throughout North America. They are well-known for their bright blue plumage on their upper parts, contrasting with their rusty or pale underparts. Bluebirds are often found in open woodlands, meadows, and grasslands, feeding mainly on insects and berries. They have a cheerful song that is a delight to hear in the springtime when they are most vocal. Bluebirds are cavity nesters and often use old woodpecker holes or nest boxes to raise their young.