The term 'Swift Flightless Bird' is a reference to the RHEA, a large flightless bird native to South America. It is also known as the Grey, Common, or American RHEA. The RHEA is related to the ostrich and emu, and is the largest bird in the Americas. It is swift on its feet and can run up to 43 miles per hour. It is also an excellent swimmer. The RHEA is a herbivore, feeding mainly on grasses, leaves, and fruit.