The hummingbird is a bird of the Americas alone, and it carried its greatest weight of meaning among the peoples of Mexico and the Andes. The supreme god of the Mexica (Aztecs), Huitzilopochtli, the god of the sun and of war who led his people to their promised land, bears a name meaning the hummingbird of the south, or the left-handed hummingbird, and warriors who died in battle or on the sacrificial stone were believed to be reborn as hummingbirds and butterflies, accompanying the sun across the sky. The tiny, brilliant, fierce and tireless bird was thus bound to the sun, to war and to the honoured dead.
The hummingbird's biology is extreme enough to rival its mythology: its heart can beat well over a thousand times a minute in flight, and to survive the energy cost each night many species enter torpor, a controlled, dramatic drop in metabolic rate and body temperature that can slow the heart to under fifty beats a minute, without which the bird would starve to death overnight given how little fuel its tiny body can store. It is also the only bird capable of sustained hovering and true backward flight, achieved by rotating its wings in a figure-eight rather than the simple up-and-down stroke of other birds.