Each one visits a thousand flowers a day. They can dive at sixty miles an hour. They can fly backwards. They can fly more than five hundred miles without pausing to rest. But when they rest they come close to death: on frigid nights, or when they are starving, they retreat into torpor, their metabolic rate slowing to a fifteenth of their normal sleep rate, their hearts sludging nearly to a halt, barely beating, and if they are not soon warmed, if they do not soon find that which is sweet, their hearts grow cold, and they cease to be. Consider for a moment those hummingbirds who did not open their eyes again today, this very day, in the Americas: bearded helmet-crests and booted racket-tails, violet-tailed sylphs and violet-capped woodnymphs, crimson topazes and purple-crowned fairies, red-tailed comets and amethyst woodstars, rainbow-bearded thornbills and glittering-bellied emeralds, velvet-purple coronets and golden-bellied star-frontlets, fiery-tailed awlbills and Andean hillstars, spatuletails and pufflegs, each the most amazing thing you have never seen, each thunderous wild heart the size of an infant’s fingernail, each mad heart silent, a brilliant music stilled.
Hummingbirds, like all flying birds but more so, have incredible enormous immense ferocious metabolisms. To drive those metabolisms