Nature: Hummingbirds: Magic in the Air

As the most diminutive warm-blooded mammals on Earth, trochilidae, or hummingbirds, have few competitors in terms of speed, with wings that beat an average of 200 times per second. This extraordinary rapidity enables them to perform spectacular feats virtually unknown to any other species of bird, including hovering, flying backwards, and, incredibly, flying upside down. Hummingbirds' metabolisms are also remarkable: the creatures must consume virtually half of their body weight in nectar every day, and even at this rate, the birds continually risk nighttime starvation; a survival mechanism compensates by lowering the body temperature of each at night, and reducing the heartbeat from a diurnal 600 beats per minute to a nocturnal 36. This episode of PBS's NATURE series uses special cameras, capable of photographing 500 frames per second, to slow the hummingbirds down and reveal much about the mechanics of their day-to-day behavior -- including not simply nectar gathering, but vicious predatory behavior and mating rituals.