Hummingbirds are tiny dynamos that expend so much energy that they survive on sugar-filled nectar. Of all animals, only certain insects have a higher metabolism. And hummingbirds can live for years. So how do they deal with cold weather in winter, when there's no blooming flowers to provide nectar?
In cold weather, hummingbird bodies enter into an "energy-conservation mode called torpor," according to Oregon State ecologist Adam Hadley. Birds that stay north for the winter experience a nightly "mini-hibernation," in which their 107-degree body temperatures can plummet to 48 degrees.
Heart rates also slow during torpor: The blue-throated hummingbird’s heart rate, for instance, drops from 1,260 beats per minute to 50 to 180 beats.
Hummingbirds can feed in chilly weather. Hadley has seen an Anna’s hummingbird visit his backyard bird feeder during a 28-degree day.
In fact, hummingbirds can use their torpor mode at night in warm weather, just to conserve energy for the next day. Read a lot more about hummingbirds at National Geographic. -via the Presurfer
(Image credit: Marcial4)