Hummingbird Torpor Looks Strange but It’s Totally Normal
Hummingbirds can drop their internal temperature, inducing a temporary state of torpor, which means they need less energy, and therefore less food, to withstand frigid temperatures.
If you spot a motionless hummingbird in an unusual position, don’t be alarmed. Learn what the experts say about hummingbird torpor.
Hummingbirds Enter Torpor to Conserve Energy
“I saw a hummingbird hanging upside down from my feeder by one foot. As I neared, it flew away. What happened to it?” asks Birds & Blooms reader Margaret Hocker of Metropolis Illinois.
Kenn and Kimberly Kaufman: Hummingbirds have a bizarre way of conserving energy. Usually at night, during periods of cold and sometimes when they’re perched at a feeder, hummingbirds can enter a deep, sleep-like state known as torpor, when all body functions slow dramatically. Metabolism slows by as much as 95 percent, and heart rate and body temperature drop significantly. Torpor allows them to conserve precious energy and survive surprisingly low temperatures.
Torpor Helps Hummingbirds Survive in Cold Weather
“Hummingbirds visit my feeders every day, year round. Where do they sleep at night in chilly weather, and how do they survive the cold? asks Kay Teseniar of Kelso, Washington.
Kenn and Kimberly: Hummingbirds often find a twig that’s sheltered from the wind to rest on for the night. Also, in winter they can enter a deep sleep-like state known as torpor. All body functions slow down dramatically; metabolism drops by as much as 95 percent, and heart rate and body temperature decline significantly. In spite of their fragile appearance, they’re tough little critters!
Follow these expert tips to attract hummingbirds in winter.
“This male broad-tailed hummingbird (above) left his more tropical winter home in the south and arrived in Colorado’s Rocky Mountains just in time for a spring snow. Not to worry, they are able to survive freezing temperatures by entering a state of torpor, where their metabolism slows way down to conserve energy during the night. Early in the morning, he was already in position on his favorite perch keeping his eye on the sky to fiercely protect his preferred feeder on our deck. By mid-morning, the sun had melted away, and all was warm and bright. These little birds may be small, but they are mighty!” says Mindy Musick King.
Is it safe to freeze hummingbird nectar?
Hummingbird Hanging Upside Down
“One morning, a female hummingbird landed on the feeder, slowly leaned back and eventually ended up upside down. She ignored the other birds and, after a few minutes, flew away. What causes this behavior?” asks Donna Jenkins of Chesapeake, Virginia.
Kenn and Kimberly: This odd behavior seems to happen because hummingbirds have weak feet and extreme variations in energy levels. Hummingbirds enter torpor (lowered breathing and heart rate) to conserve energy. This usually happens on cold nights, but sometimes they go into a torpid state during the day. When they’re sitting, their feet automatically clamp down, but on a smooth perch, they may slip and wind up hanging upside down. Usually this doesn’t last long and the bird isn’t any worse off when it awakens.
Discover more jaw-dropping hummingbird facts.
Freeze Posture in Birds
“This red-breasted nuthatch didn’t move for at least 10 minutes. Do nuthatches go into torpor, like hummingbirds, or was something else going on?” asks Michele Stark of Grand Blanc, Michigan.
Kenn and Kimberly: What your little nuthatch is doing isn’t torpor. You witnessed a reaction to a predator. We call this “freeze posture,” and it happens when there’s a predator nearby. Even when birds at feeders appear to be completely relaxed, they are on constant alert for predators. When a hawk swoops in, smaller birds have to make a split-second decision—fly for cover or freeze. Often they’ll decide that the best chance for survival is to freeze rather than take their chances in flight against something like sharp-shinned or Cooper’s hawks, which are incredibly fast flyers and masters of aerial maneuvers.