Window on Nature
By Lowell & Kaye Christie, F47246
We live in a world where the word “diet” is associated with eating less to lose weight. But the word diet is never used in this sense when discussing the smallest birds in North America.
A hummingbird must eat half of its weight in food every day. These small birds don’t eat all the time simply because there’s nothing else to do; they eat to stay alive. Hummingbirds have a higher metabolism than any other creature on Earth, with the exception of insects.
Naturally, the biggest energy drain occurs when a hummingbird’s wings beat at maximum speed, which can be as many as 50 to 80 flaps a second. No wonder a hummingbird’s wings are a blur when one zooms by. This is why they gulp down so much food, grabbing every available insect they can find and sipping nectar from hundreds of flowers a day.
Hummingbird expert Crawford H. Greenewalt deserves much of the credit for discovering how hummers fly. Back in the 1950s he came up with a way to capture their wing beats on film. He used a wind tunnel and a video camera that triggered instantly when the hummer crossed a beam of light. This enabled Greenewalt to find out just how a hummingbird flaps it wings and made it possible for him to calculate the wing speed of the tiny birds. (He arrived at roughly 50 times per second.)
Just how fast can a hummer fly? In a dive, as when a male is trying to impress a female, the bird can reach speeds exceeding 60 miles an hour.
It takes a strong heart to survive a pace like that, but the hummingbird is up to the task. Its tiny heart has been clocked at 1,260 beats per minute, with a resting rate of 250 beats per minute. Makes you wonder whether hummingbirds ever have heart attacks.
Early this morning a hummingbird flew by our office window and bumped into the glass, which it seems to do several times a day. Does it want its feeder refilled? Is its eyesight going bad?
Seeing how often these little birds visit a feeder, you might think sugar water is all they consume. Yes, sugar supplies a large part of their diet, but hummers don’t depend upon humans to provide it all. These wee feathered flyers mainly draw sweets from flower nectar and tree sap. They’ll get their necessary protein and other nutrients by downing insects and pollen.
Hummingbirds are designed to find their own food, after all. Their long bills slide easily into tubular flowers for nectar unavailable to larger birds. And in doing so, some of the pollen brushes off the flower and adheres to the bill or the top of the bird’s head. Then, when the bird sticks its bill into a different flower, pollen is deposited, helping to perpetuate the species. Just think of it as the hummingbird’s way of paying the flower for its midday snack.
Now, in the realm of “Can you believe this?” Hummers can even remember the location of a good food source from one year to the next. How do we know? We were accompanying a friendly bird-bander when he captured a previously banded hummingbird. (Visualize the size of the tiny bands.) “Hey, come on over,” he said softly, showing us that the band confirmed his having caught that same bird the previous year in the same location.
Once we had a similar experience when, during an unusual cold spell, Lowell convinced a nesting Anna’s hummingbird to feed from a tiny handheld feeder. The following year she reappeared at our office window and wouldn’t leave until he went out to feed her again.
Since hummingbirds compete for the nectar and insects they need to survive, they establish territories in places rich in tiny bugs and flowers. And they aren’t about to share their turf. We’ve watched a good many hummingbird battles over the years. They don’t need guns or swords to fight; they’re equipped with sharp bills and tiny claws.
One encounter drew our attention when we suddenly saw “” and heard “” two hummers collide. Then, with their claws locked to prevent the other’s escape, they flapped their wings madly while jabbing each other with those long, pointed bills. When one finally gave up, they both stopped, relaxed their wings, and dropped to the nearest branch.
Like all birds, hummingbirds communicate through a range of displays. A male seeking to impress a potential mate raises the brightly colored feathers on his gorget (throat and neck feathers) and pivots his head back and forth and around while uttering the avian equivalent of a mating call. That grabs the female’s attention. The females aren’t that flashy; they simply fan their tail feathers to indicate they see the performance.
Dive displays are strictly a guy thing, but they differ from species to species. One display that we are familiar with begins with the hummingbird at a high altitude. He then dives straight down, levels out near the ground, and then zips back up to his original height. Such displays are delightful to see and to hear. Their wings can produce popping, buzzing, or whistling sounds during the dive. A hummingbird specialist can distinguish the species by the type of display it puts on.
Both sexes perform the next display “” shuttle-flight. One hummer zips back and forth in front of another “” left, right, left, right. We first saw this behavior when camping in southeast Arizona. The shades of our motorhome were pulled up and the curtains parted when a brightly clad hummingbird zoomed into view. He was trying to impress the female perched on a twig just outside our window. He flew sideways about a foot in one direction, then the other; back and forth, back and forth.
It was one of those moments when you wonder whether to pinch yourself to wake up. Hummingbirds often make us feel that way.
For more insights about the natural world around us, visit the Christies’ Web site, www.OurWindowOnNature.com. Here you will find more stories and observations about the birds and butterflies, mountains and deserts, and many of the other outdoor wonders the couple has discovered during their travels.