Jimmy and his family spent spring vacation in Arizona visiting his grandparents. It was their first trip out there, and everything looked new and strange. There were huge cactus plants all over the place, and all kinds of weird rock formations.
Everything looked different from Jimmy's home in Pennsylvania. So he wasn't too surprised when he spotted the biggest bug he had ever seen buzzing around a desert flower."Look at that huge bug," he said to his grandfather.
"That's not an insect; that's a hummingbird," his grandfather said. "It moves its wings so fast that they're just a blur."
Jimmy had heard of hummingbirds, but he'd never seen one around his yard in the city. "Are there hummingbirds where I live?" he asked.
Jimmy's grandfather didn't know that much about hummingbirds. So they decided to go to the library to find out more. They looked in bird books and nature magazines for articles about hummingbirds. Here's what they discovered:
Hummingbirds are among the smallest warm-blooded animals in the world and are the smallest birds. They have the largest brains for their body size of all birds. They feed on nectar from flowers, using their long, slender beaks to sip the liquid from deep inside blossoms. They also eat a few bugs to get protein and other nutrients.
Hummingbirds have to drink a lot of nectar to keep their little bodies going. A hummingbird may visit 2,000 flowers a day. When there are plenty of flowers to go around, the tiny birds live peacefully with each other. But when flowers are scarce, they take part in spectacular air battles. Hummingbird fights are common around feeders, where the food source is concentrated in one place.
During a battle over a feeding territory, one hummingbird will chatter and buzz another one, dive-bombing out of the sky to try to drive a rival away from a flower. But even though the fights look dangerous, they're mostly for show. The birds don't actually peck each other, or even touch. Biologist Lynn Carpenter of the University of California, Irvine, has studied hummingbird behavior for 11 years, and she has seen only one fight in which two hummingbirds actually bumped into each other.
Biologist Lynn Carpenter and her colleague Mark Hixon, a zoologist at he University of Oregon, figured out a method for weighing hummingbirds. They invented a sensitive electronic perch that weighs the birds when they land on it.
The scientists studied hummingbirds during migration from the Pacific Northwest to Mexico. It's a tough journey for the tiny birds. To make the trip successfully, they need enough fat in their bodies to give them the energy for long daily flights.
Carpenter and Hixon found out that the hummingbirds seem to know just when they're fat enough to start. Using their electronic perch, the researchers found that the birds take off when they weigh about 4.6 grams (about what a nickel weighs!). The birds also time their departure so that they catch favorable weather patterns. With a good tail wind, the hummingbirds can fly 500 miles on one leg of the trip. When they stop to rest and recuperate, they weigh about 3.3 grams.
Backyard biologists have noticed that hummingbirds like brightly colored flowers. Research scientists have observed this, too. Hummingbirds see the same color range that humans do and are attracted by the color red. That's why most feeders that you can buy for your backyard come in red. You can make your feeder even more attractive to the birds by attaching some red paper to it.
Jimmy and his grandfather looked at a hummingbird range map in a field guide to birds. A range map shows where particular species of animals and birds can be found. They discovered that Jimmy might spot ruby-throated hummingbirds on the East Coast of the United States.
"I'm going to try to see a hummingbird back home," Jimmy said. "I'm going to set up a feeding station in our yard."
Backyard feeders that contain sugar water have actually played an important role in maintaining hummingbird populations in some places, Carpenter says. The feeders have increased the total amount of energy available to the little birds. When Jimmy sets up his feeding station, he'll be helping maintain the East Coast hummingbird population.
-TIPS FOR PARENTS:
Hummingbird expert Lynn Carpenter, professor of ecology and evolutionary biology at the University of California, Irvine, provides some tips for a successful feeding station.
-- Place the feeder away from the ground and away from large plate-glass windows that the hummingbirds may try to fly through.
-- Do not use honey or brown sugar as food. Both can cause fungal infections in hummingbirds. Use a mixture of one part table sugar to four parts water, a solution that closely approximates natural nectar from flowers. Higher concentrations make hummingbirds thirsty. You don't need to add the nutrients that commercial food contains. Hummingbirds get their vitamins and protein from the insects they feed on.
- Change the food when it gets cloudy.
- If one hummingbird establishes a territory and dominates your feeder - which is natural and should be expected - establish other territories with feeders in other places in the yard.
-Do you wonder about your body, your feelings, or how things work in the world around you? Send your questions to Catherine O'Neill, HOW & WHY, Universal Press Syndicate, 4900 Main St., Kansas City, Mo. 64112.