Ken Ballard, age 8, of Gastonia, North Carolina, for his question:

How can a hummingbird stop himself in mid air?

At this season of the year, the ruby throated hummingbird is around our parks and gardens. The beauteous midget is busy building, a nest or tending to the needs of his growing family. This is a good time to find a leafy corner and watch his amazing antics in the air.

A bitsy bird called the Anna hummingbird lives in Andy's Southern California garden all through the year. His cap and his vest glisten with jewel tone patches of red and he measures less than f6urinches long. Another kind spends the summery months in Gastonia, North Carolina. He is called the ruby throated hummingbird because he wears a bright ruby red bib under his chin. His feathery cap, his back and his sides are shiny emerald green. He has a white vest and there are tiny white.specks behind each of his bright birdie eyes. Lots of his ruby throated relatives spend the summer in our Eastern states.

A hummer can do more tricks in the air than any other bird. For one thing, he can fly backwards. He also can stop himself in mid air and stay right there without falling to the ground. This trick is called hovering. Many birds can soar through the air without flapping their wings. Some may stay in almost the same spot for moments. But only the hummer can stop dead in the air and stay there with no apparent motion at all. He can perform this impossible trick because his wings happen to be fixed onto his shoulders with special joints, and move with incredible speed.

You have bondable joints in your bones so that you can move your arms and legs. But the joints are not all alike. Your elbow joint is somewhat like the hinge on a door. You can move it back and forth, so far and no farther. The joint in your shoulder can move back and forth, up and down and around and around. Your shoulder joint lets you swivel your arm around in circles. Flying birds can flap and beat their wings back and forth, The little hummer can move his wings in such a way that he can do all sort of acrobatics denied to other birds. Like a helicopter, but much more gracefully, he can hover in mid air and even move straight up or straight down to the ground.

Maybe you have never noticed the wings of the clever little hummingbird. They are, of course, very small. What's more, when in the air he beats them too fast for the human eye to see. They look like fuzzy blurs. He whirls them around and around  about 60 to 70 times a second. All we see is a misty fuzz    but the speedy whirling makes a whirring hum in the air    and that is why the busy little flier is called a hummingbird.

The hummer is a bold, sassy little character and as  a rule he does not mind letting you watch him. But he tends to stay around longer if you stay still and very quiet. From the tip of his long beak to the tip of his stubby tail, he can measure as little as two or as much as four inches. He weighs about as much as a copper penny. His nest looks like half a walnut shell lined with soft bits of fluff and neatly padded on the outside with bits of moss. The nest is made to hold two tiny white eggs. When the bare baby bummers hatch, the two of them can fit nicely into half a teaspoon.