Wayne Halicki, age 13, of Willowdale, Toronto, Ont., Canada, for his question:

HOW HIGH CAN BIRDS FLY?

This is not an easy question to answer because human observers are not likely to be around when birds make their altitude records. Since the birds themselves do not divulge this information, we can form only tentative conclusions, based on a few spot checks, taken here and there.

Scientists hesitate to give a definite answer because so far they have devised no provable experiments. All we have to go on are scraps of data from reliable observers who happen to be in the right place at the right time. For example, mountain climbers report that flocks of geese and perhaps other migrating birds regularly fly over the highest peaks of the Himalayas  gossiping as they go. Considering that the air at these five mile altitudes is too thin for humans, this is remarkable.

However, based on other information it well may be true So far as we know from our scanty information, the champion altitude flier of the bird world is most likely one of the choughs. These clownish characters are crow size relatives of the ravens, jackdaws and sassy blue jays. And they have a positive passion for peaks and lofty heights, where they perform fantastic aerial acrobatics.

The yellow billed Alpine chough of Europe romps through life with a flock of 20 or so friends and relatives. Often these sky rocketing daredevils use a rising air current to ascend to five miles or more above sea level.

From this awesome altitude, the frolicking flock begins to play. Some seem to play dead, fold their wings and plummet like stones down dizzy precipices. Some descend with a series of somersaults and other impossible aerial antics. However, the reckless tumbles always end safely a few feet above the ground. After the fun, they return lazily aloft, perhaps breaking another altitude record before the next swoop down.

The Alpine chough has a cousin who lives, wouldn't you know, right there among the high Himalayas. He is known to nest on the shoulders of Mount Everest at altitudes of 27,000 feet.  No doubt this possible champion can clear the world's tallest peak, which is in his neighborhood and more than 29,000 feet above sea level. However, this has not been verified by on the ¬spot human observers.