Nature's Pilots

Man must go back to nature for information.

--Thomas Paine

Right outside my study window there's a maple tree, and, as a pilot, I never get tired of seeing the birds fly into and out of it.

Although they move very quickly, I try hard to look at what they're doing with their wings and tails as they make their approaches, landings, and takeoffs. To an aviator it is truly fascinating.

As they glide toward a branch, you might notice them raise their pitch angle to bleed off airspeed, just the way an airplane would. In layman's terms, that means they tilt their bodies up a bit, presenting more drag into the wind. Then they start flapping again just before they touch down. That addition of power slows their descent rate, much the way I would push up the throttle if I noticed too much of a sink rate on final approach.

And what's really interesting is watching birds fly in gusty winds. I've seen the branches of that maple swaying in winds that would discourage me from flying. But still the birds come and go, almost mocking me with their skill, as if to say, ''What's your problem? This is easy!''

If a gust hits the bird from the side as he's approaching a branch, he has to dip his little wing into the wind to keep from getting blown off course. He probably moves his tail feathers in the opposite direction to keep his body lined up with the spot where he wants to land.

For a human flier, learning to land in such a crosswind takes a lot of time and effort. And the aerodynamics are fairly sophisticated, with ailerons deflected to bank the airplane into the wind, and with the rudder used to move the tail in the opposite direction, which keeps the nose lined up with the runway.

You'd better watch your airspeed, too, because if you get too slow and enter a stall in that configuration, you may well spin.

But have you ever seen a bird spin in? Never do they flub up a crosswind landing and whap into the tree trunk. They don't foul up their approaches and have to do go-arounds to try for another landing, either.

And that's just their local flying.

When they decide it's time to migrate, they just head to their traditional homes for the season. How do they know which way to fly? To find my way on a long cross-country flight, I need high-tech equipment with names that sound cold and scientific: horizontal situation indicator, global positioning system, automatic direction finder. It involves geometry, numbers, and detailed charts. But a bird simply takes off and goes.

Sometimes birds fly in misty, rainy weather with very low visibility. If a human without a lot of instrument training flies into such conditions, he may become disoriented within seconds and lose control of the aircraft.

Nature has a lot of wonders, but one of the biggest, for me, is to hear geese honking just overhead -- but invisible in fog. I just shake my head in disbelief. In years of waterfowl hunting in horrible weather, I've never seen a duck or goose lose control and fall out of the sky because he couldn't see where he was going.

And birds manage to accomplish all this with tiny, tiny brains. It's pure instinct -- not intellect -- that keeps them in the air. Somehow all this aeronautical knowledge that takes a person years to assimilate is downloaded into a bird's little on-board computer, and there's never a single malfunction. This is humbling, and it inspires awe in the bird's manufacturer.

But I just wish these masters of the sky would learn to check their 6 o'clock. That's pilot talk for looking behind.

You see, I took off once in a Piper Cherokee and leveled off at 3,000 feet above the Potomac River. Just as I lowered the nose to stop the climb, a sea gull appeared, practically filling the windshield.

I banked hard to the right because I didn't want to puree that bird in my prop. But the gull banked right, too!

Fortunately, the gull banked more steeply than I did, and he blew past the passenger's side window. He kept his life, and I kept my propeller and windshield.

What he was doing up at 3,000 is beyond me. He should have been down along the river, looking for food. Perhaps he'd been inspired by reading ''Jonathan Livingston Sea-gull.''

Or maybe I was the one who didn't belong there, with my exhaust fumes and prop noise.

At any rate, he wheeled in the sky behind me, silent, graceful, and skillful, and I blasted on toward my destination.