SHE PERCHES ON A BALD CESSNA TIRE in Ken and Suzanne Franklin’s country kitchen. Frightful, a six-year-old peregrine falcon, is just being herself, loudly cacking and occasionally opening her wings to their full 41-inch span. She flaps her wings and stretches a little, then preens herself with her hooked beak.

Sixteen inches long and weighing 2.2 pounds, she catches other birds, up to the size of ducks, in midair for a living. She ignores a savory piece of barbecued chicken, even though it’s within easy reach.

Frightful is a world-class athlete whose directly recorded speed beats that of any other animal ever measured. Cheetahs, sailfish, and black cutworm moths all top out at about 70 mph. When Frightful is stooping—diving after prey—from nearly three miles up, she has been clocked at 242 mph, and it’s possible she can go faster.

Until recently, estimates of peregrines’ velocity varied wildly, from 70 to 300 mph. No one had ever measured exactly how fast the birds can fly until Ken Franklin started stooping with Frightful, or, more to the point, Frightful learned to skydive with Ken.

“Studying falcons from the ground is like studying sharks from a boat,” Franklin says. Yet entering any predator’s realm, even just to observe, entails certain risks—Frightful’s sharp talons and bill are, of course, designed to hold and tear flesh. That didn’t discourage Franklin, his wife Suzanne, his father Roy Franklin (a World War II Navy Corsair pilot), several other falconers, two film crews, and Norman Kent, a world-renowned skydiving videographer, from their plan to study a speeding falcon at arm’s length—literally. To understand how a two-pound bird can achieve higher speeds than most small airplanes, Franklin has done more than 200 skydives, sometimes as many as five a day, with Frightful.

“Birds are the blueprint for aeronautical engineering,” says Franklin, a 46-year-old pilot and master falconer from Friday Harbor, Washington. Orville Wright would have agreed. In 1941 he wrote, “Learning the secret of flight from a bird was a good deal like learning the secret of magic from a magician. After you know what to look for, you see things that you did not notice when you did not know exactly what to look for.”

Franklin first took the controls of an airplane at age nine, and now, as a pilot for Federal Express, he would like to see the knowledge he has gained skydiving with Frightful and other fast-flying birds applied to mechanized flight. “Can human flight benefit from these observations?” he asks. “What remains to be learned?”

To capture their unique data, Franklin and a few mathematicians and engineers devised an elaborate method of clocking falcons in mid-dive. They stripped down a skydiver’s Pro-Track recording altimeter/computer, usually worn like a wristwatch, to a computer chip weighing just 0.4 ounce, then fastened it to the underside of Frightful’s tail feathers in a way that wouldn’t interfere with her flying. During dozens of skydives in 1999, made while the National Geographic film Terminal Velocity was being shot, the device recorded Frightful’s stooping speeds by measuring how far she fell in a certain time interval.

It’s an improbable and wonderful sight to witness Franklin release Frightful into the slipstream of a Cessna 172 at 17,000 feet above sea level. She stabilizes immediately into level flight and matches the speed of the airplane. She flies just off the wingtip, keeping her sharp eye on Franklin, inside the airplane, as he prepares to dive out the door. Then he leaps, and they fall together for more than two miles, along with a lure that Franklin drops during the descent to simulate prey.

Franklin’s team verified Frightful’s dive velocities with measurements from altimeters worn by videographer Kent and Franklin himself as they plummeted alongside the bird. A fourth altimeter was packed into the lure, and all four altimeters were compared after each jump. The team spent a couple of months working out these techniques and training Frightful, then another seven weeks shooting the film, which aired on the National Geographic Explorer program in 2002 and was nominated for an Emmy award. Frightful also stars in Birds of Prey, a yet-to-be-released IMAX film produced by Roy Disney.