Peter Berthold teaches Alan the best way to catch a stork

Every autumn, about half a million white storks embark on an epic journey. Leaving from all over Europe, most fly east over half a dozen countries, then down across the Middle East to their wintering grounds in Africa. But stork numbers are down by half in the last 50 years. German ornithologist Peter Berthold is trying to figure out why.

In "Flight Into the Unknown," Alan Alda helps Berthold capture some of the migrating storks so they can be fitted with satellite transmitters and tracked on their journey. So far, Berthhold has obtained detailed records about the migrations of 90 individual birds.

Storks fly all day, he's found, soaring on the sun-generated warm air currents that rise off the land. But no such currents rise off of the Gulf of Suez, the only large body of water the storks must cross on their route. So the birds must wait until the wind is favorable. That's why thousands stop at the Egyptian coastal town of Sharm el Sheik.

		Migrating white storks travel up to 10 hours each day, covering 150 miles

At the town, volunteers bring exhausted, dehydrated birds in from the desert to a stork rescue center. After a good meal and often some medical treatment, volunteers like Americans Jim and Susan Dinsmore, and Adli Mestikawy, a local hotel owner, send the birds back on their way. No one's sure why the birds are arriving in the tourist town in such bad shape, and Berthold, for one, is not convinced that feeding is the solution to the problem. He says it's the loss of summer feeding grounds in Europe that's more to blame for the storks' decline, and it's natural for the birds not to feed during migration, to keep their body weight low. That doesn't stop the rescue center, though, which now hands out 800 pounds a day of chicken carcasses to the hungry storks.