Black-necked stilts are one of more than 200 species of shorebirds to make annual flights of several thousands miles each year! These guys live in Peru and Brazil when they're not with us.

Autumn, the time for many northerners to make their perilous flights south for the winter. Perilous? you might ask. Planes are quite safe, and most New Yorkers make it to Florida relatively unscathed. How can taking a flight south be that dangerous? The snowbirds of which I speak are the original long distance fliers-the migratory birds. Covering thousands of miles often alone at night, airborne for days without food or rest, they travel distances we humans mercifully make in hours. We expend little energy making our journeys, but during a migration these marathoners lose their entire lean bodyweight's worth in fat. Many succumb to predators, collide with tall structures, or are engulfed in bad weather and exhaust themselves to death. Why, given the dangerous circumstances, would anyone want to migrate? There must be something to this phenomenon, as all but two of over 200 species of Florida birds are classified as migratory by the U.S. Fish and Wildlife Service.

We have been taught that birds fly south for the winter. This implies they leave their northern home regions for temporary southern lodging until the weather improves. Recently, this has been proven not to be the case. The main argument being: why would any intelligent creature leave the tropics if food and warmth were the only factors involved? Food and warmth abound in the tropics on a relatively even and constant level. There must be more to it than that, and there is. It's a given in the natural world that the main point of being alive is to pass your genes onto the next generation as often as possible. What if you could do something radical to give yourself an edge? Springtime in the northern latitudes confers just such an advantage-even outweighing the risks taken for the annual trek. The majority of songbirds and shorebirds, be they vegetarian or carnivorous as adults, feed their young a diet consisting predominantly of insects. This is because chicks have rapid metabolisms to accommodate growth and development toward adult size within two to four weeks! The insects provide the protein source vital for this swift transformation, and most of these birds are diurnal. Therefore, an advantage would be presented to the bird that found a location providing long daylight hours and bugs out the wazoo-the Temperate Zone Phenomenon. In springtime, days lengthen to an average of 18 hours (only 12 hours year round at the equator) and insects are cued to emerge en masse. It has been proven that birds produce significantly more offspring per clutch in the North compared to related species remaining in the South. Sure, they can have more than one clutch per year in the tropics, but food sources aren't as predictable as northern spring eruption, and if you count babies produced on a yearly basis, the migrators win. In summary, the northern United States and Canada are visited by tropical birds that think North America is a good place to raise a family but wouldn't want to live there!

These Royal and Sandwich terns are relatives of the Olympic gold medallist of marathons, the Arctic tern, which puts 22,000 miles on his odometer yearly by flying from pole to pole semiannually.

What is involved in the act of migration? How do birds pack for their arduous trip? An intricate relationship between day length and hormones is responsible for laying the premigratory groundwork. Hormones cause the birds to go on a bingeing spree the likes of which no human has ever experienced. Blackpoll warblers that weigh in at a petite 11 grams pig out to a hefty 22 grams-doubling their bodyweight. Hyperactive sanderlings, the little guys seen running just at the edge of the surf at the beach, can go from 60 to 120 grams in a few weeks. The delicate ruby-throated hummingbird, our only native hummer in Florida, bellies up to the table at 2.5 grams and doesn't stop until he tips the scale at 4.5 grams! Migrators stow 50 percent to 100 percent of their bodyweight in fat for the trip. After gorging comes a phenomenon called Zugunruhe (premigratory restlessness). These guys don't feel like we do after feasting-logy and desirous of watching TV in a stupor; they actually get more active than they were before they packed on the pounds.

Migration begins when the restlessness peaks and the birds launch into the sky, psyched for the ultimate marathon. How do they know where they are going? Many new studies with radiotelemetry, radar, and old, reliable, continuous data input from banding show navigation to be multifactorial. Some birds choose erratic routes thought to be dictated by tradition-much like the twisting roads of Boston that trace back to cow paths. An experiment proved a genetic component by the interbreeding of two races of songbirds named blackcaps. A German race migrated to the southwest to North Africa, an Austrian southeast to East Africa. The interracial offsprings' path was found to be an intermediate route between those of the parents'. Yet another proof of a genetic component lies in the fact that shorebirds haven't become extinct. Most shorebird parents feed their young for two weeks and go south, leaving chicks to work out their own flight plan through genetic memory. If they didn't have a clue, they wouldn't make it to their destination. Some birds orient themselves to the sun, and nocturnal fliers orient to other celestial objects, demonstrating this by orienting on a projection in a planetarium. The magnetic fields found in the earth are also considered to help birds navigate.

We are fortunate in Florida to be at a geographic bottleneck, the eastern flyway. It is an aerial corridor from the northern United States and Canada via Florida to Central and South America. Beginning in August and extending even to December, migratory birds are amongst us. Some choose Florida as their primary homes, others use Florida as a final staging area to refuel before making the long jump to the tropics.

Unfortunately these birds are facing escalating difficulties, the likes of which their ancestors never experienced in previous millennia. Imagine flying several days nonstop, lacking the convenience of stopping in one's tracks to rest, eagerly anticipating your first rest, ravenously hungry, nearing exhaustion, longing for the haven you've been frequenting for years … SMACK! You've just slammed into a reflective building that didn't exist last year. You slide down its side to the ground, stunned. You recuperate and begin looking for familiar fare. You see plenty of weird plants, but no fruits, seeds, or insects. Development ruined your sanctuary, now planted with exotics and sprayed with insecticides. Suddenly a cat pounces; you use your last calorie to dodge it. You make it up to a tree branch and see something edible. You gratefully begin eating when you are strafed and knocked to the ground by a flock of aggressive exotic birds, intruders into the area. The cat gets you after all. Collision injuries, predation by cats and dogs, emaciation, exhaustion: these are all too common maladies seen in wildlife today.

The future of our birds can be less bleak if we do things to help them.

• Put out bird feeders.
• Landscape your yard to be wildlife-friendly.
• Support your local wildlife organizations.
• Keep cats indoors.
• Support environmentally concerned politicians.
• Encourage renovation of abandoned urban sites over development of pristine areas.
• Most important, learn more about these fascinating creatures and encourage your schools to provide programs to teach your children about the importance of nature.

"In the end, we will save only what we love, we will love only what we understand, and we will understand only what we are taught."
-Baba Dioum, African Ecologist

-Deb Anderson, D.V.M., is the Director of Veterinary Services at the Wildlife Care Center in Ft. Lauderdale, Fla. and a veterinarian for both Flamingo Gardens, Fla., and the Humane Society of Broward County, Fla. Dr. Anderson went to the University of Maryland and the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech. She is the member of numerous wildlife associations and has three cats, three dogs and an African Grey.