Bird Migration at Magee Marsh

         —the marvel and the mystery

Yes, predictable, yet puzzling and mysterious is the spectacle of avian migration. I stood in awe and marveled at the idea that I was observing this tiny black and white bird on a twig. A warbler that had already traveled nearly 4,000 miles, from South America, on its migration route north. Eventually some would arrive at their nesting grounds as far away as the northwestern boundary of Alaska—at the Russian border! Like other wood warblers, it mostly flies at night to avoid predatory hawks. About the size of a house canary, this North American songbird weighs only less than three fourths of an ounce, and is but five inches long. Nevertheless, its migratory feats are stupendous!

Here is what the Book of North American Birds says: “Picture it migrating more than 10,000 miles a year from Alaska’s tree line to the rain forests of South America and back, skimming wooded peaks, skirting urban skyscrapers, and crossing vast stretches of open water in the Atlantic Ocean and Gulf of Mexico.” Which incredible bird is this? “The blackpoll warbler! The blackpoll warbler, [Dendroica striata], is a dynamo whose traveling prowess is virtually unrivaled among North America’s land birds.”  According to the Collins Atlas of Bird Migration: “Migration is probably the most awe-inspiring natural phenomenon.”

On its journey north, from as far south as Argentina, South America, many cross over the Caribbean and the Gulf of Mexico and make landfall along the gulf coast of the southeastern USA. They then migrate northward mostly through peninsular Florida and northeastward through the Mississippi and Ohio valleys. They arrive as one of the latest spring migrants. Other migrating warblers of Central America fly a much shorter distance across the Gulf of Mexico from points to peninsulas and others follow the land-masses.

Well, on my own migration eastward to observe the migrating warblers, I met up with the Blackpoll Warbler on the southwestern shore of Lake Erie, a wooded place called Magee Marsh. It is located 17 miles west of Port Clinton, Ohio, on Route 2. This is truly a phenomenal area to go observe the spring migration of most all the eastern warbler species. Peak migration for seeing the most species is usually during the first two weeks of May.

The Magee Marsh Wildlife Area includes Crane Creek and has a mile long board walk over the heavily wooded marsh. This woodland cover provides a stopover— a feeding and resting area—for the numerous species of weary songbirds reluctant to cross the vast waters of Lake Erie to Point Pelee, Canada. With certain weather conditions the many species of warblers can literally pile up in these woods. Winds and rain can cause what has come to be called a “fall out” in which the woods become alive with hundreds of birds down low and all around. This unusual concentration of warblers in such a brief period of time is phenomenal. Teeming with so many beautiful songbirds, all in their freshly laundered breeding plumage, is an awe-inspiring experience to observe. This year (2009), I was there from May 12-19. For about three or four days, I had what was indeed, a “fall-out” birding experience!  Add to this the morning chorus, all the singers vying for attention and a mate. At times it was hard to decide which bird to observe or photograph first. So the experience also proved to be a photographer’s paradise, as well.

That being said, for the Blackpoll Warbler, its journey was just getting started. The real migratory feat begins when fall approaches. It leaves its summer home in the far reaches of Alaska and instead of flying directly south from whence it came in the spring, it flies southeast across the North American continent to the Atlantic coast. Eating voraciously along the way, this tiny warbler’s southbound trip has just begun. They congregate along the Atlantic coast by mid-September, north of Cape Hatteras, in preparation for a non-stop journey of nearly 5000 miles!

Here along the coast of New England, the blackpoll warbler waits in anticipation of the right weather conditions. It somehow knows exactly what weather pattern is necessary—a strong cold front that will pass southeast over the coast and out into the Atlantic.

When the cold front arrives, the tiny warbler sets off, helped by the favorable winds as it flies southeast—out to sea. The instinctive choice of a cold front also means that there will probably not be any tropical storms to contend with en route—a meteorologist no less!

Flying southeast puts the tiny bird on course for Africa— hopelessly distant. This is not its destination! But the blackpoll warbler doesn’t change direction. It flies nonstop past Bermuda, climbing to altitudes of 21,000 feet as it nears Antigua. The rarified atmosphere is bitterly cold and the oxygen is scarce at that altitude. Why is this tiny warbler up there? Because there it finds the prevailing winds aloft that blow it southwesterly to its real destination, South America. After a nonstop flight of over 2,400 miles, taking more than three days and nights, the warbler arrives on another continent, right on target!

Scientists marvel at the feat performed every year by this diminutive bird. How does the warbler know to wait for the cold front, and that it means good weather and a tail wind? How does it know exactly what weather conditions to look for? Does it have a barometer in its head? How does it know to climb higher and higher, where the air is thin and cold, and has 50 percent less oxygen? By what mechanism does it does it know to fly off course, toward Africa, to find the right winds to push it toward its real destination, South America? Over trackless seas, how does it know to select exactly the exact navigational heading that will allow it to intersect with those winds at the right spot over the ocean? Does it have navigational charts in its head? The warbler’s instinctive know-how is all programmed into a miniscule brain-chip the size of a pea.

Incidentally, there is good reason why the blackpoll warbler flies such an unusual route. While the sea route to South America is much shorter than an “island hopping” trip would be, at that altitude, there are few predators to contend with.

Consider too, the matter of endurance. Weighing only three quarters of an ounce, the Blackpoll warblers of North America, are the greatest marathon fliers. It is said, their 2,500-mile nonstop flight across the Atlantic, in just three and a half days, is equivalent to a race horse running consecutive, two-minute miles for 80 hours. All this because of its specially designed metabolism. In the process the warbler burns up nearly half its body weight. “If a blackpoll warbler were burning gasoline instead of its reserves of body fat,” notes one scientist, “it could boast of getting 720,000 miles to the gallon!”

Nonstop, for three and a half days, over 2,500 miles of ocean, by a bird weighing less than three quarters of an ounce? What awesome computer is in that tiny head that tells time, computes the movement of the sun, uses the stars, orients all of this to a map of his destination, and even enables the bird to arrive safely if skies are overcast? How they “map” their journeys remains a mystery. Can anyone, deep within himself, really believe that mere chance created this little blackpoll warbler? 

Scientists have come to know that any such experimental wanderings and learned behaviors are not incorporated into the genetic code and hence are not inherited by the offspring. Migration is admittedly instinctive and “independent of past experience.” One must ask, does the common simplistic theory answer or explain the astounding feats of many such astounding migrators?

So on my own migration; of the approximately thirty-four eastern warbler species, I was able to record and/or photograph twenty-seven different ones, as well as numerous other marsh and woodland birds. I even photographed a new one for my life list, a “gray-cheeked thrush”. A handsome thrush, not rare but a bit uncommon. That thrush was a rush.

Yes, indeed! Predictable, yet puzzling and mysterious is the spectacle of avian migration as I stood in awe and marveled at the idea that I was observing this tiny black and white bird on a twig. So it is, according to the Collins Atlas of Bird Migration: “[Bird] migration is probably the most awe-inspiring natural phenomenon.” Without doubt, the Blackpoll Warbler is the epitome of that statement!

Ed Keenan © 5-09