You stroll the boardwalk early on a spring morning, enjoying the quiet of an awakening woodland. The familiar song of a robin makes its way down through trees just starting to break bud.  The light is soft, the winds calm.  Cool air is pleasant against your skin. The trees are still.  This corner of the world is easing its way into spring.

The Boardwalk at Magee MarshA quiet start to the day. Nikon D2X, Sigma 24-70mm f2.8, 1/400, 24mm, f7.1, ISO 160. The Boardwalk at Magee Marsh.  

A quiet start to the day.  Nikon D2X, Sigma 24-70mm f2.8, 1/400, 24mm, f7.1, ISO 160.

Then he speaks a word, perhaps waves his hand with a flourish, and hundreds of miles away the winds shift and begin drawing up from the southwest.  Expectant travelers perceive it.  They respond to an irresistible call northward.  As evening fades into night they spread their wings and climb to ride the invisible current. 

With the breaking of a new dawn the boardwalk will be transformed.  Like dew falling from heaven, they will arrive.

You are in northwest Ohio on the shore of Lake Erie in a remnant of the Great Black Swamp. This is Magee Marsh. And the Warbler Invasion has begun.

Black-throated Blue Warbler MaleWarbling away on his migration to his breeding grounds. Nikon D810, Nikkor 600mm f4, 1/800 sec., f5.6, ISO 800.

Black-throated Blue Warbler.  Warbling away on his migration to his breeding grounds.     
Nikon D810, Nikkor 600mm f4, 1/800 sec., f5.6, ISO 800.
 

Each spring vast numbers of warblers leave their winter homes in South and Central America and the southern United States to begin a journey leading hundreds and, for most, thousands of miles north to their breeding grounds.

They are drawn north for the food they will find all spring and summer in the Eastern Deciduous and Northern Boreal Forests, in the wet meadows of the Northern Prairies, and around the intricate network of lakes of the upper Mid-west.  They come seeking insects, abundant insects.  They will depend upon these small creatures, that most of us have an aversion to, to raise their young and feed themselves until the seasons change and, like summer's warmth, what was plentiful ebbs away.

Northern ParulaThis migrating Northern Parula uses its bill to pry open a leaf in search of caterpillars or spiders. Magee Marsh State Park, Ohio.

But before they reach their breeding grounds they must make an arduous journey, traversing all manner of land and water, with much of the land no longer suitable to supply food that can sustain their travels. 
 

The migration of warblers is well studied.  We know that warblers travel mostly by night.  In fact, large flocks of them will likely pass over your neighborhood tonight.  Flocks large enough they can be detected on radar.  And just before dawn they will drop out of the skies seeking safe habitat, known as “stopover habitat”, someplace rich with insect food, so they can spend their day refueling and resting.

A typical warbler weighs about 10 or 12 grams.  That’s about the same as 2 nickles.  If you have them, pull 2 nickles from your pocket and weigh them in the palm of your hand.  In one night of migration that same warbler might expend as much as 16% to 35% of its body fat in the exertion of non-stop flight.  And then need to rise again the next night and repeat that performance.

Their lives will depend upon the quality of the land they find when they drop out of the sky, whether it is land they choose or land in which they are forced by severe weather to take refuge.                                                                                                                                                                                    

If your community has been wise and fortunate enough to have preserved good stopover habitat, you may have the pleasure of seeing a colorful warbler seeking refuge and refreshment during the day in a forest near you.  But if your community has removed large tracts of forests with all their layers of vegetation, don’t get your hopes up.  Pity the migrants who found respite last year in a forest that has since been cleared.  Pity those forced by bad weather to drop out of the night sky seeking shelter in a storm only to find the land devoid of food.

Those birds traveling up through the mid-western states into Canada will have the added challenge of navigating the Great Lakes.  Among the largest lakes in the world, the lakes themselves might as well be a desert for all they have to offer in the way of food or a place to take a break from hours of non-stop flight.  They are a formidable obstacle.  Warblers cannot risk being unprepared.  Before attempting a crossing they must find land in which to rest and regain their reserves of fat.  

Nashville Warbler MaleA migrating Nashville Warbler has found a tiny caterpillar among the native Black Willow trees (Salix nigra) of Magee Marsh. Nikon D810, Nikkor 600mm f4, TC14E, 1/640s, f5.6, ISO 800.

Magee Marsh, literally a stones throw from the southern shore of Lake Erie, has provided the perfect stopover habitat for millennia past. The warblers arrive providentially just as Magee comes alive with insect activity.  Millions of midges, a tiny non-biting mosquito-like insect, emerge from the water and flock to the tree tops, shrubby edges and undergrowth.  The rich proteins and fats warblers gain from these and many other insects populating Magee Marsh, are crucial to enabling them to continue safely northward. 

The good folks of Ohio were wise to preserve remnants of the Great Black Swamp.  Magee Marsh is one of these remnants.   Some 39 species of warblers may be seen at Magee during the roughly 6 weeks of migration spanning from mid-April to late May. This year, due to Covid-19, the annual “Biggest Week in American Birding”, a festival celebrating the migration, is cancelled.  But the birds will still migrate.  While we are sheltering at home they will find shelter in transit along the empty boardwalks of Magee Marsh.

And I look forward to next time when I can walk the boardwalk as dawn breaks.  It is like being inside a gift unwrapped for me by the sun.  It is a surprise party in the woodland garden, discovering what new arrivals have dropped from the night skies.  I'm filled with a sense of wonder, deeply satisfied in the presence of such beautiful creatures, knowing they have been cared for thus far and are well on their way to raising the next generation.

So, if you arrive at Magee Marsh longing to see warblers, and the woods are quiet with the only song you hear a familiar one, don’t worry, just wait for a southwesterly wind to blow.

Tomorrow will be a new day.

Sources:

Lincoln, Frederick C., Migration of Birds, Circular 16, 1935 (revised 1979 and 1998), US Fish and Wildlife Service, 119p.

Kerlinger, Paul, 2009, How Birds Migrate, 2nd Ed., Stackpole Books, Mechanicsburg, PA.  230p.

All photos and text are Copyright © Julia Flanagan unless otherwise noted. All rights reserved.