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  • Writer's picturePaul

Warbler Migration: an extraordinary journey

Blackburnian Warbler

More than 4 billion birds are about to begin an incredible journey from wintering grounds in the tropics to breeding grounds in North America. Some of these birds will fly thousands of miles and cross oceans along the way, only to land in the same spot they departed the previous fall.

We are excited to be going to the southern shore of Lake Erie in May to witness one of the most incredible parts of this epic journey. Each spring tens of thousands of warblers descend on the wetlands bordering the southern shore of Lake Erie to rest and feed before they make the non-stop crossing of the Great Lakes into Canada. Places like Magee Marsh have become world-famous because of the density and variety of warblers and other migrants who pause their journey in these wetlands.

The awe inspiring sight of thousands of warblers descending on Northern Ohio is only a brief snapshot of the incredible journey these little birds undertake each year. As the days begin to shorten and the weather cools in the fall, instinct tells these warblers to fatten up. Blackpoll Warblers will double their body weight before they set off! We don’t know for sure how these birds time their migrations, we suspect it is based on the shortening daylight hours and possibly the changes in star patterns.

We also don’t know exactly how these birds know where to go. Most songbirds migrate alone. An instinct tells them to fly south, but first year birds don’t follow mom & dad to the tropics, they fly alone for thousands of miles to reach a place they’ve never been before! The huge numbers of birds streaming overhead are less of an organized flock and more like a busy interstate full of cars going in the same direction to different destinations, each one traveling independently of the others. They use a combination of star patterns, landmarks, a sense of smell, and a still poorly understood ability to sense the earth's magnetic field. The Blackpoll Warbler that doubled his body mass before departing the boreal forests of Northern Canada will fly for three days nonstop over the Atlantic Ocean to reach South America for the winter! In the spring the same bird will island hop across the Caribbean and fly overland back to Canada for the breeding season.

For many years scientists were unable to determine where exactly migratory birds went in the winter. They knew the birds flew south, but the vast distances involved, limited technology, and an unwillingness on the part of scientists to spend years deep in the jungle meant that once migratory birds set off on migration they vanished into the huge and amorphous area of the map vaguely called “the tropics”, not to be seen or heard from again until they returned the following spring.

James Audubon was one of the first people to begin to study bird migration when he tied silver wires to the legs of Phoebes in his yard to see if the same birds returned to his house the following spring (they did). It would be many more years before we had any way to piece together the rest of the story of migration.

Modern technology has allowed us to much more accurately track the movements of migratory birds, and what we’ve learned is truly incredible! Migrating birds don’t just spend the winter vaguely wandering the tropics, each bird goes to a specific place, and will spend the winter in a very small area - in some cases only a few acres. What’s more incredible is that each bird will then fly back to the same place they originally left from the previous fall. The site fidelity of some of these birds is remarkable. A famous Prothonotary Warbler named Longshot was banded outside Charleston, SC. He then flew over 2,500 miles to a mangrove forest on the coast of Colombia for the winter. The 12 gram bird then flew back to the same swamp in South Carolina the following spring and was recaptured in the same tree he was first tagged in.

We are very fortunate to have the opportunity to witness several parts of this incredible yearly cycle. Some of the birds we will see in Ohio in May are likely the same birds we saw in Costa Rica last January, and there is a good chance we might see them again in the Mountains of North Carolina this fall! We hope you will have a chance to see some of these beautiful birds as they continue their journey.

Check out our upcoming warbler migration tour to Magee Marsh and more!

Wild & Wonderful Warblers Tour

When: May 15 - 21, 2022

Where: Northern Ohio: Magee Marsh, Lake Erie, Maumee Bay

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