Sep 15 2008

Night Travelers

Published by at 7:10 am under Migration

Swainson's Thrush (photo by Chuck Tague)

Swainson's Thrush (photo by Chuck Tague)

Across the continent thrushes are on the move.  Swainson's, wood thrushes and veeries are all heading south.  They travel at night.

When the weather is clear with a light north wind their urge to leave is strong.   They begin their flight half an hour after sunset, using the earth's magnetic field and the infrared glow of the western horizon as guides.  If all goes well they stop before dawn in a place with abundant food and shelter.

As they fly, the thrushes call to each other to keep the flock together.  Each species has a unique flight call so if you know the sound you can identify them in the dark as they pass overhead.  Unfortunately it's not quiet enough to do that where I live in Pittsburgh but we could hear them in Maine.

One night in Bar Harbor is especially memorable.  My husband and I had left a restaurant and were strolling along the waterfront when I heard thrushes overhead.  By the light of the street lamps I was able to see them coming in low over the bay and passing overhead only thirty feet up.  On and on they came, heading due south over the island.

It was such a thrill to finally see the night travelers.  We think of them as "our" birds but they are actually nomads.

(This photo of a Swainson's thrush was taken during spring migration by Chuck Tague.)

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