Moon-Watching for Migrating Birds

Before the high-tech gadgets used to track bird migration today, there was moon-watching: a technique dreamed up in the 1940s by ornithologist George Lowery. Using telescopes pointed at the moon to see the silhouettes of migratory birds, Lowery helped show that birds regularly migrate across the Gulf of Mexico and organized the first continent-wide survey of migration in North America. Learn more about the history of bird migration research in Rebecca Heisman’s new book Flight Paths: How a Passionate and Quirky Group of Pioneering Scientists Solved the Mystery of Bird Migration.

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Moon-Watching for Migrating Birds

Written by Rebecca Heisman

Michael Stein: This is BirdNote.

[Barn Swallow flight calls]

Before the high-tech gadgets used to track bird migration today, a Louisiana ornithologist studied migration with one simple tool: a telescope aimed at the moon.

George Lowery dreamed up moon-watching in the 1940s to prove that birds regularly migrated across the Gulf of Mexico. He knew you could see the silhouettes of migrating birds passing in front of the full moon through a telescope. Working with an astronomer, Lowery turned moon-watching counts into standardized measurements to compare the amount of migration at different places and times.

[Common Nighthawk flight calls]

On a ship docked on the coast of Yucatán, Lowery pointed his telescope out over the Gulf. He calculated that 3,700 birds crossed an imaginary one-mile line on the water every hour. Then, in the 1950s, he organized the first continent-wide survey of migration patterns, with thousands of volunteers across North America.

[Chimney Swift flight calls]

Moon-watching became obsolete once scientists began using radar to monitor migration, but you can still point a telescope at the moon and see those flickering silhouettes of birds on the move.

Learn more about the history of bird migration research in Rebecca Heisman’s new book Flight Paths: How a Passionate and Quirky Group of Pioneering Scientists Solved the Mystery of Bird Migration.

For BirdNote, I’m Michael Stein.

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Senior Producer: John Kessler
Producer: Mark Bramhill
Managing Editor: Jazzi Johnson
Managing Producer: Conor Gearin
Content Director: Jonese Franklin
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Barn Swallow ML250098541 recorded by Tom Reed, Common Nighthawk ML105376 recorded by Geoffrey A. Keller, and Chimney Swift flight calls, ML352831341 recorded by Mario Gervais.
BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.
© 2023 BirdNote August 2023
Narrator: Michael Stein

ID# moonwatching-01-2023-08-28 moonwatching-01

Reference:
https://www.jstor.org/stable/4083149