Tracking devices revealed that Black Swifts spent over 99% of their time in the air during the winter, almost never touching the ground for months. What’s more, the swifts flew to incredible heights, reaching the highest altitudes on nights when the moon was full – sometimes over 13,000 feet! It’s the first time scientists have seen birds changing their altitude along with the cycles of the moon.

More info and transcript at BirdNote.org. 

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