The largest study of flight costs in the wild finds that riding the air can make flying cheaper than swimming, overturning a textbook ranking Two of the world's heaviest birds, the trumpeter swan (left) and the Andean condor (right) and…
"To us, the sky might just look like background for flying animals, but it is an essential resource that can dramatically change the cost of a journey," says first author Dr. Martina Scacco. Textbooks rank the ways animals travel by…
Feeders, IDs, checklists, and seasonal migrations for backyard birders.
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