[a11r]

Even more incredible since the article points out that "Unlike albatross or other long-flying seabirds, godwits are active flyers, not gliders—their wings are moving the whole time." I wonder if they can use the active-flying equivalent of regenerative braking in favorable wind conditions to actually generate energy while flapping their wings. Not sure if any animals can generate energy while walking downhill.

[arrow7000]

The body's only energy store is ATP, which you can't generate from nothing

[ajb]

This isn't quite true. When muscles stretch, they store energy like a spring does. But for very long, of course, but if the cycle is repeated many times that's still many times more efficient than not storing it. Don't know if that applies here though.

[scns]

Same for humans and running, storing energy in the achilles tendon if running barefoot or in shoes without damping.

[teeray]

The Law of Conservation of Energy heartily disagrees