My understanding is they collected every 4 minutes for 200+ days, which implies 72,000 measurements.
If there were 72,000 measurements and none of them found the bird stationary, that's a pretty good sign the bird rests extremely infrequently.
Sample rate is everything.
Look - this lady can fly!!! (Neat photos, to boot...)
http://kotaku.com/this-lady-appears-to-be-floating-5950132
My understanding is they collected every 4 minutes for 200+ days, which implies 72,000 measurements.
If there were 72,000 measurements and none of them found the bird stationary, that's a pretty good sign the bird rests extremely infrequently.