Scott Weidensaul

[bird chirping] This bar-tailed godwit makes one of the longest migrations of any animal, a seven thousand two hundred mile non-stop flight each autumn from western Alaska to New Zealand in just eight or nine days.

But how do these pigeon-sized shorebirds accomplish such an epic tour de force? In his book, A World on the Wing, Scott Weidensaul shares the incredible process bar-tailed godwits use to get into migratory shape.

"They accomplish this astounding feat by first larding themselves with thick layers of fat," Weidensaul writes.

They more than double their weight in about two weeks until he says that they jiggle when they walk.