> After crunching the numbers, the scientists found the links they’d been looking for: the length of an egg correlates with bird body size. The shape of an egg—

> After crunching the numbers, the scientists found the links they’d been looking for: the length of an egg correlates with bird body size. The shape of an egg—how asymmetrical or elliptical it is—relates to flying habits. And the stronger a bird's flight, the more asymmetrical or elliptical its eggs will be. > What’s the link between flying and egg shape? Birds have a streamlined body plan, and—especially in stronger fliers—their organs are squashed and minimized.