The ice of Antarctica doesn't faze them. Nor does the heat of the tropics. They thrive in the desert, in swamps, on the open ocean, on sheer rock faces, on treeless tundra, atop airless mountaintops, and burrowed into barren soil.

Some fly nonstop for days on end. With just the feathers on their backs, they crisscross the hemisphere, dodging hurricanes and predators along the way, arriving unerringly at a precise spot, year after year.

They have penetrated nearly every ecosystem on Earth and then tailored their own size, habits, and colors to each one, pollinating, dispersing seeds, controlling bugs, cleaning up carrion, and fertilizing plants.

But for all their superhero powers, birds are in trouble.

Globally, one in eight—more than 1,300 species—are threatened