This is bird note.

You can find these calico-colored, ruddy turnstones, foraging for crustaceans across six continents

in the winter.

But when it's time to breed, turnstones and many other shorebirds high-tail it to the

Arctic tundra.

It's such a unique and important ecosystem that every year, the National Oceanic and

Atmospheric Administration issues an Arctic report card that details how the region has

been affected by rising global temperatures.

One of the biggest changes can be seen from space.

The tundra is becoming shrubbier.

Shubs in general are becoming more abundant, they're becoming denser, they're colonizing

new areas.

That's landscape ecologist J.J. Frost, who studies this phenomenon called tundra greening.

Over the last ten years, satellite data has shown the five highest greenness measurements

ever recorded, indicating that shrubs are spreading in the north.

And so for birds, what that means is there are winners and losers.

Shorebirds that nest among low-lying tundra plants may soon find woody thickets encroaching

on their breeding grounds.

But songbirds, like yellow-rumped warblers, may venture beyond their boreal forest breeding

habitat as the tundra becomes more wooded.

Shifting Arctic ecosystems could have ripple effects for migratory birds around the world,

because every time you see a ready-turned stone, you are actually witnessing and seeing

...