This is

bird note.

On a chilly February morning near Seattle,

with the temperature hovering below 40 degrees, a bird is singing lustily.

And not just any bird, it's a hummingbird, a male Anna's hummingbird whose throat and crown flash iridescent rows.

But what is a hummingbird doing this far north in winter?

While most hummingbirds retreat south in autumn,

Anna's are found in northern latitudes throughout the year.

Since 1960, they've moved their year-round limit north from California to British Columbia.

They're taking advantage of widely planted

flowering plants and shrubs as well as hummingbird feeders. But how do they

survive the northern cold? They seem unlikely pioneers since hummingbirds have no down feathers for insulation

and a metabolism that runs so high that they would exhaust their energy reserves on a cold night.

The Hummingbird's solution?

Suspend that high rate of metabolism

by entering a state of torpor,

a sort of nightly hibernation where heart rate and body temperature are

reduced to a bare minimum. Many hummingbirds, such as those residing in the high Andes,

rely on the same strategy.

Yes, Anna's hummingbird has come north to stay,

and its jewel-like presence at the nectar feeder

adds a sparkle to any winter day.

...