Snowbird Shape-shifters

Those small slate-and-white sparrows hopping across the frozen ground are true snowbirds. They spend summer in Canada and move south to the U.S. during the winter. Some, like their human counterparts, even migrate to Florida.

In the late 1800s, R.W. Shufeldt wrote of two birds called “snowbirds.” One medium-sized bird, the Snow Bunting, became known as the “snowflake.” The smaller bird, the Dark-eyed Junco, was unequivocally called the “snowbird.” Shufeldt expressed his displeasure at the bird’s new moniker “junco” – he tried to determine, unsuccessfully, the etymology of the word (it means “reeds or rushes”) since the Dark-eyed Junco does not live among reeds or rushes.

Shufeldt’s article also referenced Alexander Wilson’s description of Junco folklore. New Englanders told Wilson that Dark-eyed Juncos change their plumage to become the Chipping Sparrows of summer. Before you laugh (or after you’re through), many birds significantly alter their plumage during the breeding season… although the Dark-eyed Junco does not. These two birds are both sparrows, trill similar songs, and feed on the ground.

While Dark-eyed Juncos do not morph into Chipping Sparrows, they have their own form of transmutation. Those round balls of bird aren’t fat, they’re fluffy. Feathers trap air, an excellent insulator. The birds puff up their feathers, a downy winter coat, keeping them toasty warm.

p.s. Red and the Peanut wrote a great post about the name “snowbird.” I recommend it!

G’night, Groundhog

It may seem like an odd time for a post about groundhogs (Marmota monax) – a couple months early, right? But I think now is an even better time. Groundhogs (a.k.a. woodchucks or whistle-pigs) are considered one of the few true hibernators of winter.

What about bears? This is where we get into an issue of degrees (pun totally intended). Bears lower their metabolism and body temperature, and by doing so, conserve energy in winter when food supplies dwindle. Normally, bear body temperature is ~98.6⁰ F (37⁰ C), just like humans. In torpor (like a mild hibernation), their body temperatures drop to 86⁰ F (30⁰ C).

The groundhog, in comparison, can lower its body temperature from 99⁰F to 37⁰ F (5⁰ C)! That’s hibernation! It allows the rodent to decrease its energy use to 1% of normal.

Think of torpor and hibernation like changing the temperature settings in your house. In torpor, you drop the settings a couple of degrees while you’re at work. Hibernation is like shutting temps way down, just enough to keep the pipes from freezing, while you head to Florida for a month-long vacation.

Some scientists study how the groundhog accomplishes this marvelous feat. Figuring out those specifics could impact healthcare and space travel for humans.

p.s. Some animals hibernate in the summer, but this is called aestivation (est-eh-VAY-shun).

p.p.s. This watercolor is now available on RedNewtGallery’s Etsy site. (yay!)