Monday, December 27, 2010

Carolina Wren

This snow brought some excellent snapshot opportunities for me. First, as you might have noticed, I replaced the header with a new one of a dark-eyed junco on a snowy redbud branch. I also got a Carolina wren to stop for a moment so that I could take a picture that wasn't a brown blur (those of you who are familiar with wrens know they are frantic little bundle of feathers).

The two pictures brought to mind a question that was asked and answered on the Web -  Why don't birds' feet freeze? Here's a good explanation why:
Birds actually use several tricks to keep their legs from freezing. First they can stand on one leg and pull the other up under their feathers when one leg starts getting too cold. And if it gets really cold, they can squat to cover both legs with breast feathers. If you see a bird doing this, they may be getting uncomfortably cold legs.
Also birds’ feet are mostly bone and tendons, so unlike mammals, they have a limited supply of nerves, blood vessels or muscles to freeze. Their feet are also covered with scales [Me: Just like the reptiles which they descended from] which isn’t a living tissue and less susceptible to freezing.
 Finally, birds don’t have sweat glands in their skin to produce any moisture to freeze. Heat and moisture are accumulated in sacs, transferred to the lungs and eliminated through the mouth. No moisture escaping through their feet is also the reason they don’t stick to metal perches in the winter.
And now you know the reason birds' feet don't freeze!


frayedattheedge said...

Your wren looks a lot like our robin! We saw on the news tonight how bad the snow storms have been for you. We have thawed slightly, with the promise of getting above freezing later in the week!

Dartford Warbler said...

How interesting!

Your wren is a beautiful little bird. Much like ours in shape, but, as frayedattheedge says, more like our robin in colour.

It`s good to know that your birds have a well stocked feeding station to visit during your snow storms. Hope you are keeping warm.

Karen said...

Anne: How interesting that the two birds are similar in color. Our American robin is probably twice the size of your robin and is actually a thrush. I'm kind of surprised I haven't gotten a robin here in the small garden this winter. I had probably half a dozen last year as daily guests.

DW: I love the contrasts and comparisons with your birds and my birds. Would you believe while we had seven inches of snow over the weekend, we will be up to 60F by Saturday. I just bought some new snow boots which means no more snow this winter, I think.