December 13: Winter PB & J

"At every moment of every day, morning or midnight regardless of the season, there are birds aloft in the skies of the Western Hemisphere, migrating.  If it is spring or fall, the great pivot points of the year, then the continents are swarming with billions of traveling birds -- a flood so great even the most ignorant or unobservant notice the skeins of geese or the flocks of robins."
- Scott Weidensaul, from Living on the Wind

As winter settles around us, we find ways to deal with the darker days and colder weather. We have sweaters and central heating, stored food and electric light. Wildlife doesn't have the same tools that we have, but they must deal with this season just the same. Animals deal with winter in one of three ways; migration, hibernation or adaptation. All three provide great fodder for stories that highlight what Bill Nye calls the PB & J of science - the passion, beauty and joy.

Did you know that grizzly bears hibernate in a completely unique way? Their heart rate drops to 25 beats per minute and they drop their body temperature by about 10 degrees, a considerably more shallow hibernation than that of say the marmot (who drop their temperature by close to 60 degrees to just 5 degrees Celsius!). This shallow hibernation, though, allows grizzlys to do something a marmot could never dream of doing - giving birth while hibernating.  They also are able to re-synthesize 

Pacific Tree Frog

urea from their urine into protein so they actually gain muscle mass during their winter nap. How cool is that?

Grizzlys are not common in my particular part of the country, but Pacific chorus frogs are. These are tiny little frogs with giant voices that breed near still water all over the Pacific northwest. In colder parts of the country many amphibians will burrow underground or under deep leaf litter and snow to hibernate through the coldest times of the year, but not here in Oregon and Washington. Our winters are mild enough that not only are our chorus frogs active, they're starting to breed in the late winter! They have special anti-freeze like compounds in their blood that keep them alive despite being cold blooded and may start singing for mates as early as February. Getting this jump start on the breeding season means those hardy frogs' babies will be able to out compete other, later hatched tadpoles and have a better chance to grow up to breed themselves the next winter. They play a tight balancing game between the rigors of winter with it's cold temperatures and lack of insects to eat and the benefits of breeding early. It's a frog eat frog world out there!

Sauvies Island

If you live in Portland, this time of year is wonderful for winter birding at Crystal Springs Rhododendron Garden, Oaks Bottom Wildlife Refuge or Sauvies Island. In addition to the mallards, coots and cormorants we see all year round in Portland, you are likely to see buffleheads, wood ducks, or wigeons or any number of other more exotic birds. Local birders have seen up to 65 species in a single day at Oaks Bottom, including the Bald Eagles that prey on the ducks. Many of these birds have migrated south to Western Oregon for the winter, as improbable as that seems to those of us who get bummed at the rain. As long as it's not freezing and snowing these birds are happy to spend their winter vacations here. One winter day I was up on Sauvie's Island and had to stop in my tracks as the sky filled with Snow Geese, honking and flapping overhead. Talk about passion, beauty and joy!

What animal feats inspire you in the winter? What crazy stories or observations fill you with passion for the natural world? What is beautiful and joyful in the winter woods or fields near your house? If you were a wild animal who had to survive the winter, which would you like to be, a hibernating bear or a migrating duck? 

For more on Grizzlys, check out this article. 
For more on Pacific chorus frogs, go read this.
And for information on winter birding in Portland, see this one here.