I am constantly amazed by how much I do not know about the world. There are many things that are dauntingly mind-boggling. For instance: I was reading up on quantum theory this winter to get ready for our new exhibit about energy from the sun. I learned that the characteristics of the tiniest particle – which is smaller than I can ever imagine – impact the characteristics of the entire universe – which is larger than I can ever imagine. As the English author, Eden Phillpotts said: “The universe is full of magical things patiently waiting for our wits to grow sharper.”
On a much more human scale, I have just discovered that Common Redpolls, those brown-streaked, red-foreheaded finches, are not as common as I had thought. If you feed the birds, you have probably noticed sizable flocks of Redpolls moving frenetically, foraging determinedly, and then swirling away at the slightest thing. You have likely observed that they prefer tiny thistle, or nijer seeds.
This is an example of the specialized beaks of the finch family. Darwin’s Finches are the classic model for this, with beaks that are quite varied in order to be highly adapted to their diverse food sources. Other local examples include Crossbills, which are finches with curved bills that can pry open tightly closed spruce cones; and Rose-breasted Grosbeaks, which have robust, cone-shaped beaks that can crack bigger seeds and catch bigger insects.
The tiny beaks of the Redpolls are much better suited for thin thistle seeds than they are for big sunflower seeds. While not at your feeder, Redpolls feast on the tiny seeds of birches, alders, willows, spruces, pines, grasses, buttercups, and mustards. In warm weather, they eat quite a few small insects and spiders.
Birches, willows, and spruces are some of the farthest-north-growing trees, so it makes sense that Redpolls, who breed in the taiga and tundra, prefer their seeds. Food is not the only issue when you are a circumpolar species, though. And this is where I think they get interesting. I just learned that Redpolls can survive temperatures of negative 65 degrees Fahrenheit. That’s cold!
Redpolls have several physiological and behavior adaptations to living in the cold. First, they increase their insulation. Just like you dig your down jacket out of the closet each fall, Redpolls grow about 31% more feathers by November. Then Redpolls take a hint from the Subnivean Chronicles – they sometimes tunnel into the snow to stay warm during long winter nights. Their tunnels can be over a foot long and four inches under the surface. For such a tiny bird, that is impressive!
Redpolls share a behavioral adaptation with another Subnivean resident, too. Just like chipmunks stuffing their cheeks full of seeds, Redpolls have a pocket in their neck, called an esophageal diverticulum, where they can store seeds. The extra seeds allow them to “feed” while huddling in a protected place, overnight, or during a storm. These seeds fuel the birds’ metabolism, and allow them to maintain their body temperature.
Enjoy watching these gregarious flocks of finches while you can! Soon they will swirl away north to their breeding grounds. Although we are happy to see ten, twenty, or a hundred in our yard, their global population is estimated in the tens of millions. Yes, the Universe really is full of magical things.
For over 44 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opened in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/