Atop Hawk Mountain, Pa., 2010

Atop Hawk Mountain, Pa., 2010
Photo by R.E. Berg-Andersson

Sunday, January 24, 2021

The Smallest Survivor

If we had no winter, the spring would not be so pleasant: if we did not sometimes taste of adversity, prosperity would not be so welcome. 

--Anne Bradstreet

I'm thinking about a gold-crowned kinglet this winter morning. 

It is at 8 a.m. the rising sun now comes out from behind my neighbor's house and hits me as I sit on my enclosed porch. Little by little the sun's arc has been lengthening as it rises higher in the sky. At this point I can only sit outside on the weekend for the 35 minutes or so I am in full sun at this point of the year because I need time to have breakfast and then ready for work. (In the pre-coronavirus days I would be on a train during this time.) 

The thermometer shows me it is 20 degrees F on the enclosed but unheated porch and my phone showed me it is 19 degrees outside, windchill of 9. That's why I'm thinking about the kinglet.

I am wearing a number of layers from head to toe, including a long down coat with hood. A gold-crowned kinglet, a tiny bird (about the weight of a couple of pennies) with bold markings on its face and wings and a yellow patch on its head (the male has an orange stripe on that yellow patch), does not have that luxury. The one I saw while taking a recent hike in the woods, trying to stay out of a fierce, cold wind, was flitting around quickly in a low shrub, looking for food. 

Gold-crowned kinglet, Pennsylvania, December 2013
(Margo D. Beller)
Usually I see this tiny bird high in a conifer, its preferred habitat, once I'm alerted to its presence by its buzzy tse-tse-tse call. They breed in conifer forests but when I see them it is during migration periods, mainly in autumn. But this bird seems to hang around in areas like mine in winter, as long as it can find food.

According to the people at the Cornell Ornithology Lab, a gold-crowned kinglet can survive in temperatures of -40 degrees F at night. That's 40 degrees below zero. How do they survive?

The scientist Bernd Heinrich wanted to know that, too. The gold-crowned kinglet (as opposed to its cousin, the ruby-crowned kinglet, which does not hang around here in winter) is among the creatures he studied in his book "Winter World" about survival in the harshest conditions. Heinrich, who is professor emeritus at the University of Vermont, owns a lot of property in Maine, which he has traveled for the observations in his many books. He found these kinglets, which normally eat insects, will eat what they can find in winter including spiders, insect eggs and moth caterpillars. They need to maintain an internal temperature of 110 degrees F, Heinrich found.

The gold-crowned will use old squirrel or bird nests and huddle together to stay warm, he found after following several to their roost one December twilight. Like me in my coat, sleeping kinglets fluff up their feathers to make an inch-thick, downy blanket. These feathers make up 10% of a kinglet's body weight

Heinrich also found that without this down layer, a naked kinglet would cool rapidly, which would be fatal. He caught one bird and weighed the wing and tail feathers, which are primarily used for flying, and compared them to the weight of the body feathers, which are primarily used for insulation. Kinglets have four times more feather mass committed to insulation than to flying, he learned.

Still, as I sit in the sun's warmth, warmly dressed in my down layer and holding a hot cup of coffee, I can't help but think of that little bird having to stay in perpetual motion on such a wicked cold day so it eat and thus survive. It is a cold, cruel world out there. I hope it survives.