The smallest birds to winter in the New England woods, golden-crowned kinglets are about the size of a thumb and weigh as much as a nickel. They travel as a foraging flock and keep warm at night by cuddling together, creating more volume with less surface area exposed.
Kent McFarland and Sara Zahendra, biologists at the Vermont Center for Ecostudies, took a trip into the woods in Montpelier to try to locate a flock of golden-crowned kinglets.
Kent McFarland: We’re out in the woods looking for the minute golden-crowned kinglets. Like a lot of species out here in the woods, they’re still trying to make it through the night. It’s not that bad out here – about 45 degrees – and we have the sun on us, but last night it got down to 23 degrees.
Sara Zahendra: These birds are tiny, really small, about the size of my thumb.
KM: They weigh about the same as a nickel. The really cool thing about golden-crowned kinglets is that they spend about four times as much weight on their body in feathers as they do on the feathers on their wings to fly. This tiny thing is carrying a lot of weight in feathers. But still, you have this problem of this very tiny object with a lot of surface area, losing heat all night long, even though it’s fluffed up.
They have greenish-yellow wings, almost non-descript looking, camouflaged, and a lighter belly. What’s really striking about them, and where they get their name, is on the tops, sort of like a mohawk, they have a yellow stripe, and when they’re really irritated with each other, the males, they’ll flip the crown up. It’s almost hidden when you watch it but when another male approaches, or when they’re irritated, they’ll flip that up like a mohawk and that screaming, bright-yellow color is unbelievable. It’s the purest yellow you could imagine. Even though they’re the size of my thumb, when they crank that crown up of that yellow, you can see it with a naked eye – it’s blazing.
The cool thing about these kinglets is they run around with the chickadees in these loose foraging flocks… being in a foraging flock has its advantages. When there’s danger, everybody starts chattering at the danger. They’ll start calling and making bird calls. If you’re a bird watcher, you can sort of trick them by making a bird noise and waiting for them to answer…”
SZ: So, we have these really tiny birds and they’re losing heat to the environment really quickly. So, do they eat a lot? Do they need to eat a lot of fatty foods to stay alive?
KM: Well, unlike some birds, they don’t eat fruit. They only eat insects. So, they are amazing at picking around at the nooks and crannies of trees and branches, even in the dead of winter, to find an old insect sitting there, maybe some egg casings from a spider. Right now, they’re probably in these pine stands because they are a little sheltered, so they tend to be warmer, and there’s probably more food on the ends of these pine branches. But they could be out on the hardwoods – they’re constantly on the move looking for food.
SZ: So, they have a lot of feathers that keep them warm. They eat a lot of fatty food that keeps them warm at night, but they don’t make nests for the night or find nests or holes to stay in. Then it’s kind of a mystery, right? It’s got to be impossible to find a Kinglet at night, right?
KM: I threw out the hint. They are traveling in flocks.
SZ: Can I guess? They cuddle. They cuddle, right?
KM: Exactly. They get past the problem of having too much surface area to volume by cuddling and creating much more volume and less surface area exposed.
SZ: So they get really close together, like they’re one entity with lower surface area to volume ratio.
Kent calls to them.
SZ: Oh, there are two chickadees.
KM: But we’re waiting for are some high-pitched calls of the Kinglets. I could barely hear it. They’re too busy eating right now to talk to us.
SZ: Well, even though we didn’t hear them really, really loudly, it was still nice to be out here.
KM: They are almost like artwork, a masterpiece of evolution and adaptation. And these masterpieces, I feel, even when they’re common species like kinglet, we should learn as much as we can about them and look at them and marvel at them and get excited about them.
SZ: You learn something about nature. These spectacular things are happening all around us and most of us don’t even notice it. It’s just cool.
Outdoor Radio is a monthly feature produced in collaboration with the Vermont Center for Ecostudies in Norwich Vermont. The program is made possible by the VPR Journalism Fund and by a grant to VCE from the Vermont Community Foundation.
The program is produced and edited by VPR's Chief Production Engineer, Chris Albertine.
Broadcast Thursday, Dec. 18, 2014 at 7:50 a.m.