For the Birds Radio Program: Watertight Down
Reworked from 12/5/1986 (3:35) Date veriifed.
Ounce for ounce, down is the finest insulating material known to man. And the softest, best insulation of all comes from a northern sea duck, the Common Eider. Eiders can easily survive temperatures of 50 degrees below zero, thanks to their exquisite down feathers.
A female eider pulls the soft inner feathers from her own body to line her nest, protecting her eggs and young from the permafrost of the ground beneath. Although eiders have been known to sit on their nests for the entire 28-day incubating period without a single break, if the mother does take a seventh inning stretch, she blankets the eggs with down until her return.
If you ever read Journey to the Center of the Earth, you may recall that back in the days of Jules Verne, people collected down from the nests every few days until the ducks had stripped themselves of the best down and started pulling off inferior feathers in desperation. Now, fortunately, the eider down industry is heavily regulated in the countries where most eiders nest,—Greenland, Iceland, and Canada. An eider’s body produces enough down for about one and a half nests, so down collectors can take a bit of down from each nest without harm, but it takes the down from 35-40 nests to make just one pound of eider down. Eiders don’t breed in captivity, and so the collecting of eider down is so painstaking that a pound of it costs $400. In 1986, only 36 pounds of pure eider down were brought into the United States, and it isn’t available commercially at all.
So where do we get the down in our sleeping bags and jackets? About 80% of it is imported. The main source is China; then Germany, and then France. The down feathers are a by-product of their goose and duck meat industries.
Ducks and geese actually stay warmer in their down jackets than people do. For one thing, down can’t insulate when wet. Waterfowl can stay dry both in the water and out, because they have preen glands at the base of their tails which they use to coat their outer feathers with oil; hence the expression “like water off a duck’s back.” Perfectly waterproofed outerwear for people makes us sweat, causing the down to absorb water from the inside. After a month of their journey to the North Pole, the Steger expedition sleeping bags each weighed over 50 pounds from absorbed body moisture, and so the team was forced to jettison two bags. They zipped the remaining four bags together into doubles for the final weeks, sleeping three people in each. Ducks and geese can fluff up their down with a twitch of their skin muscles whenever they feel like it. Down jackets and sleeping bags mat down rather quickly.
Down has one other minor problem. People dressed in the warmest down clothing tend to look like the Michelin Man.” Synthetic down substitutes like thinsulate work almost as well as the real thing, and may be a bit more stylish, but then again, that is a matter of taste. After all, you’ll never see an eider in a turtle neck.
This is Laura Erickson, and this coast-to-coast investigative reporting has been “For the Birds.”
(Recording of a Common Eider)