The surface feathers are oil coated, but I don't know that the down
proper is  oil-coated.
Why would it be, if the surface barrier is sufficient?   Oil in the
down would mat the down, make it heavier, make it colder to the bird.
And, since birds don't sweat, there's no significant source of water
between the surface barrier and the skin?

PJ


On Sat, Dec 15, 2012 at 10:16 PM, Denis Bogan <[log in to unmask]> wrote:
>> This comment is on par with "why do we park in driveways and not
>> parkways?" question.
>
> It was a serious question.  Obviously a goose needs good insulation when
> floating in freezing water.  Their insulation is down.  How do they do that?
> Probably oils secreted from glands to coat the down so it doesn't get wet.
> The irony is that we humans devise a process, which is no doubt expensive
> and demanding, to remove the oils so as to obtain a material that has great
> insulating ability when dry but virtually none when wet.  Then we devise a
> still more demanding and expensive process to coat it with nano particles,
> or something, so as to restore the properties it had when it was harvested
> from the goose.  Well, we can't have oil stains on our expensive hi tech ski
> jackets, can we?
>
> (I like to ask questions disguised as dumb questions.  It was my specialty
> at NASA and the reason I was valued there.)
>
>
> Sent from my iPad
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