PJ has it right. If the waterfowl's down was oiled, it would lose its
insulating abilities just as much as our down coat would if it gets wet.
Ironically, when birds die in oil spills, it's partly because they get
so soaked in oil that the down gets soaked too.
When a bird preens, it's realigning the feather barbs on the outer
feathers, at the same time coating them with a thin layer of oil from
the sebaceous gland. (The sebaceous gland is located at the base of the
tail -- that's why when you see a bid preening it's always poking around
the base of its tail.) Down feathers have no barbs, so there's nothing
Dave G., bird guy filling in for the absent JustinW
On 12/16/2012 01:32 AM, comprex wrote:
> 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?
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