The committed mother

The female Eider that I blipped a while ago is still sitting on her eggs and must be coming towards the end of her 21 days of incubation.

Eiders really are the most committed and conscientious of mothers. During incubation they may leave their nest for a few minutes to drink but they never eat. Instead they break down their own body tissues in order to survive. Prior to incubation they usually have about 400 grams of fat stored in their bodies, but by the end less than 10 grams remain. They also break down their flight muscles and use them as a source of energy. By the end of incubation over half of their body protein will have been lost in this way, mainly from their muscles and from the alimentary canal. They are in a really poor shape by the end of the breeding season, so much so that females suffer a higher annual mortality rate than do the males. The result is that in a population of eider ducks there is an excess of males, usually 1.2 or more for every female.
To use the old adage, the female is committed but the male is only involved.