Jon Anderson wrote:
>
>I can't recall seeing diving ducks behaving in this manner, and was wondering
>how often forced copulation occurs in this group relative to the dabblers?
> Is it documented in, say, Canvasbacks as well?
>
One of the reasons puddle ducks are so adept at force copulation is that
they have an extendible penis-like organ, which allows them to copulate
without having the female in the correct position. Most other birds have to
touch cloacas, which is a lot more difficult and needs the cooperation of
the female to achieve successful fertilization. Perhaps divers differ in the
structure of this organ? The other question that comes up then is what came
first, the forced copulation behaviour or the duck's organ?

Alvaro Jaramillo "You are better off not knowing
Half Moon Bay, CA how sausages and laws are made"
alvaro at quake.net Otto von Bismarck,
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