> 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

I believe all duck species have a penis ("copulatory organ" or
"intromittent organ" or "protrusible cloaca" for the delicate of ear). It
seems an appropriate adaptation for birds that copulate in the water.
Ostriches have them, too, although of course they don't copulate in the
water. Maybe they do it at full run. Swifts do it in full flight but
don't have a copulatory organ; the "cloacal kiss" serves them quite well.

The Ruddy Duck's penis can be almost as long as the bird. I've never seen
Ruddies copulate, but I've been watching. I have a feeling I posted this
some time ago, but it's a little-known fact that should be shared.

There are a lot of books on waterfowl out there. Maybe someone can
research the subject in ducks.

Dennis Paulson phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416