Friday, April 2, 2010

Mallard Copulation

Last year a Mallard pair used our water feature in the early spring.  The pair retired elsewhere to nest (or at least went their separate ways) later in the summer.  Today, an early April evening, we were delighted when a pair strolled up our brick entryway, copulated, and fed in the water.

If you look closely at this male's vent, you might notice a pink, slightly curly structure.  Since I have assisted Federal duck banders, I was aware that ducks and ratities (flightless birds like ostriches and emus) are the only birds with penises. (All other birds get the job done with a cloacal "kiss," with little or no penetration.) Tonight I discovered that I am mistaken, instead of a true penis, ducks and ratites  have an erectile cloacal phallus.  Sperm are deposited in the male duck's cloaca and travel down the outside of the phallus.  In mammals, of course, sperm travel through the penis's interior in the urethra.  Thus the two structures are not homologous.

You learn something new every day; in this case from Cornell Laboratory's Handbook of Bird Biology.

1 comment:

  1. Interesting. Our urban pond also attracts a pair. We were kinda hoping they would nest nearby - would like to see the ducklings - but alas - like the pair you describe - ours appear to have departed to nest elsewhere. Fun while it lasted.

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