Thursday: My duck

On the way back from the hospital (verdict: no surgery, just finger therapy—yay!), I passed the pond and called for Honey, my female mallard (hen), which I do by emitting three quick whistles. She didn’t come swimming towards me as usual, and at first I thought she’d flown the coop for good, which is going to happen when her molt is over and her flight feathers mature. But then I heard a faint quack, and discovered her standing on the bank just a few feet away from me.

Here she is, displaying the characteristic mallard speculum: a band of violet-blue feathers marked with white on the inner remiges (posterior feathers on the wing). The photos are fuzzy because they’re zoomed in with my iPhone camera:

Both sexes have the speculum, although the male also has an iridescent green head, a lighter belly, and a white neck ring (not my photo):

Why did the speculum evolve? I can think of at least three possibilities (actually, there are more). First, the male head and wing patch evolved by sexual selection based on female preference for colorful males, and the female has the trait as a nonadaptive byproduct of selection for male coloration. (But why not a green female head? Maybe the green head but not the speculum makes you more visible to predators.) Nonadaptive features in one sex that are a byproduct of selection on the other sex are common: the nipples of human males are one example. I can’t imagine that male nipples ever were useful in either natural or sexual selection.

Second, the speculum could be a product of mutual sexual selection (I won’t go into that, but you can Google it).

Finally, it could be a trait used in species recognition—to assure both members of a pair that they are indeed mallards. Of course all three of these could operate, but this description, from a Stanford University page on duck displays, suggests the latter two possibilities, for the feathers seem to be used in bonding displays:

As pairs are formed, both sexes may be observed lifting a wing, spreading the feathers to expose the speculum (the patch of bright color at the trailing edge of the wing), and placing the beak behind the raised wing as if preening. Then just before copulation, the male and female typically float face-to-face and pump their heads up and down.

You can see that cool pumping here, but I couldn’t find a video of the wing display.

As for what the answer is, well, as far as I know it’s a mystery. How sexual selection operates, and why males have colorful plumage, strange displays, and do things like build bowers—these things we don’t understand, as that depends largely on what the females are looking for, and that’s hard to figure out. (One form of sexual selection—the kind of male-male competition that’s led to the evolution of such things as huge bodies in elephant seals and big mandibles in male stag beetles—is well understood.)

But I digress. Here’s Honey: isn’t she cute?

And Selfie with Duck (yes, I know I need a haircut!):

 

 

30 Comments

  1. Posted August 3, 2017 at 9:55 am | Permalink

    Do you suppose that a hawk from above would find the speculum (I thought that went in the throat?) a bit like dazzle painting on a WW1 ship? I wondered if (Columba palumbus) Eurasian wood pigeon white wing flashes – sorry, speculum (specula plural?) have a similar reason, or those of the magpie Pica pica…? Or sexual selection…

    • Ken Kukec
      Posted August 3, 2017 at 10:40 am | Permalink

      “(I thought that went in the throat?)”

      Been a while since you accompanied a loved one to the gynecologist, has it? 🙂

    • Mary L
      Posted August 4, 2017 at 6:29 pm | Permalink

      You’re correct; specula is the plural.

  2. Randy schenck
    Posted August 3, 2017 at 9:56 am | Permalink

    That look could be – quit screwing around with that phone and feed me. The mallard green and blue make it the most recognizable duck. One of the larger ducks as well.

  3. Rita
    Posted August 3, 2017 at 10:07 am | Permalink

    Beautiful!

  4. Kevin
    Posted August 3, 2017 at 10:18 am | Permalink

    Duck as metaphor. This moment is fleeting. A life is fleeting. Our species time in the whole of the universe is very likely fleeting. Carpe diem.

    • David Harper
      Posted August 3, 2017 at 11:02 am | Permalink

      Vita brevis, anas longa?

  5. Gregory Kusnick
    Posted August 3, 2017 at 10:26 am | Permalink

    I can’t imagine that male nipples ever were useful in either natural or sexual selection.

    I can easily imagine that male nipples might play a role in sexual selection, and it seems simple enough to test. Take a bunch of bare-chested pictures of hunky male models, and photoshop them to either enhance or shrink the size of the nipples. Show the altered and unaltered images randomly to a bunch of women and have them score the men by sexiness. It’s not unimaginable that there might be a detectable correlation between nipple size and perceived sexiness.

    • Ken Kukec
      Posted August 3, 2017 at 10:36 am | Permalink

      Maybe it’s not size, but sensitivity, that’s been selected for — or as Ms. Muldaur might put it, it ain’t the meat it’s the motion.

      • Ken Kukec
        Posted August 3, 2017 at 1:25 pm | Permalink

        And if that seems a bit off-color, don’t blame me; blame Jerry. He’s the one posting the pics of all the hot man-on-duck action.

  6. rickflick
    Posted August 3, 2017 at 10:53 am | Permalink

    “I know I need a haircut!”

    In the 1970s, the thing would be – “I almost cut my hair! Happened just the other day
    It’s gettin’ kind of long
    I could’ve said it was in my way…”

    Michio Kaku, Steven Pinker,etc. have managed to maintain the 1970s coiffure. It’s an option anyway.

    • Michael Fisher
      Posted August 3, 2017 at 11:44 am | Permalink

      CSN&Y… Young was the only one of the four NOT to buy a Porsche sports car for use as a Laurel Canyon penis extension [Young drove a hearse just before his B. Springfield days, dunno about his time with B.S. & with these posers].

      That Crosby tune about long hair as a symbol of rebellion is a very bad joke given how champagne radicalist the band was. I am still confused about Kent State & the raw emotion of “Ohio” – if those geezers [& the record company] had given up the profit to some appropriate cause I would perhaps feel better…

      [Beatles etc – have all travelled the same B.S. road]

      • rickflick
        Posted August 3, 2017 at 1:37 pm | Permalink

        Young was so thoroughly full of himself independent, and eccentrics, he probably couldn’t see driving the same car as his musical brothers or anyone else for that matter.

    • Michael Fisher
      Posted August 3, 2017 at 11:47 am | Permalink

      P.S. Don’t get me started on that fraud Michio Kaku

      I’ll go shave my head

    • Ken Kukec
      Posted August 3, 2017 at 12:47 pm | Permalink

      Pinker’s bête noire from The New Republic, Leon Wieseltier, has refused to come in from the tonsorial cold, as well.

  7. Michieux
    Posted August 3, 2017 at 10:54 am | Permalink

    Both creatures of indescribable beauty.

  8. Posted August 3, 2017 at 10:56 am | Permalink

    Nice one of you and Honey! 🙂

  9. Posted August 3, 2017 at 10:58 am | Permalink

    Why a green head? First I would want to know what colors the females see. The females tend to be drab as a form of camouflage as they are often confined to nests and thus require invisibility as they cannot flee without abandoning their eggs. So, the males get the colors, the females not so. But what colors can the ducks see. I am unaware of any research on that basis. It would be very interesting if we find they cannot see that gorgeous blue or green.

    • gravelinspector-Aidan
      Posted August 3, 2017 at 11:26 am | Permalink

      It would be very interesting if we find they cannot see that gorgeous blue or green.

      It would be remarkable. Their perception of the colours may well be different, but that has been a staple of philosophy within humans let alone between classes (orders?).
      The Wiki page makes no specific mention of ducks (“Anasiformes”, or something like that, IIRC), so I assume that they’re covered in the general statement that “Most birds are tetrachromatic, possessing four types of cone cells each with a distinctive maximal absorption peak.” There’s a complicating factor that “Each cone of a bird or reptile contains a coloured oil droplet; these no longer exist in mammals. The droplets, which contain high concentrations of carotenoids, are placed so that light passes through them before reaching the visual pigment. […] Six types of cone oil droplets have been identified; five of these have carotenoid mixtures that absorb at different wavelengths and intensities, and the sixth type has no pigments.” That considerably increases the range of possibilities for relatively small genetic changes.

  10. Posted August 3, 2017 at 10:59 am | Permalink

    Are ducks honorary cats?

  11. koseighty
    Posted August 3, 2017 at 11:12 am | Permalink

    I think it’s time we wonder at how clever it was of Honey to evolve an evolutionary biologist to bring her noms.

    Nature works in mysterious ways. 🙂

  12. David Duncan
    Posted August 3, 2017 at 12:06 pm | Permalink

    Is the resident duck the mum or the daughter? A few days ago I thought you implied that you now thought the daughter had left but mum was still moulting.

    Nice pictures!

    • Posted August 3, 2017 at 1:37 pm | Permalink

      Various duck experts have told me that the mother is missing the feathers that she needs to fly. Adults molt once a year, around this time, but juveniles don’t, so in all probability this is the mother, who is named Honey.

  13. Mark R.
    Posted August 3, 2017 at 2:35 pm | Permalink

    Honey makes me happy!

  14. Diana MacPherson
    Posted August 3, 2017 at 3:31 pm | Permalink

    She’s standing there as if to say, “yes, you summoned me?”

  15. Posted August 3, 2017 at 4:05 pm | Permalink

    Thank you for the explanation of the blue coloring. When I saw a bit of blue in the wing area in a previous photo, I thought I was misperceiving.

  16. Barbara Radcliffe
    Posted August 3, 2017 at 4:49 pm | Permalink

    I recall having read many years ago, a snippet in New Scientist (I think), that the female Pacific Black Duck (Anas superciliosa) preferred male Mallards (introduced) when given the choice. The Pacific Black Duck do not have a speculum or brightly coloured head. It was suggested that the resulting hybridisation would threaten the Australian species.
    I’ve heard nothing more of this issue since.

  17. busterggi
    Posted August 3, 2017 at 8:20 pm | Permalink

    Face it dude – you are in a relationship.

  18. Andrea Kenner
    Posted August 4, 2017 at 5:39 am | Permalink

    Awwwww……


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