A new observation on my wood ducks

Frisky’s girlfriend, whom we’ve named Ruth, was here this morning, but flew away before breakfast. There’s no telling if she’ll return, but I always have my camera at the pond.

In the meantime, I noticed today, as Frisky climbed atop his Sacred Cypress Knee and took a midmorning nap, that when he closes his eyes, a white patch of feathers appears that is hidden when his eyes are open. I’m wondering what, if anything, this means. A tentative hypothesis, which is mine, is to prevent potential predators from seeing that the duck is sleeping, as the white patches look like “eyespots.” Or, it could be an ornament that attracts females even when a male is asleep.

Now I’m sure that this pattern is well known, and that there are explanations for it, and I’ve written to expert Bruce Lyon for his take. But in the meantime, here’s what I saw:

Frisky awake:

Getting weary (white patch appearing):

Eyes closed (big white patch):

Closeup of white patch:

19 Comments

  1. BobTerrace
    Posted October 21, 2020 at 3:00 pm | Permalink

    Maybe he flew in from Bunker (Breeds) hill.

  2. ThyroidPlanet
    Posted October 21, 2020 at 3:03 pm | Permalink

    I love these kinds of observations – those that produce notions that the observer discovered something new…

  3. Scott McCleve
    Posted October 21, 2020 at 3:38 pm | Permalink

    Very interesting.
    I have been paying attention to birds’ eyes for some time.
    Many of the bird photos on this site beg for attention to the eyes of the birds, & for some kind of evolutionary analysis.
    Many species seem to have their eyes camouflaged or hidden.
    But other have their eyes emphasized.
    There seem to be 3 methods of adaptive coloring/shading —
    1] with feathers
    2] with the skin around the eye
    3] with the color of the iris or pupil itself
    But this phenomenon is a new one to me!

  4. Posted October 21, 2020 at 4:22 pm | Permalink

    Deceptive false eyes to fool predators?

    • Posted October 21, 2020 at 4:27 pm | Permalink

      Sorry, that hypothesis already belongs to PCC.

    • ThyroidPlanet
      Posted October 21, 2020 at 4:39 pm | Permalink

      how about deterring egg thieves – it looks like he is keeping watch. But if a predator snatched him from behind, it’s all over.

    • Posted October 22, 2020 at 3:08 am | Permalink

      But the open eye is almost black?!

      • ThyroidPlanet
        Posted October 22, 2020 at 6:07 am | Permalink

        Depends on the receptors in the predator retina.

      • Posted October 22, 2020 at 8:55 am | Permalink

        Good point, but perhaps all that is needed is the impression of an eye to fool a predator.

  5. ThyroidPlanet
    Posted October 21, 2020 at 4:42 pm | Permalink

    These photos are excellent documentation of the false eye

  6. Steve Gerrard
    Posted October 21, 2020 at 8:02 pm | Permalink

    Need two more male ducks with the same spots. The old lab rule was 1, 2, infinity. One time is a fluke; two times is a possible discovery; three establishes a new fact. In this case the fact would be the existence of the spot on males in breeding plumage, not any particular explanation of why they have it.

  7. rickflick
    Posted October 21, 2020 at 8:07 pm | Permalink

    I wonder if other ducks have the white spot? I agree that it’s probably to disguise sleep mode.

  8. Posted October 21, 2020 at 8:25 pm | Permalink

    I wonder if the white under the eye could be an adaptation to mimic a nictitating membrane. My guess would be like Jerry’s, to make predators think the duck is awake, as well as perhaps to protect the actual eye from an injurious attack.

  9. Warren Johnson
    Posted October 21, 2020 at 8:36 pm | Permalink

    Not dead yet! A sweet observation! That’s why science is such fun! Now some further observations will certainly lead somewhere.

  10. Posted October 22, 2020 at 3:07 am | Permalink

    Yet the open eye is dark so how does a light spot mimic that? Nice idea but not convinced. Suggest that we do an experiment with dye to darken the spots, then see what predation does…

  11. Jonathan Wallace
    Posted October 22, 2020 at 5:59 am | Permalink

    The other thing shown by the photos would seem to be that whereas we close our eyes primarily by the upper lid coming down, in the ducks case it would appear to be the lower ‘lid’ moving up. I am not suggesting that there is any adaptive significance to that!

  12. ThyroidPlanet
    Posted October 22, 2020 at 8:59 am | Permalink

    I’d like to know precisely how the Wood Duck perceives color. Is the red/orange of their coloration around their eyes exactly what H. sapiens perceives as red/orange? Which color pigments do Wood Duck retinas contain? Etc.


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