Mystery Bird: Wood Duck, Aix sponsa

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[Mystery bird] Wood Duck, Aix sponsa, photographed at Hermann Park, Houston, Texas. [I will identify this bird for you tomorrow]
Image: Joseph Kennedy, 19 January 2008 [larger view].
Nikon D200, Kowa 883 telescope TSN-PZ camera eyepiece 1/160s f/8.0 at 1000.0mm iso400.

Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:
What a sweet bird, friendly-looking and gentle! From near-extinction less than a century ago, this species has rebounded in its North American range to be the most abundant breeding duck in the eastern US — and it is increasing in the west, too. Thanks to the profile view, we can start at the rear, where we’re impressed by the long tail and long wingtip. There aren’t many long-tailed ducks (I mean ducks with long tails); wigeons and Northern Pintail come to mind, as do Hooded Merganser and Wood Duck, plus a few seaduck species including the capital “L” Long-tailed Duck.
The extensive blue and white on the wing– unusually noticeable in this pose — identify our mystery right away as a Wood Duck. The diffuse white blotches on the flanks, the extravagant crest, the long “teardrop” around the eye, and the gray face and bill confirm the identification.
The alert among you will be wondering how we can rule out another species of Aix, the lovely little Mandarin Duck, which is frequently seen as an escape from captivity all around the world and has established breeding populations in western Europe and the US. A female Mandarin would never have an eyepatch this broad, usually showing instead a narrow eyering and “bridle” extending back onto the side of the head; the sides are more distinctly and more regularly spotted on Mandarin, too. The feathering at the base of the bill is slightly more vertical on Mandarin than on Wood Duck, in which, as here, the feathering extends onto the base of the bill. The very tip of the bill is pale in Mandarin, dark in Wood Duck. A distinguishing feature I have just learned myself is that the secondary coverts in Wood Duck are blue with a black terminal bar, plain in Mandarin Duck; it’s a rare view that lets us make that determination, but we have here a rare view.
Because both species are common in captivity, both can be seen anywhere in the world; and because both are common in captivity, those escapes can include birds with puzzlingly anomalous plumage features. The list of known hybrids involving one or the other of these two species covers two pages in McCarthy [Handbook of Avian Hybrids of the World, Eugene M. McCarthy, Oxford University Press, 2006], making it always possible that a wandering Aix is the product of some odd miscegenation. Just as confusingly, both captive Wood Ducks and Mandarin Ducks occur as blond “sports,” pale beige birds that in the worst of cases can be distinguished only by the shape of the feathering at the base of the bill. So look closely at Wood Ducks — if not for their uncontested beauty, then at least for some small sense of certainty that that’s what are actually looking at.
Review all mystery birds to date.


About GrrlScientist

grrlscientist is the pseudonym of an evolutionary biologist and ornithologist who writes about evolution, ethology, and ecology, especially in birds. After earning a degree in microbiology (thesis focus: virology) and working at the Fred Hutchinson Cancer Research Center in Seattle, she earned her PhD in zoology from the University of Washington in Seattle, where she studied the molecular correlates of testosterone and behaviour in white-crowned sparrows. She then worked a Chapman Postdoctoral Fellow at the American Museum of Natural History in New York City, where she studied the speciation and distribution of lories and other parrots throughout the South Pacific Islands. A discarded scientist, she returned to her roots: writing. Formerly hosted by The Guardian (UK), she now writes about science for Forbes and for the non-profit think tank, the Evolution Institute and she writes podcasts for BirdNote Radio. An avid lifelong birder and aviculturist, she lives with a flock of songbirds and parrots somewhere in Germany.
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0 Responses to Mystery Bird: Wood Duck, Aix sponsa

  1. Alethea says:

    Looks like a female wood duck to me. But maybe it’s a trick question?

  2. JohnB says:

    It’s not a House Sparrow, so it must be a female Wood Duck.

  3. Ian says:

    It can’t be a duck. I don’t see any duck tape….
    I think it’s an aquatic, black-eyed, white-patched, black-capped, gray- & white-feathered aviator bird….

  4. Notagod says:

    Well, then, what is the gray stuff that appears to be holding the bill in place on the head? Surely not mask tape?
    Nice picture, with the cool water effects and all.

  5. Scott Lewis says:

    Wood Duck hen. Used to have one.

  6. RM says:

    I’ll go with hen wood duck, but it could easily be a mandarin hen.

  7. Selasphorus says:

    Wood Duck hen.

  8. Hilary says:

    Female Wood Duck – the white around the eye is unmistakable. But she’s in the shade, so you can’t see all the amazing variations in color, rust and turquoise and who-knows-what. (One spent the afternoon slumming with the mallards at a local lake, so I got a really good, close look.)

  9. The Ridger says:

    Funny thing – I hit the blog link not the post link and saw the fiddler crab photo. I was extremely confused for a moment!
    I say female wood duck.

  10. bobk says:

    Aix sponsta beupa tree!
    I flinched the first time I saw one of these females as it flew smack into the side of a tree. As it turned out, they’re cavity nesters. I can deal with that. But the male dandies sitting about the tree limbs were just too much for my little world. Thankfully, I have since regained my composure.

  11. aedis says:

    Female Wood duck.
    You can just about see traces of the blue speculum. Female Mandarin has a green speculum, and usually less white around the eye.