Sunday Duck O’ the Week

June 21, 2020 • 7:45 am

Evolutionary geneticist John Avise is continuing his series of the ducks of North America. The goal is to educate readers about all the species in this group during lockdown, so that at the ends you will graduate with either an M. A. (master of Anas) or a Ph.D. (Duck of Philosophy). Your goal is to first guess the species from John’s photos, and then go below the fold to read the answer, some Duck Facts, and see a range map.

And so on to this week’s “Guess the Duck”. John’s comments are indented.

The week seems to have sped by, so it’s time for another batch of duck pictures (eight photos plus my brief comments).  Although the plumage of this week’s species is subtly understated, the drake remains elegant and dapper.


To get the IDs, Duck Facts, and range map, click on “read more”.

The species: Gadwall (Anas strepera)

Handsome drakes of this dabbling duck always give me the impression that they are dressed in fine tweed suits of browns, grays, and black.  Perhaps the most definitive field mark for both hens and drakes is the white speculum (a rectangle of secondary feathers on the trailing edge of the wing), visible in flight and sometimes (but not always) when a bird is standing, swimming, or tipping-up.  Many members of this species breed in “prairie potholes” (shallow wetlands formed by snowmelt and rainwater) in the Northern Plains of the U.S. and central Canada.

And the range map from the Cornell bird site:


9 thoughts on “Sunday Duck O’ the Week

  1. The preamble of the International Code of Zoological nomenclature specifies that…
    “The objects of the Code are to promote stability and universality in the scientific names of animals…”
    Alas molecular systematics undermines old certainties: the old genus Anas was splitted in four, and now, the gadwall and the widgeon were put in the genus Mareca…thus Mareca strepera.
    But they are still ducks !

    1. Thank you for pointing out this taxonomic revision, of which I had been unaware. I do wonder if nuclear genes (in addition to mitochondrial DNA sequences) also support this finding.

  2. The range for where I live is “year-around” but I don’t know if I’ve seen a Gadwall. Perhaps I have and mistaken it for a mallard hen. The white speculum is the tell I’ll have to pay attention to. I like the description of the drake wearing tweeds.

    1. The black near the rump is what first gets me thinking of gadwall. The white may be harder to see.

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