Verification of Unusual
Rec. # 2020-18a
|Scientific name:||Anas diazi|
|Date:||May 17, 2020|
|Length of time observed:||5 minutes|
|Location:||Powell Lake? Far south end|
|Distance to bird:||100 feet|
|Optical equipment:||8X42 Binoculars|
|Weather:||Clear and sunny to partial cloudy|
|Light Conditions:||Good. Bright.|
|Description: Size of bird:||Mallard sized|
|(Description:) Basic Shape:||Duck|
|(Description:) Overall Pattern:||Dark brown. Lighter brown head with dark crown of head dark eye stripe.|
|(Description:) Bill Type:||Duck bill. Yellow.|
Field Marks and
It had the initially basic appearance of a female mallard, though more dark
brown, and I initially noticed more contrast between its lighter brown head and
its darker brown body than the nearby female mallards, whose heads seemed almost
more gray in comparison to the MEDU, and less contrast with its body color. I
also originally noticed this duck as the other mallards nearby were paired up
drakes with hens, and the MEDU was swimming closely to a female mallard, giving
the quick glance appearance of two female mallards together.
I put the binoculars on the MEDU, and saw clearly it s yellow bill, easily distinguishing it from the female mallards whose bills were darker. I also noticed how the dark crown of its head stood out more distinctly from the brown face than the female mallards. Finally there were no curly tail feathers. I only saw the duck swimming, never on land, never in flight, so I never saw the wing color pattern.
Since others had seen this MEDU at Powell Lake, I focused entirely on distinguishing it from the associated mallards. That is what I wrote above.
When asked to submit this form, I looked at American black duck and mottled duck descriptions and pictures to see if I could distinguish this duck from those after the fact. I stress I did not do this thinking or analysis while looking at the MEDU. Regarding the AMBLDU, the duck I saw, while darker than the female mallards, and showing more contrast between the head and body than the mallards, those distinctions were more subtle, or intermediate between mallard and AMBLDU.. Also, the pictures I see of the black duck seems to show a slightly broader dark strip on the crown of the head, and a slightly messier gradation from the crown to the eye stripe. I remember being struck by a sharper distinction from the crown to the lighter color above the eye to the eye stripe. A cleaner demarcation. I remember this distinctly as my wife had kiddingly asked me if the Mexican Duck might be wearing a sombrero, and I was noticing it s crown of the head to report back to her what I saw as
its hat .
Regarding mottled duck, it s harder for me to look at the mottled duck pictures and see a clear distinction with the MEDU I saw. Maybe matters of degree, sort of like the black duck, but even more subtle. I d be making things up to be able to say I know I saw a Mexican Duck, not a mottled duck, other than range.
The eBird range chart of the Mexican Duck is much closer to Utah County, Utah, and in fact there are occasional MEDU sightings in Utah. Neither mottled duck nor American black duck ranges are anywhere close to where I saw this duck, so Mexican Duck is my only reasonable determination.
|Song or call & method of delivery:||None heard|
|Behavior:||Swimming placidly, hanging out with a female mallard to which it seemed paired up.|
|Habitat:||In the water near the shores of Powell Lake.|
were they eliminated:
See above description of bird.
Mallard (female). Darker brown body color, more contrast from body color to head color. More distinct dark crown of head. Yellow rather than darker, smudgy bill.
American black duck. Range. The MEDU was not as dark as AMBLDU body (from pictures and field guides). The crown of head of MEDU was cleaner, sharper in appearance than the crown of AMBLDU.
Mottled duck. Range.
this & similar species:
I have hundreds of documented sightings of mallards, male and female.
This is my first sighting of a Mexican Duck.
I have one sighting of an American black duck, from 2012.
I have two sight8ngs of mottled duck, one in 2012, one in 2019.
Audubon Field Guide
EBird species pictures, descriptions, ranges.
|Description from:||Notes taken at the time of the sighting|
|Observer's address:||2811 E. Ksel Drive, Sandy, Utah 84092|
|Observer's e-mail address:||**|
|Other observers who independently identified this bird:|
|Date prepared:||May 22, 2020|