Verification of Unusual Sight Record
For Utah

Rec. # 2020-74

Common name:

Mexican Duck

Scientific name: Anas diazi
Date: 11/23/2020
Time: 3:30
Length of time observed: 3-4 minutes
Number: 1
Age: Adult
Sex: Male
Location: Sullivan Virgin River Park
County: Washington
Latilong: 37.117762, -113.500062
Elevation: Approx. 2850 ft
Distance to bird: 60 ft
Optical equipment: Monarch binoculars and Nikon P600 camera
Weather: Overcast and mild
Light Conditions: Good (no harsh glare, relatively flat light)
Description:        Size of bird: Roughly the size of a Mallard
(Description:)       Basic Shape:  Oval-shaped, somewhat stocky
(Description:)  Overall Pattern: Dark brown body, paler tan head and neck
(Description:)            Bill Type: Essentially like that of a Mallard
Field Marks and
Identifying Characteristics:
Anas duck similar in size and structure to a Mallard. The bill was deep yellowish-olive. Strong contrast between the dark brown breast and paler tan neck. The face was grayish-tan with a dark eyeline and crown. The body was dark chestnut brown with internal markings on the sides. I did not get a good look at the speculum. The tail and undertail coverts were solid brown, and the tail feathers were uncurled.
(see photos)
Song or call & method of delivery: No vocalizations were heard
Behavior: It was in the Virgin River with a female Mallard or Mexican Duck x Mallard. It was sitting in shallow water when I arrived, but began swimming slowly upriver upon seeing me.
Habitat: It was in a shallow section of the Virgin River, which is lined by lush deciduous habitat that goes through an otherwise arid environment.
Similar species and how
were they eliminated:
This bird might be confused with a male Mottled Duck, male American Black Duck, or any assortment of hybrids described below. American Black Duck would be more blackish-brown than chestnut-brown, and would have a grayer face and longer eyeline. Also, the internal markings on the body feathers eliminate American Black Duck. Another possibility would be Mallard x American Black Duck. However, this hybrid combo would have a longer eyeline and considerably darker body plumage (again, tending more toward blackish-brown than chestnut-brown). Male Mottled Duck is similar but would have a pronounced dark gape spot, cleaner buffy-tan face, and shorter eyeline. Mottled x Mexican is another possibility. However, such a bird would likely exibit a buffier face, a shorter eyeline, and more of a black gape spot. Mottled x Mexican is also exceedingly rare, likely restricted to a small sliver of Texas, and has only been documented a handful of times. The last alternative
is Mallard x Mexican Duck (which I observed in St. George earlier the same day at a different location). This bird does not show any signs of hybridization with a Mallard such as white in tail and undertail coverts, black uppertail coverts, green in the head, a reddish breast, or minimal contrast between the breast and neck. Thus, I feel confident that this bird is a pure Mexican Duck.
Previous experience with
this & similar species:
I have extensive experience observing Mexican Ducks and their hybrids in Colorado and Arizona. I also authored an article in the American Birding Association's Birding magazine about Mexican Duck identification.
References consulted: No references were consulted
Description from: From memory
From photo(s) taken at the time of the sighting
Observer: Jack Bushong
Observer's address: 713 Grant Ave
Observer's e-mail address: **
Other observers who independently identified this bird: Ryan Bushong
Date prepared: 11/30/2020
Additional material: Photos
Additional comments:  I have several photos of the male Mexican Duck.