Sighting Record for Utah

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
(Description:) 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.