Sighting Record for Utah

Common name:	Mexican Duck
Scientific name:	Anas diazi
Date:	2/25/26
Time:	5:45pm
Length of time observed:	10 minutes
Number:	1
Age:	adult
Sex:	male
Location:	Cross E Ranch Corn Maze field
County:	Salt Lake
Latilong:	40.839838, -111.950496
Elevation:	4250ft~
Distance to bird:	80m
Optical equipment:	Kowa 66mm Spotting Scope
Weather:	Mostly cloudy, calm, 50F
Light Conditions:	Mixed, overcast then sun shown through at sunset
Description: Size of bird:	Large duck
(Description:) Basic Shape:	duck
(Description:) Overall Pattern:	mostly dark brown
(Description:) Bill Type:	Flat dabbling duck
(Description:) Field Marks and Identifying Characteristics:	"Drake, in the corn maze field with 50~ MALL, all dark chestnut brown except buff brown head, bright yellow bill. Viewed in the scope fore 10 minutes trying to get a good look at the rump and tail. Rump mottled brown, not black, tail uniform brown with some pale feather edging but no solid white feathers. Couldn't see a curl but distant. Eventually flew west with a hen." From notes taken at time of sighting. I was scoping through the waterfowl in the field looking for Cacklers and a Ross's Goose I had here last week, then came to the mallard flock and was counting them when I noticed a duck with rich dark chestnut tones, so I checked to see the bill color, which was bright yellow, and noted the buff brown head without green visible as well. I watched the duck feeding on the corn trying to get a view of the rump and tail, this took awhile since the lighting, distance, and the debris in the field obstructed views, but eventually noted the mottled brown rump and brown tail. (see photos)
Song or call & method of delivery:	None heard
Behavior:	Feeding in a corn field with many Mallards, Geese and Sandhill Cranes
Habitat:	Freshly cut corn field
Similar species and how were they eliminated:	Mallard: Hen should have an orange and black bill, not bright yellow, overall paler brown without the deep chestnut tones or buff tones in the head. Drake Should have a green head and gray body, all drakes should be in full breeding plumage now. All Mallards should have white outer tail feathers. Mallard X Mexican Duck hybrids. When we speak of hybrids in this complex, we have to talk about phonetic hybrids since we usually can't take DNA samples. Generally we only consider males, females are too difficulty to assess in the field except under the most extreme circumstances. With drakes we look at several features: The amount of Green in the crown, the color of the rump, the amount of white in the outer tail feathers, and the color of the breast, Most hybrids will show an obvious green crown, black rump and the outer 2 tail feathers will be white, and an obvious redder breast. In some backcross hybrids drakes, the green on the crown can be reduced, but they still typically show a black rump and the base of the outer tail feathers are whitish, and most show contrasting redder breast than the rest of the body. Since this drake had no green in the crown, and had a uniform colored breast and body, I made an effort to view the tail and rump. The rump was shaded in the poor lightin g, but when I could see it, it was not solid black, but had obvious brown mottling. The tail was also hard to assess, but all feathers looked brown, although some had pale edging, which is typical of this time of year due to wear. So this bird showed no obvious signs of hybridization. An additional feature listed in guides is the white edging of the speculum, being thinner in Mexican than Mallards, especially the upper edge. whoever I find this field mark difficult to assess in the field and subject to lighting and is only useful for close looks at resting ducks. However the flight photos do show the upper speculum white edge is fairly thin.
Previous experience with this & similar species:	Yes, many in Utah and AZ
References consulted:
Description from:	Notes taken at the time of the sighting From photo(s) taken at the time of the sighting
Observer:	Bryant Olsen
Observer's address:	84102
Observer's e-mail address:	**
Other observers who independently identified this bird:	None that I know of
Date prepared:	2/25/26
Additional material:	Photos
Additional comments:	Bird checklist: https://ebird.org/checklist/S303884120