Sighting Record for Utah

Common name:	Mexican Duck
Scientific name:	Anas Diazi
Date:	Nov, 22nd 2024
Time:	4:51
Length of time observed:	10 minutes
Number:	1
Age:	Adult
Sex:	M
Location:	Goshen reservoir
County:	Utah county
Latilong:
Elevation:
Distance to bird:	Tough to say - roughly 70 yards
Optical equipment:	Leupold SX-4 20-60x85
Weather:	Slight overcast, moderate winds.
Light Conditions:	Good, great for scoping due to overcast.
Description: Size of bird:	Large dabbler - identical to mallards
(Description:) Basic Shape:	Dabbler shape, large bill, rounded head - identical to mallards
(Description:) Overall Pattern:	Dark bodied, light headed, strong contrast between the head and body. Brown. Bright yellow bill. No black in rump or tail coverts
(Description:) Bill Type:
(Description:) Field Marks and Identifying Characteristics:	After scoping through waterfowl on the reservoir for 5ish minutes (the reservoir was covered in a large number of waterfowl), I sifted through a large group of mallards and stumbled on this one. Immediately notable was the bright yellow bill, strong contrasting dark to light body to head. I spent the next 3-4 minutes observing it to sus out hybrid qualities. I noted the pale tail edging being much closer to brown than white, over a brown rump/tail coverts. I ve seen a few Mexican x mallard duck hybrids this year, which have always shown bright tail edges with darker tail coverts, and a few tail curls. This individual was showing significantly darker tail edging (I ll include a photo with a nearby drake and hen mallard for reference. This individual had no curls in the tail coverts. This individual disappeared into some hidden phragmites areas at which point I scoped through the remaining waterfowl. After a sufficient scope I returned to the area and refound the Mexican duck, again watching it for a few minutes, noting the same characteristics, and trying for some digiscopes. Admittedly, one digiscope photo shows a shape that almost looks to be a tail curl. I believe this to be a problem with the quality of the photo, some sort of weird glare coming off the wing primaries. If you reference the other photo, you will see uniform dark primary showing no glare in the same spot as the first photo. In person, this bird was well within range to be seen clearly having no tail curls. (see photos)
Song or call & method of delivery:	Any possible calls from this duck would have been drowned out by the others.
Behavior:	Feeding in shallow water with many mallards
Habitat:	Goshen Reservoir is a small relatively shallow body of water, lined with reeds and cattails, frequently full of dabbler ducks.
Similar species and how were they eliminated:	Mallard and Mexican x mallard ; Lack of tail covert curls, a more uniform bring rump and tail coverts, darker tail edging, and a contrasting light head/dark body eliminate both options here. Mottled duck; Aside from being wildly more unlikely, the lack of a black gape patch, a brighter and streak free face, and a lack of Buffy warm feather edging on the body rule out mottled for me.
Previous experience with this & similar species:	2 individuals I deemed Mexican x malled, and countless mallards. I have never seen a pure Mexican duck. No previous experience with mottled ducks.
References consulted:	Sibley. Mexican duck, and mexican x mallard photos on macauley librar
Description from:	Notes taken at the time of the sighting From photo(s) taken at the time of the sighting
Observer:	McKay Olson
Observer's address:
Observer's e-mail address:	**
Other observers who independently identified this bird:	Esther Sumner
Date prepared:	12/02/24
Additional material:	Photos;
Additional comments:	As pure of a candidate as I ve ever seen. Beautiful duck at that.