Verification of Unusual Sight Record
For Utah

Rec. # 2020-76

Common name:

Mexican Duck

Scientific name: Anas diazi
Date: 12/05/2020
Time: 1:40p
Length of time observed: 10-15 min
Number: 1
Age: adult
Sex: male
Location: Oquirrh Lake, Daybreak, UT
County: Salt Lake
Latilong: 40.553022821346836, -112.0053577316148
Elevation: 1,483 MASL
Distance to bird: 30 meters
Optical equipment: Vortex Diamondback 10x42 HD binoculars & Nikon D4 SLR w/ 300 mm lens
Weather: clear, calm
Light Conditions: excellent, low angle sun to my back, bird out front (looking NE)
Description:        Size of bird: comparable to Mallard
(Description:)       Basic Shape: duck (Mallard)
(Description:)  Overall Pattern: Rich brown, mottled, contrasting head
(Description:)            Bill Type: duck, uniform color (yellow)
Field Marks and
Identifying Characteristics:
Overall impression is rich, brown version of female Mallard with contrasting light head, dark eye line, and dark cap. Bill is black-tipped, medium yellow with no hint of a saddle or other colors. There are hundreds (maybe thousands) of Mallards present here and this is the only one that I could find that looks like this.
(see photos)
Song or call & method of delivery: N/A
Behavior: Walking on thin ice, feeding/drinking from puddles on the ice. Mixed in with Canada Geese, Mallards, gulls, and other waterfowl.
Habitat: Series of shallow ponds (manmade lakes) with marsh grasses planted along the banks.
Similar species and how
were they eliminated:
Obvious comparison is to Mallard. Specifically adult male in non-breeding or eclipse plumage. All references I could find did not show the richness in brown coloration or amount of mottling on the wings and flanks. All other Mallards that I have seen here (and there are many) are noticeably past this plumage phase. Females have the orange bills with dark saddle. This one a smoothly even, medium yellow color with black tip. Honestly, I went back and forth on this bird quite a bit... ultimately decided it was worth the review as 2020 seems to be a crazy year for rare birds and this spot (Oquirrh Lake) has proven to be a magnet for rarities for some reason (GWFG, LTDU, CACG, BAGO, others all confirmed here recently).
Previous experience with
this & similar species:
Mallards of course in droves, but this one looked immediately different.
References consulted: Nat Geo 7th edition, Sibley's 2nd edition, eBird, other on-line searches
Description from: Notes taken at the time of the sighting
From photo(s) taken at the time of the sighting
Observer: Joe Dziedzina
Observer's address: 11350 Sandy Gulch Road
Observer's e-mail address: **
Other observers who independently identified this bird: None (yet), but I did submit a checklist on eBird so others may follow.
Date prepared: 12/05/2020
Additional material: Photos
Additional comments: Photos (5) emailed to address as directed.