Verification of Unusual
Sight Record
For Utah
Rec. # 2020-18
| Common name: |
Mexican Duck |
| Scientific name: | Anas diazi |
| Date: | 05-17-2020 |
| Time: | 3:45PM |
| Length of time observed: | 10 minutes |
| Number: | 1 |
| Age: | ? |
| Sex: | male |
| Location: | Powell Lake |
| County: | Utah |
| Latilong: | 40.380143,-111.9033374 |
| Elevation: | 4500ft |
| Distance to bird: | 20m |
| Optical equipment: | 10x50 Nikon Binos, Canon SX50 Digital Camera |
| Weather: | Mostly sunny |
| Light Conditions: | Good |
| Description: Size of bird: | 23 inches |
| (Description:) Basic Shape: | Typical Duck |
| (Description:) Overall Pattern: | Uniformly dark brown |
| (Description:) Bill Type: | Flat dabbling duck bill |
|
(Description:)
Field Marks and Identifying Characteristics: |
Dark brown body, with a paler brown head contrasting with the
breast, and a bright yellow bill. This drake had no sign of any curl in the
tail, or any black in the rump, or green in the crown that one would expect with
a Hybrid with a (Northern)Mallard. The only thing that gave me pause was the
tail which appeared rather pale, however upon closer examination, the tail can
be seen to be brown, but with the individual feathers having lots of pale
edging, but is not truly white. Since Dabbling Ducks molt into alternate plumage
in the fall, by this date their feathers often show a lot of wear and I
attribute the paleness in the tail to wear of the feathers rather than to the
presence of (Northern)Mallard genes in the bird. Terry Reid got a great photo of
the spread tail which shows its true colors, which can be seen here:
https://macaulaylibrary.org/asset/235970161 (see photos) |
| Song or call & method of delivery: | None heard |
| Behavior: | Feeding on freshwater pond by submerging head under water, hard to get good shots of the head because of active feeding. |
| Habitat: | Fresh Water pond near Jordan River and Utah Lake |
| Similar
species and
how were they eliminated: |
(Northern) Mallard: I won't get into the debate as to whether Mexican Duck
is a ssp of Mallard or not, but I have seen many pure
Mexican Ducks over the years, in both Utah and Arizona, and even more hybrids.
Typically Hybrids have a noticeably darker rump, a half curl to the tail, and
variable amounts of green on the crown, plus have white outer tail feathers,
none of these traits were shown by this duck Mottled Duck: Mostly by range, but they also have a cleaner buffy cheek and dark corner on the gape of the bill that this duck lacked. American Black Duck:Also mostly by range, but typically are a darker sooty brown overall with a more greenish bill |
| Previous
experience with this & similar species: |
Yes, many |
| References consulted: | Macaulay Library |
| Description from: | 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: | Max Malmquist was with me, also reported by many other to eBird |
| Date prepared: | 5-20-2020 |
| Additional material: | Photos |
| Additional comments: | eBird checklist: https://ebird.org/checklist/S69234710 |