Contributor
Date
Location
- Age
- Not specified
- Sex
- Not specified
Observation details
Chased after previous report by Craig Fosdick of a possible American Black Duck. Photographed. Scroll down for discussion of features and purity. I believe this is close to a pure Mexican Duck, if such a thing exists. It is an adult male, which greatly simplifies things. There are a few traits that are somewhat Mallard-like, but I don't know how variable these traits are within pure Mexican Ducks. At certain angles, a slight green sheen can be detected in a small part of the top of the crown. The central retrix (tail feather) curls up just slightly, not looping around like that of a Mallard's, but lifting just subtly off the plane of the other tail feathers. Otherwise, the duck looks to me like a pure Mexican Duck. The tail is very dark, with no white patches. The rump seems concolor with the back and flanks in most shots, not noticeably darker. (It does look darker in one or two photos, but I believe this is an effect of shading from the wingtips. When directly illuminated, it does not look darker.) The white at the front and back of the speculum is rather limited, although it would be nice to see a photograph of the full spread wing. The speculum has a greenish, not purplish sheen (great comparison in the second shot above), which has been reported by Scott and Reynolds 1984 as the most useful feature in distinguishing Mallards from Mexican Ducks. To be absolutely precise, I believe the slightly uplifted central tail feather is indication of some limited Mallard heritage in this individual. (According to Pyle, pure Mexican Ducks can have a faint greenish sheen on the crown.) I have entered it as a "pure" Mexican Duck because I feel this bird is much closer to pure than to a first-generation hybrid. That is, this bird is probably more than 95% Mexican Duck, and less than 5% Mallard, but there is a small Mallard component to this duck. UPDATE (8 Feb 2012): Rich Stallcup, expert birder from California, says in a personal email to Andy Kleinhesselink, regarding this individual, "From what I recall (and that is a lot of Mexican Ducks) your bird looks as good as it gets. One of the reasons Mallard and Mexican Ducks were lumped was because researchers in New Mexico said that all Mexican Ducks were polluted with Mallard blood! Thanks for giving me a look. That is quite a record. If Mexican Ducks were migratory the old "overshoot" theory would work well in this case. RICH"
Technical information
- Model
- NIKON D90
- ISO
- 320
- Focal length
- 400 mm
- Flash
- Flash did not fire
- f-stop
- f/5.6
- Shutter speed
- 1/500 sec
- Dimensions
- 3990 pixels x 2386 pixels
- Original file size
- 3.05 MB