I have received many responses about the female Goldeneye that I photographed. Most of the responders thought it was a Common Goldeneye, some thought it was a Barrow's Goldeneye, and others either couldn't decide or suggested a hybrid. I looked at many resources, and the best resource for this bird that I found was David Sibley's on-line resource:
Distinguishing female Barrow's and Common Goldeneyes.
Quotes shown below are from Sibley's on-line resource.
I arrived at Smith Lake (on private property, permission required) and saw a few shorebirds and ducks. There were four ducks on the lake. Three of them were female Hooded Mergansers. The other duck was a female Goldeneye. I have only see a few Goldeneyes, and they all have been Common Goldeneyes (uncommon here). This one looked different from those I had seen previously. A Barrow's Goldeneye would be exceptionally rare here, but with the record low pressure in Canada, and massive cold and snowfall in the upper U.S., perhaps one these western or northeastern ducks was here. However, a Common Goldeneye with an all yellow bill is also rare.
Goldeneye and Hooded Mergansers
Goldeneye and Hooded Mergansers
Most of the responders who thought it was a Common Goldeneye based their conclusion on bill size and shape, and forehead slope. Sibley states that this is not always reliable:
"Identifying female goldeneyes is extremely challenging. Differences are subtle, subjective, and inconsistent, but experienced observers still build up a “template” of expected impressions that allow them to identify the species with confidence. Describing these differences, and identifying individual birds from photos, can be very challenging because the process of identification relies so heavily on gestalt.
. . . Head shape is often mentioned and emphasized in discussions and in field guides, but head shape is variable, ephemeral, and hard to describe. It is still important as part of the overall impression of shape and proportions, but to assess head shape properly you must watch the bird for a significant length of time, compare it to adjacent birds at the same angle that are doing the same things, and have a basic understanding of the variations in head shape.
. . . These classic head shapes are seen on relaxed birds with head feathers more or less erect. Active, diving, or alert birds show quite different head shapes. As the feathers are compressed against the head the tall forehead of Barrow’s and tall crown of Common disappear, both species have a smoothly rounded forehead and long sloping crown. The longer mane of Barrow’s is still evident, as is a small angle at the rear crown of Common.
. . . Birders often emphasize the shorter bill of Barrow’s as a field mark, but this is a vague and overly simplistic description of the differences in bill shape and size.
. . . Even with calipers and a calculator, many goldeneyes can’t be identified by bill size."
For comparison purposes, here is a photo of female Common Goldeneyes that I took last February in Delaware. Note the black bills with yellow only on the tips.
Below are all of the photos (except for a few that are badly out of focus) that I took of the female Goldeneye at Smith Lake. Perhaps some of these photos will add to the discussion, or perhaps to the confusion!
There is a diagram on Sibley's on-line page show three drawings of the back of the head of Common and Barrow's. Although the following photo I took yesterday isn't a full back view, it does look more like the top right drawing on Sibley's page (Barrow's).
The rest are flight photos as all four ducks flew from the lake. The wing markings look much more like the flight photo of a Barrow's in Ted Floyd's guide than that that of a Common in the same reference.
I am hoping that someone with a lot more experience with these two species can re-locate this bird either at Smith Lake (with permission) or at a nearby pond or lake.