Friday, March 14, 2014

Photo study of Green-winged vs Common Teal...

In my last blog post, I promised readers additional images of the Common Teal that I found on March 1st in Brookville Park Queens, NY.  In this post, I present photos of both American Green-winged and Common or Green-winged Teal (Eurasian) for comparison and walk through some of the field marks.  While Green-winged Teal is considered a single species by the AOU (American Ornithologists' Union), 2 of its subspecies are very distinctive in adult plumage and are recognized as two separate species by many authorized ornithology bodies. Hence, we have American Green Winged Teal (Anas crecca carolinensis) and Eurasian Green-winged Teal or Common Teal (Anas crecca crecca).  The Common Teal is a rare visitor to North America, with records showing that the best chances of seeing one is in late winter early spring. It is important to note the time of the records; chances are Common Teal in non breeding plumage are overlooked or just unidentifiable in the field (now there is a nice challenge).

American Green-winged Teal. Note: The vertical stripe.
This is not the first one that I have seen or found in Queens, NYC, but it is the first that I got very close up looks of, which I took advantage in getting in some good field study time. One of the first field marks that stood out when I spotted this duck as it made its way out of Phragmites was how well marked the facial pattern appeared to be and how paler the breast was in comparison to a nearby American Green-winged Teal. At that time, I was not sure it was a Common Teal. However, once the duck turned slightly in side profile and I saw the white horizontal stripe in the lower scapulars and no sign of a vertical stripe. I began thinking, it was possible that I had found a Common Teal.

Common or Green-wing Teal (Eurasian) Note: the prominent facial marks and lighter breast.
I carefully studied the bird to ensure there was not a trace of anything like a vertical stripe, which would mean it was more of an intergrade (American X Common Teal) instead of a pure Common Teal.  After studying the bird for a bit, I was convinced it was a pure Common Teal and so put out a post to the list serves before trying to obtain additional documentation in the form of field notes and photos.  Coincidentally, following this bird, I saw an intergrade American X Common Teal last Sunday at Saggaponak Pond on Long Island with friends Tom Burke, Gail Benson, Douglas Futuyma, and others but it was too far out for even a digiscope attempt.  That would have been nice to include here for comparison as well.

Common or Green-winged Teal (Eurasian) with a nice side profile showing the horizontal stripe.

Common or Green-winged Teal (Eurasian). Note: the nicely marked facial pattern.

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