Date: 11/21/20 3:00 pm From: David L. Keeling <dkeeling...> Subject: [slocobirding] Please Barrow with me
A three-part message about the goldeneye I saw and photographed on Nov 04 in the Pismo Creek mouth lagoon and misidentified as a Common Goldeneye. Since it now seems more important, I have posted my only other good photo of the bird on my Flickr site.
WHY I NOW THINK IT IS A BARROW'S: First, it has been proposed by Tom Edell, Brad Schram and Curtis Marantz, as well as others, all with identification skills far greater than my own. The mane is long, the forehead looks appropriately steep, and it shows a nail on the bill, all positive indicators, but when I look at a host of photos on-line, each of these traits exhibit significant variation from individual variation, pose, and angle of the photograph, and an exceptional claim requires exceptional documentation. So I attempted to be quantitative about the Barrow's shorter bill. I measured the distance in photos from the tip of the bill to the center of the eye and also noted the distance to the bill/feather boundary and calculated the ratio of Bill Length/Total Distance. For 10 on-line Barrow's, the ratio ranged from .57-.60 and averaged .59. For 10 on-line Common Goldeneyes, the ratio ranged from .65-.67 and averaged .66. The results gave good precision. The value for my bird is .60, in agreement with the Barrow's and not the Common. In other words, the bill really is shorter, it doesn't merely look shorter.
EXTRA CREDIT FOR THE PHOTO: I walked more than a complete loop around the lagoon (including backtracking through the RV Park), over 1.5 miles, all trying to get closer and with a decent angle of light. I finally got ahead of the bird and got myself seated as the bird swam into view and peacefully by me. The satisfaction of putting in the legwork and employing a successful viewing strategy undoubtedly influenced me to post its picture. I'm so glad I did.
AN APOLOGY: Sincere and measured. I'm sorry my ID skills and my judgement were not up to the task, resulting in missed opportunities for others to see the bird. I'm a slow learner.