Monday, January 18, 2010
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Answer by Kevin Kerr and Tony Leukering
First off, I want to provide a quoted part of Peter Wilkinson's response to this week's quiz: "Oh, jolly good, a gull!" I so appreciate those that appreciate gulls!
I received an interesting array of answers for this quiz and, given my particular interest in the group to which our quiz bird belongs, I was looking forward to writing this answer. However, I'm using Kevin Kerr's response to save myself some time in the attempt at catching up on the backlog of answers that I've got to write. Thanks, Kevin, and take it away!
"The gestalt of this bird - mostly white bird with webbed feet, soaring on slender, pointed wings - should lead us to the gulls. However, it looks unusual, at least compared to the gulls I'm used to seeing! A quick inventory of field marks racks up the following:
- black feet, black bill,
- wide, black terminal tail band,
- hooded appearance (actually, darker breast with a paler throat), and
- dark underwings, with thin white trailing edge.
"The black feet, alone, really limit our options in ABA area gulls: Ivory, Sabine's, Franklin's, Laughing, and Heerman's gulls, and Black-legged Kittiwake. The bird is way too dark to consider Ivory. The kittiwake would also be much paler under the wings and on the breast; ditto for Sabine's, for which the quiz bird is also lacking the signature "chevron" wing pattern. Heermann's is about the only species that would be darker than our bird. Also, Heermann's would have a fully black tail (not just a terminal band) and we would probably expect a bright red bill given the white chin. Our two remaining suspects, Franklin's and Laughing gulls, are quite similar, but differ in a sufficient number of ways in most plumages, including this one. First-cycle Laughing Gulls exhibit a broad terminal band on the tail and a sooty breast, two features that match our mystery bird. We would expect to see white outer tail feathers and a whiter breast if we were dealing with a similarly-aged Franklin's Gull."
I'd like to add just a few more bits and pieces to Kevin's answer. A number of respondents may have been fooled by the bird's thin bill, but since the bird is directly overhead, we can see that the species actually sports a pretty thin bill. There just aren't any ABA-area terns that have our bird's white tail with a wide black terminal band. I took this picture of a first-cycle Laughing Gull at Cape May Co., NJ, in fall 2009.
Incorrect species provided as answers:
Sooty Tern - 1
White-faced Storm-Petrel - 1
Black Tern - 1
Northern Gannet - 1
Heermann's Gull - 1
Franklin's Gull - 1
Congratulations to the 20 of 26 getting the quiz correct:
Answer: Laughing Gull