Want to add a couple of things to Bill's comment. For a long time I "slob birded" in that I would ID the bird and move on to the next. Don't know if it was age, meeting up and birding/working with folks like Bill (and many others), and getting deeper into photography that made me look more closely. I learned (probably already forgot) some of the very subtle differences between species. Those little behavioral things.
Having "played" with fish as a career it became obvious that there is no one picture/drawing/description that can perfectly describe a species. Which why "But it doesn't look like Sibley" makes me shake my head. As Bill said, closely studying that goose told us a lot about it. A question I like to ask about an odd bird is why is it not X?
As for papers with odd titles, one in my collection is "Kamikaze sperm". And it is rather interesting.
A last note, also gleaned from Bill, is that if you see something that is odd/rare/out of place report it. If you are convinced, through good views and such let others know. Decades ago I came across what I believe to be a Yellow-billed Cuckoo. Fairly good view, but it was in branches. Now, e-bird might not "accept" it, the rare bird committee might also reject it (all on good grounds) but the record is there. If, over the years, the species keeps getting reported in the area then, based on the pattern, folks might look closer and find that they really are there at times.
Hal Michael
Science Outreach Director, Sustainable Fisheries Foundation
Olympia WA
360-459-4005
360-791-7702 (C)
ucd880 at comcast.net
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On January 16, 2018 at 9:53 PM Bill Tweit <bill.tweit at gmail.com> wrote:
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There is a story here. The conclusion is that it is a Ross's Goose. Likely an older male. The story is both cautionary and instructive, and explains how we have a reasonably educated guess about the sex and age.
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A lot of folks have gone to see that goose, called it a Ross's, and a lot of great photos have been posted on eBird. One observer, Rachel Hudson, had trouble convincing herself that it was a Ross's, for some very good reasons. She thought the beak looked a bit too wedge-shaped, the feather line seemed wrong, the head did not look as rounded as it should, and overall the bird looked too bulky. The collected eBird photos show she was right on all counts; it has an unusually shaped beak with a lot of caruncles and does not have a typical head shape. As a result of her concerns, she submitted it to eBird as a candidate for Snow X Ross's, a fairly frequently noted hybrid, as it didn't seem to her to fit a pure Ross's and it clearly was not a Snow.
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When I read her analysis contained in her eBird checklist, I'll admit to smacking my forehead in some exasperation at myself. I had seen the bird just a couple of days previous, from a distance, and casually called it a Ross's without giving thought to the hybrid possibility. I ignored a nagging doubt I felt at the time that the bird did not look as small as it should have in comparison to the Greater White-fronted Geese, and was content to "slob bird" it as a Ross's. After all, I had more important things to do like looking for more crossbills!
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We, the eBird editor crew, circulated some of the better photos to others with more white goose experience for their opinion about the possibility of a hybrid. Meanwhile, Rachel did some digging of her own, finding an older scientific paper titled "Winning with warts? A threat posture suggests a function for caruncles in Ross's Geese." This paper noted that older male Ross's develop more extensive caruncles on their beaks, which explains the different beak shape and feather line. Males also tend to be larger than females, explaining the bulky appearance. And, the response we got from Steve Mlodinow, who has the opportunity to study a lot of white geese of both species on his home turf in Colorado provided confirmation that it is a Ross's; he also noted it was likely a male. The instructive part of the story is that it is sometimes possible to ascertain the sex of an individual Ross's Goose in the field, with close attention to detail.
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The cautionary part of the story is that it confirms several birding adages.
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* Identify it for yourself, don't just take someone else's word for it.
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* Ask questions if the identification doesn't seem to fit. This is how we continue to improve at our craft, by close observation and keeping an open mind.
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* And, do your own research. After all, you might stumble across a scientific paper with an even better title than "Winning with warts"!
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Bill Tweit
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O lympia, Washington
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