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Post by oldfulica on Feb 8, 2008 20:50:16 GMT -8
Hi I said in an earlier post Roger Foxall had sent my pix of the Iceland to an expert in Newfoundland. Here is his reply. As Gord stated and my contact in California also concluded this is about as close as we will get to an Iceland Gull without taking DNA. If you want to check out the references of Rogers source here is a link to his biography; www.eagle-eye.com/Guides/BruceM.htmland here is reply if you want to decipher it; Roger, The bird is definitely not a Glaucous Gull - small head, long tapered wings are all Iceland Gull. It is an Iceland Gull probably in 4th year based on dark tipped bill and hints of brownish in the upper wing coverts. The bird seems pale above like a typical glaucoides and in the range of some Kumlien's. It is petite, typical of glaucoides but well within range of many Kumlien's. It is impossible to know if there is any darker pigment in the outer five primaries from this shot. The last and smallest amount of darker gray to occur in a Kumlien's wingtip is a pencil line along the shaft of P10 or P9 and in the gray part of the feather, not in the white coloured end of the feather. Only microscopic scope views or extra sharp photos can see this. And even so the difference between this darker peppering along the shaft and a totally unmarked wingtip pattern is meaningless anyway. In the end, a pure white wing tip is not a 100% clinching mark for glaucoides. There is probably no way to be 100% definitive on identifying a glaucoides outside normal range. However, compared to Kumlien's, glaucoides tend to be smaller, more petite, often appearing to extremely long primaries. They are pale (sometimes even paler) as a Glaucous Gull (Atlantic Ocean GLGUs) above, and therefore paler than Kumlien's which are typically closer to Herring Gull than Glaucous Gull in upper parts colour. Many adult glaucoides tend to have massive amount of white wing tips. Birds like that, you can guess have no white in the wing tips. This BC seems to show large amount of white in the wing tip and broad white tips to tertials - nice glaucoides tendancies. The bottom line. It is an Iceland Gull with characters hinting at glaucoides. You can't get better than that. Maybe strongly hinting at glaucoides. I like the two preening shots best but they are a little over exposed. If any more good shots appear I'd be happy to look at them Nice Glaucous-winged Gulls in the background! Bruce
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Post by Deleted on Feb 8, 2008 22:43:15 GMT -8
Hi, Len and everyone.
Very interesting reply. I don't think we had any doubt that it is an Iceland, not a Glaucous Gull.
Regarding his comment that the smallest amount of darker gray in a Kumlien's would appear as a pencil line of gray along the shaft of P10 or P9 -- I already noticed in the photo of the bird in flight that Gord posted on this site in the thread Re: Iceland Gull continues-Feb 4 « Reply #7 on Feb 5, 2008, 2:43pm » that there seems to be a faint gray line along the outer portion of the underside of P10 because a similar faint line appears in P10 in my photo of the underside of the outstretched wing that I posted the other day in the Files section of bcvanbirds in Stan's Photos.
So I wonder if this indicates that our bird is a Kumlien's at the pale end of the scale.
Since Bruce says he would be interested in seeing any further photos that might shed light, I don't mind if my photo is sent to Bruce if it helps. Can you pass this on to Roger? I can email the photo directly to Roger, or to Bruce, if needed, if you give me an email address. I would suggest that Gord's photo should also be sent to Bruce as additional evidence.
It would be a bit of a disappointment to have it finally identified as "only" a Kumlein's subspecies of Iceland Gull when it looked like we might have a bona fide record of a nominate glaucoides Iceland Gull here, a bird that is an extremely rare find for anywhere in North America, but it would also be nice to finally have it nailed down to subspecies. And a Kumlien's Gull is not a bad addition to my life list. I'll take it.
What does everyone think?
Feeling a bit like a party-pooper,
Stan
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Post by oldfulica on Feb 9, 2008 8:26:17 GMT -8
HI Stan I just checked out yours and Gords pix and I see what you mean. There is definitley a line there on the outer primary. Roger is in Florida right now but he checks his email. If you guys could pass on the pictures to him I'm sure he would pass them on to Bruce. It would be interesting to see what his comments would be. rafoxall@shaw.ca
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Post by Gord on Feb 9, 2008 15:24:08 GMT -8
Good work Len. I might 'amass' and then number the photos taken here for further discussion. I'm trying to see if I have the email for a fellow from the UK who may throw in his two cents (pence) as well. #1 #2 #3 #4 #5 #6 #7 #8 #9
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Post by Deleted on Feb 9, 2008 16:05:41 GMT -8
Hi, Gord.
If you help me out with instructions, I can try to post to this site my photo of the gull with fully extended underwing. It's cropped right down but it's still about 1.3 MB in size.
I've forwarded it to Roger asking him to send it to Bruce for comments.
Stan
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Post by Gord on Feb 10, 2008 0:19:00 GMT -8
Stan, email sent about the above. The dark streak seems to be the feather's rachis (shaft) which is very thick on the P10. Im grasping at straws here, but could it just be darker in appearance due to it being thicker and less translucent than the white feathers? However, photo #3 seems to have a little bit of streaking or is it shadows from the primaries above...? (ok, Ill stop there!) Another thought I had about this gull is size. While dangerous ground to go on (like shadows... ), I think it's worth noting. Size in gulls can vary, especially between males and females. I've seen this in the field too. A good example is Herring and Thayer's Gulls. Ive seen small Herring Gulls that approach Thayer's Gull and large Thayer's Gulls that approach Herring Gulls. I would not say that identifying them changes based on the size variance, but it sure is noticeable when you come across these individuals. With this Iceland Gull, it is without doubt considerably smaller than the smallest Thayer's Gull Ive ever seen. But this might not mean very much as Kumlien's Iceland Gull is smaller than Thayer's Gull and a nominate Iceland Gull is smaller still. The gray area is between the Kumlien's and nominate. How much difference is there between the smallest Kumlien's and smallest nominate? Ive never seen Kumlien's Iceland Gulls so I cant say if it's smaller than an average (or any!) Kumlien's Ive seen. I know that Thayer's and Kumlien's are sometimes difficult to tell apart which may indicate that size is not very reliable between those two, and, for those keen to throughly explore this bird, makes one wonder how much smaller than a Thayer's a Kumlien's gets. Should this bird have had dark in the wingtips, I would not have thought for a second it was a Thayer's unless they're being made in midget size now ;D. Ill stop my rambling/musing. Ive sent this off to some birders in the UK who could have some further good insight to share.
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Post by Deleted on Feb 11, 2008 10:33:07 GMT -8
Thanks, Gord, for adding my photo showing the underside of the wing to the gallery you assembled above.
My focus is on the fine dark gray line along P10 visible on both your and my photos of the underwing, in light of the comments by Bruce Mactavish quoted in Len's post at the top of this thread.
If the mark that shows on our photos is the same thing Bruce is referring to, then this could be fairly conclusive evidence that our bird is a Kumlein's subspecies of Iceland Gull (approaching the light end of Kumlein's wingtip pattern colour range), and not a nominate subspecies, since apparently the nominate subspecies should show nothing but white in the primary tips and light gray along the rest of the primaries--no darker markings at all of the type that characterize Kumlien's.
If these marks are somehow just artifacts of the photos, and not what he's referring to, and the bird really does have all white wingtips, with no dark markings, then, as he says, we still can't be sure which subspecies it is unless we can prove it by size and shape, which I don't think we can do from what we saw, nor can experts do so from the photos we have in the gallery above.
I do have a couple of photos of the gull standing among a group, which might be useful but I very much doubt it. I had a whole bunch more but I deleted them because none were very good.
Incidentally if anyone wonders about Bruce, you need only look at the latest gull book, the Reference Guide to Gulls of the Americas, to see how much he has contributed to gull knowledge in that excellent resource.
This whole exercise has been very instructive.
By the way, I went down to the Waste transfer station off Riverside last Friday to check the gulls there, but apart from one nice adult Thayer's I saw only lots of Glaucous-winged and hybrids.
Thanks,
Stan
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Post by Gord on Feb 11, 2008 14:14:36 GMT -8
I dont think there can be any dispute of the dark on the feather shaft. The darkness might be a little exaggerated in shot #9 as it looks like it's up at the edge of the frame that can happen during digiscoping.
I think there's plenty of photos out there showing the bird among other species but like you say, it will be pretty tough to go on any size unless you have it among a bunch of other Iceland Gulls.
Certainly an educational experience.
I need to get Bruce's book. Ive seen it and it's great!
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Post by Mike Tabak on Feb 20, 2008 12:09:29 GMT -8
Re: Iceland Gull subspecies identification I just came across this discussion, so thought I'd add a few of my comments. We are discussing the differences between a white-winged Kumlien's Iceland Gull, and a nominate Iceland Gull normally found in Greenland. The bottom line is that there is very little difference between these two types, and it may be not possible to separate these two types on out of range birds in the field. Never the less, Bruce has said the photos suggest the Chilliwack Iceland Gull looks to be strongly hinting at Larus glaucoides glaucoides, ie the nominate subspecies. Since I saw this gull at close range in the field I will add a few comments. First, I don't think any of the photos of the wing tip pattern indicate any reason to identify this bird as a Kumlien's Iceland Gull. What gray is shown may be shadow, or feather shaft, as Gord has suggested. This Iceland Gull does show massive amounts of white in the primary tips. This gull is smaller, and more petite with side by side comparison with Thayer's Gulls. The bill is very small and petite, thin and short, compared with Thayer's Gulls, or any Kumlien's Iceland Gull I have seen in BC. And finally, one of the best features to distinguish between the two subspecies is the mantle colour. The pale gray mantle is much paler than any adult Herring Gull, or Thayer's Gull, or Kumlien's Iceland Gull that I have seen in BC. The paleness of the mantle is as pale or paler than any adult Glaucous Gull I have ever seen. This pale gray mantle colour is easy to see in the available photos. The extremely pale gray mantle, with the very small size and structure of this gull, combined with the apparently pure white wing tips identify this gull as very likely the nominate Iceland Gull, and not a white-winged Kumlien's Iceland Gull.
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Post by Gord on Feb 20, 2008 23:42:23 GMT -8
Mike, not much to dispute there outside of the ever-present gray areas (of varying size) with gulls. Myself, I think the pictures are a little misleading when it comes to size. In the field, that bird is SMALL. I have not had the chance to view other Iceland Gulls but in my reading their size is smaller, but not hugely smaller, than Thayer's Gulls, the next closest species that I have good experience with. If Kumlien's Iceland Gulls are this small then I would have to wonder why the difficulty telling them from Thayer's Gulls. I know that last sentence is a little bold especially with no experience with Kumliens Iceland Gulls that might provide me with the knowledge that some individual females can be very petit. But a below average size (if this would indeed be such) AND maybe all white wingtips a coincidence that's more likely than the chance of a gull from Greenland showing up here (to join Lesser Black-backed Gulls, Ivory Gull...you get my point) Im comfortable with the 'very likely' status on this guy! My fishing for thoughts from across the pond have not brought much out yet to my surprise.
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