Hannu Koskinen said:
"May I correct a bit: Actually I was not confirming the id of this
Lithuanian Gull (I have no experience about Pacific Gulls). My first comment
was as follows:
"Wau, this is definately not a GBBG L. marinus in my opinion. Seems like
having a Herring Gull's head + bill, but very dark grey mantle excluding
argentatus. My first crazy idea for this is that it's resembling an adult
Slaty-backedcGull L.schistisagus! An NE Asian species i'm not familiar with.
Very pale eye + extremely rich flesh coloured legs! Very broad-winged; white
tips to secondaries visible..."
But anyway, because news are now released worldwide: Here's a one more link
to finder's photos,
and discussion is opened: Can this Gull be identified (safely) as
Slaty-backed Gull? And more importantly: Can it be identified as such in WP,
long away from Pacific?!"
Jared Clarke commented:
"While some better pictures of the wingtips would help, I think the
Lithuanian gull presents a pretty clear case for identification as
Slaty-backed Gull. My experience with Slaty-backed Gull is somewhat limited
living here in Newfoundland (eastern Canada), but we did have our first
record in January 2006 and had 8 (!) well documented records over the past
two winter/spring periods. The upside of our situation is that hybrids
involving either Great Black-backed Gull (L. marinus), Lesser Black-backed
Gull (L.f. graellsi) or Herring Gull (L.a. smithsonianus) are relatively
common here, and we have had to learn to rule out those hybrids in
identifying Slaty-backed Gull.
The gull in question does not, in my opinion, suggest any hybrid combination
that I would think likely in that part of the world (I'm less familiar with
hybrids of the Pacific species, but have studied photos and literature
somewhat). The size, structure, eye colour, mantle colour, pattern and
distribution streaking on the head & chest, broad white edging to the
tertials, pattern on the folded wingtip and (from what we can see) on the
extended wing are ALL within normal range for Slaty-backed Gull and strongly
suggest that identifcation. As I mentioned, photos more clearly showing the
"string of pearls" pattern in the extended wingtip would be helpful, but it
is indicated in some of the photos and described by the observer.
If numerous Slaty-backed Gulls have made it to Newfoundland (and several to
other parts of eastern North America), then Lithuania might not be that far
a stretch. It really was just a matter of time for it to stray to the
Western Palearctic. Great bird . great find."
Nick Lethaby added:
"Provisionally, I think this looks like a pretty good candidate for a
Slaty-backed Gull. Other than the fact we can't see the wing-tip pattern
properly, the only minor strike is the head shape looks flatter and angular
than typical for a SBGU. We definitely need better wing-tip shots."
And finally, Alvaro Jaramillo wrote:
"... this bird looks great for Slaty-backed. I see no reason to think it is
anything else other than that. It is even a bird that appears to have a lot
of white on the wingtip (p10 is growing in and shows to have nearly an
entirely white tip). On the underside of the wing you can also see a pale
area inside of the black primary tip, this is the edge of the "pearl" on P8.
So this bird will show a good string of pearls to at least P8. The mantle
color, width of white crescents on tertials/scapulars, head streaking, leg
color, bill shape, bill color, eye color..etc all are classic for