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adult winter Large gull - off-black primaries | january | Hokkaido, japan (1 Viewer)


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Not my own observation but I thought this might be an interesting bird to have a look at.

attila21 at inaturalist posted this one photo of a beast of a large gull. Strong bill like Glaucous-winged Gull, off black primaries and a dark mantle.
I have not enough experience with GWG to say something about it but could it be just an overly darkly photographed Glaucous-winged Gull or could it - even more fun- be a hybrid of some sort.... Glaucous-winged x Slaty-backed Gull springs to mind as these are both regular in the area. It turns out it is hard to find more than probable shots of this hybrid.

I thought that maybe the distance between the levels of grey of mantle and primaries is similar to or equal to that in a well lit bird... (not sure...novice on pacific gulls)

Would be great to hear your thoughts on this,
Gerben (this time on behalf of the JP birding community at inaturalist)
of course posted after asking permission to do so.


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Hi Gerben, it's MacNara again. Two things.

1. In our previous conversation a day or two ago, I had forgotten that I also saw some gulls in Hokkaido in November 2014. In my catalogue, some are recorded as 'Glaucous-winged x Slaty (or other) hybrids' which is relevant to your post today. I don't remember now how this 'hybrid' ID came about, but it's surely from help on BirdForum - I would certainly never make such an ID myself without advice (and so, I don't vouch for these IDs, but just offer them as a suggestion). I attach two photos of these birds. I seem to recall that I read somewhere that Glaucous-winged are actually quite promiscuous and hybridise easily. But as for the bird you posted today, you'll have to wait for someone who knows - maybe Lou will generously step up again.

2. Nothing to do with birds, but your location and comments encouraged me to bring up a video I had of a trip that my oldest friend and his three daughters (7, 9 and 10) made in 2003, renting a barge in Koudum, going along the canals via Sneek, out to Terschelling and back. Fun, but I remember being terrified on a very windy very wide section of what seemed open sea!

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These lakes and Wadden Sea apparently can be very treacherous in that they look innocent enough, but often aren't...undeep water, strong currents during the changing of the tides... Good memories to have i hope.

On topic.
These primaries look also blackish, like Attila's bird. The head is a bit more friendly...maybe yours is a female?

It is a shame (and telling) that not even Gull Research would dare claim a definite GWGxSBG hybrid... Maybe that should have kept me from posting this altogether but it was also the thought that this might just be a badly lit normal GWG which drove me: i am also not an expert on photoeffects...maybe there are some here.
If all leads to nothing much, i have had the opportunity to post this quite pretty big, hefty gull...to celebrate gulls.

Btw a fellow inaturalist (and -by the looks of it- more of pacific guller than i am) had fairly views against and id as GWG, but i could not translate it to here as i did not quite grasp what he meant...(sorry @psweet)

Cheers, gerben
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