I can't help in the least with your ID, but since no-one else has answered, can I just say that I am really surprised to have a gull question here from Sichuan! I've been to Lake Baikal and seen Mongolian Gulls there, but I would never have expected gulls in Sichuan - are they winter visitors and what kind of location are they in? Lake Baikal is a sea in itself obviously, but I didn't know there was any similar location in Sichuan.
Some people on Bird Forum object to posts or replies that are even a little bit 'off-topic'. So I will declare my connection with this topic by saying that:
1. My brother went to university in Cardiff, and my nephew was born there (Taff)
2. I visited Chengdu in 1983 (Sichuan)
3. We sometimes have gulls near my house - but strangely never Vega or Slaty-backed
In 1983, for a foreigner to get a tourist visa for China was not so easy, but an ex- (or semi-) girlfriend was studying Chinese in the country and her father was a visiting professor (English Literature, nothing to do with China as such at all) in Shanghai (Fudan), so things were worked out. We did a five-week tour by train. Because of her father ('distinguished foreign professor') we all got permits to visit Xishuanbanna which in those days was not merely closed, but landlocked (a very scary flight from Kunming to Simao was part of the package) - though even there Deng XiaoPing's reforms were having an effect (jeans had reached Xishuanbanna).
The main thing I remember from Chengdu is visiting a temple. My friend was a blondish white Canadian. We were approached by an old lady and her grand-daughter. The grand-daughter had Chinese features but straw-blonde hair. Remember that until a couple of years earlier China had been closed off, television had barely reached China, and so knowledge of the outside world by 'ordinary' Chinese was little. So, we guessed that the child had possibly been bullied because of her hair colour. Anyway, the granny approached us saying to the child, 'See, you're not alone, a sister of yours has come to visit'. My friend and the grandmother had a short conversation. I don't remember whether the grandmother was surprised or not that my friend spoke Chinese - on the one hand, foreigners were 'foreign'; on the other hand, I remember that many 'ordinary' Chinese thought that the only language in the world was Chinese and that if you didn't speak it you were mentally defective in some way (so they were actually especially kind to you, at least in my personal experience).
There are theories about various 'European' groups ending up in China and being the cause of this 'blonde Chinese' thing (just as Mongol groups ended up in Europe). It doesn't matter; it's just an anecdote.
I haven't visited China since I took up birding, but I wish I had been into birds before our last visit there in 2005.
In those days, of course, there was no digital stuff. You put film in your camera and hoped things worked out when it was developed. And it was expensive, so you didn't take so many shots (and indeed, you photographed what your saw, not yourself). Forunately, most of my slides were OK.
Photo One: Temple in Chengdu (I think)
Photo Two: Xishuanbanna village
Photo Three: We photographed this potter and his family - at their request - we sent photos to them later, though whether they arrived or not we never knew. I suppose those children would now be late forties; I wonder what they are doing? The potter ran a 'Climbing Kiln' - slightly angled up a hillside, so the temperatures are different at different heights, I think.
Photo Four: The daughter and her children from photo Two - the take-away is that the children have no idea what is happening when a camera is pointed at them, unlike the automatic V-signs of today.
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