Thanks so much for your feedback! That will be of great help. Compared to last time (2012) I have a smartphone which I can use to create a shortlist with soundbits of these birds. I am also excited about having a recording app that can make good enough recordings for IDing afterwards. Hopefully I can post some here in a couple of weeks.
Also thanks very much for your invitation. Unfortunately, I don't think this is a realistic option for me. My family are really not keen on me travelling by myself. I am not sure yet how much of the a day I can spend in Yingkou. Probably we will already travel half a day from Shenyang to Yinkou and I will only have the afternoon. I will feel already very lucky if I can reach the coast or the river from where our friends live.