The second bird looks like an Arctic Warbler to me.
Hi John, that was my first gut feeling but I’ve no experience of separating Japanese/Kamchatka Leaf Warblers from Arctic...https://www.shanghaibirding.com/wp-...4/Alstrom-et-al-2011-Arctic-Warblers-IBIS.pdf
Hi Deb: I don't want to pre-empt John, but I think he meant one of the three species which were lumped as Arctic Warbler before the split, not the one of the three which has been given the name after the split.
I was referring to Japanese/Kamchatka Leaf warblers as John was in his post - what are you referring to?
You're right; I was wrong. Apologies.
But I can't understand any more than you can ... about the differences between these species or sub-species, and especially in autumn. I wonder if it's an assumption about which species will be going through in a particular week than an actual voice ID ...
I have lots of Kamchatka come through where I am in central Japan - in the spring in early May to mid-June and coming back in mid to late October (earliest recent records on 16 June 2019, and on return 16 October this year) (all voice as well as views) ....