Jonathmartinez

pale base of lower mandible indicates Brown Bush Warbler.  a very good find.

Jonathmartinez

sorry, from my experience in Hunan where both occur I never saw a Russet BW with so pale lower mandible, but after a quick check on OBI, I can only agree.
And agree with Paul that undertail covert are well marked, I focus to much on the mandible on my first post, sorry abouth that. So a less better find:-) but always a very enjoyable bird to look at:-)