I put up a page with CHESTNUT-SIDED WARBLER photos, made 03 and 04
October 2007 in Goleta (Santa Barbara County), at Stow House (Los
Carneros County Park):
It has been tentatively ID'd as male, but I wonder about the pale
yellow at rear of flank, which may be a female characteristic (?),
along with virtual lack of back streaks... though of trivial
importance, any thoughts from others who may be able to ID these to
sex is appreciated. Thanks.