Its theme song should be something called Furtive Movement.
Nectaring on Evergreen Huckleberry flowers (Vaccinium ovatum)
Flocks of 10-20 or so of these warblers have been foraging in the yard for the past week, mainly in Evergreen Huckleberry thickets and Pacific Wax Myrtle trees, but also in Pacific Rhododendrons and Western Hemlocks.
Arctostaphylos uva-ursi at the bottom (with darker & shinier leaves) next to x media hybrid (with brighter green leaves) on the top in the first photo and left in the second photo. The second photo shows the difference in height between them nicely. The x media hybrid has its own observation here.